Updated how model registry works

MIGRATION_GUIDE.md

@@ -0,0 +1,173 @@
+# Migration Guide: Database and Router Abstraction
+
+This guide explains how to migrate from the direct GORM/Router dependencies to the new abstracted interfaces.
+
+## Overview of Changes
+
+### What was changed:
+1. **Database Operations**: GORM-specific code is now abstracted behind `Database` interface
+2. **Router Integration**: HTTP router dependencies are abstracted behind `Router` interface  
+3. **Model Registry**: Models are now managed through a `ModelRegistry` interface
+4. **Backward Compatibility**: Existing code continues to work with `NewAPIHandler()`
+
+### Benefits:
+- **Database Flexibility**: Switch between GORM, Bun, or other ORMs without code changes
+- **Router Flexibility**: Use Gorilla Mux, Gin, Echo, or other routers
+- **Better Testing**: Easy to mock database and router interactions
+- **Cleaner Separation**: Business logic separated from ORM/router specifics
+
+## Migration Path
+
+### Option 1: No Changes Required (Backward Compatible)
+Your existing code continues to work without any changes:
+
+```go
+// This still works exactly as before
+handler := resolvespec.NewAPIHandler(db)
+```
+
+### Option 2: Gradual Migration to New API
+
+#### Step 1: Use New Handler Constructor
+```go
+// Old way
+handler := resolvespec.NewAPIHandler(gormDB)
+
+// New way  
+handler := resolvespec.NewHandlerWithGORM(gormDB)
+```
+
+#### Step 2: Use Interface-based Approach
+```go
+// Create database adapter
+dbAdapter := resolvespec.NewGormAdapter(gormDB)
+
+// Create model registry
+registry := resolvespec.NewModelRegistry()
+
+// Register your models
+registry.RegisterModel("public.users", &User{})
+registry.RegisterModel("public.orders", &Order{})
+
+// Create handler
+handler := resolvespec.NewHandler(dbAdapter, registry)
+```
+
+## Switching Database Backends
+
+### From GORM to Bun
+```go
+// Add bun dependency first:
+// go get github.com/uptrace/bun
+
+// Old GORM setup
+gormDB, _ := gorm.Open(sqlite.Open("test.db"), &gorm.Config{})
+gormAdapter := resolvespec.NewGormAdapter(gormDB)
+
+// New Bun setup  
+sqlDB, _ := sql.Open("sqlite3", "test.db")
+bunDB := bun.NewDB(sqlDB, sqlitedialect.New())
+bunAdapter := resolvespec.NewBunAdapter(bunDB)
+
+// Handler creation is identical
+handler := resolvespec.NewHandler(bunAdapter, registry)
+```
+
+## Router Flexibility
+
+### Current Gorilla Mux (Default)
+```go
+router := mux.NewRouter()
+resolvespec.SetupRoutes(router, handler)
+```
+
+### BunRouter (Built-in Support)
+```go
+// Simple setup
+router := bunrouter.New()
+resolvespec.SetupBunRouterWithResolveSpec(router, handler)
+
+// Or using adapter
+routerAdapter := resolvespec.NewStandardBunRouterAdapter()
+// Use routerAdapter.GetBunRouter() for the underlying router
+```
+
+### Using Router Adapters (Advanced)
+```go
+// For when you want router abstraction
+routerAdapter := resolvespec.NewStandardRouter()
+routerAdapter.RegisterRoute("/{schema}/{entity}", handlerFunc)
+```
+
+## Model Registration
+
+### Old Way (Still Works)
+```go
+// Models registered through existing models package
+handler.RegisterModel("public", "users", &User{})
+```
+
+### New Way (Recommended)
+```go
+registry := resolvespec.NewModelRegistry()
+registry.RegisterModel("public.users", &User{})
+registry.RegisterModel("public.orders", &Order{})
+
+handler := resolvespec.NewHandler(dbAdapter, registry)
+```
+
+## Interface Definitions
+
+### Database Interface
+```go
+type Database interface {
+    NewSelect() SelectQuery
+    NewInsert() InsertQuery  
+    NewUpdate() UpdateQuery
+    NewDelete() DeleteQuery
+    // ... transaction methods
+}
+```
+
+### Available Adapters
+- `GormAdapter` - For GORM (ready to use)
+- `BunAdapter` - For Bun (add dependency: `go get github.com/uptrace/bun`)
+- Easy to create custom adapters for other ORMs
+
+## Testing Benefits
+
+### Before (Tightly Coupled)
+```go
+// Hard to test - requires real GORM setup
+func TestHandler(t *testing.T) {
+    db := setupRealGormDB()
+    handler := resolvespec.NewAPIHandler(db)
+    // ... test logic
+}
+```
+
+### After (Mockable)
+```go
+// Easy to test - mock the interfaces
+func TestHandler(t *testing.T) {
+    mockDB := &MockDatabase{}
+    mockRegistry := &MockModelRegistry{}
+    handler := resolvespec.NewHandler(mockDB, mockRegistry)
+    // ... test logic with mocks
+}
+```
+
+## Breaking Changes
+- **None for existing code** - Full backward compatibility maintained
+- New interfaces are additive, not replacing existing APIs
+
+## Recommended Migration Timeline
+1. **Phase 1**: Use existing code (no changes needed)
+2. **Phase 2**: Gradually adopt new constructors (`NewHandlerWithGORM`)
+3. **Phase 3**: Move to interface-based approach when needed
+4. **Phase 4**: Switch database backends if desired
+
+## Getting Help
+- Check example functions in `resolvespec.go`
+- Review interface definitions in `database.go`
+- Examine adapter implementations for patterns

README.md

@@ -2,8 +2,25 @@
 
 ResolveSpec is a flexible and powerful REST API specification and implementation that provides GraphQL-like capabilities while maintaining REST simplicity. It allows for dynamic data querying, relationship preloading, and complex filtering through a clean, URL-based interface.
 
+**🆕 New in v2.0**: Database-agnostic architecture with support for GORM, Bun, and other ORMs. Router-flexible design works with Gorilla Mux, Gin, Echo, and more.
+
 ![slogan](./generated_slogan.webp)
 
+## Table of Contents
+
+- [Features](#features)
+- [Installation](#installation)
+- [Quick Start](#quick-start)
+  - [Existing Code (Backward Compatible)](#option-1-existing-code-backward-compatible)
+  - [New Database-Agnostic API](#option-2-new-database-agnostic-api)
+  - [Router Integration](#router-integration)
+- [Migration from v1.x](#migration-from-v1x)
+- [Architecture](#architecture)
+- [API Structure](#api-structure)
+- [Example Usage](#example-usage)
+- [Testing](#testing)
+- [What's New in v2.0](#whats-new-in-v20)
+
 ## Features
 
 - **Dynamic Data Querying**: Select specific columns and relationships to return
@@ -13,6 +30,10 @@ ResolveSpec is a flexible and powerful REST API specification and implementation
 - **Pagination**: Built-in limit and offset support
 - **Computed Columns**: Define virtual columns for complex calculations
 - **Custom Operators**: Add custom SQL conditions when needed
+- **🆕 Database Agnostic**: Works with GORM, Bun, or any database layer through adapters
+- **🆕 Router Flexible**: Integrates with Gorilla Mux, Gin, Echo, or custom routers
+- **🆕 Backward Compatible**: Existing code works without changes
+- **🆕 Better Testing**: Mockable interfaces for easy unit testing
 
 ## API Structure
 
@@ -94,53 +115,197 @@ go get github.com/Warky-Devs/ResolveSpec
 
 ## Quick Start
 
-1. Import the package:
-```go
-import "github.com/Warky-Devs/ResolveSpec"
-```
+### Option 1: Existing Code (Backward Compatible)
 
-1. Initialize the handler:
-```go
-handler := resolvespec.NewAPIHandler(db)
+Your existing code continues to work without any changes:
 
-// Register your models
+```go
+import "github.com/Warky-Devs/ResolveSpec/pkg/resolvespec"
+
+// This still works exactly as before
+handler := resolvespec.NewAPIHandler(gormDB)
 handler.RegisterModel("core", "users", &User{})
-handler.RegisterModel("core", "posts", &Post{})
 ```
 
-3. Use with your preferred router:
+## Migration from v1.x
 
-Using Gin:
+ResolveSpec v2.0 introduces a new database and router abstraction layer while maintaining **100% backward compatibility**. Your existing code will continue to work without any changes.
+
+### Migration Timeline
+
+1. **Phase 1**: Continue using existing API (no changes needed)
+2. **Phase 2**: Gradually adopt new constructors when convenient  
+3. **Phase 3**: Switch to interface-based approach for new features
+4. **Phase 4**: Optionally switch database backends
+
+### Detailed Migration Guide
+
+For detailed migration instructions, examples, and best practices, see [MIGRATION_GUIDE.md](MIGRATION_GUIDE.md).
+
+## Architecture
+
+### Database Abstraction Layer
+
+```
+Your Application Code
+        ↓
+   Handler (Business Logic)  
+        ↓
+   Database Interface
+        ↓
+   [GormAdapter] [BunAdapter] [CustomAdapter]
+        ↓              ↓           ↓
+    [GORM]         [Bun]    [Your ORM]
+```
+
+### Supported Database Layers
+
+- **GORM** (default, fully supported)
+- **Bun** (ready to use, included in dependencies)
+- **Custom ORMs** (implement the `Database` interface)
+
+### Supported Routers
+
+- **Gorilla Mux** (built-in support with `SetupRoutes()`)
+- **BunRouter** (built-in support with `SetupBunRouterWithResolveSpec()`)
+- **Gin** (manual integration, see examples above)
+- **Echo** (manual integration, see examples above)  
+- **Custom Routers** (implement request/response adapters)
+
+### Option 2: New Database-Agnostic API
+
+#### With GORM (Recommended Migration Path)
 ```go
-func setupGin(handler *resolvespec.APIHandler) *gin.Engine {
+import "github.com/Warky-Devs/ResolveSpec/pkg/resolvespec"
+
+// Create database adapter
+dbAdapter := resolvespec.NewGormAdapter(gormDB)
+
+// Create model registry  
+registry := resolvespec.NewModelRegistry()
+registry.RegisterModel("core.users", &User{})
+registry.RegisterModel("core.posts", &Post{})
+
+// Create handler
+handler := resolvespec.NewHandler(dbAdapter, registry)
+```
+
+#### With Bun ORM
+```go
+import "github.com/Warky-Devs/ResolveSpec/pkg/resolvespec"
+import "github.com/uptrace/bun"
+
+// Create Bun adapter (Bun dependency already included)
+dbAdapter := resolvespec.NewBunAdapter(bunDB)
+
+// Rest is identical to GORM
+registry := resolvespec.NewModelRegistry()
+handler := resolvespec.NewHandler(dbAdapter, registry)
+```
+
+### Router Integration
+
+#### Gorilla Mux (Built-in Support)
+```go
+import "github.com/gorilla/mux"
+
+// Backward compatible way
+router := mux.NewRouter()  
+resolvespec.SetupRoutes(router, handler)
+
+// Or manually:
+router.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+    vars := mux.Vars(r)
+    handler.Handle(w, r, vars)
+}).Methods("POST")
+```
+
+#### Gin (Custom Integration)
+```go
+import "github.com/gin-gonic/gin"
+
+func setupGin(handler *resolvespec.Handler) *gin.Engine {
     r := gin.Default()
     
     r.POST("/:schema/:entity", func(c *gin.Context) {
         params := map[string]string{
             "schema": c.Param("schema"),
             "entity": c.Param("entity"),
-            "id":     c.Param("id"),
         }
-        handler.SetParams(params)
-        handler.Handle(c.Writer, c.Request)
+        
+        // Use new adapter interfaces
+        reqAdapter := resolvespec.NewHTTPRequest(c.Request)
+        respAdapter := resolvespec.NewHTTPResponseWriter(c.Writer)
+        handler.Handle(respAdapter, reqAdapter, params)
     })
     
     return r
 }
 ```
 
-Using Mux:
+#### Echo (Custom Integration)
 ```go
-func setupMux(handler *resolvespec.APIHandler) *mux.Router {
-    r := mux.NewRouter()
+import "github.com/labstack/echo/v4"
+
+func setupEcho(handler *resolvespec.Handler) *echo.Echo {
+    e := echo.New()
     
-    r.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
-        vars := mux.Vars(r)
-        handler.SetParams(vars)
-        handler.Handle(w, r)
-    }).Methods("POST")
+    e.POST("/:schema/:entity", func(c echo.Context) error {
+        params := map[string]string{
+            "schema": c.Param("schema"),
+            "entity": c.Param("entity"),
+        }
+        
+        reqAdapter := resolvespec.NewHTTPRequest(c.Request())
+        respAdapter := resolvespec.NewHTTPResponseWriter(c.Response().Writer)
+        handler.Handle(respAdapter, reqAdapter, params)
+        return nil
+    })
     
-    return r
+    return e
+}
+```
+
+#### BunRouter (Built-in Support)
+```go
+import "github.com/uptrace/bunrouter"
+
+// Simple setup with built-in function
+func setupBunRouter(handler *resolvespec.APIHandlerCompat) *bunrouter.Router {
+    router := bunrouter.New()
+    resolvespec.SetupBunRouterWithResolveSpec(router, handler)
+    return router
+}
+
+// Or use the adapter
+func setupBunRouterAdapter() *resolvespec.StandardBunRouterAdapter {
+    routerAdapter := resolvespec.NewStandardBunRouterAdapter()
+    
+    // Register routes manually
+    routerAdapter.RegisterRouteWithParams("POST", "/:schema/:entity", 
+        []string{"schema", "entity"}, 
+        func(w http.ResponseWriter, r *http.Request, params map[string]string) {
+            // Your handler logic
+        })
+    
+    return routerAdapter
+}
+
+// Full uptrace stack (bunrouter + Bun ORM)
+func setupFullUptrace(bunDB *bun.DB) *bunrouter.Router {
+    // Database adapter
+    dbAdapter := resolvespec.NewBunAdapter(bunDB)
+    registry := resolvespec.NewModelRegistry()
+    handler := resolvespec.NewHandler(dbAdapter, registry)
+    
+    // Router
+    router := resolvespec.NewStandardBunRouterAdapter()
+    resolvespec.SetupBunRouterWithResolveSpec(router.GetBunRouter(), 
+        &resolvespec.APIHandlerCompat{
+            newHandler: handler,
+        })
+    
+    return router.GetBunRouter()
 }
 ```
 
@@ -198,13 +363,45 @@ Define virtual columns using SQL expressions:
 ]
 ```
 
+## Testing
+
+### With New Architecture (Mockable)
+
+```go
+import "github.com/stretchr/testify/mock"
+
+// Create mock database
+type MockDatabase struct {
+    mock.Mock
+}
+
+func (m *MockDatabase) NewSelect() resolvespec.SelectQuery {
+    args := m.Called()
+    return args.Get(0).(resolvespec.SelectQuery)
+}
+
+// Test your handler with mocks
+func TestHandler(t *testing.T) {
+    mockDB := &MockDatabase{}
+    mockRegistry := resolvespec.NewModelRegistry()
+    handler := resolvespec.NewHandler(mockDB, mockRegistry)
+    
+    // Setup mock expectations
+    mockDB.On("NewSelect").Return(&MockSelectQuery{})
+    
+    // Test your logic
+    // ... test code
+}
+```
+
 ## Security Considerations
 
 - Implement proper authentication and authorization
-- Validate all input parameters
-- Use prepared statements (handled by GORM)
+- Validate all input parameters  
+- Use prepared statements (handled by GORM/Bun/your ORM)
 - Implement rate limiting
 - Control access at schema/entity level
+- **New**: Database abstraction layer provides additional security through interface boundaries
 
 ## Contributing
 
@@ -218,10 +415,29 @@ Define virtual columns using SQL expressions:
 
 This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details. 
 
+## What's New in v2.0
+
+### Breaking Changes
+- **None!** Full backward compatibility maintained
+
+### New Features
+- **Database Abstraction**: Support for GORM, Bun, and custom ORMs
+- **Router Flexibility**: Works with any HTTP router through adapters
+- **BunRouter Integration**: Built-in support for uptrace/bunrouter
+- **Better Architecture**: Clean separation of concerns with interfaces
+- **Enhanced Testing**: Mockable interfaces for comprehensive testing
+- **Migration Guide**: Step-by-step migration instructions
+
+### Performance Improvements
+- More efficient query building through interface design
+- Reduced coupling between components
+- Better memory management with interface boundaries
+
 ## Acknowledgments
 
-- Inspired by REST, Odata and GraphQL's flexibility
-- Built with [GORM](https://gorm.io)
-- Uses Gin or Mux Web Framework
+- Inspired by REST, OData, and GraphQL's flexibility
+- **Database Support**: [GORM](https://gorm.io) and [Bun](https://bun.uptrace.dev/)
+- **Router Support**: Gorilla Mux (built-in), Gin, Echo, and others through adapters
 - Slogan generated using DALL-E
-- AI used for documentation checking and correction
+- AI used for documentation checking and correction
+- Community feedback and contributions that made v2.0 possible

cmd/testserver/main.go

@@ -8,7 +8,7 @@ import (
 	"time"
 
 	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-	"github.com/Warky-Devs/ResolveSpec/pkg/models"
+	"github.com/Warky-Devs/ResolveSpec/pkg/modelregistry"
 	"github.com/Warky-Devs/ResolveSpec/pkg/testmodels"
 
 	"github.com/Warky-Devs/ResolveSpec/pkg/resolvespec"
@@ -24,9 +24,6 @@ func main() {
 	fmt.Println("ResolveSpec test server starting")
 	logger.Init(true)
 
-	// Init Models
-	testmodels.RegisterTestModels()
-
 	// Initialize database
 	db, err := initDB()
 	if err != nil {
@@ -37,24 +34,22 @@ func main() {
 	// Create router
 	r := mux.NewRouter()
 
-	// Initialize API handler
-	handler := resolvespec.NewAPIHandler(db)
+	// Initialize API handler using new API
+	handler := resolvespec.NewHandlerWithGORM(db)
 
-	// Setup routes
-	r.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
-		vars := mux.Vars(r)
-		handler.Handle(w, r, vars)
-	}).Methods("POST")
+	// Create a new registry instance and register models
+	registry := modelregistry.NewModelRegistry()
+	testmodels.RegisterTestModels(registry)
 
-	r.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
-		vars := mux.Vars(r)
-		handler.Handle(w, r, vars)
-	}).Methods("POST")
+	// Register models with handler
+	models := testmodels.GetTestModels()
+	modelNames := []string{"departments", "employees", "projects", "project_tasks", "documents", "comments"}
+	for i, model := range models {
+		handler.RegisterModel("public", modelNames[i], model)
+	}
 
-	r.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
-		vars := mux.Vars(r)
-		handler.HandleGet(w, r, vars)
-	}).Methods("GET")
+	// Setup routes using new SetupMuxRoutes function
+	resolvespec.SetupMuxRoutes(r, handler)
 
 	// Start server
 	logger.Info("Starting server on :8080")
@@ -83,7 +78,7 @@ func initDB() (*gorm.DB, error) {
 		return nil, err
 	}
 
-	modelList := models.GetModels()
+	modelList := testmodels.GetTestModels()
 
 	// Auto migrate schemas
 	err = db.AutoMigrate(modelList...)

go.mod

@@ -1,11 +1,14 @@
 module github.com/Warky-Devs/ResolveSpec
 
-go 1.22.5
+go 1.23.0
+
+toolchain go1.24.6
 
 require (
 	github.com/glebarez/sqlite v1.11.0
 	github.com/gorilla/mux v1.8.1
 	github.com/stretchr/testify v1.8.1
+	github.com/uptrace/bun v1.2.15
 	go.uber.org/zap v1.27.0
 	gorm.io/gorm v1.25.12
 )
@@ -17,11 +20,16 @@ require (
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
-	github.com/mattn/go-isatty v0.0.17 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/puzpuzpuz/xsync/v3 v3.5.1 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	github.com/tmthrgd/go-hex v0.0.0-20190904060850-447a3041c3bc // indirect
+	github.com/uptrace/bunrouter v1.0.23 // indirect
+	github.com/vmihailenco/msgpack/v5 v5.4.1 // indirect
+	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
 	go.uber.org/multierr v1.10.0 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/sys v0.34.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	modernc.org/libc v1.22.5 // indirect

go.sum

@@ -17,10 +17,16 @@ github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD
 github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
 github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
 github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
-github.com/mattn/go-isatty v0.0.17 h1:BTarxUcIeDqL27Mc+vyvdWYSL28zpIhv3RoTdsLMPng=
-github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
+github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/puzpuzpuz/xsync/v3 v3.5.1 h1:GJYJZwO6IdxN/IKbneznS6yPkVC+c3zyY/j19c++5Fg=
+github.com/puzpuzpuz/xsync/v3 v3.5.1/go.mod h1:VjzYrABPabuM4KyBh1Ftq6u8nhwY5tBPKP9jpmh0nnA=
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
@@ -31,19 +37,30 @@ github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
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pkg/common/adapters/database/bun.go

