Massive refactor and introduction of restheadspec

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
+	// Initialize API handler using new API
-	handler := resolvespec.NewAPIHandler(db)
+	handler := resolvespec.NewHandlerWithGORM(db)
 
-	// Setup routes
+	// Create a new registry instance and register models
-	r.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+	registry := modelregistry.NewModelRegistry()
-		vars := mux.Vars(r)
+	testmodels.RegisterTestModels(registry)
-		handler.Handle(w, r, vars)
-	}).Methods("POST")
 
-	r.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
+	// Register models with handler
-		vars := mux.Vars(r)
+	models := testmodels.GetTestModels()
-		handler.Handle(w, r, vars)
+	modelNames := []string{"departments", "employees", "projects", "project_tasks", "documents", "comments"}
-	}).Methods("POST")
+	for i, model := range models {
+		handler.RegisterModel("public", modelNames[i], model)
+	}
 
-	r.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+	// Setup routes using new SetupMuxRoutes function
-		vars := mux.Vars(r)
+	resolvespec.SetupMuxRoutes(r, handler)
-		handler.HandleGet(w, r, vars)
-	}).Methods("GET")
 
 	// 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...)

pkg/common/adapters/database/bun.go

@@ -1,10 +1,11 @@
-package resolvespec
+package database
 
 import (
 	"context"
 	"database/sql"
 	"fmt"
 
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
 	"github.com/uptrace/bun"
 )
 
@@ -19,23 +20,23 @@ func NewBunAdapter(db *bun.DB) *BunAdapter {
 	return &BunAdapter{db: db}
 }
 
-func (b *BunAdapter) NewSelect() SelectQuery {
+func (b *BunAdapter) NewSelect() common.SelectQuery {
 	return &BunSelectQuery{query: b.db.NewSelect()}
 }
 
-func (b *BunAdapter) NewInsert() InsertQuery {
+func (b *BunAdapter) NewInsert() common.InsertQuery {
 	return &BunInsertQuery{query: b.db.NewInsert()}
 }
 
-func (b *BunAdapter) NewUpdate() UpdateQuery {
+func (b *BunAdapter) NewUpdate() common.UpdateQuery {
 	return &BunUpdateQuery{query: b.db.NewUpdate()}
 }
 
-func (b *BunAdapter) NewDelete() DeleteQuery {
+func (b *BunAdapter) NewDelete() common.DeleteQuery {
 	return &BunDeleteQuery{query: b.db.NewDelete()}
 }
 
-func (b *BunAdapter) Exec(ctx context.Context, query string, args ...interface{}) (Result, error) {
+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
 }
@@ -44,7 +45,7 @@ func (b *BunAdapter) Query(ctx context.Context, dest interface{}, query string,
 	return b.db.NewRaw(query, args...).Scan(ctx, dest)
 }
 
-func (b *BunAdapter) BeginTx(ctx context.Context) (Database, error) {
+func (b *BunAdapter) BeginTx(ctx context.Context) (common.Database, error) {
 	tx, err := b.db.BeginTx(ctx, &sql.TxOptions{})
 	if err != nil {
 		return nil, err
@@ -60,14 +61,14 @@ func (b *BunAdapter) CommitTx(ctx context.Context) error {
 }
 
 func (b *BunAdapter) RollbackTx(ctx context.Context) error {
-	// For Bun, we need to handle this differently  
+	// For Bun, we need to handle this differently
 	// This is a simplified implementation
 	return nil
 }
 
-func (b *BunAdapter) RunInTransaction(ctx context.Context, fn func(Database) error) error {
+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  
+		// Create adapter with transaction
 		adapter := &BunTxAdapter{tx: tx}
 		return fn(adapter)
 	})
@@ -78,62 +79,70 @@ type BunSelectQuery struct {
 	query *bun.SelectQuery
 }
 
-func (b *BunSelectQuery) Model(model interface{}) SelectQuery {
+func (b *BunSelectQuery) Model(model interface{}) common.SelectQuery {
 	b.query = b.query.Model(model)
 	return b
 }
 