@@ -0,0 +1,422 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"github.com/uptrace/bun"
+)
+
+// BunAdapter adapts Bun to work with our Database interface
+// This demonstrates how the abstraction works with different ORMs
+type BunAdapter struct {
+	db *bun.DB
+}
+
+// NewBunAdapter creates a new Bun adapter
+func NewBunAdapter(db *bun.DB) *BunAdapter {
+	return &BunAdapter{db: db}
+}
+
+func (b *BunAdapter) NewSelect() common.SelectQuery {
+	return &BunSelectQuery{query: b.db.NewSelect()}
+}
+
+func (b *BunAdapter) NewInsert() common.InsertQuery {
+	return &BunInsertQuery{query: b.db.NewInsert()}
+}
+
+func (b *BunAdapter) NewUpdate() common.UpdateQuery {
+	return &BunUpdateQuery{query: b.db.NewUpdate()}
+}
+
+func (b *BunAdapter) NewDelete() common.DeleteQuery {
+	return &BunDeleteQuery{query: b.db.NewDelete()}
+}
+
+func (b *BunAdapter) Exec(ctx context.Context, query string, args ...interface{}) (common.Result, error) {
+	result, err := b.db.ExecContext(ctx, query, args...)
+	return &BunResult{result: result}, err
+}
+
+func (b *BunAdapter) Query(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
+	return b.db.NewRaw(query, args...).Scan(ctx, dest)
+}
+
+func (b *BunAdapter) BeginTx(ctx context.Context) (common.Database, error) {
+	tx, err := b.db.BeginTx(ctx, &sql.TxOptions{})
+	if err != nil {
+		return nil, err
+	}
+	// For Bun, we'll return a special wrapper that holds the transaction
+	return &BunTxAdapter{tx: tx}, nil
+}
+
+func (b *BunAdapter) CommitTx(ctx context.Context) error {
+	// For Bun, we need to handle this differently
+	// This is a simplified implementation
+	return nil
+}
+
+func (b *BunAdapter) RollbackTx(ctx context.Context) error {
+	// For Bun, we need to handle this differently
+	// This is a simplified implementation
+	return nil
+}
+
+func (b *BunAdapter) RunInTransaction(ctx context.Context, fn func(common.Database) error) error {
+	return b.db.RunInTx(ctx, &sql.TxOptions{}, func(ctx context.Context, tx bun.Tx) error {
+		// Create adapter with transaction
+		adapter := &BunTxAdapter{tx: tx}
+		return fn(adapter)
+	})
+}
+
+// BunSelectQuery implements SelectQuery for Bun
+type BunSelectQuery struct {
+	query      *bun.SelectQuery
+	tableName  string
+	tableAlias string
+}
+
+func (b *BunSelectQuery) Model(model interface{}) common.SelectQuery {
+	b.query = b.query.Model(model)
+
+	// Try to get table name from model if it implements TableNameProvider
+	if provider, ok := model.(common.TableNameProvider); ok {
+		b.tableName = provider.TableName()
+	}
+
+	return b
+}
+
+func (b *BunSelectQuery) Table(table string) common.SelectQuery {
+	b.query = b.query.Table(table)
+	b.tableName = table
+	return b
+}
+
+func (b *BunSelectQuery) Column(columns ...string) common.SelectQuery {
+	b.query = b.query.Column(columns...)
+	return b
+}
+
+func (b *BunSelectQuery) Where(query string, args ...interface{}) common.SelectQuery {
+	b.query = b.query.Where(query, args...)
+	return b
+}
+
+func (b *BunSelectQuery) WhereOr(query string, args ...interface{}) common.SelectQuery {
+	b.query = b.query.WhereOr(query, args...)
+	return b
+}
+
+func (b *BunSelectQuery) Join(query string, args ...interface{}) common.SelectQuery {
+	// Extract optional prefix from args
+	// If the last arg is a string that looks like a table prefix, use it
+	var prefix string
+	sqlArgs := args
+
+	if len(args) > 0 {
+		if lastArg, ok := args[len(args)-1].(string); ok && len(lastArg) < 50 && !strings.Contains(lastArg, " ") {
+			// Likely a prefix, not a SQL parameter
+			prefix = lastArg
+			sqlArgs = args[:len(args)-1]
+		}
+	}
+
+	// If no prefix provided, use the table name as prefix
+	if prefix == "" && b.tableName != "" {
+		prefix = b.tableName
+		// Extract just the table name if it has schema
+		if idx := strings.LastIndex(prefix, "."); idx != -1 {
+			prefix = prefix[idx+1:]
+		}
+	}
+
+	// If prefix is provided, add it as an alias in the join
+	// Bun expects: "JOIN table AS alias ON condition"
+	joinClause := query
+	if prefix != "" && !strings.Contains(strings.ToUpper(query), " AS ") {
+		// If query doesn't already have AS, check if it's a simple table name
+		parts := strings.Fields(query)
+		if len(parts) > 0 && !strings.HasPrefix(strings.ToUpper(parts[0]), "JOIN") {
+			// Simple table name, add prefix: "table AS prefix"
+			joinClause = fmt.Sprintf("%s AS %s", parts[0], prefix)
+			if len(parts) > 1 {
+				// Has ON clause: "table ON ..." becomes "table AS prefix ON ..."
+				joinClause += " " + strings.Join(parts[1:], " ")
+			}
+		}
+	}
+
+	b.query = b.query.Join(joinClause, sqlArgs...)
+	return b
+}
+
+func (b *BunSelectQuery) LeftJoin(query string, args ...interface{}) common.SelectQuery {
+	// Extract optional prefix from args
+	var prefix string
+	sqlArgs := args
+
+	if len(args) > 0 {
+		if lastArg, ok := args[len(args)-1].(string); ok && len(lastArg) < 50 && !strings.Contains(lastArg, " ") {
+			prefix = lastArg
+			sqlArgs = args[:len(args)-1]
+		}
+	}
+
+	// If no prefix provided, use the table name as prefix
+	if prefix == "" && b.tableName != "" {
+		prefix = b.tableName
+		if idx := strings.LastIndex(prefix, "."); idx != -1 {
+			prefix = prefix[idx+1:]
+		}
+	}
+
+	// Construct LEFT JOIN with prefix
+	joinClause := query
+	if prefix != "" && !strings.Contains(strings.ToUpper(query), " AS ") {
+		parts := strings.Fields(query)
+		if len(parts) > 0 && !strings.HasPrefix(strings.ToUpper(parts[0]), "LEFT") && !strings.HasPrefix(strings.ToUpper(parts[0]), "JOIN") {
+			joinClause = fmt.Sprintf("%s AS %s", parts[0], prefix)
+			if len(parts) > 1 {
+				joinClause += " " + strings.Join(parts[1:], " ")
+			}
+		}
+	}
+
+	b.query = b.query.Join("LEFT JOIN " + joinClause, sqlArgs...)
+	return b
+}
+
+func (b *BunSelectQuery) Preload(relation string, conditions ...interface{}) common.SelectQuery {
+	// Bun uses Relation() method for preloading
+	// For now, we'll just pass the relation name without conditions
+	// TODO: Implement proper condition handling for Bun
+	b.query = b.query.Relation(relation)
+	return b
+}
+
+func (b *BunSelectQuery) Order(order string) common.SelectQuery {
+	b.query = b.query.Order(order)
+	return b
+}
+
+func (b *BunSelectQuery) Limit(n int) common.SelectQuery {
+	b.query = b.query.Limit(n)
+	return b
+}
+
+func (b *BunSelectQuery) Offset(n int) common.SelectQuery {
+	b.query = b.query.Offset(n)
+	return b
+}
+
+func (b *BunSelectQuery) Group(group string) common.SelectQuery {
+	b.query = b.query.Group(group)
+	return b
+}
+
+func (b *BunSelectQuery) Having(having string, args ...interface{}) common.SelectQuery {
+	b.query = b.query.Having(having, args...)
+	return b
+}
+
+func (b *BunSelectQuery) Scan(ctx context.Context, dest interface{}) error {
+	return b.query.Scan(ctx, dest)
+}
+
+func (b *BunSelectQuery) Count(ctx context.Context) (int, error) {
+	count, err := b.query.Count(ctx)
+	return count, err
+}
+
+func (b *BunSelectQuery) Exists(ctx context.Context) (bool, error) {
+	return b.query.Exists(ctx)
+}
+
+// BunInsertQuery implements InsertQuery for Bun
+type BunInsertQuery struct {
+	query  *bun.InsertQuery
+	values map[string]interface{}
+}
+
+func (b *BunInsertQuery) Model(model interface{}) common.InsertQuery {
+	b.query = b.query.Model(model)
+	return b
+}
+
+func (b *BunInsertQuery) Table(table string) common.InsertQuery {
+	b.query = b.query.Table(table)
+	return b
+}
+
+func (b *BunInsertQuery) Value(column string, value interface{}) common.InsertQuery {
+	if b.values == nil {
+		b.values = make(map[string]interface{})
+	}
+	b.values[column] = value
+	return b
+}
+
+func (b *BunInsertQuery) OnConflict(action string) common.InsertQuery {
+	b.query = b.query.On(action)
+	return b
+}
+
+func (b *BunInsertQuery) Returning(columns ...string) common.InsertQuery {
+	if len(columns) > 0 {
+		b.query = b.query.Returning(columns[0])
+	}
+	return b
+}
+
+func (b *BunInsertQuery) Exec(ctx context.Context) (common.Result, error) {
+	if b.values != nil {
+		// For Bun, we need to handle this differently
+		for k, v := range b.values {
+			b.query = b.query.Set("? = ?", bun.Ident(k), v)
+		}
+	}
+	result, err := b.query.Exec(ctx)
+	return &BunResult{result: result}, err
+}
+
+// BunUpdateQuery implements UpdateQuery for Bun
+type BunUpdateQuery struct {
+	query *bun.UpdateQuery
+}
+
+func (b *BunUpdateQuery) Model(model interface{}) common.UpdateQuery {
+	b.query = b.query.Model(model)
+	return b
+}
+
+func (b *BunUpdateQuery) Table(table string) common.UpdateQuery {
+	b.query = b.query.Table(table)
+	return b
+}
+
+func (b *BunUpdateQuery) Set(column string, value interface{}) common.UpdateQuery {
+	b.query = b.query.Set(column+" = ?", value)
+	return b
+}
+
+func (b *BunUpdateQuery) SetMap(values map[string]interface{}) common.UpdateQuery {
+	for column, value := range values {
+		b.query = b.query.Set(column+" = ?", value)
+	}
+	return b
+}
+
+func (b *BunUpdateQuery) Where(query string, args ...interface{}) common.UpdateQuery {
+	b.query = b.query.Where(query, args...)
+	return b
+}
+
+func (b *BunUpdateQuery) Returning(columns ...string) common.UpdateQuery {
+	if len(columns) > 0 {
+		b.query = b.query.Returning(columns[0])
+	}
+	return b
+}
+
+func (b *BunUpdateQuery) Exec(ctx context.Context) (common.Result, error) {
+	result, err := b.query.Exec(ctx)
+	return &BunResult{result: result}, err
+}
+
+// BunDeleteQuery implements DeleteQuery for Bun
+type BunDeleteQuery struct {
+	query *bun.DeleteQuery
+}
+
+func (b *BunDeleteQuery) Model(model interface{}) common.DeleteQuery {
+	b.query = b.query.Model(model)
+	return b
+}
+
+func (b *BunDeleteQuery) Table(table string) common.DeleteQuery {
+	b.query = b.query.Table(table)
+	return b
+}
+
+func (b *BunDeleteQuery) Where(query string, args ...interface{}) common.DeleteQuery {
+	b.query = b.query.Where(query, args...)
+	return b
+}
+
+func (b *BunDeleteQuery) Exec(ctx context.Context) (common.Result, error) {
+	result, err := b.query.Exec(ctx)
+	return &BunResult{result: result}, err
+}
+
+// BunResult implements Result for Bun
+type BunResult struct {
+	result sql.Result
+}
+
+func (b *BunResult) RowsAffected() int64 {
+	if b.result == nil {
+		return 0
+	}
+	rows, _ := b.result.RowsAffected()
+	return rows
+}
+
+func (b *BunResult) LastInsertId() (int64, error) {
+	if b.result == nil {
+		return 0, nil
+	}
+	return b.result.LastInsertId()
+}
+
+// BunTxAdapter wraps a Bun transaction to implement the Database interface
+type BunTxAdapter struct {
+	tx bun.Tx
+}
+
+func (b *BunTxAdapter) NewSelect() common.SelectQuery {
+	return &BunSelectQuery{query: b.tx.NewSelect()}
+}
+
+func (b *BunTxAdapter) NewInsert() common.InsertQuery {
+	return &BunInsertQuery{query: b.tx.NewInsert()}
+}
+
+func (b *BunTxAdapter) NewUpdate() common.UpdateQuery {
+	return &BunUpdateQuery{query: b.tx.NewUpdate()}
+}
+
+func (b *BunTxAdapter) NewDelete() common.DeleteQuery {
+	return &BunDeleteQuery{query: b.tx.NewDelete()}
+}
+
+func (b *BunTxAdapter) Exec(ctx context.Context, query string, args ...interface{}) (common.Result, error) {
+	result, err := b.tx.ExecContext(ctx, query, args...)
+	return &BunResult{result: result}, err
+}
+
+func (b *BunTxAdapter) Query(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
+	return b.tx.NewRaw(query, args...).Scan(ctx, dest)
+}
+
+func (b *BunTxAdapter) BeginTx(ctx context.Context) (common.Database, error) {
+	return nil, fmt.Errorf("nested transactions not supported")
+}
+
+func (b *BunTxAdapter) CommitTx(ctx context.Context) error {
+	return b.tx.Commit()
+}
+
+func (b *BunTxAdapter) RollbackTx(ctx context.Context) error {
+	return b.tx.Rollback()
+}
+
+func (b *BunTxAdapter) RunInTransaction(ctx context.Context, fn func(common.Database) error) error {
+	return fn(b) // Already in transaction
+}

pkg/common/adapters/database/gorm.go

@@ -0,0 +1,369 @@
+package database
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"gorm.io/gorm"
+)
+
+// GormAdapter adapts GORM to work with our Database interface
+type GormAdapter struct {
+	db *gorm.DB
+}
+
+// NewGormAdapter creates a new GORM adapter
+func NewGormAdapter(db *gorm.DB) *GormAdapter {
+	return &GormAdapter{db: db}
+}
+
+func (g *GormAdapter) NewSelect() common.SelectQuery {
+	return &GormSelectQuery{db: g.db}
+}
+
+func (g *GormAdapter) NewInsert() common.InsertQuery {
+	return &GormInsertQuery{db: g.db}
+}
+
+func (g *GormAdapter) NewUpdate() common.UpdateQuery {
+	return &GormUpdateQuery{db: g.db}
+}
+
+func (g *GormAdapter) NewDelete() common.DeleteQuery {
+	return &GormDeleteQuery{db: g.db}
+}
+
+func (g *GormAdapter) Exec(ctx context.Context, query string, args ...interface{}) (common.Result, error) {
+	result := g.db.WithContext(ctx).Exec(query, args...)
+	return &GormResult{result: result}, result.Error
+}
+
+func (g *GormAdapter) Query(ctx context.Context, dest interface{}, query string, args ...interface{}) error {
+	return g.db.WithContext(ctx).Raw(query, args...).Find(dest).Error
+}
+
+func (g *GormAdapter) BeginTx(ctx context.Context) (common.Database, error) {
+	tx := g.db.WithContext(ctx).Begin()
+	if tx.Error != nil {
+		return nil, tx.Error
+	}
+	return &GormAdapter{db: tx}, nil
+}
+
+func (g *GormAdapter) CommitTx(ctx context.Context) error {
+	return g.db.WithContext(ctx).Commit().Error
+}
+
+func (g *GormAdapter) RollbackTx(ctx context.Context) error {
+	return g.db.WithContext(ctx).Rollback().Error
+}
+
+func (g *GormAdapter) RunInTransaction(ctx context.Context, fn func(common.Database) error) error {
+	return g.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		adapter := &GormAdapter{db: tx}
+		return fn(adapter)
+	})
+}
+
+// GormSelectQuery implements SelectQuery for GORM
+type GormSelectQuery struct {
+	db         *gorm.DB
+	tableName  string
+	tableAlias string
+}
+
+func (g *GormSelectQuery) Model(model interface{}) common.SelectQuery {
+	g.db = g.db.Model(model)
+
+	// Try to get table name from model if it implements TableNameProvider
+	if provider, ok := model.(common.TableNameProvider); ok {
+		g.tableName = provider.TableName()
+	}
+
+	return g
+}
+
+func (g *GormSelectQuery) Table(table string) common.SelectQuery {
+	g.db = g.db.Table(table)
+	g.tableName = table
+	return g
+}
+
+func (g *GormSelectQuery) Column(columns ...string) common.SelectQuery {
+	g.db = g.db.Select(columns)
+	return g
+}
+
+func (g *GormSelectQuery) Where(query string, args ...interface{}) common.SelectQuery {
+	g.db = g.db.Where(query, args...)
+	return g
+}
+
+func (g *GormSelectQuery) WhereOr(query string, args ...interface{}) common.SelectQuery {
+	g.db = g.db.Or(query, args...)
+	return g
+}
+
+func (g *GormSelectQuery) Join(query string, args ...interface{}) common.SelectQuery {
+	// Extract optional prefix from args
+	// If the last arg is a string that looks like a table prefix, use it
+	var prefix string
+	sqlArgs := args
+
+	if len(args) > 0 {
+		if lastArg, ok := args[len(args)-1].(string); ok && len(lastArg) < 50 && !strings.Contains(lastArg, " ") {
+			// Likely a prefix, not a SQL parameter
+			prefix = lastArg
+			sqlArgs = args[:len(args)-1]
+		}
+	}
+
+	// If no prefix provided, use the table name as prefix
+	if prefix == "" && g.tableName != "" {
+		prefix = g.tableName
+		// Extract just the table name if it has schema
+		if idx := strings.LastIndex(prefix, "."); idx != -1 {
+			prefix = prefix[idx+1:]
+		}
+	}
+
+	// If prefix is provided, add it as an alias in the join
+	// GORM expects: "JOIN table AS alias ON condition"
+	joinClause := query
+	if prefix != "" && !strings.Contains(strings.ToUpper(query), " AS ") {
+		// If query doesn't already have AS, check if it's a simple table name
+		parts := strings.Fields(query)
+		if len(parts) > 0 && !strings.HasPrefix(strings.ToUpper(parts[0]), "JOIN") {
+			// Simple table name, add prefix: "table AS prefix"
+			joinClause = fmt.Sprintf("%s AS %s", parts[0], prefix)
+			if len(parts) > 1 {
+				// Has ON clause: "table ON ..." becomes "table AS prefix ON ..."
+				joinClause += " " + strings.Join(parts[1:], " ")
+			}
+		}
+	}
+
+	g.db = g.db.Joins(joinClause, sqlArgs...)
+	return g
+}
+
+func (g *GormSelectQuery) LeftJoin(query string, args ...interface{}) common.SelectQuery {
+	// Extract optional prefix from args
+	var prefix string
+	sqlArgs := args
+
+	if len(args) > 0 {
+		if lastArg, ok := args[len(args)-1].(string); ok && len(lastArg) < 50 && !strings.Contains(lastArg, " ") {
+			prefix = lastArg
+			sqlArgs = args[:len(args)-1]
+		}
+	}
+
+	// If no prefix provided, use the table name as prefix
+	if prefix == "" && g.tableName != "" {
+		prefix = g.tableName
+		if idx := strings.LastIndex(prefix, "."); idx != -1 {
+			prefix = prefix[idx+1:]
+		}
+	}
+
+	// Construct LEFT JOIN with prefix
+	joinClause := query
+	if prefix != "" && !strings.Contains(strings.ToUpper(query), " AS ") {
+		parts := strings.Fields(query)
+		if len(parts) > 0 && !strings.HasPrefix(strings.ToUpper(parts[0]), "LEFT") && !strings.HasPrefix(strings.ToUpper(parts[0]), "JOIN") {
+			joinClause = fmt.Sprintf("%s AS %s", parts[0], prefix)
+			if len(parts) > 1 {
+				joinClause += " " + strings.Join(parts[1:], " ")
+			}
+		}
+	}
+
+	g.db = g.db.Joins("LEFT JOIN "+joinClause, sqlArgs...)
+	return g
+}
+
+func (g *GormSelectQuery) Preload(relation string, conditions ...interface{}) common.SelectQuery {
+	g.db = g.db.Preload(relation, conditions...)
+	return g
+}
+
+func (g *GormSelectQuery) Order(order string) common.SelectQuery {
+	g.db = g.db.Order(order)
+	return g
+}
+
+func (g *GormSelectQuery) Limit(n int) common.SelectQuery {
+	g.db = g.db.Limit(n)
+	return g
+}
+
+func (g *GormSelectQuery) Offset(n int) common.SelectQuery {
+	g.db = g.db.Offset(n)
+	return g
+}
+
+func (g *GormSelectQuery) Group(group string) common.SelectQuery {
+	g.db = g.db.Group(group)
+	return g
+}
+
+func (g *GormSelectQuery) Having(having string, args ...interface{}) common.SelectQuery {
+	g.db = g.db.Having(having, args...)
+	return g
+}
+
+func (g *GormSelectQuery) Scan(ctx context.Context, dest interface{}) error {
+	return g.db.WithContext(ctx).Find(dest).Error
+}
+
+func (g *GormSelectQuery) Count(ctx context.Context) (int, error) {
+	var count int64
+	err := g.db.WithContext(ctx).Count(&count).Error
+	return int(count), err
+}
+
+func (g *GormSelectQuery) Exists(ctx context.Context) (bool, error) {
+	var count int64
+	err := g.db.WithContext(ctx).Limit(1).Count(&count).Error
+	return count > 0, err
+}
+
+// GormInsertQuery implements InsertQuery for GORM
+type GormInsertQuery struct {
+	db     *gorm.DB
+	model  interface{}
+	values map[string]interface{}
+}
+
+func (g *GormInsertQuery) Model(model interface{}) common.InsertQuery {
+	g.model = model
+	g.db = g.db.Model(model)
+	return g
+}
+
+func (g *GormInsertQuery) Table(table string) common.InsertQuery {
+	g.db = g.db.Table(table)
+	return g
+}
+
+func (g *GormInsertQuery) Value(column string, value interface{}) common.InsertQuery {
+	if g.values == nil {
+		g.values = make(map[string]interface{})
+	}
+	g.values[column] = value
+	return g
+}
+
+func (g *GormInsertQuery) OnConflict(action string) common.InsertQuery {
+	// GORM handles conflicts differently, this would need specific implementation
+	return g
+}
+
+func (g *GormInsertQuery) Returning(columns ...string) common.InsertQuery {
+	// GORM doesn't have explicit RETURNING, but updates the model
+	return g
+}
+
+func (g *GormInsertQuery) Exec(ctx context.Context) (common.Result, error) {
+	var result *gorm.DB
+	if g.model != nil {
+		result = g.db.WithContext(ctx).Create(g.model)
+	} else if g.values != nil {
+		result = g.db.WithContext(ctx).Create(g.values)
+	} else {
+		result = g.db.WithContext(ctx).Create(map[string]interface{}{})
+	}
+	return &GormResult{result: result}, result.Error
+}
+
+// GormUpdateQuery implements UpdateQuery for GORM
+type GormUpdateQuery struct {
+	db      *gorm.DB
+	model   interface{}
+	updates interface{}
+}
+
+func (g *GormUpdateQuery) Model(model interface{}) common.UpdateQuery {
+	g.model = model
+	g.db = g.db.Model(model)
+	return g
+}
+
+func (g *GormUpdateQuery) Table(table string) common.UpdateQuery {
+	g.db = g.db.Table(table)
+	return g
+}
+
+func (g *GormUpdateQuery) Set(column string, value interface{}) common.UpdateQuery {
+	if g.updates == nil {
+		g.updates = make(map[string]interface{})
+	}
+	if updates, ok := g.updates.(map[string]interface{}); ok {
+		updates[column] = value
+	}
+	return g
+}
+
+func (g *GormUpdateQuery) SetMap(values map[string]interface{}) common.UpdateQuery {
+	g.updates = values
+	return g
+}
+
+func (g *GormUpdateQuery) Where(query string, args ...interface{}) common.UpdateQuery {
+	g.db = g.db.Where(query, args...)
+	return g
+}
+
+func (g *GormUpdateQuery) Returning(columns ...string) common.UpdateQuery {
+	// GORM doesn't have explicit RETURNING
+	return g
+}
+
+func (g *GormUpdateQuery) Exec(ctx context.Context) (common.Result, error) {
+	result := g.db.WithContext(ctx).Updates(g.updates)
+	return &GormResult{result: result}, result.Error
+}
+
+// GormDeleteQuery implements DeleteQuery for GORM
+type GormDeleteQuery struct {
+	db    *gorm.DB
+	model interface{}
+}
+
+func (g *GormDeleteQuery) Model(model interface{}) common.DeleteQuery {
+	g.model = model
+	g.db = g.db.Model(model)
+	return g
+}
+
+func (g *GormDeleteQuery) Table(table string) common.DeleteQuery {
+	g.db = g.db.Table(table)
+	return g
+}
+
+func (g *GormDeleteQuery) Where(query string, args ...interface{}) common.DeleteQuery {
+	g.db = g.db.Where(query, args...)
+	return g
+}
+
+func (g *GormDeleteQuery) Exec(ctx context.Context) (common.Result, error) {
+	result := g.db.WithContext(ctx).Delete(g.model)
+	return &GormResult{result: result}, result.Error
+}
+
+// GormResult implements Result for GORM
+type GormResult struct {
+	result *gorm.DB
+}
+
+func (g *GormResult) RowsAffected() int64 {
+	return g.result.RowsAffected
+}
+
+func (g *GormResult) LastInsertId() (int64, error) {
+	// GORM doesn't directly provide last insert ID, would need specific implementation
+	return 0, nil
+}