-func (b *BunSelectQuery) Table(table string) SelectQuery {
+func (b *BunSelectQuery) Table(table string) common.SelectQuery {
 	b.query = b.query.Table(table)
 	return b
 }
 
-func (b *BunSelectQuery) Column(columns ...string) SelectQuery {
+func (b *BunSelectQuery) Column(columns ...string) common.SelectQuery {
 	b.query = b.query.Column(columns...)
 	return b
 }
 
-func (b *BunSelectQuery) Where(query string, args ...interface{}) SelectQuery {
+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{}) SelectQuery {
+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{}) SelectQuery {
+func (b *BunSelectQuery) Join(query string, args ...interface{}) common.SelectQuery {
 	b.query = b.query.Join(query, args...)
 	return b
 }
 
-func (b *BunSelectQuery) LeftJoin(query string, args ...interface{}) SelectQuery {
+func (b *BunSelectQuery) LeftJoin(query string, args ...interface{}) common.SelectQuery {
 	b.query = b.query.Join("LEFT JOIN " + query, args...)
 	return b
 }
 
-func (b *BunSelectQuery) Order(order string) SelectQuery {
+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) SelectQuery {
+func (b *BunSelectQuery) Limit(n int) common.SelectQuery {
 	b.query = b.query.Limit(n)
 	return b
 }
 
-func (b *BunSelectQuery) Offset(n int) SelectQuery {
+func (b *BunSelectQuery) Offset(n int) common.SelectQuery {
 	b.query = b.query.Offset(n)
 	return b
 }
 
-func (b *BunSelectQuery) Group(group string) SelectQuery {
+func (b *BunSelectQuery) Group(group string) common.SelectQuery {
 	b.query = b.query.Group(group)
 	return b
 }
 
-func (b *BunSelectQuery) Having(having string, args ...interface{}) SelectQuery {
+func (b *BunSelectQuery) Having(having string, args ...interface{}) common.SelectQuery {
 	b.query = b.query.Having(having, args...)
 	return b
 }
@@ -157,17 +166,17 @@ type BunInsertQuery struct {
 	values map[string]interface{}
 }
 
-func (b *BunInsertQuery) Model(model interface{}) InsertQuery {
+func (b *BunInsertQuery) Model(model interface{}) common.InsertQuery {
 	b.query = b.query.Model(model)
 	return b
 }
 
-func (b *BunInsertQuery) Table(table string) InsertQuery {
+func (b *BunInsertQuery) Table(table string) common.InsertQuery {
 	b.query = b.query.Table(table)
 	return b
 }
 
-func (b *BunInsertQuery) Value(column string, value interface{}) InsertQuery {
+func (b *BunInsertQuery) Value(column string, value interface{}) common.InsertQuery {
 	if b.values == nil {
 		b.values = make(map[string]interface{})
 	}
@@ -175,19 +184,19 @@ func (b *BunInsertQuery) Value(column string, value interface{}) InsertQuery {
 	return b
 }
 
-func (b *BunInsertQuery) OnConflict(action string) InsertQuery {
+func (b *BunInsertQuery) OnConflict(action string) common.InsertQuery {
 	b.query = b.query.On(action)
 	return b
 }
 
-func (b *BunInsertQuery) Returning(columns ...string) InsertQuery {
+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) (Result, error) {
+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 {
@@ -203,41 +212,41 @@ type BunUpdateQuery struct {
 	query *bun.UpdateQuery
 }
 
-func (b *BunUpdateQuery) Model(model interface{}) UpdateQuery {
+func (b *BunUpdateQuery) Model(model interface{}) common.UpdateQuery {
 	b.query = b.query.Model(model)
 	return b
 }
 
-func (b *BunUpdateQuery) Table(table string) UpdateQuery {
+func (b *BunUpdateQuery) Table(table string) common.UpdateQuery {
 	b.query = b.query.Table(table)
 	return b
 }
 
-func (b *BunUpdateQuery) Set(column string, value interface{}) UpdateQuery {
+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{}) UpdateQuery {
+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{}) UpdateQuery {
+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) UpdateQuery {
+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) (Result, error) {
+func (b *BunUpdateQuery) Exec(ctx context.Context) (common.Result, error) {
 	result, err := b.query.Exec(ctx)
 	return &BunResult{result: result}, err
 }
@@ -247,22 +256,22 @@ type BunDeleteQuery struct {
 	query *bun.DeleteQuery
 }
 
-func (b *BunDeleteQuery) Model(model interface{}) DeleteQuery {
+func (b *BunDeleteQuery) Model(model interface{}) common.DeleteQuery {
 	b.query = b.query.Model(model)
 	return b
 }
 
-func (b *BunDeleteQuery) Table(table string) DeleteQuery {
+func (b *BunDeleteQuery) Table(table string) common.DeleteQuery {
 	b.query = b.query.Table(table)
 	return b
 }
 
-func (b *BunDeleteQuery) Where(query string, args ...interface{}) DeleteQuery {
+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) (Result, error) {
+func (b *BunDeleteQuery) Exec(ctx context.Context) (common.Result, error) {
 	result, err := b.query.Exec(ctx)
 	return &BunResult{result: result}, err
 }
@@ -292,23 +301,23 @@ type BunTxAdapter struct {
 	tx bun.Tx
 }
 
-func (b *BunTxAdapter) NewSelect() SelectQuery {
+func (b *BunTxAdapter) NewSelect() common.SelectQuery {
 	return &BunSelectQuery{query: b.tx.NewSelect()}
 }
 
-func (b *BunTxAdapter) NewInsert() InsertQuery {
+func (b *BunTxAdapter) NewInsert() common.InsertQuery {
 	return &BunInsertQuery{query: b.tx.NewInsert()}
 }
 
-func (b *BunTxAdapter) NewUpdate() UpdateQuery {
+func (b *BunTxAdapter) NewUpdate() common.UpdateQuery {
 	return &BunUpdateQuery{query: b.tx.NewUpdate()}
 }
 
-func (b *BunTxAdapter) NewDelete() DeleteQuery {
+func (b *BunTxAdapter) NewDelete() common.DeleteQuery {
 	return &BunDeleteQuery{query: b.tx.NewDelete()}
 }
 
-func (b *BunTxAdapter) Exec(ctx context.Context, query string, args ...interface{}) (Result, error) {
+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
 }
@@ -317,7 +326,7 @@ func (b *BunTxAdapter) Query(ctx context.Context, dest interface{}, query string
 	return b.tx.NewRaw(query, args...).Scan(ctx, dest)
 }
 
-func (b *BunTxAdapter) BeginTx(ctx context.Context) (Database, error) {
+func (b *BunTxAdapter) BeginTx(ctx context.Context) (common.Database, error) {
 	return nil, fmt.Errorf("nested transactions not supported")
 }
 
@@ -329,6 +338,6 @@ func (b *BunTxAdapter) RollbackTx(ctx context.Context) error {
 	return b.tx.Rollback()
 }
 
-func (b *BunTxAdapter) RunInTransaction(ctx context.Context, fn func(Database) error) error {
+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

@@ -1,7 +1,9 @@
-package resolvespec
+package database
 
 import (
 	"context"
+
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
 	"gorm.io/gorm"
 )
 
@@ -15,23 +17,23 @@ func NewGormAdapter(db *gorm.DB) *GormAdapter {
 	return &GormAdapter{db: db}
 }
 
-func (g *GormAdapter) NewSelect() SelectQuery {
+func (g *GormAdapter) NewSelect() common.SelectQuery {
 	return &GormSelectQuery{db: g.db}
 }
 
-func (g *GormAdapter) NewInsert() InsertQuery {
+func (g *GormAdapter) NewInsert() common.InsertQuery {
 	return &GormInsertQuery{db: g.db}
 }
 