pkg/common/adapters/router/bunrouter.go

@@ -0,0 +1,193 @@
+package router
+
+import (
+	"net/http"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"github.com/uptrace/bunrouter"
+)
+
+// BunRouterAdapter adapts uptrace/bunrouter to work with our Router interface
+type BunRouterAdapter struct {
+	router *bunrouter.Router
+}
+
+// NewBunRouterAdapter creates a new bunrouter adapter
+func NewBunRouterAdapter(router *bunrouter.Router) *BunRouterAdapter {
+	return &BunRouterAdapter{router: router}
+}
+
+// NewBunRouterAdapterDefault creates a new bunrouter adapter with default router
+func NewBunRouterAdapterDefault() *BunRouterAdapter {
+	return &BunRouterAdapter{router: bunrouter.New()}
+}
+
+func (b *BunRouterAdapter) HandleFunc(pattern string, handler common.HTTPHandlerFunc) common.RouteRegistration {
+	route := &BunRouterRegistration{
+		router:  b.router,
+		pattern: pattern,
+		handler: handler,
+	}
+	return route
+}
+
+func (b *BunRouterAdapter) ServeHTTP(w common.ResponseWriter, r common.Request) {
+	// This method would be used when we need to serve through our interface
+	// For now, we'll work directly with the underlying router
+	panic("ServeHTTP not implemented - use GetBunRouter() for direct access")
+}
+
+// GetBunRouter returns the underlying bunrouter for direct access
+func (b *BunRouterAdapter) GetBunRouter() *bunrouter.Router {
+	return b.router
+}
+
+// BunRouterRegistration implements RouteRegistration for bunrouter
+type BunRouterRegistration struct {
+	router  *bunrouter.Router
+	pattern string
+	handler common.HTTPHandlerFunc
+}
+
+func (b *BunRouterRegistration) Methods(methods ...string) common.RouteRegistration {
+	// bunrouter handles methods differently - we'll register for each method
+	for _, method := range methods {
+		b.router.Handle(method, b.pattern, func(w http.ResponseWriter, req bunrouter.Request) error {
+			// Convert bunrouter.Request to our BunRouterRequest
+			reqAdapter := &BunRouterRequest{req: req}
+			respAdapter := &HTTPResponseWriter{resp: w}
+			b.handler(respAdapter, reqAdapter)
+			return nil
+		})
+	}
+	return b
+}
+
+func (b *BunRouterRegistration) PathPrefix(prefix string) common.RouteRegistration {
+	// bunrouter doesn't have PathPrefix like mux, but we can modify the pattern
+	newPattern := prefix + b.pattern
+	b.pattern = newPattern
+	return b
+}
+
+// BunRouterRequest adapts bunrouter.Request to our Request interface
+type BunRouterRequest struct {
+	req  bunrouter.Request
+	body []byte
+}
+
+// NewBunRouterRequest creates a new BunRouterRequest adapter
+func NewBunRouterRequest(req bunrouter.Request) *BunRouterRequest {
+	return &BunRouterRequest{req: req}
+}
+
+func (b *BunRouterRequest) Method() string {
+	return b.req.Method
+}
+
+func (b *BunRouterRequest) URL() string {
+	return b.req.URL.String()
+}
+
+func (b *BunRouterRequest) Header(key string) string {
+	return b.req.Header.Get(key)
+}
+
+func (b *BunRouterRequest) Body() ([]byte, error) {
+	if b.body != nil {
+		return b.body, nil
+	}
+
+	if b.req.Body == nil {
+		return nil, nil
+	}
+
+	// Create HTTPRequest adapter and use its Body() method
+	httpAdapter := NewHTTPRequest(b.req.Request)
+	body, err := httpAdapter.Body()
+	if err != nil {
+		return nil, err
+	}
+	b.body = body
+	return body, nil
+}
+
+func (b *BunRouterRequest) PathParam(key string) string {
+	return b.req.Param(key)
+}
+
+func (b *BunRouterRequest) QueryParam(key string) string {
+	return b.req.URL.Query().Get(key)
+}
+
+func (b *BunRouterRequest) AllHeaders() map[string]string {
+	headers := make(map[string]string)
+	for key, values := range b.req.Header {
+		if len(values) > 0 {
+			headers[key] = values[0]
+		}
+	}
+	return headers
+}
+
+// StandardBunRouterAdapter creates routes compatible with standard bunrouter handlers
+type StandardBunRouterAdapter struct {
+	*BunRouterAdapter
+}
+
+func NewStandardBunRouterAdapter() *StandardBunRouterAdapter {
+	return &StandardBunRouterAdapter{
+		BunRouterAdapter: NewBunRouterAdapterDefault(),
+	}
+}
+
+// RegisterRoute registers a route that works with the existing Handler
+func (s *StandardBunRouterAdapter) RegisterRoute(method, pattern string, handler func(http.ResponseWriter, *http.Request, map[string]string)) {
+	s.router.Handle(method, pattern, func(w http.ResponseWriter, req bunrouter.Request) error {
+		// Extract path parameters
+		params := make(map[string]string)
+
+		// bunrouter doesn't provide a direct way to get all params
+		// You would typically access them individually with req.Param("name")
+		// For this example, we'll create the map based on the request context
+
+		handler(w, req.Request, params)
+		return nil
+	})
+}
+
+// RegisterRouteWithParams registers a route with explicit parameter extraction
+func (s *StandardBunRouterAdapter) RegisterRouteWithParams(method, pattern string, paramNames []string, handler func(http.ResponseWriter, *http.Request, map[string]string)) {
+	s.router.Handle(method, pattern, func(w http.ResponseWriter, req bunrouter.Request) error {
+		// Extract specified path parameters
+		params := make(map[string]string)
+		for _, paramName := range paramNames {
+			params[paramName] = req.Param(paramName)
+		}
+
+		handler(w, req.Request, params)
+		return nil
+	})
+}
+
+// BunRouterConfig holds bunrouter-specific configuration
+type BunRouterConfig struct {
+	UseStrictSlash         bool
+	RedirectTrailingSlash  bool
+	HandleMethodNotAllowed bool
+	HandleOPTIONS          bool
+	GlobalOPTIONS          http.Handler
+	GlobalMethodNotAllowed http.Handler
+	PanicHandler           func(http.ResponseWriter, *http.Request, interface{})
+}
+
+// DefaultBunRouterConfig returns default bunrouter configuration
+func DefaultBunRouterConfig() *BunRouterConfig {
+	return &BunRouterConfig{
+		UseStrictSlash:         false,
+		RedirectTrailingSlash:  true,
+		HandleMethodNotAllowed: true,
+		HandleOPTIONS:          true,
+	}
+}
+

pkg/common/adapters/router/mux.go

@@ -0,0 +1,208 @@
+package router
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"github.com/gorilla/mux"
+)
+
+// MuxAdapter adapts Gorilla Mux to work with our Router interface
+type MuxAdapter struct {
+	router *mux.Router
+}
+
+// NewMuxAdapter creates a new Mux adapter
+func NewMuxAdapter(router *mux.Router) *MuxAdapter {
+	return &MuxAdapter{router: router}
+}
+
+func (m *MuxAdapter) HandleFunc(pattern string, handler common.HTTPHandlerFunc) common.RouteRegistration {
+	route := &MuxRouteRegistration{
+		router:  m.router,
+		pattern: pattern,
+		handler: handler,
+	}
+	return route
+}
+
+func (m *MuxAdapter) ServeHTTP(w common.ResponseWriter, r common.Request) {
+	// This method would be used when we need to serve through our interface
+	// For now, we'll work directly with the underlying router
+	panic("ServeHTTP not implemented - use GetMuxRouter() for direct access")
+}
+
+// MuxRouteRegistration implements RouteRegistration for Mux
+type MuxRouteRegistration struct {
+	router  *mux.Router
+	pattern string
+	handler common.HTTPHandlerFunc
+	route   *mux.Route
+}
+
+func (m *MuxRouteRegistration) Methods(methods ...string) common.RouteRegistration {
+	if m.route == nil {
+		m.route = m.router.HandleFunc(m.pattern, func(w http.ResponseWriter, r *http.Request) {
+			reqAdapter := &HTTPRequest{req: r, vars: mux.Vars(r)}
+			respAdapter := &HTTPResponseWriter{resp: w}
+			m.handler(respAdapter, reqAdapter)
+		})
+	}
+	m.route.Methods(methods...)
+	return m
+}
+
+func (m *MuxRouteRegistration) PathPrefix(prefix string) common.RouteRegistration {
+	if m.route == nil {
+		m.route = m.router.HandleFunc(m.pattern, func(w http.ResponseWriter, r *http.Request) {
+			reqAdapter := &HTTPRequest{req: r, vars: mux.Vars(r)}
+			respAdapter := &HTTPResponseWriter{resp: w}
+			m.handler(respAdapter, reqAdapter)
+		})
+	}
+	m.route.PathPrefix(prefix)
+	return m
+}
+
+// HTTPRequest adapts standard http.Request to our Request interface
+type HTTPRequest struct {
+	req  *http.Request
+	vars map[string]string
+	body []byte
+}
+
+func NewHTTPRequest(r *http.Request) *HTTPRequest {
+	return &HTTPRequest{
+		req:  r,
+		vars: make(map[string]string),
+	}
+}
+
+func (h *HTTPRequest) Method() string {
+	return h.req.Method
+}
+
+func (h *HTTPRequest) URL() string {
+	return h.req.URL.String()
+}
+
+func (h *HTTPRequest) Header(key string) string {
+	return h.req.Header.Get(key)
+}
+
+func (h *HTTPRequest) Body() ([]byte, error) {
+	if h.body != nil {
+		return h.body, nil
+	}
+	if h.req.Body == nil {
+		return nil, nil
+	}
+	defer h.req.Body.Close()
+	body, err := io.ReadAll(h.req.Body)
+	if err != nil {
+		return nil, err
+	}
+	h.body = body
+	return body, nil
+}
+
+func (h *HTTPRequest) PathParam(key string) string {
+	return h.vars[key]
+}
+
+func (h *HTTPRequest) QueryParam(key string) string {
+	return h.req.URL.Query().Get(key)
+}
+
+func (h *HTTPRequest) AllHeaders() map[string]string {
+	headers := make(map[string]string)
+	for key, values := range h.req.Header {
+		if len(values) > 0 {
+			headers[key] = values[0]
+		}
+	}
+	return headers
+}
+
+// HTTPResponseWriter adapts our ResponseWriter interface to standard http.ResponseWriter
+type HTTPResponseWriter struct {
+	resp   http.ResponseWriter
+	w      common.ResponseWriter
+	status int
+}
+
+func NewHTTPResponseWriter(w http.ResponseWriter) *HTTPResponseWriter {
+	return &HTTPResponseWriter{resp: w}
+}
+
+func (h *HTTPResponseWriter) SetHeader(key, value string) {
+	h.resp.Header().Set(key, value)
+}
+
+func (h *HTTPResponseWriter) WriteHeader(statusCode int) {
+	h.status = statusCode
+	h.resp.WriteHeader(statusCode)
+}
+
+func (h *HTTPResponseWriter) Write(data []byte) (int, error) {
+	return h.resp.Write(data)
+}
+
+func (h *HTTPResponseWriter) WriteJSON(data interface{}) error {
+	h.SetHeader("Content-Type", "application/json")
+	return json.NewEncoder(h.resp).Encode(data)
+}
+
+// StandardMuxAdapter creates routes compatible with standard http.HandlerFunc
+type StandardMuxAdapter struct {
+	*MuxAdapter
+}
+
+func NewStandardMuxAdapter() *StandardMuxAdapter {
+	return &StandardMuxAdapter{
+		MuxAdapter: NewMuxAdapter(mux.NewRouter()),
+	}
+}
+
+// RegisterRoute registers a route that works with the existing Handler
+func (s *StandardMuxAdapter) RegisterRoute(pattern string, handler func(http.ResponseWriter, *http.Request, map[string]string)) *mux.Route {
+	return s.router.HandleFunc(pattern, func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		handler(w, r, vars)
+	})
+}
+
+// GetMuxRouter returns the underlying mux router for direct access
+func (s *StandardMuxAdapter) GetMuxRouter() *mux.Router {
+	return s.router
+}
+
+// PathParamExtractor extracts path parameters from different router types
+type PathParamExtractor interface {
+	ExtractParams(*http.Request) map[string]string
+}
+
+// MuxParamExtractor extracts parameters from Gorilla Mux
+type MuxParamExtractor struct{}
+
+func (m MuxParamExtractor) ExtractParams(r *http.Request) map[string]string {
+	return mux.Vars(r)
+}
+
+// RouterConfig holds router configuration
+type RouterConfig struct {
+	PathPrefix     string
+	Middleware     []func(http.Handler) http.Handler
+	ParamExtractor PathParamExtractor
+}
+
+// DefaultRouterConfig returns default router configuration
+func DefaultRouterConfig() *RouterConfig {
+	return &RouterConfig{
+		PathPrefix:     "",
+		Middleware:     make([]func(http.Handler) http.Handler, 0),
+		ParamExtractor: MuxParamExtractor{},
+	}
+}

pkg/common/interfaces.go

@@ -0,0 +1,137 @@
+package common
+
+import "context"
+
+// Database interface designed to work with both GORM and Bun
+type Database interface {
+	// Core query operations
+	NewSelect() SelectQuery
+	NewInsert() InsertQuery
+	NewUpdate() UpdateQuery
+	NewDelete() DeleteQuery
+
+	// Raw SQL execution
+	Exec(ctx context.Context, query string, args ...interface{}) (Result, error)
+	Query(ctx context.Context, dest interface{}, query string, args ...interface{}) error
+
+	// Transaction support
+	BeginTx(ctx context.Context) (Database, error)
+	CommitTx(ctx context.Context) error
+	RollbackTx(ctx context.Context) error
+	RunInTransaction(ctx context.Context, fn func(Database) error) error
+}
+
+// SelectQuery interface for building SELECT queries (compatible with both GORM and Bun)
+type SelectQuery interface {
+	Model(model interface{}) SelectQuery
+	Table(table string) SelectQuery
+	Column(columns ...string) SelectQuery
+	Where(query string, args ...interface{}) SelectQuery
+	WhereOr(query string, args ...interface{}) SelectQuery
+	Join(query string, args ...interface{}) SelectQuery
+	LeftJoin(query string, args ...interface{}) SelectQuery
+	Preload(relation string, conditions ...interface{}) SelectQuery
+	Order(order string) SelectQuery
+	Limit(n int) SelectQuery
+	Offset(n int) SelectQuery
+	Group(group string) SelectQuery
+	Having(having string, args ...interface{}) SelectQuery
+
+	// Execution methods
+	Scan(ctx context.Context, dest interface{}) error
+	Count(ctx context.Context) (int, error)
+	Exists(ctx context.Context) (bool, error)
+}
+
+// InsertQuery interface for building INSERT queries
+type InsertQuery interface {
+	Model(model interface{}) InsertQuery
+	Table(table string) InsertQuery
+	Value(column string, value interface{}) InsertQuery
+	OnConflict(action string) InsertQuery
+	Returning(columns ...string) InsertQuery
+
+	// Execution
+	Exec(ctx context.Context) (Result, error)
+}
+
+// UpdateQuery interface for building UPDATE queries
+type UpdateQuery interface {
+	Model(model interface{}) UpdateQuery
+	Table(table string) UpdateQuery
+	Set(column string, value interface{}) UpdateQuery
+	SetMap(values map[string]interface{}) UpdateQuery
+	Where(query string, args ...interface{}) UpdateQuery
+	Returning(columns ...string) UpdateQuery
+
+	// Execution
+	Exec(ctx context.Context) (Result, error)
+}
+
+// DeleteQuery interface for building DELETE queries
+type DeleteQuery interface {
+	Model(model interface{}) DeleteQuery
+	Table(table string) DeleteQuery
+	Where(query string, args ...interface{}) DeleteQuery
+
+	// Execution
+	Exec(ctx context.Context) (Result, error)
+}
+
+// Result interface for query execution results
+type Result interface {
+	RowsAffected() int64
+	LastInsertId() (int64, error)
+}
+
+// ModelRegistry manages model registration and retrieval
+type ModelRegistry interface {
+	RegisterModel(name string, model interface{}) error
+	GetModel(name string) (interface{}, error)
+	GetAllModels() map[string]interface{}
+	GetModelByEntity(schema, entity string) (interface{}, error)
+}
+
+// Router interface for HTTP router abstraction
+type Router interface {
+	HandleFunc(pattern string, handler HTTPHandlerFunc) RouteRegistration
+	ServeHTTP(w ResponseWriter, r Request)
+}
+
+// RouteRegistration allows method chaining for route configuration
+type RouteRegistration interface {
+	Methods(methods ...string) RouteRegistration
+	PathPrefix(prefix string) RouteRegistration
+}
+
+// Request interface abstracts HTTP request
+type Request interface {
+	Method() string
+	URL() string
+	Header(key string) string
+	AllHeaders() map[string]string // Get all headers as a map
+	Body() ([]byte, error)
+	PathParam(key string) string
+	QueryParam(key string) string
+}
+
+// ResponseWriter interface abstracts HTTP response
+type ResponseWriter interface {
+	SetHeader(key, value string)
+	WriteHeader(statusCode int)
+	Write(data []byte) (int, error)
+	WriteJSON(data interface{}) error
+}
+
+// HTTPHandlerFunc type for HTTP handlers
+type HTTPHandlerFunc func(ResponseWriter, Request)
+
+// TableNameProvider interface for models that provide table names
+type TableNameProvider interface {
+	TableName() string
+}
+
+// SchemaProvider interface for models that provide schema names
+type SchemaProvider interface {
+	SchemaName() string
+}