-func (g *GormAdapter) NewUpdate() UpdateQuery {
+func (g *GormAdapter) NewUpdate() common.UpdateQuery {
 	return &GormUpdateQuery{db: g.db}
 }
 
-func (g *GormAdapter) NewDelete() DeleteQuery {
+func (g *GormAdapter) NewDelete() common.DeleteQuery {
 	return &GormDeleteQuery{db: g.db}
 }
 
-func (g *GormAdapter) Exec(ctx context.Context, query string, args ...interface{}) (Result, error) {
+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
 }
@@ -40,7 +42,7 @@ func (g *GormAdapter) Query(ctx context.Context, dest interface{}, query string,
 	return g.db.WithContext(ctx).Raw(query, args...).Find(dest).Error
 }
 
-func (g *GormAdapter) BeginTx(ctx context.Context) (Database, 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
@@ -56,7 +58,7 @@ func (g *GormAdapter) RollbackTx(ctx context.Context) error {
 	return g.db.WithContext(ctx).Rollback().Error
 }
 
-func (g *GormAdapter) RunInTransaction(ctx context.Context, fn func(Database) error) 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)
@@ -68,62 +70,67 @@ type GormSelectQuery struct {
 	db *gorm.DB
 }
 
-func (g *GormSelectQuery) Model(model interface{}) SelectQuery {
+func (g *GormSelectQuery) Model(model interface{}) common.SelectQuery {
 	g.db = g.db.Model(model)
 	return g
 }
 
-func (g *GormSelectQuery) Table(table string) SelectQuery {
+func (g *GormSelectQuery) Table(table string) common.SelectQuery {
 	g.db = g.db.Table(table)
 	return g
 }
 
-func (g *GormSelectQuery) Column(columns ...string) SelectQuery {
+func (g *GormSelectQuery) Column(columns ...string) common.SelectQuery {
 	g.db = g.db.Select(columns)
 	return g
 }
 
-func (g *GormSelectQuery) Where(query string, args ...interface{}) SelectQuery {
+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{}) SelectQuery {
+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{}) SelectQuery {
+func (g *GormSelectQuery) Join(query string, args ...interface{}) common.SelectQuery {
 	g.db = g.db.Joins(query, args...)
 	return g
 }
 
-func (g *GormSelectQuery) LeftJoin(query string, args ...interface{}) SelectQuery {
+func (g *GormSelectQuery) LeftJoin(query string, args ...interface{}) common.SelectQuery {
 	g.db = g.db.Joins("LEFT JOIN "+query, args...)
 	return g
 }
 
-func (g *GormSelectQuery) Order(order string) SelectQuery {
+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) SelectQuery {
+func (g *GormSelectQuery) Limit(n int) common.SelectQuery {
 	g.db = g.db.Limit(n)
 	return g
 }
 
-func (g *GormSelectQuery) Offset(n int) SelectQuery {
+func (g *GormSelectQuery) Offset(n int) common.SelectQuery {
 	g.db = g.db.Offset(n)
 	return g
 }
 
-func (g *GormSelectQuery) Group(group string) SelectQuery {
+func (g *GormSelectQuery) Group(group string) common.SelectQuery {
 	g.db = g.db.Group(group)
 	return g
 }
 
-func (g *GormSelectQuery) Having(having string, args ...interface{}) SelectQuery {
+func (g *GormSelectQuery) Having(having string, args ...interface{}) common.SelectQuery {
 	g.db = g.db.Having(having, args...)
 	return g
 }
@@ -146,23 +153,23 @@ func (g *GormSelectQuery) Exists(ctx context.Context) (bool, error) {
 
 // GormInsertQuery implements InsertQuery for GORM
 type GormInsertQuery struct {
-	db    *gorm.DB
+	db     *gorm.DB
-	model interface{}
+	model  interface{}
 	values map[string]interface{}
 }
 
-func (g *GormInsertQuery) Model(model interface{}) InsertQuery {
+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) InsertQuery {
+func (g *GormInsertQuery) Table(table string) common.InsertQuery {
 	g.db = g.db.Table(table)
 	return g
 }
 
-func (g *GormInsertQuery) Value(column string, value interface{}) InsertQuery {
+func (g *GormInsertQuery) Value(column string, value interface{}) common.InsertQuery {
 	if g.values == nil {
 		g.values = make(map[string]interface{})
 	}
@@ -170,17 +177,17 @@ func (g *GormInsertQuery) Value(column string, value interface{}) InsertQuery {
 	return g
 }
 
-func (g *GormInsertQuery) OnConflict(action string) InsertQuery {
+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) InsertQuery {
+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) (Result, error) {
+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)
@@ -194,23 +201,23 @@ func (g *GormInsertQuery) Exec(ctx context.Context) (Result, error) {
 
 // GormUpdateQuery implements UpdateQuery for GORM
 type GormUpdateQuery struct {
-	db     *gorm.DB
+	db      *gorm.DB
-	model  interface{}
+	model   interface{}
 	updates interface{}
 }
 
-func (g *GormUpdateQuery) Model(model interface{}) UpdateQuery {
+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) UpdateQuery {
+func (g *GormUpdateQuery) Table(table string) common.UpdateQuery {
 	g.db = g.db.Table(table)
 	return g
 }
 
-func (g *GormUpdateQuery) Set(column string, value interface{}) UpdateQuery {
+func (g *GormUpdateQuery) Set(column string, value interface{}) common.UpdateQuery {
 	if g.updates == nil {
 		g.updates = make(map[string]interface{})
 	}
@@ -220,22 +227,22 @@ func (g *GormUpdateQuery) Set(column string, value interface{}) UpdateQuery {
 	return g
 }
 
-func (g *GormUpdateQuery) SetMap(values map[string]interface{}) UpdateQuery {
+func (g *GormUpdateQuery) SetMap(values map[string]interface{}) common.UpdateQuery {
 	g.updates = values
 	return g
 }
 
-func (g *GormUpdateQuery) Where(query string, args ...interface{}) UpdateQuery {
+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) UpdateQuery {
+func (g *GormUpdateQuery) Returning(columns ...string) common.UpdateQuery {
 	// GORM doesn't have explicit RETURNING
 	return g
 }
 
-func (g *GormUpdateQuery) Exec(ctx context.Context) (Result, error) {
+func (g *GormUpdateQuery) Exec(ctx context.Context) (common.Result, error) {
 	result := g.db.WithContext(ctx).Updates(g.updates)
 	return &GormResult{result: result}, result.Error
 }
@@ -246,23 +253,23 @@ type GormDeleteQuery struct {
 	model interface{}
 }
 
-func (g *GormDeleteQuery) Model(model interface{}) DeleteQuery {
+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) DeleteQuery {
+func (g *GormDeleteQuery) Table(table string) common.DeleteQuery {
 	g.db = g.db.Table(table)
 	return g
 }
 
-func (g *GormDeleteQuery) Where(query string, args ...interface{}) DeleteQuery {
+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) (Result, error) {
+func (g *GormDeleteQuery) Exec(ctx context.Context) (common.Result, error) {
 	result := g.db.WithContext(ctx).Delete(g.model)
 	return &GormResult{result: result}, result.Error
 }
@@ -279,4 +286,4 @@ func (g *GormResult) RowsAffected() int64 {
 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

@@ -1,8 +1,9 @@
-package resolvespec
+package router
 
 import (
 	"net/http"
 
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
 	"github.com/uptrace/bunrouter"
 )
 
@@ -21,7 +22,7 @@ func NewBunRouterAdapterDefault() *BunRouterAdapter {
 	return &BunRouterAdapter{router: bunrouter.New()}
 }
 
-func (b *BunRouterAdapter) HandleFunc(pattern string, handler HTTPHandlerFunc) RouteRegistration {
+func (b *BunRouterAdapter) HandleFunc(pattern string, handler common.HTTPHandlerFunc) common.RouteRegistration {
 	route := &BunRouterRegistration{
 		router:  b.router,
 		pattern: pattern,
@@ -30,7 +31,7 @@ func (b *BunRouterAdapter) HandleFunc(pattern string, handler HTTPHandlerFunc) R
 	return route
 }
 