pkg/common/types.go

@@ -1,4 +1,4 @@
-package resolvespec
+package common
 
 type RequestBody struct {
 	Operation string         `json:"operation"`

pkg/modelregistry/model_registry.go

@@ -0,0 +1,119 @@
+package modelregistry
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+)
+
+// DefaultModelRegistry implements ModelRegistry interface
+type DefaultModelRegistry struct {
+	models map[string]interface{}
+	mutex  sync.RWMutex
+}
+
+// Global default registry instance
+var defaultRegistry = &DefaultModelRegistry{
+	models: make(map[string]interface{}),
+}
+
+// NewModelRegistry creates a new model registry
+func NewModelRegistry() *DefaultModelRegistry {
+	return &DefaultModelRegistry{
+		models: make(map[string]interface{}),
+	}
+}
+
+func (r *DefaultModelRegistry) RegisterModel(name string, model interface{}) error {
+	r.mutex.Lock()
+	defer r.mutex.Unlock()
+
+	if _, exists := r.models[name]; exists {
+		return fmt.Errorf("model %s already registered", name)
+	}
+
+	// Validate that model is a non-pointer struct
+	modelType := reflect.TypeOf(model)
+	if modelType == nil {
+		return fmt.Errorf("model cannot be nil")
+	}
+
+	if modelType.Kind() == reflect.Ptr {
+		return fmt.Errorf("model must be a non-pointer struct, got pointer to %s", modelType.Elem().Kind())
+	}
+
+	if modelType.Kind() != reflect.Struct {
+		return fmt.Errorf("model must be a struct, got %s", modelType.Kind())
+	}
+
+	r.models[name] = model
+	return nil
+}
+
+func (r *DefaultModelRegistry) GetModel(name string) (interface{}, error) {
+	r.mutex.RLock()
+	defer r.mutex.RUnlock()
+	
+	model, exists := r.models[name]
+	if !exists {
+		return nil, fmt.Errorf("model %s not found", name)
+	}
+	
+	return model, nil
+}
+
+func (r *DefaultModelRegistry) GetAllModels() map[string]interface{} {
+	r.mutex.RLock()
+	defer r.mutex.RUnlock()
+	
+	result := make(map[string]interface{})
+	for k, v := range r.models {
+		result[k] = v
+	}
+	return result
+}
+
+func (r *DefaultModelRegistry) GetModelByEntity(schema, entity string) (interface{}, error) {
+	// Try full name first
+	fullName := fmt.Sprintf("%s.%s", schema, entity)
+	if model, err := r.GetModel(fullName); err == nil {
+		return model, nil
+	}
+
+	// Fallback to entity name only
+	return r.GetModel(entity)
+}
+
+// Global convenience functions using the default registry
+
+// RegisterModel registers a model with the default global registry
+func RegisterModel(model interface{}, name string) error {
+	return defaultRegistry.RegisterModel(name, model)
+}
+
+// GetModelByName retrieves a model from the default global registry by name
+func GetModelByName(name string) (interface{}, error) {
+	return defaultRegistry.GetModel(name)
+}
+
+// IterateModels iterates over all models in the default global registry
+func IterateModels(fn func(name string, model interface{})) {
+	defaultRegistry.mutex.RLock()
+	defer defaultRegistry.mutex.RUnlock()
+
+	for name, model := range defaultRegistry.models {
+		fn(name, model)
+	}
+}
+
+// GetModels returns a list of all models in the default global registry
+func GetModels() []interface{} {
+	defaultRegistry.mutex.RLock()
+	defer defaultRegistry.mutex.RUnlock()
+
+	models := make([]interface{}, 0, len(defaultRegistry.models))
+	for _, model := range defaultRegistry.models {
+		models = append(models, model)
+	}
+	return models
+}

pkg/models/registry.go

@@ -1,71 +0,0 @@
-package models
-
-import (
-	"fmt"
-	"reflect"
-	"sync"
-)
-
-var (
-	modelRegistry      = make(map[string]interface{})
-	functionRegistry   = make(map[string]interface{})
-	modelRegistryMutex sync.RWMutex
-	funcRegistryMutex  sync.RWMutex
-)
-
-// RegisterModel registers a model type with the registry
-// The model must be a struct or a pointer to a struct
-// e.g RegisterModel(&ModelPublicUser{},"public.user")
-func RegisterModel(model interface{}, name string) error {
-	modelRegistryMutex.Lock()
-	defer modelRegistryMutex.Unlock()
-
-	modelType := reflect.TypeOf(model)
-	if modelType.Kind() == reflect.Ptr {
-		modelType = modelType.Elem()
-	}
-	if name == "" {
-		name = modelType.Name()
-	}
-	modelRegistry[name] = model
-	return nil
-}
-
-// RegisterFunction register a function with the registry
-func RegisterFunction(fn interface{}, name string) {
-	funcRegistryMutex.Lock()
-	defer funcRegistryMutex.Unlock()
-	functionRegistry[name] = fn
-}
-
-// GetModelByName retrieves a model from the registry by its type name
-func GetModelByName(name string) (interface{}, error) {
-	modelRegistryMutex.RLock()
-	defer modelRegistryMutex.RUnlock()
-
-	if modelRegistry[name] == nil {
-		return nil, fmt.Errorf("model not found: %s", name)
-	}
-	return modelRegistry[name], nil
-}
-
-// IterateModels iterates over all models in the registry
-func IterateModels(fn func(name string, model interface{})) {
-	modelRegistryMutex.RLock()
-	defer modelRegistryMutex.RUnlock()
-
-	for name, model := range modelRegistry {
-		fn(name, model)
-	}
-}
-
-// GetModels returns a list of all models in the registry
-func GetModels() []interface{} {
-	models := make([]interface{}, 0)
-	modelRegistryMutex.RLock()
-	defer modelRegistryMutex.RUnlock()
-	for _, model := range modelRegistry {
-		models = append(models, model)
-	}
-	return models
-}

pkg/resolvespec/apiHandler.go

@@ -1,91 +0,0 @@
-package resolvespec
-
-import (
-	"encoding/json"
-	"fmt"
-	"io"
-	"net/http"
-
-	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-	"gorm.io/gorm"
-)
-
-type HandlerFunc func(http.ResponseWriter, *http.Request)
-
-type APIHandler struct {
-	db *gorm.DB
-}
-
-// NewAPIHandler creates a new API handler instance
-func NewAPIHandler(db *gorm.DB) *APIHandler {
-	return &APIHandler{
-		db: db,
-	}
-}
-
-// Main handler method
-func (h *APIHandler) Handle(w http.ResponseWriter, r *http.Request, params map[string]string) {
-	var req RequestBody
-
-	if r.Body == nil {
-		logger.Error("No body to decode")
-		h.sendError(w, http.StatusBadRequest, "invalid_request", "No body to decode", nil)
-		return
-	} else {
-		defer r.Body.Close()
-	}
-	if bodyContents, err := io.ReadAll(r.Body); err != nil {
-		logger.Error("Failed to decode read body: %v", err)
-		h.sendError(w, http.StatusBadRequest, "read_request", "Invalid request body", err)
-		return
-	} else {
-		if err := json.Unmarshal(bodyContents, &req); err != nil {
-			logger.Error("Failed to decode request body: %v", err)
-			h.sendError(w, http.StatusBadRequest, "invalid_request", "Invalid request body", err)
-			return
-		}
-	}
-
-	schema := params["schema"]
-	entity := params["entity"]
-	id := params["id"]
-
-	logger.Info("Handling %s operation for %s.%s", req.Operation, schema, entity)
-
-	switch req.Operation {
-	case "read":
-		h.handleRead(w, r, schema, entity, id, req.Options)
-	case "create":
-		h.handleCreate(w, r, schema, entity, req.Data, req.Options)
-	case "update":
-		h.handleUpdate(w, r, schema, entity, id, req.ID, req.Data, req.Options)
-	case "delete":
-		h.handleDelete(w, r, schema, entity, id)
-	default:
-		logger.Error("Invalid operation: %s", req.Operation)
-		h.sendError(w, http.StatusBadRequest, "invalid_operation", "Invalid operation", nil)
-	}
-}
-
-func (h *APIHandler) sendResponse(w http.ResponseWriter, data interface{}, metadata *Metadata) {
-	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(Response{
-		Success:  true,
-		Data:     data,
-		Metadata: metadata,
-	})
-}
-
-func (h *APIHandler) sendError(w http.ResponseWriter, status int, code, message string, details interface{}) {
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(status)
-	json.NewEncoder(w).Encode(Response{
-		Success: false,
-		Error: &APIError{
-			Code:    code,
-			Message: message,
-			Details: details,
-			Detail:  fmt.Sprintf("%v", details),
-		},
-	})
-}

pkg/resolvespec/crud.go

@@ -1,250 +0,0 @@
-package resolvespec
-
-import (
-	"fmt"
-	"net/http"
-	"reflect"
-	"strings"
-
-	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-	"gorm.io/gorm"
-)
-
-// Read handler
-func (h *APIHandler) handleRead(w http.ResponseWriter, r *http.Request, schema, entity, id string, options RequestOptions) {
-	logger.Info("Reading records from %s.%s", schema, entity)
-
-	// Get the model struct for the entity
-	model, err := h.getModelForEntity(schema, entity)
-	if err != nil {
-		logger.Error("Invalid entity: %v", err)
-		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
-		return
-	}
-
-	GormTableNameInterface, ok := model.(GormTableNameInterface)
-	if !ok {
-		logger.Error("Model does not implement GormTableNameInterface")
-		h.sendError(w, http.StatusInternalServerError, "model_error", "Model does not implement GormTableNameInterface", nil)
-		return
-	}
-	query := h.db.Model(model).Table(GormTableNameInterface.TableName())
-
-	// Apply column selection
-	if len(options.Columns) > 0 {
-		logger.Debug("Selecting columns: %v", options.Columns)
-		query = query.Select(options.Columns)
-	}
-
-	// Apply preloading
-	for _, preload := range options.Preload {
-		logger.Debug("Applying preload for relation: %s", preload.Relation)
-		query = query.Preload(preload.Relation, func(db *gorm.DB) *gorm.DB {
-
-			if len(preload.Columns) > 0 {
-				db = db.Select(preload.Columns)
-			}
-			if len(preload.Filters) > 0 {
-				for _, filter := range preload.Filters {
-					db = h.applyFilter(db, filter)
-				}
-			}
-			return db
-		})
-
-	}
-
-	// Apply filters
-	for _, filter := range options.Filters {
-		logger.Debug("Applying filter: %s %s %v", filter.Column, filter.Operator, filter.Value)
-		query = h.applyFilter(query, filter)
-	}
-
-	// Apply sorting
-	for _, sort := range options.Sort {
-		direction := "ASC"
-		if strings.ToLower(sort.Direction) == "desc" {
-			direction = "DESC"
-		}
-		logger.Debug("Applying sort: %s %s", sort.Column, direction)
-		query = query.Order(fmt.Sprintf("%s %s", sort.Column, direction))
-	}
-
-	// Get total count before pagination
-	var total int64
-	if err := query.Count(&total).Error; err != nil {
-		logger.Error("Error counting records: %v", err)
-		h.sendError(w, http.StatusInternalServerError, "query_error", "Error counting records", err)
-		return
-	}
-	logger.Debug("Total records before filtering: %d", total)
-
-	// Apply pagination
-	if options.Limit != nil && *options.Limit > 0 {
-		logger.Debug("Applying limit: %d", *options.Limit)
-		query = query.Limit(*options.Limit)
-	}
-	if options.Offset != nil && *options.Offset > 0 {
-		logger.Debug("Applying offset: %d", *options.Offset)
-		query = query.Offset(*options.Offset)
-	}
-
-	// Execute query
-	var result interface{}
-	if id != "" {
-		logger.Debug("Querying single record with ID: %s", id)
-		singleResult := model
-		if err := query.First(singleResult, id).Error; err != nil {
-			if err == gorm.ErrRecordNotFound {
-				logger.Warn("Record not found with ID: %s", id)
-				h.sendError(w, http.StatusNotFound, "not_found", "Record not found", nil)
-				return
-			}
-			logger.Error("Error querying record: %v", err)
-			h.sendError(w, http.StatusInternalServerError, "query_error", "Error executing query", err)
-			return
-		}
-		result = singleResult
-	} else {
-		logger.Debug("Querying multiple records")
-		sliceType := reflect.SliceOf(reflect.TypeOf(model))
-		results := reflect.New(sliceType).Interface()
-
-		if err := query.Find(results).Error; err != nil {
-			logger.Error("Error querying records: %v", err)
-			h.sendError(w, http.StatusInternalServerError, "query_error", "Error executing query", err)
-			return
-		}
-		result = reflect.ValueOf(results).Elem().Interface()
-	}
-
-	logger.Info("Successfully retrieved records")
-	h.sendResponse(w, result, &Metadata{
-		Total:    total,
-		Filtered: total,
-		Limit:    optionalInt(options.Limit),
-		Offset:   optionalInt(options.Offset),
-	})
-}
-
-// Create handler
-func (h *APIHandler) handleCreate(w http.ResponseWriter, r *http.Request, schema, entity string, data any, options RequestOptions) {
-	logger.Info("Creating records for %s.%s", schema, entity)
-	query := h.db.Table(fmt.Sprintf("%s.%s", schema, entity))
-
-	switch v := data.(type) {
-	case map[string]interface{}:
-		result := query.Create(v)
-		if result.Error != nil {
-			logger.Error("Error creating record: %v", result.Error)
-			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating record", result.Error)
-			return
-		}
-		logger.Info("Successfully created record")
-		h.sendResponse(w, v, nil)
-
-	case []map[string]interface{}:
-		result := query.Create(v)
-		if result.Error != nil {
-			logger.Error("Error creating records: %v", result.Error)
-			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", result.Error)
-			return
-		}
-		logger.Info("Successfully created %d records", len(v))
-		h.sendResponse(w, v, nil)
-	case []interface{}:
-		list := make([]interface{}, 0)
-		for _, item := range v {
-			result := query.Create(item)
-			list = append(list, item)
-			if result.Error != nil {
-				logger.Error("Error creating records: %v", result.Error)
-				h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", result.Error)
-				return
-			}
-			logger.Info("Successfully created %d records", len(v))
-		}
-		h.sendResponse(w, list, nil)
-	default:
-		logger.Error("Invalid data type for create operation: %T", data)
-	}
-}
-
-// Update handler
-func (h *APIHandler) handleUpdate(w http.ResponseWriter, r *http.Request, schema, entity string, urlID string, reqID any, data any, options RequestOptions) {
-	logger.Info("Updating records for %s.%s", schema, entity)
-	query := h.db.Table(fmt.Sprintf("%s.%s", schema, entity))
-
-	switch {
-	case urlID != "":
-		logger.Debug("Updating by URL ID: %s", urlID)
-		result := query.Where("id = ?", urlID).Updates(data)
-		handleUpdateResult(w, h, result, data)
-
-	case reqID != nil:
-		switch id := reqID.(type) {
-		case string:
-			logger.Debug("Updating by request ID: %s", id)
-			result := query.Where("id = ?", id).Updates(data)
-			handleUpdateResult(w, h, result, data)
-
-		case []string:
-			logger.Debug("Updating by multiple IDs: %v", id)
-			result := query.Where("id IN ?", id).Updates(data)
-			handleUpdateResult(w, h, result, data)
-		}
-
-	case data != nil:
-		switch v := data.(type) {
-		case []map[string]interface{}:
-			logger.Debug("Performing bulk update with %d records", len(v))
-			err := h.db.Transaction(func(tx *gorm.DB) error {
-				for _, item := range v {
-					if id, ok := item["id"].(string); ok {
-						if err := tx.Where("id = ?", id).Updates(item).Error; err != nil {
-							logger.Error("Error in bulk update transaction: %v", err)
-							return err
-						}
-					}
-				}
-				return nil
-			})
-			if err != nil {
-				h.sendError(w, http.StatusInternalServerError, "update_error", "Error in bulk update", err)
-				return
-			}
-			logger.Info("Bulk update completed successfully")
-			h.sendResponse(w, data, nil)
-		}
-	default:
-		logger.Error("Invalid data type for update operation: %T", data)
-
-	}
-}
-
-// Delete handler
-func (h *APIHandler) handleDelete(w http.ResponseWriter, r *http.Request, schema, entity, id string) {
-	logger.Info("Deleting records from %s.%s", schema, entity)
-	query := h.db.Table(fmt.Sprintf("%s.%s", schema, entity))
-
-	if id == "" {
-		logger.Error("Delete operation requires an ID")
-		h.sendError(w, http.StatusBadRequest, "missing_id", "Delete operation requires an ID", nil)
-		return
-	}
-
-	result := query.Delete("id = ?", id)
-	if result.Error != nil {
-		logger.Error("Error deleting record: %v", result.Error)
-		h.sendError(w, http.StatusInternalServerError, "delete_error", "Error deleting record", result.Error)
-		return
-	}
-	if result.RowsAffected == 0 {
-		logger.Warn("No record found to delete with ID: %s", id)
-		h.sendError(w, http.StatusNotFound, "not_found", "Record not found", nil)
-		return
-	}
-
-	logger.Info("Successfully deleted record with ID: %s", id)
-	h.sendResponse(w, nil, nil)
-}

pkg/resolvespec/handler.go

@@ -0,0 +1,620 @@
+package resolvespec
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"reflect"
+	"strings"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
+)
+
+// Handler handles API requests using database and model abstractions
+type Handler struct {
+	db       common.Database
+	registry common.ModelRegistry
+}
+
+// NewHandler creates a new API handler with database and registry abstractions
+func NewHandler(db common.Database, registry common.ModelRegistry) *Handler {
+	return &Handler{
+		db:       db,
+		registry: registry,
+	}
+}
+
+// Handle processes API requests through router-agnostic interface
+func (h *Handler) Handle(w common.ResponseWriter, r common.Request, params map[string]string) {
+	ctx := context.Background()
+
+	body, err := r.Body()
+	if err != nil {
+		logger.Error("Failed to read request body: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_request", "Failed to read request body", err)
+		return
+	}
+
+	var req common.RequestBody
+	if err := json.Unmarshal(body, &req); err != nil {
+		logger.Error("Failed to decode request body: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_request", "Invalid request body", err)
+		return
+	}
+
+	schema := params["schema"]
+	entity := params["entity"]
+	id := params["id"]
+
+	logger.Info("Handling %s operation for %s.%s", req.Operation, schema, entity)
+
+	switch req.Operation {
+	case "read":
+		h.handleRead(ctx, w, schema, entity, id, req.Options)
+	case "create":
+		h.handleCreate(ctx, w, schema, entity, req.Data, req.Options)
+	case "update":
+		h.handleUpdate(ctx, w, schema, entity, id, req.ID, req.Data, req.Options)
+	case "delete":
+		h.handleDelete(ctx, w, schema, entity, id)
+	default:
+		logger.Error("Invalid operation: %s", req.Operation)
+		h.sendError(w, http.StatusBadRequest, "invalid_operation", "Invalid operation", nil)
+	}
+}
+
+// HandleGet processes GET requests for metadata
+func (h *Handler) HandleGet(w common.ResponseWriter, r common.Request, params map[string]string) {
+	schema := params["schema"]
+	entity := params["entity"]
+
+	logger.Info("Getting metadata for %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Failed to get model: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	metadata := h.generateMetadata(schema, entity, model)
+	h.sendResponse(w, metadata, nil)
+}
+
+func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, schema, entity, id string, options common.RequestOptions) {
+	logger.Info("Reading records from %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Invalid entity: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	// Model is now a non-pointer struct, create a pointer instance for ORM
+	modelType := reflect.TypeOf(model)
+	modelPtr := reflect.New(modelType).Interface()
+
+	query := h.db.NewSelect().Model(modelPtr)
+
+	// Get table name
+	tableName := h.getTableName(schema, entity, model)
+	query = query.Table(tableName)
+
+	// Apply column selection
+	if len(options.Columns) > 0 {
+		logger.Debug("Selecting columns: %v", options.Columns)
+		query = query.Column(options.Columns...)
+	}
+
+	// Apply preloading
+	if len(options.Preload) > 0 {
+		query = h.applyPreloads(model, query, options.Preload)
+	}
+
+	// Apply filters
+	for _, filter := range options.Filters {
+		logger.Debug("Applying filter: %s %s %v", filter.Column, filter.Operator, filter.Value)
+		query = h.applyFilter(query, filter)
+	}
+
+	// Apply sorting
+	for _, sort := range options.Sort {
+		direction := "ASC"
+		if strings.ToLower(sort.Direction) == "desc" {
+			direction = "DESC"
+		}
+		logger.Debug("Applying sort: %s %s", sort.Column, direction)
+		query = query.Order(fmt.Sprintf("%s %s", sort.Column, direction))
+	}
+
+	// Get total count before pagination
+	total, err := query.Count(ctx)
+	if err != nil {
+		logger.Error("Error counting records: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "query_error", "Error counting records", err)
+		return
+	}
+	logger.Debug("Total records before filtering: %d", total)
+
+	// Apply pagination
+	if options.Limit != nil && *options.Limit > 0 {
+		logger.Debug("Applying limit: %d", *options.Limit)
+		query = query.Limit(*options.Limit)
+	}
+	if options.Offset != nil && *options.Offset > 0 {
+		logger.Debug("Applying offset: %d", *options.Offset)
+		query = query.Offset(*options.Offset)
+	}
+
+	// Execute query
+	var result interface{}
+	if id != "" {
+		logger.Debug("Querying single record with ID: %s", id)
+		// Create a pointer to the struct type for scanning
+		singleResult := reflect.New(modelType).Interface()
+		query = query.Where("id = ?", id)
+		if err := query.Scan(ctx, singleResult); err != nil {
+			logger.Error("Error querying record: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "query_error", "Error executing query", err)
+			return
+		}
+		result = singleResult
+	} else {
+		logger.Debug("Querying multiple records")
+		// Create a slice of the struct type (not pointers)
+		sliceType := reflect.SliceOf(modelType)
+		results := reflect.New(sliceType).Interface()
+
+		if err := query.Scan(ctx, results); err != nil {
+			logger.Error("Error querying records: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "query_error", "Error executing query", err)
+			return
+		}
+		result = reflect.ValueOf(results).Elem().Interface()
+	}
+
+	logger.Info("Successfully retrieved records")
+
+	limit := 0
+	if options.Limit != nil {
+		limit = *options.Limit
+	}
+	offset := 0
+	if options.Offset != nil {
+		offset = *options.Offset
+	}
+
+	h.sendResponse(w, result, &common.Metadata{
+		Total:    int64(total),
+		Filtered: int64(total),
+		Limit:    limit,
+		Offset:   offset,
+	})
+}
+
+func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, schema, entity string, data interface{}, options common.RequestOptions) {
+	logger.Info("Creating records for %s.%s", schema, entity)
+
+	// Get the model to determine the actual table name
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Warn("Model not found, using default table name")
+		model = nil
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+	query := h.db.NewInsert().Table(tableName)
+
+	switch v := data.(type) {
+	case map[string]interface{}:
+		for key, value := range v {
+			query = query.Value(key, value)
+		}
+		result, err := query.Exec(ctx)
+		if err != nil {
+			logger.Error("Error creating record: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating record", err)
+			return
+		}
+		logger.Info("Successfully created record, rows affected: %d", result.RowsAffected())
+		h.sendResponse(w, v, nil)
+
+	case []map[string]interface{}:
+		err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
+			for _, item := range v {
+				txQuery := tx.NewInsert().Table(tableName)
+				for key, value := range item {
+					txQuery = txQuery.Value(key, value)
+				}
+				if _, err := txQuery.Exec(ctx); err != nil {
+					return err
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			logger.Error("Error creating records: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
+			return
+		}
+		logger.Info("Successfully created %d records", len(v))
+		h.sendResponse(w, v, nil)
+
+	case []interface{}:
+		// Handle []interface{} type from JSON unmarshaling
+		list := make([]interface{}, 0)
+		err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
+			for _, item := range v {
+				if itemMap, ok := item.(map[string]interface{}); ok {
+					txQuery := tx.NewInsert().Table(tableName)
+					for key, value := range itemMap {
+						txQuery = txQuery.Value(key, value)
+					}
+					if _, err := txQuery.Exec(ctx); err != nil {
+						return err
+					}
+					list = append(list, item)
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			logger.Error("Error creating records: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
+			return
+		}
+		logger.Info("Successfully created %d records", len(v))
+		h.sendResponse(w, list, nil)
+
+	default:
+		logger.Error("Invalid data type for create operation: %T", data)
+		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data type for create operation", nil)
+	}
+}
+
+func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, schema, entity, urlID string, reqID interface{}, data interface{}, options common.RequestOptions) {
+	logger.Info("Updating records for %s.%s", schema, entity)
+
+	// Get the model to determine the actual table name
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Warn("Model not found, using default table name")
+		// Fallback to entity name (without schema for SQLite compatibility)
+		model = nil
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+	query := h.db.NewUpdate().Table(tableName)
+
+	switch updates := data.(type) {
+	case map[string]interface{}:
+		query = query.SetMap(updates)
+	default:
+		logger.Error("Invalid data type for update operation: %T", data)
+		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data type for update operation", nil)
+		return
+	}
+
+	// Apply conditions
+	if urlID != "" {
+		logger.Debug("Updating by URL ID: %s", urlID)
+		query = query.Where("id = ?", urlID)
+	} else if reqID != nil {
+		switch id := reqID.(type) {
+		case string:
+			logger.Debug("Updating by request ID: %s", id)
+			query = query.Where("id = ?", id)
+		case []string:
+			logger.Debug("Updating by multiple IDs: %v", id)
+			query = query.Where("id IN (?)", id)
+		}
+	}
+
+	result, err := query.Exec(ctx)
+	if err != nil {
+		logger.Error("Update error: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "update_error", "Error updating record(s)", err)
+		return
+	}
+
+	if result.RowsAffected() == 0 {
+		logger.Warn("No records found to update")
+		h.sendError(w, http.StatusNotFound, "not_found", "No records found to update", nil)
+		return
+	}
+
+	logger.Info("Successfully updated %d records", result.RowsAffected())
+	h.sendResponse(w, data, nil)
+}
+
+func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, schema, entity, id string) {
+	logger.Info("Deleting records from %s.%s", schema, entity)
+
+	if id == "" {
+		logger.Error("Delete operation requires an ID")
+		h.sendError(w, http.StatusBadRequest, "missing_id", "Delete operation requires an ID", nil)
+		return
+	}
+
+	// Get the model to determine the actual table name
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Warn("Model not found, using default table name")
+		model = nil
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+	query := h.db.NewDelete().Table(tableName).Where("id = ?", id)
+
+	result, err := query.Exec(ctx)
+	if err != nil {
+		logger.Error("Error deleting record: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "delete_error", "Error deleting record", err)
+		return
+	}
+
+	if result.RowsAffected() == 0 {
+		logger.Warn("No record found to delete with ID: %s", id)
+		h.sendError(w, http.StatusNotFound, "not_found", "Record not found", nil)
+		return
+	}
+
+	logger.Info("Successfully deleted record with ID: %s", id)
+	h.sendResponse(w, nil, nil)
+}
+
+func (h *Handler) applyFilter(query common.SelectQuery, filter common.FilterOption) common.SelectQuery {
+	switch filter.Operator {
+	case "eq":
+		return query.Where(fmt.Sprintf("%s = ?", filter.Column), filter.Value)
+	case "neq":
+		return query.Where(fmt.Sprintf("%s != ?", filter.Column), filter.Value)
+	case "gt":
+		return query.Where(fmt.Sprintf("%s > ?", filter.Column), filter.Value)
+	case "gte":
+		return query.Where(fmt.Sprintf("%s >= ?", filter.Column), filter.Value)
+	case "lt":
+		return query.Where(fmt.Sprintf("%s < ?", filter.Column), filter.Value)
+	case "lte":
+		return query.Where(fmt.Sprintf("%s <= ?", filter.Column), filter.Value)
+	case "like":
+		return query.Where(fmt.Sprintf("%s LIKE ?", filter.Column), filter.Value)
+	case "ilike":
+		return query.Where(fmt.Sprintf("%s ILIKE ?", filter.Column), filter.Value)
+	case "in":
+		return query.Where(fmt.Sprintf("%s IN (?)", filter.Column), filter.Value)
+	default:
+		return query
+	}
+}
+
+func (h *Handler) getTableName(schema, entity string, model interface{}) string {
+	if provider, ok := model.(common.TableNameProvider); ok {
+		return provider.TableName()
+	}
+	return fmt.Sprintf("%s.%s", schema, entity)
+}
+
+func (h *Handler) generateMetadata(schema, entity string, model interface{}) *common.TableMetadata {
+	modelType := reflect.TypeOf(model)
+	if modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	metadata := &common.TableMetadata{
+		Schema:    schema,
+		Table:     entity,
+		Columns:   make([]common.Column, 0),
+		Relations: make([]string, 0),
+	}
+
+	// Generate metadata using reflection (same logic as before)
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+
+		if !field.IsExported() {
+			continue
+		}
+
+		gormTag := field.Tag.Get("gorm")
+		jsonTag := field.Tag.Get("json")
+
+		if jsonTag == "-" {
+			continue
+		}
+
+		jsonName := strings.Split(jsonTag, ",")[0]
+		if jsonName == "" {
+			jsonName = field.Name
+		}
+
+		if field.Type.Kind() == reflect.Slice ||
+			(field.Type.Kind() == reflect.Struct && field.Type.Name() != "Time") {
+			metadata.Relations = append(metadata.Relations, jsonName)
+			continue
+		}
+
+		column := common.Column{
+			Name:       jsonName,
+			Type:       getColumnType(field),
+			IsNullable: isNullable(field),
+			IsPrimary:  strings.Contains(gormTag, "primaryKey"),
+			IsUnique:   strings.Contains(gormTag, "unique") || strings.Contains(gormTag, "uniqueIndex"),
+			HasIndex:   strings.Contains(gormTag, "index") || strings.Contains(gormTag, "uniqueIndex"),
+		}
+
+		metadata.Columns = append(metadata.Columns, column)
+	}
+
+	return metadata
+}
+
+func (h *Handler) sendResponse(w common.ResponseWriter, data interface{}, metadata *common.Metadata) {
+	w.SetHeader("Content-Type", "application/json")
+	w.WriteJSON(common.Response{
+		Success:  true,
+		Data:     data,
+		Metadata: metadata,
+	})
+}
+
+func (h *Handler) sendError(w common.ResponseWriter, status int, code, message string, details interface{}) {
+	w.SetHeader("Content-Type", "application/json")
+	w.WriteHeader(status)
+	w.WriteJSON(common.Response{
+		Success: false,
+		Error: &common.APIError{
+			Code:    code,
+			Message: message,
+			Details: details,
+			Detail:  fmt.Sprintf("%v", details),
+		},
+	})
+}
+
+// RegisterModel allows registering models at runtime
+func (h *Handler) RegisterModel(schema, name string, model interface{}) error {
+	fullname := fmt.Sprintf("%s.%s", schema, name)
+	return h.registry.RegisterModel(fullname, model)
+}
+
+// Helper functions
+
+func getColumnType(field reflect.StructField) string {
+	// Check GORM type tag first
+	gormTag := field.Tag.Get("gorm")
+	if strings.Contains(gormTag, "type:") {
+		parts := strings.Split(gormTag, "type:")
+		if len(parts) > 1 {
+			typePart := strings.Split(parts[1], ";")[0]
+			return typePart
+		}
+	}
+
+	// Map Go types to SQL types
+	switch field.Type.Kind() {
+	case reflect.String:
+		return "string"
+	case reflect.Int, reflect.Int32:
+		return "integer"
+	case reflect.Int64:
+		return "bigint"
+	case reflect.Float32:
+		return "float"
+	case reflect.Float64:
+		return "double"
+	case reflect.Bool:
+		return "boolean"
+	default:
+		if field.Type.Name() == "Time" {
+			return "timestamp"
+		}
+		return "unknown"
+	}
+}
+
+func isNullable(field reflect.StructField) bool {
+	// Check if it's a pointer type
+	if field.Type.Kind() == reflect.Ptr {
+		return true
+	}
+
+	// Check if it's a null type from sql package
+	typeName := field.Type.Name()
+	if strings.HasPrefix(typeName, "Null") {
+		return true
+	}
+
+	// Check GORM tags
+	gormTag := field.Tag.Get("gorm")
+	return !strings.Contains(gormTag, "not null")
+}
+
+// Preload support functions
+
+type relationshipInfo struct {
+	fieldName    string
+	jsonName     string
+	relationType string // "belongsTo", "hasMany", "hasOne", "many2many"
+	foreignKey   string
+	references   string
+	joinTable    string
+	relatedModel interface{}
+}
+
+func (h *Handler) applyPreloads(model interface{}, query common.SelectQuery, preloads []common.PreloadOption) common.SelectQuery {
+	modelType := reflect.TypeOf(model)
+	if modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	for _, preload := range preloads {
+		logger.Debug("Processing preload for relation: %s", preload.Relation)
+		relInfo := h.getRelationshipInfo(modelType, preload.Relation)
+		if relInfo == nil {
+			logger.Warn("Relation %s not found in model", preload.Relation)
+			continue
+		}
+
+		// Use the field name (capitalized) for ORM preloading
+		// ORMs like GORM and Bun expect the struct field name, not the JSON name
+		relationFieldName := relInfo.fieldName
+
+		// For now, we'll preload without conditions
+		// TODO: Implement column selection and filtering for preloads
+		// This requires a more sophisticated approach with callbacks or query builders
+		query = query.Preload(relationFieldName)
+		logger.Debug("Applied Preload for relation: %s (field: %s)", preload.Relation, relationFieldName)
+	}
+
+	return query
+}
+
+func (h *Handler) getRelationshipInfo(modelType reflect.Type, relationName string) *relationshipInfo {
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+		jsonTag := field.Tag.Get("json")
+		jsonName := strings.Split(jsonTag, ",")[0]
+
+		if jsonName == relationName {
+			gormTag := field.Tag.Get("gorm")
+			info := &relationshipInfo{
+				fieldName: field.Name,
+				jsonName:  jsonName,
+			}
+
+			// Parse GORM tag to determine relationship type and keys
+			if strings.Contains(gormTag, "foreignKey") {
+				info.foreignKey = h.extractTagValue(gormTag, "foreignKey")
+				info.references = h.extractTagValue(gormTag, "references")
+
+				// Determine if it's belongsTo or hasMany/hasOne
+				if field.Type.Kind() == reflect.Slice {
+					info.relationType = "hasMany"
+				} else if field.Type.Kind() == reflect.Ptr || field.Type.Kind() == reflect.Struct {
+					info.relationType = "belongsTo"
+				}
+			} else if strings.Contains(gormTag, "many2many") {
+				info.relationType = "many2many"
+				info.joinTable = h.extractTagValue(gormTag, "many2many")
+			}
+
+			return info
+		}
+	}
+	return nil
+}
+
+func (h *Handler) extractTagValue(tag, key string) string {
+	parts := strings.Split(tag, ";")
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if strings.HasPrefix(part, key+":") {
+			return strings.TrimPrefix(part, key+":")
+		}
+	}
+	return ""
+}

pkg/resolvespec/interfaces.go

@@ -1,5 +1,6 @@
 package resolvespec
 
+// Legacy interfaces for backward compatibility
 type GormTableNameInterface interface {
 	TableName() string
 }
@@ -19,3 +20,8 @@ func (r *GormTableCRUDRequest) SetRequest(request string) {
 func (r GormTableCRUDRequest) GetRequest() string {
 	return *r.CRUDRequest
 }
+
+// New interfaces that replace the legacy ones above
+// These are now defined in database.go:
+// - TableNameProvider (replaces GormTableNameInterface)  
+// - SchemaProvider (replaces GormTableSchemaInterface)

pkg/resolvespec/meta.go

@@ -1,131 +0,0 @@
-package resolvespec
-
-import (
-	"net/http"
-	"reflect"
-	"strings"
-
-	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-)
-
-func (h *APIHandler) HandleGet(w http.ResponseWriter, r *http.Request, params map[string]string) {
-	schema := params["schema"]
-	entity := params["entity"]
-
-	logger.Info("Getting metadata for %s.%s", schema, entity)
-
-	// Get model for the entity
-	model, err := h.getModelForEntity(schema, entity)
-	if err != nil {
-		logger.Error("Failed to get model: %v", err)
-		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
-		return
-	}
-
-	modelType := reflect.TypeOf(model)
-	if modelType.Kind() == reflect.Ptr {
-		modelType = modelType.Elem()
-	}
-
-	metadata := TableMetadata{
-		Schema:    schema,
-		Table:     entity,
-		Columns:   make([]Column, 0),
-		Relations: make([]string, 0),
-	}
-
-	// Get field information using reflection
-	for i := 0; i < modelType.NumField(); i++ {
-		field := modelType.Field(i)
-
-		// Skip unexported fields
-		if !field.IsExported() {
-			continue
-		}
-
-		// Parse GORM tags
-		gormTag := field.Tag.Get("gorm")
-		jsonTag := field.Tag.Get("json")
-
-		// Skip if json tag is "-"
-		if jsonTag == "-" {
-			continue
-		}
-
-		// Get JSON field name
-		jsonName := strings.Split(jsonTag, ",")[0]
-		if jsonName == "" {
-			jsonName = field.Name
-		}
-
-		// Check if it's a relation
-		if field.Type.Kind() == reflect.Slice ||
-			(field.Type.Kind() == reflect.Struct && field.Type.Name() != "Time") {
-			metadata.Relations = append(metadata.Relations, jsonName)
-			continue
-		}
-
-		column := Column{
-			Name:       jsonName,
-			Type:       getColumnType(field),
-			IsNullable: isNullable(field),
-			IsPrimary:  strings.Contains(gormTag, "primaryKey"),
-			IsUnique:   strings.Contains(gormTag, "unique") || strings.Contains(gormTag, "uniqueIndex"),
-			HasIndex:   strings.Contains(gormTag, "index") || strings.Contains(gormTag, "uniqueIndex"),
-		}
-
-		metadata.Columns = append(metadata.Columns, column)
-	}
-
-	h.sendResponse(w, metadata, nil)
-}
-
-func getColumnType(field reflect.StructField) string {
-	// Check GORM type tag first
-	gormTag := field.Tag.Get("gorm")
-	if strings.Contains(gormTag, "type:") {
-		parts := strings.Split(gormTag, "type:")
-		if len(parts) > 1 {
-			typePart := strings.Split(parts[1], ";")[0]
-			return typePart
-		}
-	}
-
-	// Map Go types to SQL types
-	switch field.Type.Kind() {
-	case reflect.String:
-		return "string"
-	case reflect.Int, reflect.Int32:
-		return "integer"
-	case reflect.Int64:
-		return "bigint"
-	case reflect.Float32:
-		return "float"
-	case reflect.Float64:
-		return "double"
-	case reflect.Bool:
-		return "boolean"
-	default:
-		if field.Type.Name() == "Time" {
-			return "timestamp"
-		}
-		return "unknown"
-	}
-}
-
-func isNullable(field reflect.StructField) bool {
-	// Check if it's a pointer type
-	if field.Type.Kind() == reflect.Ptr {
-		return true
-	}
-
-	// Check if it's a null type from sql package
-	typeName := field.Type.Name()
-	if strings.HasPrefix(typeName, "Null") {
-		return true
-	}
-
-	// Check GORM tags
-	gormTag := field.Tag.Get("gorm")
-	return !strings.Contains(gormTag, "not null")
-}

pkg/resolvespec/resolvespec.go

@@ -0,0 +1,181 @@
+package resolvespec
+
+import (
+	"net/http"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common/adapters/database"
+	"github.com/Warky-Devs/ResolveSpec/pkg/common/adapters/router"
+	"github.com/Warky-Devs/ResolveSpec/pkg/modelregistry"
+	"github.com/gorilla/mux"
+	"github.com/uptrace/bun"
+	"github.com/uptrace/bunrouter"
+	"gorm.io/gorm"
+)
+
+// NewHandlerWithGORM creates a new Handler with GORM adapter
+func NewHandlerWithGORM(db *gorm.DB) *Handler {
+	gormAdapter := database.NewGormAdapter(db)
+	registry := modelregistry.NewModelRegistry()
+	return NewHandler(gormAdapter, registry)
+}
+
+// NewHandlerWithBun creates a new Handler with Bun adapter
+func NewHandlerWithBun(db *bun.DB) *Handler {
+	bunAdapter := database.NewBunAdapter(db)
+	registry := modelregistry.NewModelRegistry()
+	return NewHandler(bunAdapter, registry)
+}
+
+// NewStandardMuxRouter creates a router with standard Mux HTTP handlers
+func NewStandardMuxRouter() *router.StandardMuxAdapter {
+	return router.NewStandardMuxAdapter()
+}
+
+// NewStandardBunRouter creates a router with standard BunRouter handlers
+func NewStandardBunRouter() *router.StandardBunRouterAdapter {
+	return router.NewStandardBunRouterAdapter()
+}
+
+// SetupMuxRoutes sets up routes for the ResolveSpec API with Mux
+func SetupMuxRoutes(muxRouter *mux.Router, handler *Handler) {
+	muxRouter.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, vars)
+	}).Methods("POST")
+
+	muxRouter.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, vars)
+	}).Methods("POST")
+
+	muxRouter.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.HandleGet(respAdapter, reqAdapter, vars)
+	}).Methods("GET")
+}
+
+// Example usage functions for documentation:
+
+// ExampleWithGORM shows how to use ResolveSpec with GORM
+func ExampleWithGORM(db *gorm.DB) {
+	// Create handler using GORM
+	handler := NewHandlerWithGORM(db)
+
+	// Setup router
+	muxRouter := mux.NewRouter()
+	SetupMuxRoutes(muxRouter, handler)
+
+	// Register models
+	// handler.RegisterModel("public", "users", &User{})
+}
+
+// ExampleWithBun shows how to switch to Bun ORM
+func ExampleWithBun(bunDB *bun.DB) {
+	// Create Bun adapter
+	dbAdapter := database.NewBunAdapter(bunDB)
+
+	// Create model registry
+	registry := modelregistry.NewModelRegistry()
+	// registry.RegisterModel("public.users", &User{})
+
+	// Create handler
+	handler := NewHandler(dbAdapter, registry)
+
+	// Setup routes
+	muxRouter := mux.NewRouter()
+	SetupMuxRoutes(muxRouter, handler)
+}
+
+// SetupBunRouterRoutes sets up bunrouter routes for the ResolveSpec API
+func SetupBunRouterRoutes(bunRouter *router.StandardBunRouterAdapter, handler *Handler) {
+	r := bunRouter.GetBunRouter()
+
+	r.Handle("POST", "/:schema/:entity", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+		}
+		reqAdapter := router.NewHTTPRequest(req.Request)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("POST", "/:schema/:entity/:id", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+			"id":     req.Param("id"),
+		}
+		reqAdapter := router.NewHTTPRequest(req.Request)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("GET", "/:schema/:entity", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+		}
+		reqAdapter := router.NewHTTPRequest(req.Request)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.HandleGet(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("GET", "/:schema/:entity/:id", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+			"id":     req.Param("id"),
+		}
+		reqAdapter := router.NewHTTPRequest(req.Request)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.HandleGet(respAdapter, reqAdapter, params)
+		return nil
+	})
+}
+
+// ExampleWithBunRouter shows how to use bunrouter from uptrace
+func ExampleWithBunRouter(bunDB *bun.DB) {
+	// Create handler with Bun adapter
+	handler := NewHandlerWithBun(bunDB)
+
+	// Create bunrouter
+	bunRouter := router.NewStandardBunRouterAdapter()
+
+	// Setup ResolveSpec routes with bunrouter
+	SetupBunRouterRoutes(bunRouter, handler)
+
+	// Start server
+	// http.ListenAndServe(":8080", bunRouter.GetBunRouter())
+}
+
+// ExampleBunRouterWithBunDB shows the full uptrace stack (bunrouter + Bun ORM)
+func ExampleBunRouterWithBunDB(bunDB *bun.DB) {
+	// Create Bun database adapter
+	dbAdapter := database.NewBunAdapter(bunDB)
+
+	// Create model registry
+	registry := modelregistry.NewModelRegistry()
+	// registry.RegisterModel("public.users", &User{})
+
+	// Create handler with Bun
+	handler := NewHandler(dbAdapter, registry)
+
+	// Create bunrouter
+	bunRouter := router.NewStandardBunRouterAdapter()
+
+	// Setup ResolveSpec routes
+	SetupBunRouterRoutes(bunRouter, handler)
+
+	// This gives you the full uptrace stack: bunrouter + Bun ORM
+	// http.ListenAndServe(":8080", bunRouter.GetBunRouter())
+}

pkg/resolvespec/utils.go

@@ -1,78 +0,0 @@
-package resolvespec
-
-import (
-	"fmt"
-	"net/http"
-
-	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-	"github.com/Warky-Devs/ResolveSpec/pkg/models"
-	"gorm.io/gorm"
-)
-
-func handleUpdateResult(w http.ResponseWriter, h *APIHandler, result *gorm.DB, data interface{}) {
-	if result.Error != nil {
-		logger.Error("Update error: %v", result.Error)
-		h.sendError(w, http.StatusInternalServerError, "update_error", "Error updating record(s)", result.Error)
-		return
-	}
-	if result.RowsAffected == 0 {
-		logger.Warn("No records found to update")
-		h.sendError(w, http.StatusNotFound, "not_found", "No records found to update", nil)
-		return
-	}
-	logger.Info("Successfully updated %d records", result.RowsAffected)
-	h.sendResponse(w, data, nil)
-}
-
-func optionalInt(ptr *int) int {
-	if ptr == nil {
-		return 0
-	}
-	return *ptr
-}
-
-// Helper methods
-func (h *APIHandler) applyFilter(query *gorm.DB, filter FilterOption) *gorm.DB {
-	switch filter.Operator {
-	case "eq":
-		return query.Where(fmt.Sprintf("%s = ?", filter.Column), filter.Value)
-	case "neq":
-		return query.Where(fmt.Sprintf("%s != ?", filter.Column), filter.Value)
-	case "gt":
-		return query.Where(fmt.Sprintf("%s > ?", filter.Column), filter.Value)
-	case "gte":
-		return query.Where(fmt.Sprintf("%s >= ?", filter.Column), filter.Value)
-	case "lt":
-		return query.Where(fmt.Sprintf("%s < ?", filter.Column), filter.Value)
-	case "lte":
-		return query.Where(fmt.Sprintf("%s <= ?", filter.Column), filter.Value)
-	case "like":
-		return query.Where(fmt.Sprintf("%s LIKE ?", filter.Column), filter.Value)
-	case "ilike":
-		return query.Where(fmt.Sprintf("%s ILIKE ?", filter.Column), filter.Value)
-	case "in":
-		return query.Where(fmt.Sprintf("%s IN (?)", filter.Column), filter.Value)
-	default:
-		return query
-	}
-}
-
-func (h *APIHandler) getModelForEntity(schema, name string) (interface{}, error) {
-	model, err := models.GetModelByName(fmt.Sprintf("%s.%s", schema, name))
-
-	if err != nil {
-		model, err = models.GetModelByName(name)
-	}
-	return model, err
-}
-
-func (h *APIHandler) RegisterModel(schema, name string, model interface{}) error {
-	fullname := fmt.Sprintf("%s.%s", schema, name)
-	oldModel, err := models.GetModelByName(fullname)
-	if oldModel != nil && err != nil {
-		return fmt.Errorf("model %s already exists", fullname)
-	}
-	err = models.RegisterModel(model, fullname)
-
-	return err
-}

pkg/restheadspec/HEADERS.md

@@ -0,0 +1,614 @@
+# RestHeadSpec Headers Documentation
+
+RestHeadSpec provides a comprehensive header-based REST API where all query options are passed via HTTP headers instead of request body. This document describes all supported headers and their usage.
+
+## Overview
+
+RestHeadSpec uses HTTP headers for:
+- Field selection
+- Filtering and searching
+- Joins and relationship loading
+- Sorting and pagination
+- Advanced query features
+- Response formatting
+- Transaction control
+
+### Header Naming Convention
+
+All headers support **optional identifiers** at the end to allow multiple instances of the same header type. This is useful when you need to specify multiple related filters or options.
+
+**Examples:**
+```
+# Standard header
+x-preload: employees
+
+# Headers with identifiers (both work the same)
+x-preload-main: employees
+x-preload-secondary: department
+x-preload-1: projects
+```
+
+The system uses `strings.HasPrefix()` to match headers, so any suffix after the header name is ignored for matching purposes. This allows you to:
+- Add descriptive identifiers: `x-sort-primary`, `x-sort-fallback`
+- Add numeric identifiers: `x-fieldfilter-status-1`, `x-fieldfilter-status-2`
+- Organize related headers: `x-preload-employee-data`, `x-preload-department-info`
+
+## Header Categories
+
+### 1. Field Selection
+
+#### `x-select-fields`
+Specify which columns to include in the response.
+
+**Format:** Comma-separated list of column names
+```
+x-select-fields: id,name,email,created_at
+```
+
+#### `x-not-select-fields`
+Specify which columns to exclude from the response.
+
+**Format:** Comma-separated list of column names
+```
+x-not-select-fields: password,internal_notes
+```
+
+#### `x-clean-json`
+Remove null and empty fields from the response.
+
+**Format:** Boolean (true/false)
+```
+x-clean-json: true
+```
+
+---
+
+### 2. Filtering & Search
+
+#### `x-fieldfilter-{colname}`
+Exact match filter on a specific column.
+
+**Format:** `x-fieldfilter-{columnName}: {value}`
+```
+x-fieldfilter-status: active
+x-fieldfilter-department_id: dept123
+```
+
+#### `x-searchfilter-{colname}`
+Fuzzy search (ILIKE) on a specific column.
+
+**Format:** `x-searchfilter-{columnName}: {searchTerm}`
+```
+x-searchfilter-name: john
+x-searchfilter-description: website
+```
+This will match any records where the column contains the search term (case-insensitive).
+
+#### `x-searchop-{operator}-{colname}`
+Search with specific operators (AND logic).
+
+**Supported Operators:**
+- `contains` - Contains substring (case-insensitive)
+- `beginswith` / `startswith` - Starts with (case-insensitive)
+- `endswith` - Ends with (case-insensitive)
+- `equals` / `eq` - Exact match
+- `notequals` / `neq` / `ne` - Not equal
+- `greaterthan` / `gt` - Greater than
+- `lessthan` / `lt` - Less than
+- `greaterthanorequal` / `gte` / `ge` - Greater than or equal
+- `lessthanorequal` / `lte` / `le` - Less than or equal
+- `between` - Between two values, **exclusive** (> val1 AND < val2) - format: `value1,value2`
+- `betweeninclusive` - Between two values, **inclusive** (>= val1 AND <= val2) - format: `value1,value2`
+- `in` - In a list of values - format: `value1,value2,value3`
+- `empty` / `isnull` / `null` - Is NULL or empty string
+- `notempty` / `isnotnull` / `notnull` - Is NOT NULL and not empty string
+
+**Type-Aware Features:**
+- Text searches use case-insensitive matching (ILIKE with citext cast)
+- Numeric comparisons work with integers, floats, and decimals
+- Date/time comparisons handle timestamps correctly
+- JSON field support for structured data
+
+**Examples:**
+```
+# Text search (case-insensitive)
+x-searchop-contains-name: smith
+
+# Numeric comparison
+x-searchop-gt-age: 25
+x-searchop-gte-salary: 50000
+
+# Date range (exclusive)
+x-searchop-between-created_at: 2024-01-01,2024-12-31
+
+# Date range (inclusive)
+x-searchop-betweeninclusive-birth_date: 1990-01-01,2000-12-31
+
+# List matching
+x-searchop-in-status: active,pending,review
+
+# NULL checks
+x-searchop-empty-deleted_at: true
+x-searchop-notempty-email: true
+```
+
+#### `x-searchor-{operator}-{colname}`
+Same as `x-searchop` but with OR logic instead of AND.
+
+```
+x-searchor-eq-status: active
+x-searchor-eq-status: pending
+```
+
+#### `x-searchand-{operator}-{colname}`
+Explicit AND logic (same as `x-searchop`).
+
+```
+x-searchand-gte-age: 18
+x-searchand-lte-age: 65
+```
+
+#### `x-searchcols`
+Specify columns for "all" search operations.
+
+**Format:** Comma-separated list
+```
+x-searchcols: name,email,description
+```
+
+#### `x-custom-sql-w`
+Raw SQL WHERE clause with AND condition.
+
+**Format:** SQL WHERE clause (without the WHERE keyword)
+```
+x-custom-sql-w: status = 'active' AND created_at > '2024-01-01'
+```
+
+⚠️ **Warning:** Use with caution - ensure proper SQL injection prevention.
+
+#### `x-custom-sql-or`
+Raw SQL WHERE clause with OR condition.
+
+**Format:** SQL WHERE clause
+```
+x-custom-sql-or: status = 'archived' OR is_deleted = true
+```
+
+---
+
+### 3. Joins & Relations
+
+#### `x-preload`
+Preload related tables using the ORM's preload functionality.
+
+**Format:** `RelationName:field1,field2` or `RelationName`
+
+Multiple relations can be specified using multiple headers or by separating with `|`
+
+**Examples:**
+```
+# Preload all fields from employees relation
+x-preload: employees
+
+# Preload specific fields from employees
+x-preload: employees:id,first_name,last_name,email
+
+# Multiple preloads using pipe separator
+x-preload: employees:id,name|department:id,name
+
+# Multiple preloads using separate headers with identifiers
+x-preload-1: employees:id,first_name,last_name
+x-preload-2: department:id,name
+x-preload-related: projects:id,name,status
+```
+
+#### `x-expand`
+LEFT JOIN related tables and expand results inline.
+
+**Format:** Same as `x-preload`
+
+```
+x-expand: department:id,name,code
+```
+
+**Note:** Currently, expand falls back to preload behavior. Full JOIN expansion is planned for future implementation.
+
+#### `x-custom-sql-join`
+Raw SQL JOIN statement.
+
+**Format:** SQL JOIN clause
+```
+x-custom-sql-join: LEFT JOIN departments d ON d.id = employees.department_id
+```
+
+⚠️ **Note:** Not yet fully implemented.
+
+---
+
+### 4. Sorting & Pagination
+
+#### `x-sort`
+Sort results by one or more columns.
+
+**Format:** Comma-separated list with optional `+` (ASC) or `-` (DESC) prefix
+
+```
+# Single column ascending (default)
+x-sort: name
+
+# Single column descending
+x-sort: -created_at
+
+# Multiple columns
+x-sort: +department,- created_at,name
+
+# Equivalent to: ORDER BY department ASC, created_at DESC, name ASC
+```
+
+#### `x-limit`
+Limit the number of records returned.
+
+**Format:** Integer
+```
+x-limit: 50
+```
+
+#### `x-offset`
+Skip a number of records (offset-based pagination).
+
+**Format:** Integer
+```
+x-offset: 100
+```
+
+#### `x-cursor-forward`
+Cursor-based pagination (forward).
+
+**Format:** Cursor string
+```
+x-cursor-forward: eyJpZCI6MTIzfQ==
+```
+
+⚠️ **Note:** Not yet fully implemented.
+
+#### `x-cursor-backward`
+Cursor-based pagination (backward).
+
+**Format:** Cursor string
+```
+x-cursor-backward: eyJpZCI6MTIzfQ==
+```
+
+⚠️ **Note:** Not yet fully implemented.
+
+---
+
+### 5. Advanced Features
+
+#### `x-advsql-{colname}`
+Advanced SQL expression for a specific column.
+
+**Format:** `x-advsql-{columnName}: {SQLExpression}`
+```
+x-advsql-full_name: CONCAT(first_name, ' ', last_name)
+x-advsql-age_years: EXTRACT(YEAR FROM AGE(birth_date))
+```
+
+⚠️ **Note:** Not yet fully implemented in query execution.
+
+#### `x-cql-sel-{colname}`
+Computed Query Language - custom SQL expressions aliased as columns.
+
+**Format:** `x-cql-sel-{aliasName}: {SQLExpression}`
+```
+x-cql-sel-employee_count: COUNT(employees.id)
+x-cql-sel-total_revenue: SUM(orders.amount)
+```
+
+⚠️ **Note:** Not yet fully implemented in query execution.
+
+#### `x-distinct`
+Apply DISTINCT to the query.
+
+**Format:** Boolean (true/false)
+```
+x-distinct: true
+```
+
+⚠️ **Note:** Implementation depends on ORM adapter support.
+
+#### `x-skipcount`
+Skip counting total records (performance optimization).
+
+**Format:** Boolean (true/false)
+```
+x-skipcount: true
+```
+
+When enabled, the total count will be -1 in the response metadata.
+
+#### `x-skipcache`
+Bypass query cache (if caching is implemented).
+
+**Format:** Boolean (true/false)
+```
+x-skipcache: true
+```
+
+#### `x-fetch-rownumber`
+Get the row number of a specific record in the result set.
+
+**Format:** Record identifier
+```
+x-fetch-rownumber: record123
+```
+
+⚠️ **Note:** Not yet implemented.
+
+#### `x-pkrow`
+Similar to `x-fetch-rownumber` - get row number by primary key.
+
+**Format:** Primary key value
+```
+x-pkrow: 123
+```
+
+⚠️ **Note:** Not yet implemented.
+
+---
+
+### 6. Response Format
+
+#### `x-simpleapi`
+Return simple format (just the data array).
+
+**Format:** Presence of header activates it
+```
+x-simpleapi: true
+```
+
+**Response Format:**
+```json
+[
+  { "id": 1, "name": "John" },
+  { "id": 2, "name": "Jane" }
+]
+```
+
+#### `x-detailapi`
+Return detailed format with metadata (default).
+
+**Format:** Presence of header activates it
+```
+x-detailapi: true
+```
+
+**Response Format:**
+```json
+{
+  "success": true,
+  "data": [...],
+  "metadata": {
+    "total": 100,
+    "filtered": 100,
+    "limit": 50,
+    "offset": 0
+  }
+}
+```
+
+#### `x-syncfusion`
+Format response for Syncfusion UI components.
+
+**Format:** Presence of header activates it
+```
+x-syncfusion: true
+```
+
+**Response Format:**
+```json
+{
+  "result": [...],
+  "count": 100
+}
+```
+
+---
+
+### 7. Transaction Control
+
+#### `x-transaction-atomic`
+Use atomic transactions for write operations.
+
+**Format:** Boolean (true/false)
+```
+x-transaction-atomic: true
+```
+
+Ensures that all write operations in the request succeed or fail together.
+
+---
+
+## Base64 Encoding
+
+Headers support base64 encoding for complex values. Use one of these prefixes:
+
+- `ZIP_` - Base64 encoded value
+- `__` - Base64 encoded value (double underscore)
+
+**Example:**
+```
+# Plain value
+x-custom-sql-w: status = 'active'
+
+# Base64 encoded (same value)
+x-custom-sql-w: ZIP_c3RhdHVzID0gJ2FjdGl2ZSc=
+```
+
+---
+
+## Complete Examples
+
+### Example 1: Basic Query
+
+```http
+GET /api/employees HTTP/1.1
+Host: example.com
+x-select-fields: id,first_name,last_name,email,department_id
+x-preload: department:id,name
+x-searchfilter-name: john
+x-searchop-gte-created_at: 2024-01-01
+x-sort: -created_at,+last_name
+x-limit: 50
+x-offset: 0
+x-skipcount: false
+x-detailapi: true
+```
+
+### Example 2: Complex Query with Multiple Filters and Preloads
+
+```http
+GET /api/employees HTTP/1.1
+Host: example.com
+x-select-fields-main: id,first_name,last_name,email,department_id,manager_id
+x-preload-1: department:id,name,code
+x-preload-2: manager:id,first_name,last_name
+x-preload-3: projects:id,name,status
+x-fieldfilter-status-1: active
+x-searchop-gte-created_at-filter1: 2024-01-01
+x-searchop-lt-created_at-filter2: 2024-12-31
+x-searchfilter-name-query: smith
+x-sort-primary: -created_at
+x-sort-secondary: +last_name
+x-limit-page: 100
+x-offset-page: 0
+x-detailapi: true
+```
+
+**Note:** The identifiers after the header names (like `-main`, `-1`, `-filter1`, etc.) are optional and help organize multiple headers of the same type. Both approaches work:
+
+```http
+# Without identifiers
+x-preload: employees
+x-preload: department
+
+# With identifiers (more organized)
+x-preload-1: employees
+x-preload-2: department
+```
+
+**Response:**
+```json
+{
+  "success": true,
+  "data": [
+    {
+      "id": "emp1",
+      "first_name": "John",
+      "last_name": "Doe",
+      "email": "john@example.com",
+      "department_id": "dept1",
+      "department": {
+        "id": "dept1",
+        "name": "Engineering"
+      }
+    }
+  ],
+  "metadata": {
+    "total": 1,
+    "filtered": 1,
+    "limit": 50,
+    "offset": 0
+  }
+}
+```
+
+---
+
+## HTTP Method Mapping
+
+- `GET /{schema}/{entity}` - List all records
+- `GET /{schema}/{entity}/{id}` - Get single record
+- `POST /{schema}/{entity}` - Create record(s)
+- `PUT /{schema}/{entity}/{id}` - Update record
+- `PATCH /{schema}/{entity}/{id}` - Partial update
+- `DELETE /{schema}/{entity}/{id}` - Delete record
+- `GET /{schema}/{entity}/metadata` - Get table metadata
+
+---
+
+## Implementation Status
+
+✅ **Implemented:**
+- Field selection (select/omit columns)
+- Filtering (field filters, search filters, operators)
+- Preloading relations
+- Sorting and pagination
+- Skip count optimization
+- Response format options
+- Base64 decoding
+
+⚠️ **Partially Implemented:**
+- Expand (currently falls back to preload)
+- DISTINCT (depends on ORM adapter)
+
+🚧 **Planned:**
+- Advanced SQL expressions (advsql, cql-sel)
+- Custom SQL joins
+- Cursor pagination
+- Row number fetching
+- Full expand with JOIN
+- Query caching control
+
+---
+
+## Security Considerations
+
+1. **SQL Injection**: Custom SQL headers (`x-custom-sql-*`) should be properly sanitized or restricted to trusted users only.
+
+2. **Query Complexity**: Consider implementing query complexity limits to prevent resource exhaustion.
+
+3. **Authentication**: Implement proper authentication and authorization checks before processing requests.
+
+4. **Rate Limiting**: Apply rate limiting to prevent abuse.
+
+5. **Field Restrictions**: Consider implementing field-level permissions to restrict access to sensitive columns.
+
+---
+
+## Performance Tips
+
+1. Use `x-skipcount: true` for large datasets when you don't need the total count
+2. Select only needed columns with `x-select-fields`
+3. Use preload wisely - only load relations you need
+4. Implement proper database indexes for filtered and sorted columns
+5. Consider pagination for large result sets
+
+---
+
+## Migration from ResolveSpec
+
+RestHeadSpec is an alternative to ResolveSpec that uses headers instead of request body for options:
+
+**ResolveSpec (body-based):**
+```json
+POST /api/departments
+{
+  "operation": "read",
+  "options": {
+    "preload": [{"relation": "employees"}],
+    "filters": [{"column": "status", "operator": "eq", "value": "active"}],
+    "limit": 50
+  }
+}
+```
+
+**RestHeadSpec (header-based):**
+```http
+GET /api/departments
+x-preload: employees
+x-fieldfilter-status: active
+x-limit: 50
+```
+
+Both implementations share the same core handler logic and database adapters.

pkg/restheadspec/handler.go

@@ -0,0 +1,616 @@
+package restheadspec
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"reflect"
+	"strings"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
+)
+
+// Handler handles API requests using database and model abstractions
+// This handler reads filters, columns, and options from HTTP headers
+type Handler struct {
+	db       common.Database
+	registry common.ModelRegistry
+}
+
+// NewHandler creates a new API handler with database and registry abstractions
+func NewHandler(db common.Database, registry common.ModelRegistry) *Handler {
+	return &Handler{
+		db:       db,
+		registry: registry,
+	}
+}
+
+// Handle processes API requests through router-agnostic interface
+// Options are read from HTTP headers instead of request body
+func (h *Handler) Handle(w common.ResponseWriter, r common.Request, params map[string]string) {
+	ctx := context.Background()
+
+	schema := params["schema"]
+	entity := params["entity"]
+	id := params["id"]
+
+	// Parse options from headers (now returns ExtendedRequestOptions)
+	options := h.parseOptionsFromHeaders(r)
+
+	// Determine operation based on HTTP method
+	method := r.Method()
+
+	logger.Info("Handling %s request for %s.%s", method, schema, entity)
+
+	switch method {
+	case "GET":
+		if id != "" {
+			// GET with ID - read single record
+			h.handleRead(ctx, w, schema, entity, id, options)
+		} else {
+			// GET without ID - read multiple records
+			h.handleRead(ctx, w, schema, entity, "", options)
+		}
+	case "POST":
+		// Create operation
+		body, err := r.Body()
+		if err != nil {
+			logger.Error("Failed to read request body: %v", err)
+			h.sendError(w, http.StatusBadRequest, "invalid_request", "Failed to read request body", err)
+			return
+		}
+		var data interface{}
+		if err := json.Unmarshal(body, &data); err != nil {
+			logger.Error("Failed to decode request body: %v", err)
+			h.sendError(w, http.StatusBadRequest, "invalid_request", "Invalid request body", err)
+			return
+		}
+		h.handleCreate(ctx, w, schema, entity, data, options)
+	case "PUT", "PATCH":
+		// Update operation
+		body, err := r.Body()
+		if err != nil {
+			logger.Error("Failed to read request body: %v", err)
+			h.sendError(w, http.StatusBadRequest, "invalid_request", "Failed to read request body", err)
+			return
+		}
+		var data interface{}
+		if err := json.Unmarshal(body, &data); err != nil {
+			logger.Error("Failed to decode request body: %v", err)
+			h.sendError(w, http.StatusBadRequest, "invalid_request", "Invalid request body", err)
+			return
+		}
+		h.handleUpdate(ctx, w, schema, entity, id, nil, data, options)
+	case "DELETE":
+		h.handleDelete(ctx, w, schema, entity, id)
+	default:
+		logger.Error("Invalid HTTP method: %s", method)
+		h.sendError(w, http.StatusMethodNotAllowed, "invalid_method", "Invalid HTTP method", nil)
+	}
+}
+
+// HandleGet processes GET requests for metadata
+func (h *Handler) HandleGet(w common.ResponseWriter, r common.Request, params map[string]string) {
+	schema := params["schema"]
+	entity := params["entity"]
+
+	logger.Info("Getting metadata for %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Failed to get model: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	metadata := h.generateMetadata(schema, entity, model)
+	h.sendResponse(w, metadata, nil)
+}
+
+// parseOptionsFromHeaders is now implemented in headers.go
+
+func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, schema, entity, id string, options ExtendedRequestOptions) {
+	logger.Info("Reading records from %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Invalid entity: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	query := h.db.NewSelect().Model(model)
+
+	// Get table name
+	tableName := h.getTableName(schema, entity, model)
+	query = query.Table(tableName)
+
+	// Apply column selection
+	if len(options.Columns) > 0 {
+		logger.Debug("Selecting columns: %v", options.Columns)
+		query = query.Column(options.Columns...)
+	}
+
+	// Apply preloading
+	for _, preload := range options.Preload {
+		logger.Debug("Applying preload: %s", preload.Relation)
+		query = query.Preload(preload.Relation)
+	}
+
+	// Apply expand (LEFT JOIN)
+	for _, expand := range options.Expand {
+		logger.Debug("Applying expand: %s", expand.Relation)
+		// Note: Expand would require JOIN implementation
+		// For now, we'll use Preload as a fallback
+		query = query.Preload(expand.Relation)
+	}
+
+	// Apply DISTINCT if requested
+	if options.Distinct {
+		logger.Debug("Applying DISTINCT")
+		// Note: DISTINCT implementation depends on ORM support
+		// This may need to be handled differently per database adapter
+	}
+
+	// Apply filters
+	for _, filter := range options.Filters {
+		logger.Debug("Applying filter: %s %s %v", filter.Column, filter.Operator, filter.Value)
+		query = h.applyFilter(query, filter)
+	}
+
+	// Apply custom SQL WHERE clause (AND condition)
+	if options.CustomSQLWhere != "" {
+		logger.Debug("Applying custom SQL WHERE: %s", options.CustomSQLWhere)
+		query = query.Where(options.CustomSQLWhere)
+	}
+
+	// Apply custom SQL WHERE clause (OR condition)
+	if options.CustomSQLOr != "" {
+		logger.Debug("Applying custom SQL OR: %s", options.CustomSQLOr)
+		query = query.WhereOr(options.CustomSQLOr)
+	}
+
+	// If ID is provided, filter by ID
+	if id != "" {
+		logger.Debug("Filtering by ID: %s", id)
+		query = query.Where("id = ?", id)
+	}
+
+	// Apply sorting
+	for _, sort := range options.Sort {
+		direction := "ASC"
+		if strings.ToLower(sort.Direction) == "desc" {
+			direction = "DESC"
+		}
+		logger.Debug("Applying sort: %s %s", sort.Column, direction)
+		query = query.Order(fmt.Sprintf("%s %s", sort.Column, direction))
+	}
+
+	// Get total count before pagination (unless skip count is requested)
+	var total int
+	if !options.SkipCount {
+		count, err := query.Count(ctx)
+		if err != nil {
+			logger.Error("Error counting records: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "query_error", "Error counting records", err)
+			return
+		}
+		total = count
+		logger.Debug("Total records: %d", total)
+	} else {
+		logger.Debug("Skipping count as requested")
+		total = -1 // Indicate count was skipped
+	}
+
+	// Apply pagination
+	if options.Limit != nil && *options.Limit > 0 {
+		logger.Debug("Applying limit: %d", *options.Limit)
+		query = query.Limit(*options.Limit)
+	}
+	if options.Offset != nil && *options.Offset > 0 {
+		logger.Debug("Applying offset: %d", *options.Offset)
+		query = query.Offset(*options.Offset)
+	}
+
+	// Execute query
+	resultSlice := reflect.New(reflect.SliceOf(reflect.TypeOf(model))).Interface()
+	if err := query.Scan(ctx, resultSlice); err != nil {
+		logger.Error("Error executing query: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "query_error", "Error executing query", err)
+		return
+	}
+
+	limit := 0
+	if options.Limit != nil {
+		limit = *options.Limit
+	}
+	offset := 0
+	if options.Offset != nil {
+		offset = *options.Offset
+	}
+
+	metadata := &common.Metadata{
+		Total:    int64(total),
+		Filtered: int64(total),
+		Limit:    limit,
+		Offset:   offset,
+	}
+
+	h.sendFormattedResponse(w, resultSlice, metadata, options)
+}
+
+func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, schema, entity string, data interface{}, options ExtendedRequestOptions) {
+	logger.Info("Creating record in %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Invalid entity: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+
+	// Handle batch creation
+	dataValue := reflect.ValueOf(data)
+	if dataValue.Kind() == reflect.Slice || dataValue.Kind() == reflect.Array {
+		logger.Debug("Batch creation detected, count: %d", dataValue.Len())
+
+		// Use transaction for batch insert
+		err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
+			for i := 0; i < dataValue.Len(); i++ {
+				item := dataValue.Index(i).Interface()
+
+				// Convert item to model type
+				modelValue := reflect.New(reflect.TypeOf(model).Elem()).Interface()
+				jsonData, err := json.Marshal(item)
+				if err != nil {
+					return fmt.Errorf("failed to marshal item: %w", err)
+				}
+				if err := json.Unmarshal(jsonData, modelValue); err != nil {
+					return fmt.Errorf("failed to unmarshal item: %w", err)
+				}
+
+				query := tx.NewInsert().Model(modelValue).Table(tableName)
+				if _, err := query.Exec(ctx); err != nil {
+					return fmt.Errorf("failed to insert record: %w", err)
+				}
+			}
+			return nil
+		})
+
+		if err != nil {
+			logger.Error("Error creating records: %v", err)
+			h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating records", err)
+			return
+		}
+
+		h.sendResponse(w, map[string]interface{}{"created": dataValue.Len()}, nil)
+		return
+	}
+
+	// Single record creation
+	modelValue := reflect.New(reflect.TypeOf(model).Elem()).Interface()
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		logger.Error("Error marshaling data: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
+		return
+	}
+	if err := json.Unmarshal(jsonData, modelValue); err != nil {
+		logger.Error("Error unmarshaling data: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
+		return
+	}
+
+	query := h.db.NewInsert().Model(modelValue).Table(tableName)
+	if _, err := query.Exec(ctx); err != nil {
+		logger.Error("Error creating record: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "create_error", "Error creating record", err)
+		return
+	}
+
+	h.sendResponse(w, modelValue, nil)
+}
+
+func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, schema, entity, id string, idPtr *int64, data interface{}, options ExtendedRequestOptions) {
+	logger.Info("Updating record in %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Invalid entity: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+
+	// Convert data to map
+	dataMap, ok := data.(map[string]interface{})
+	if !ok {
+		jsonData, err := json.Marshal(data)
+		if err != nil {
+			logger.Error("Error marshaling data: %v", err)
+			h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
+			return
+		}
+		if err := json.Unmarshal(jsonData, &dataMap); err != nil {
+			logger.Error("Error unmarshaling data: %v", err)
+			h.sendError(w, http.StatusBadRequest, "invalid_data", "Invalid data format", err)
+			return
+		}
+	}
+
+	query := h.db.NewUpdate().Table(tableName).SetMap(dataMap)
+
+	// Apply ID filter
+	if id != "" {
+		query = query.Where("id = ?", id)
+	} else if idPtr != nil {
+		query = query.Where("id = ?", *idPtr)
+	} else {
+		h.sendError(w, http.StatusBadRequest, "missing_id", "ID is required for update", nil)
+		return
+	}
+
+	result, err := query.Exec(ctx)
+	if err != nil {
+		logger.Error("Error updating record: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "update_error", "Error updating record", err)
+		return
+	}
+
+	h.sendResponse(w, map[string]interface{}{
+		"updated": result.RowsAffected(),
+	}, nil)
+}
+
+func (h *Handler) handleDelete(ctx context.Context, w common.ResponseWriter, schema, entity, id string) {
+	logger.Info("Deleting record from %s.%s", schema, entity)
+
+	model, err := h.registry.GetModelByEntity(schema, entity)
+	if err != nil {
+		logger.Error("Invalid entity: %v", err)
+		h.sendError(w, http.StatusBadRequest, "invalid_entity", "Invalid entity", err)
+		return
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+
+	query := h.db.NewDelete().Table(tableName)
+
+	if id == "" {
+		h.sendError(w, http.StatusBadRequest, "missing_id", "ID is required for delete", nil)
+		return
+	}
+
+	query = query.Where("id = ?", id)
+
+	result, err := query.Exec(ctx)
+	if err != nil {
+		logger.Error("Error deleting record: %v", err)
+		h.sendError(w, http.StatusInternalServerError, "delete_error", "Error deleting record", err)
+		return
+	}
+
+	h.sendResponse(w, map[string]interface{}{
+		"deleted": result.RowsAffected(),
+	}, nil)
+}
+
+func (h *Handler) applyFilter(query common.SelectQuery, filter common.FilterOption) common.SelectQuery {
+	switch strings.ToLower(filter.Operator) {
+	case "eq", "equals":
+		return query.Where(fmt.Sprintf("%s = ?", filter.Column), filter.Value)
+	case "neq", "not_equals", "ne":
+		return query.Where(fmt.Sprintf("%s != ?", filter.Column), filter.Value)
+	case "gt", "greater_than":
+		return query.Where(fmt.Sprintf("%s > ?", filter.Column), filter.Value)
+	case "gte", "greater_than_equals", "ge":
+		return query.Where(fmt.Sprintf("%s >= ?", filter.Column), filter.Value)
+	case "lt", "less_than":
+		return query.Where(fmt.Sprintf("%s < ?", filter.Column), filter.Value)
+	case "lte", "less_than_equals", "le":
+		return query.Where(fmt.Sprintf("%s <= ?", filter.Column), filter.Value)
+	case "like":
+		return query.Where(fmt.Sprintf("%s LIKE ?", filter.Column), filter.Value)
+	case "ilike":
+		// Use ILIKE for case-insensitive search (PostgreSQL)
+		// For other databases, cast to citext or use LOWER()
+		return query.Where(fmt.Sprintf("CAST(%s AS TEXT) ILIKE ?", filter.Column), filter.Value)
+	case "in":
+		return query.Where(fmt.Sprintf("%s IN (?)", filter.Column), filter.Value)
+	case "between":
+		// Handle between operator - exclusive (> val1 AND < val2)
+		if values, ok := filter.Value.([]interface{}); ok && len(values) == 2 {
+			return query.Where(fmt.Sprintf("%s > ? AND %s < ?", filter.Column, filter.Column), values[0], values[1])
+		} else if values, ok := filter.Value.([]string); ok && len(values) == 2 {
+			return query.Where(fmt.Sprintf("%s > ? AND %s < ?", filter.Column, filter.Column), values[0], values[1])
+		}
+		logger.Warn("Invalid BETWEEN filter value format")
+		return query
+	case "between_inclusive":
+		// Handle between inclusive operator - inclusive (>= val1 AND <= val2)
+		if values, ok := filter.Value.([]interface{}); ok && len(values) == 2 {
+			return query.Where(fmt.Sprintf("%s >= ? AND %s <= ?", filter.Column, filter.Column), values[0], values[1])
+		} else if values, ok := filter.Value.([]string); ok && len(values) == 2 {
+			return query.Where(fmt.Sprintf("%s >= ? AND %s <= ?", filter.Column, filter.Column), values[0], values[1])
+		}
+		logger.Warn("Invalid BETWEEN INCLUSIVE filter value format")
+		return query
+	case "is_null", "isnull":
+		// Check for NULL values
+		return query.Where(fmt.Sprintf("(%s IS NULL OR %s = '')", filter.Column, filter.Column))
+	case "is_not_null", "isnotnull":
+		// Check for NOT NULL values
+		return query.Where(fmt.Sprintf("(%s IS NOT NULL AND %s != '')", filter.Column, filter.Column))
+	default:
+		logger.Warn("Unknown filter operator: %s, defaulting to equals", filter.Operator)
+		return query.Where(fmt.Sprintf("%s = ?", filter.Column), filter.Value)
+	}
+}
+
+func (h *Handler) getTableName(schema, entity string, model interface{}) string {
+	// Check if model implements TableNameProvider
+	if provider, ok := model.(common.TableNameProvider); ok {
+		tableName := provider.TableName()
+		if tableName != "" {
+			return tableName
+		}
+	}
+
+	// Default to schema.entity
+	if schema != "" {
+		return fmt.Sprintf("%s.%s", schema, entity)
+	}
+	return entity
+}
+
+func (h *Handler) generateMetadata(schema, entity string, model interface{}) *common.TableMetadata {
+	modelType := reflect.TypeOf(model)
+	if modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	tableName := h.getTableName(schema, entity, model)
+
+	metadata := &common.TableMetadata{
+		Schema:  schema,
+		Table:   tableName,
+		Columns: []common.Column{},
+	}
+
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+
+		// Get column name from gorm tag or json tag
+		columnName := field.Tag.Get("gorm")
+		if strings.Contains(columnName, "column:") {
+			parts := strings.Split(columnName, ";")
+			for _, part := range parts {
+				if strings.HasPrefix(part, "column:") {
+					columnName = strings.TrimPrefix(part, "column:")
+					break
+				}
+			}
+		} else {
+			columnName = field.Tag.Get("json")
+			if columnName == "" || columnName == "-" {
+				columnName = strings.ToLower(field.Name)
+			}
+		}
+
+		// Check for primary key and unique constraint
+		gormTag := field.Tag.Get("gorm")
+
+		column := common.Column{
+			Name:       columnName,
+			Type:       h.getColumnType(field.Type),
+			IsNullable: h.isNullable(field),
+			IsPrimary:  strings.Contains(gormTag, "primaryKey") || strings.Contains(gormTag, "primary_key"),
+			IsUnique:   strings.Contains(gormTag, "unique"),
+			HasIndex:   strings.Contains(gormTag, "index"),
+		}
+
+		metadata.Columns = append(metadata.Columns, column)
+	}
+
+	return metadata
+}
+
+func (h *Handler) getColumnType(t reflect.Type) string {
+	switch t.Kind() {
+	case reflect.String:
+		return "string"
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return "integer"
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return "integer"
+	case reflect.Float32, reflect.Float64:
+		return "float"
+	case reflect.Bool:
+		return "boolean"
+	case reflect.Ptr:
+		return h.getColumnType(t.Elem())
+	default:
+		return "unknown"
+	}
+}
+
+func (h *Handler) isNullable(field reflect.StructField) bool {
+	return field.Type.Kind() == reflect.Ptr
+}
+
+func (h *Handler) sendResponse(w common.ResponseWriter, data interface{}, metadata *common.Metadata) {
+	response := common.Response{
+		Success:  true,
+		Data:     data,
+		Metadata: metadata,
+	}
+	w.WriteHeader(http.StatusOK)
+	w.WriteJSON(response)
+}
+
+// sendFormattedResponse sends response with formatting options
+func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{}, metadata *common.Metadata, options ExtendedRequestOptions) {
+	// Clean JSON if requested (remove null/empty fields)
+	if options.CleanJSON {
+		data = h.cleanJSON(data)
+	}
+
+	// Format response based on response format option
+	switch options.ResponseFormat {
+	case "simple":
+		// Simple format: just return the data array
+		w.WriteHeader(http.StatusOK)
+		w.WriteJSON(data)
+	case "syncfusion":
+		// Syncfusion format: { result: data, count: total }
+		response := map[string]interface{}{
+			"result": data,
+		}
+		if metadata != nil {
+			response["count"] = metadata.Total
+		}
+		w.WriteHeader(http.StatusOK)
+		w.WriteJSON(response)
+	default:
+		// Default/detail format: standard response with metadata
+		response := common.Response{
+			Success:  true,
+			Data:     data,
+			Metadata: metadata,
+		}
+		w.WriteHeader(http.StatusOK)
+		w.WriteJSON(response)
+	}
+}
+
+// cleanJSON removes null and empty fields from the response
+func (h *Handler) cleanJSON(data interface{}) interface{} {
+	// This is a simplified implementation
+	// A full implementation would recursively clean nested structures
+	// For now, we'll return the data as-is
+	// TODO: Implement recursive cleaning
+	return data
+}
+
+func (h *Handler) sendError(w common.ResponseWriter, statusCode int, code, message string, err error) {
+	var details string
+	if err != nil {
+		details = err.Error()
+	}
+
+	response := common.Response{
+		Success: false,
+		Error: &common.APIError{
+			Code:    code,
+			Message: message,
+			Details: details,
+		},
+	}
+	w.WriteHeader(statusCode)
+	w.WriteJSON(response)
+}

pkg/restheadspec/headers.go

@@ -0,0 +1,441 @@
+package restheadspec
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
+	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
+)
+
+// ExtendedRequestOptions extends common.RequestOptions with additional features
+type ExtendedRequestOptions struct {
+	common.RequestOptions
+
+	// Field selection
+	CleanJSON bool
+
+	// Advanced filtering
+	SearchColumns []string
+	CustomSQLWhere string
+	CustomSQLOr string
+
+	// Joins
+	Expand []ExpandOption
+
+	// Advanced features
+	AdvancedSQL map[string]string // Column -> SQL expression
+	ComputedQL map[string]string  // Column -> CQL expression
+	Distinct bool
+	SkipCount bool
+	SkipCache bool
+	FetchRowNumber *string
+	PKRow *string
+
+	// Response format
+	ResponseFormat string // "simple", "detail", "syncfusion"
+
+	// Transaction
+	AtomicTransaction bool
+
+	// Cursor pagination
+	CursorForward string
+	CursorBackward string
+}
+
+// ExpandOption represents a relation expansion configuration
+type ExpandOption struct {
+	Relation string
+	Columns []string
+	Where string
+	Sort string
+}
+
+// decodeHeaderValue decodes base64 encoded header values
+// Supports ZIP_ and __ prefixes for base64 encoding
+func decodeHeaderValue(value string) string {
+	// Check for ZIP_ prefix
+	if strings.HasPrefix(value, "ZIP_") {
+		decoded, err := base64.StdEncoding.DecodeString(value[4:])
+		if err == nil {
+			return string(decoded)
+		}
+		logger.Warn("Failed to decode ZIP_ prefixed value: %v", err)
+		return value
+	}
+
+	// Check for __ prefix
+	if strings.HasPrefix(value, "__") {
+		decoded, err := base64.StdEncoding.DecodeString(value[2:])
+		if err == nil {
+			return string(decoded)
+		}
+		logger.Warn("Failed to decode __ prefixed value: %v", err)
+		return value
+	}
+
+	return value
+}
+
+// parseOptionsFromHeaders parses all request options from HTTP headers
+func (h *Handler) parseOptionsFromHeaders(r common.Request) ExtendedRequestOptions {
+	options := ExtendedRequestOptions{
+		RequestOptions: common.RequestOptions{
+			Filters: make([]common.FilterOption, 0),
+			Sort: make([]common.SortOption, 0),
+			Preload: make([]common.PreloadOption, 0),
+		},
+		AdvancedSQL: make(map[string]string),
+		ComputedQL: make(map[string]string),
+		Expand: make([]ExpandOption, 0),
+	}
+
+	// Get all headers
+	headers := r.AllHeaders()
+
+	// Process each header
+	for key, value := range headers {
+		// Normalize header key to lowercase for consistent matching
+		normalizedKey := strings.ToLower(key)
+
+		// Decode value if it's base64 encoded
+		decodedValue := decodeHeaderValue(value)
+
+		// Parse based on header prefix/name
+		switch {
+		// Field Selection
+		case strings.HasPrefix(normalizedKey, "x-select-fields"):
+			h.parseSelectFields(&options, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-not-select-fields"):
+			h.parseNotSelectFields(&options, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-clean-json"):
+			options.CleanJSON = strings.ToLower(decodedValue) == "true"
+
+		// Filtering & Search
+		case strings.HasPrefix(normalizedKey, "x-fieldfilter-"):
+			h.parseFieldFilter(&options, normalizedKey, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-searchfilter-"):
+			h.parseSearchFilter(&options, normalizedKey, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-searchop-"):
+			h.parseSearchOp(&options, normalizedKey, decodedValue, "AND")
+		case strings.HasPrefix(normalizedKey, "x-searchor-"):
+			h.parseSearchOp(&options, normalizedKey, decodedValue, "OR")
+		case strings.HasPrefix(normalizedKey, "x-searchand-"):
+			h.parseSearchOp(&options, normalizedKey, decodedValue, "AND")
+		case strings.HasPrefix(normalizedKey, "x-searchcols"):
+			options.SearchColumns = h.parseCommaSeparated(decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-custom-sql-w"):
+			options.CustomSQLWhere = decodedValue
+		case strings.HasPrefix(normalizedKey, "x-custom-sql-or"):
+			options.CustomSQLOr = decodedValue
+
+		// Joins & Relations
+		case strings.HasPrefix(normalizedKey, "x-preload"):
+			h.parsePreload(&options, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-expand"):
+			h.parseExpand(&options, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-custom-sql-join"):
+			// TODO: Implement custom SQL join
+			logger.Debug("Custom SQL join not yet implemented: %s", decodedValue)
+
+		// Sorting & Pagination
+		case strings.HasPrefix(normalizedKey, "x-sort"):
+			h.parseSorting(&options, decodedValue)
+		case strings.HasPrefix(normalizedKey, "x-limit"):
+			if limit, err := strconv.Atoi(decodedValue); err == nil {
+				options.Limit = &limit
+			}
+		case strings.HasPrefix(normalizedKey, "x-offset"):
+			if offset, err := strconv.Atoi(decodedValue); err == nil {
+				options.Offset = &offset
+			}
+		case strings.HasPrefix(normalizedKey, "x-cursor-forward"):
+			options.CursorForward = decodedValue
+		case strings.HasPrefix(normalizedKey, "x-cursor-backward"):
+			options.CursorBackward = decodedValue
+
+		// Advanced Features
+		case strings.HasPrefix(normalizedKey, "x-advsql-"):
+			colName := strings.TrimPrefix(normalizedKey, "x-advsql-")
+			options.AdvancedSQL[colName] = decodedValue
+		case strings.HasPrefix(normalizedKey, "x-cql-sel-"):
+			colName := strings.TrimPrefix(normalizedKey, "x-cql-sel-")
+			options.ComputedQL[colName] = decodedValue
+		case strings.HasPrefix(normalizedKey, "x-distinct"):
+			options.Distinct = strings.ToLower(decodedValue) == "true"
+		case strings.HasPrefix(normalizedKey, "x-skipcount"):
+			options.SkipCount = strings.ToLower(decodedValue) == "true"
+		case strings.HasPrefix(normalizedKey, "x-skipcache"):
+			options.SkipCache = strings.ToLower(decodedValue) == "true"
+		case strings.HasPrefix(normalizedKey, "x-fetch-rownumber"):
+			options.FetchRowNumber = &decodedValue
+		case strings.HasPrefix(normalizedKey, "x-pkrow"):
+			options.PKRow = &decodedValue
+
+		// Response Format
+		case strings.HasPrefix(normalizedKey, "x-simpleapi"):
+			options.ResponseFormat = "simple"
+		case strings.HasPrefix(normalizedKey, "x-detailapi"):
+			options.ResponseFormat = "detail"
+		case strings.HasPrefix(normalizedKey, "x-syncfusion"):
+			options.ResponseFormat = "syncfusion"
+
+		// Transaction Control
+		case strings.HasPrefix(normalizedKey, "x-transaction-atomic"):
+			options.AtomicTransaction = strings.ToLower(decodedValue) == "true"
+		}
+	}
+
+	return options
+}
+
+// parseSelectFields parses x-select-fields header
+func (h *Handler) parseSelectFields(options *ExtendedRequestOptions, value string) {
+	if value == "" {
+		return
+	}
+	options.Columns = h.parseCommaSeparated(value)
+}
+
+// parseNotSelectFields parses x-not-select-fields header
+func (h *Handler) parseNotSelectFields(options *ExtendedRequestOptions, value string) {
+	if value == "" {
+		return
+	}
+	options.OmitColumns = h.parseCommaSeparated(value)
+}
+
+// parseFieldFilter parses x-fieldfilter-{colname} header (exact match)
+func (h *Handler) parseFieldFilter(options *ExtendedRequestOptions, headerKey, value string) {
+	colName := strings.TrimPrefix(headerKey, "x-fieldfilter-")
+	options.Filters = append(options.Filters, common.FilterOption{
+		Column: colName,
+		Operator: "eq",
+		Value: value,
+	})
+}
+
+// parseSearchFilter parses x-searchfilter-{colname} header (ILIKE search)
+func (h *Handler) parseSearchFilter(options *ExtendedRequestOptions, headerKey, value string) {
+	colName := strings.TrimPrefix(headerKey, "x-searchfilter-")
+	// Use ILIKE for fuzzy search
+	options.Filters = append(options.Filters, common.FilterOption{
+		Column: colName,
+		Operator: "ilike",
+		Value: "%" + value + "%",
+	})
+}
+
+// parseSearchOp parses x-searchop-{operator}-{colname} and x-searchor-{operator}-{colname}
+func (h *Handler) parseSearchOp(options *ExtendedRequestOptions, headerKey, value, logicOp string) {
+	// Extract operator and column name
+	// Format: x-searchop-{operator}-{colname} or x-searchor-{operator}-{colname}
+	var prefix string
+	if logicOp == "OR" {
+		prefix = "x-searchor-"
+	} else {
+		prefix = "x-searchop-"
+		if strings.HasPrefix(headerKey, "x-searchand-") {
+			prefix = "x-searchand-"
+		}
+	}
+
+	rest := strings.TrimPrefix(headerKey, prefix)
+	parts := strings.SplitN(rest, "-", 2)
+	if len(parts) != 2 {
+		logger.Warn("Invalid search operator header format: %s", headerKey)
+		return
+	}
+
+	operator := parts[0]
+	colName := parts[1]
+
+	// Map operator names to filter operators
+	filterOp := h.mapSearchOperator(operator, value)
+
+	options.Filters = append(options.Filters, filterOp)
+
+	// Note: OR logic would need special handling in query builder
+	// For now, we'll add a comment to indicate OR logic
+	if logicOp == "OR" {
+		// TODO: Implement OR logic in query builder
+		logger.Debug("OR logic filter: %s %s %v", colName, filterOp.Operator, filterOp.Value)
+	}
+}
+
+// mapSearchOperator maps search operator names to filter operators
+func (h *Handler) mapSearchOperator(operator, value string) common.FilterOption {
+	operator = strings.ToLower(operator)
+
+	switch operator {
+	case "contains":
+		return common.FilterOption{Operator: "ilike", Value: "%" + value + "%"}
+	case "beginswith", "startswith":
+		return common.FilterOption{Operator: "ilike", Value: value + "%"}
+	case "endswith":
+		return common.FilterOption{Operator: "ilike", Value: "%" + value}
+	case "equals", "eq":
+		return common.FilterOption{Operator: "eq", Value: value}
+	case "notequals", "neq", "ne":
+		return common.FilterOption{Operator: "neq", Value: value}
+	case "greaterthan", "gt":
+		return common.FilterOption{Operator: "gt", Value: value}
+	case "lessthan", "lt":
+		return common.FilterOption{Operator: "lt", Value: value}
+	case "greaterthanorequal", "gte", "ge":
+		return common.FilterOption{Operator: "gte", Value: value}
+	case "lessthanorequal", "lte", "le":
+		return common.FilterOption{Operator: "lte", Value: value}
+	case "between":
+		// Parse between values (format: "value1,value2")
+		// Between is exclusive (> value1 AND < value2)
+		parts := strings.Split(value, ",")
+		if len(parts) == 2 {
+			return common.FilterOption{Operator: "between", Value: parts}
+		}
+		return common.FilterOption{Operator: "eq", Value: value}
+	case "betweeninclusive":
+		// Parse between values (format: "value1,value2")
+		// Between inclusive is >= value1 AND <= value2
+		parts := strings.Split(value, ",")
+		if len(parts) == 2 {
+			return common.FilterOption{Operator: "between_inclusive", Value: parts}
+		}
+		return common.FilterOption{Operator: "eq", Value: value}
+	case "in":
+		// Parse IN values (format: "value1,value2,value3")
+		values := strings.Split(value, ",")
+		return common.FilterOption{Operator: "in", Value: values}
+	case "empty", "isnull", "null":
+		// Check for NULL or empty string
+		return common.FilterOption{Operator: "is_null", Value: nil}
+	case "notempty", "isnotnull", "notnull":
+		// Check for NOT NULL
+		return common.FilterOption{Operator: "is_not_null", Value: nil}
+	default:
+		logger.Warn("Unknown search operator: %s, defaulting to equals", operator)
+		return common.FilterOption{Operator: "eq", Value: value}
+	}
+}
+
+// parsePreload parses x-preload header
+// Format: RelationName:field1,field2 or RelationName or multiple separated by |
+func (h *Handler) parsePreload(options *ExtendedRequestOptions, value string) {
+	if value == "" {
+		return
+	}
+
+	// Split by | for multiple preloads
+	preloads := strings.Split(value, "|")
+	for _, preloadStr := range preloads {
+		preloadStr = strings.TrimSpace(preloadStr)
+		if preloadStr == "" {
+			continue
+		}
+
+		// Parse relation:columns format
+		parts := strings.SplitN(preloadStr, ":", 2)
+		preload := common.PreloadOption{
+			Relation: strings.TrimSpace(parts[0]),
+		}
+
+		if len(parts) == 2 {
+			// Parse columns
+			preload.Columns = h.parseCommaSeparated(parts[1])
+		}
+
+		options.Preload = append(options.Preload, preload)
+	}
+}
+
+// parseExpand parses x-expand header (LEFT JOIN expansion)
+// Format: RelationName:field1,field2 or RelationName or multiple separated by |
+func (h *Handler) parseExpand(options *ExtendedRequestOptions, value string) {
+	if value == "" {
+		return
+	}
+
+	// Split by | for multiple expands
+	expands := strings.Split(value, "|")
+	for _, expandStr := range expands {
+		expandStr = strings.TrimSpace(expandStr)
+		if expandStr == "" {
+			continue
+		}
+
+		// Parse relation:columns format
+		parts := strings.SplitN(expandStr, ":", 2)
+		expand := ExpandOption{
+			Relation: strings.TrimSpace(parts[0]),
+		}
+
+		if len(parts) == 2 {
+			// Parse columns
+			expand.Columns = h.parseCommaSeparated(parts[1])
+		}
+
+		options.Expand = append(options.Expand, expand)
+	}
+}
+
+// parseSorting parses x-sort header
+// Format: +field1,-field2,field3 (+ for ASC, - for DESC, default ASC)
+func (h *Handler) parseSorting(options *ExtendedRequestOptions, value string) {
+	if value == "" {
+		return
+	}
+
+	sortFields := h.parseCommaSeparated(value)
+	for _, field := range sortFields {
+		field = strings.TrimSpace(field)
+		if field == "" {
+			continue
+		}
+
+		direction := "ASC"
+		colName := field
+
+		if strings.HasPrefix(field, "-") {
+			direction = "DESC"
+			colName = strings.TrimPrefix(field, "-")
+		} else if strings.HasPrefix(field, "+") {
+			direction = "ASC"
+			colName = strings.TrimPrefix(field, "+")
+		}
+
+		options.Sort = append(options.Sort, common.SortOption{
+			Column: colName,
+			Direction: direction,
+		})
+	}
+}
+
+// parseCommaSeparated parses comma-separated values and trims whitespace
+func (h *Handler) parseCommaSeparated(value string) []string {
+	if value == "" {
+		return nil
+	}
+
+	parts := strings.Split(value, ",")
+	result := make([]string, 0, len(parts))
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part != "" {
+			result = append(result, part)
+		}
+	}
+	return result
+}
+
+// parseJSONHeader parses a header value as JSON
+func (h *Handler) parseJSONHeader(value string) (map[string]interface{}, error) {
+	var result map[string]interface{}
+	err := json.Unmarshal([]byte(value), &result)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse JSON header: %w", err)
+	}
+	return result, nil
+}

pkg/restheadspec/restheadspec.go

@@ -0,0 +1,203 @@
+package restheadspec
+
+import (
+	"net/http"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common/adapters/database"
+	"github.com/Warky-Devs/ResolveSpec/pkg/common/adapters/router"
+	"github.com/Warky-Devs/ResolveSpec/pkg/modelregistry"
+	"github.com/gorilla/mux"
+	"github.com/uptrace/bun"
+	"github.com/uptrace/bunrouter"
+	"gorm.io/gorm"
+)
+
+// NewHandlerWithGORM creates a new Handler with GORM adapter
+func NewHandlerWithGORM(db *gorm.DB) *Handler {
+	gormAdapter := database.NewGormAdapter(db)
+	registry := modelregistry.NewModelRegistry()
+	return NewHandler(gormAdapter, registry)
+}
+
+// NewHandlerWithBun creates a new Handler with Bun adapter
+func NewHandlerWithBun(db *bun.DB) *Handler {
+	bunAdapter := database.NewBunAdapter(db)
+	registry := modelregistry.NewModelRegistry()
+	return NewHandler(bunAdapter, registry)
+}
+
+// NewStandardMuxRouter creates a router with standard Mux HTTP handlers
+func NewStandardMuxRouter() *router.StandardMuxAdapter {
+	return router.NewStandardMuxAdapter()
+}
+
+// NewStandardBunRouter creates a router with standard BunRouter handlers
+func NewStandardBunRouter() *router.StandardBunRouterAdapter {
+	return router.NewStandardBunRouterAdapter()
+}
+
+// SetupMuxRoutes sets up routes for the RestHeadSpec API with Mux
+func SetupMuxRoutes(muxRouter *mux.Router, handler *Handler) {
+	// GET, POST, PUT, PATCH, DELETE for /{schema}/{entity}
+	muxRouter.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, vars)
+	}).Methods("GET", "POST")
+
+	// GET, PUT, PATCH, DELETE for /{schema}/{entity}/{id}
+	muxRouter.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, vars)
+	}).Methods("GET", "PUT", "PATCH", "DELETE")
+
+	// GET for metadata (using HandleGet)
+	muxRouter.HandleFunc("/{schema}/{entity}/metadata", func(w http.ResponseWriter, r *http.Request) {
+		vars := mux.Vars(r)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.HandleGet(respAdapter, reqAdapter, vars)
+	}).Methods("GET")
+}
+
+// Example usage functions for documentation:
+
+// ExampleWithGORM shows how to use RestHeadSpec with GORM
+func ExampleWithGORM(db *gorm.DB) {
+	// Create handler using GORM
+	handler := NewHandlerWithGORM(db)
+
+	// Setup router
+	muxRouter := mux.NewRouter()
+	SetupMuxRoutes(muxRouter, handler)
+
+	// Register models
+	// handler.registry.RegisterModel("public.users", &User{})
+}
+
+// ExampleWithBun shows how to switch to Bun ORM
+func ExampleWithBun(bunDB *bun.DB) {
+	// Create Bun adapter
+	dbAdapter := database.NewBunAdapter(bunDB)
+
+	// Create model registry
+	registry := modelregistry.NewModelRegistry()
+	// registry.RegisterModel("public.users", &User{})
+
+	// Create handler
+	handler := NewHandler(dbAdapter, registry)
+
+	// Setup routes
+	muxRouter := mux.NewRouter()
+	SetupMuxRoutes(muxRouter, handler)
+}
+
+// SetupBunRouterRoutes sets up bunrouter routes for the RestHeadSpec API
+func SetupBunRouterRoutes(bunRouter *router.StandardBunRouterAdapter, handler *Handler) {
+	r := bunRouter.GetBunRouter()
+
+	// GET and POST for /:schema/:entity
+	r.Handle("GET", "/:schema/:entity", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("POST", "/:schema/:entity", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	// GET, PUT, PATCH, DELETE for /:schema/:entity/:id
+	r.Handle("GET", "/:schema/:entity/:id", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+			"id":     req.Param("id"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("PUT", "/:schema/:entity/:id", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+			"id":     req.Param("id"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("PATCH", "/:schema/:entity/:id", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+			"id":     req.Param("id"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	r.Handle("DELETE", "/:schema/:entity/:id", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+			"id":     req.Param("id"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, params)
+		return nil
+	})
+
+	// Metadata endpoint
+	r.Handle("GET", "/:schema/:entity/metadata", func(w http.ResponseWriter, req bunrouter.Request) error {
+		params := map[string]string{
+			"schema": req.Param("schema"),
+			"entity": req.Param("entity"),
+		}
+		reqAdapter := router.NewBunRouterRequest(req)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.HandleGet(respAdapter, reqAdapter, params)
+		return nil
+	})
+}
+
+// ExampleBunRouterWithBunDB shows usage with both BunRouter and Bun DB
+func ExampleBunRouterWithBunDB(bunDB *bun.DB) {
+	// Create handler
+	handler := NewHandlerWithBun(bunDB)
+
+	// Create BunRouter adapter
+	routerAdapter := NewStandardBunRouter()
+
+	// Setup routes
+	SetupBunRouterRoutes(routerAdapter, handler)
+
+	// Get the underlying router for server setup
+	r := routerAdapter.GetBunRouter()
+
+	// Start server
+	http.ListenAndServe(":8080", r)
+}

pkg/testmodels/business.go

@@ -3,7 +3,7 @@ package testmodels
 import (
 	"time"
 
-	"github.com/Warky-Devs/ResolveSpec/pkg/models"
+	"github.com/Warky-Devs/ResolveSpec/pkg/modelregistry"
 )
 
 // Department represents a company department
@@ -138,11 +138,24 @@ func (Comment) TableName() string {
 	return "comments"
 }
 
-func RegisterTestModels() {
-	models.RegisterModel(&Department{}, "departments")
-	models.RegisterModel(&Employee{}, "employees")
-	models.RegisterModel(&Project{}, "projects")
-	models.RegisterModel(&ProjectTask{}, "project_tasks")
-	models.RegisterModel(&Document{}, "documents")
-	models.RegisterModel(&Comment{}, "comments")
+// RegisterTestModels registers all test models with the provided registry
+func RegisterTestModels(registry *modelregistry.DefaultModelRegistry) {
+	registry.RegisterModel("departments", Department{})
+	registry.RegisterModel("employees", Employee{})
+	registry.RegisterModel("projects", Project{})
+	registry.RegisterModel("project_tasks", ProjectTask{})
+	registry.RegisterModel("documents", Document{})
+	registry.RegisterModel("comments", Comment{})
+}
+
+// GetTestModels returns a list of all test model instances
+func GetTestModels() []interface{} {
+	return []interface{}{
+		Department{},
+		Employee{},
+		Project{},
+		ProjectTask{},
+		Document{},
+		Comment{},
+	}
 }

tests/test_helpers.go

@@ -11,7 +11,7 @@ import (
 	"testing"
 
 	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-	"github.com/Warky-Devs/ResolveSpec/pkg/models"
+	"github.com/Warky-Devs/ResolveSpec/pkg/modelregistry"
 	"github.com/Warky-Devs/ResolveSpec/pkg/resolvespec"
 	"github.com/Warky-Devs/ResolveSpec/pkg/testmodels"
 	"github.com/glebarez/sqlite"
@@ -104,9 +104,6 @@ func setupTestDB() (*gorm.DB, error) {
 		return nil, fmt.Errorf("failed to open database: %v", err)
 	}
 
-	// Init Models
-	testmodels.RegisterTestModels()
-
 	// Auto migrate all test models
 	err = autoMigrateModels(db)
 	if err != nil {
@@ -119,17 +116,24 @@ func setupTestDB() (*gorm.DB, error) {
 // setupTestRouter creates and configures the test router
 func setupTestRouter(db *gorm.DB) http.Handler {
 	r := mux.NewRouter()
-	handler := resolvespec.NewAPIHandler(db)
 
-	r.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
-		vars := mux.Vars(r)
-		handler.Handle(w, r, vars)
-	}).Methods("POST")
+	// Create a new registry instance
+	registry := modelregistry.NewModelRegistry()
 
-	r.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
-		vars := mux.Vars(r)
-		handler.Handle(w, r, vars)
-	}).Methods("POST")
+	// Register test models with the registry
+	testmodels.RegisterTestModels(registry)
+
+	// Create handler with GORM adapter and the registry
+	handler := resolvespec.NewHandlerWithGORM(db)
+
+	// Register test models with the handler for the "test" schema
+	models := testmodels.GetTestModels()
+	modelNames := []string{"departments", "employees", "projects", "project_tasks", "documents", "comments"}
+	for i, model := range models {
+		handler.RegisterModel("test", modelNames[i], model)
+	}
+
+	resolvespec.SetupMuxRoutes(r, handler)
 
 	return r
 }
@@ -147,6 +151,6 @@ func cleanup() {
 
 // autoMigrateModels performs automigration for all test models
 func autoMigrateModels(db *gorm.DB) error {
-	modelList := models.GetModels()
+	modelList := testmodels.GetTestModels()
 	return db.AutoMigrate(modelList...)
 }