-func (b *BunRouterAdapter) ServeHTTP(w ResponseWriter, r Request) {
+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")
@@ -45,16 +46,16 @@ func (b *BunRouterAdapter) GetBunRouter() *bunrouter.Router {
 type BunRouterRegistration struct {
 	router  *bunrouter.Router
 	pattern string
-	handler HTTPHandlerFunc
+	handler common.HTTPHandlerFunc
 }
 
-func (b *BunRouterRegistration) Methods(methods ...string) RouteRegistration {
+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 HTTPRequest
+			// Convert bunrouter.Request to our BunRouterRequest
 			reqAdapter := &BunRouterRequest{req: req}
-			respAdapter := NewHTTPResponseWriter(w)
+			respAdapter := &HTTPResponseWriter{resp: w}
 			b.handler(respAdapter, reqAdapter)
 			return nil
 		})
@@ -62,7 +63,7 @@ func (b *BunRouterRegistration) Methods(methods ...string) RouteRegistration {
 	return b
 }
 
-func (b *BunRouterRegistration) PathPrefix(prefix string) RouteRegistration {
+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
@@ -75,6 +76,11 @@ type BunRouterRequest struct {
 	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
 }
@@ -91,11 +97,11 @@ 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()
@@ -114,6 +120,16 @@ 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
@@ -125,16 +141,16 @@ func NewStandardBunRouterAdapter() *StandardBunRouterAdapter {
 	}
 }
 
-// RegisterRoute registers a route that works with the existing APIHandler
+// 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
 	})
@@ -148,7 +164,7 @@ func (s *StandardBunRouterAdapter) RegisterRouteWithParams(method, pattern strin
 		for _, paramName := range paramNames {
 			params[paramName] = req.Param(paramName)
 		}
-		
+
 		handler(w, req.Request, params)
 		return nil
 	})
@@ -156,63 +172,22 @@ func (s *StandardBunRouterAdapter) RegisterRouteWithParams(method, pattern strin
 
 // BunRouterConfig holds bunrouter-specific configuration
 type BunRouterConfig struct {
-	UseStrictSlash    bool
+	UseStrictSlash         bool
-	RedirectTrailingSlash bool
+	RedirectTrailingSlash  bool
 	HandleMethodNotAllowed bool
-	HandleOPTIONS     bool
+	HandleOPTIONS          bool
-	GlobalOPTIONS     http.Handler
+	GlobalOPTIONS          http.Handler
 	GlobalMethodNotAllowed http.Handler
-	PanicHandler      func(http.ResponseWriter, *http.Request, interface{})
+	PanicHandler           func(http.ResponseWriter, *http.Request, interface{})
 }
 
 // DefaultBunRouterConfig returns default bunrouter configuration
 func DefaultBunRouterConfig() *BunRouterConfig {
 	return &BunRouterConfig{
-		UseStrictSlash:    false,
+		UseStrictSlash:         false,
-		RedirectTrailingSlash: true,
+		RedirectTrailingSlash:  true,
 		HandleMethodNotAllowed: true,
-		HandleOPTIONS:     true,
+		HandleOPTIONS:          true,
 	}
 }
 
-// SetupBunRouterWithResolveSpec sets up bunrouter routes for ResolveSpec
-func SetupBunRouterWithResolveSpec(router *bunrouter.Router, handler *APIHandlerCompat) {
-	// Setup standard ResolveSpec routes with bunrouter
-	router.Handle("POST", "/:schema/:entity", func(w http.ResponseWriter, req bunrouter.Request) error {
-		params := map[string]string{
-			"schema": req.Param("schema"),
-			"entity": req.Param("entity"),
-		}
-		handler.Handle(w, req.Request, params)
-		return nil
-	})
-
-	router.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"),
-		}
-		handler.Handle(w, req.Request, params)
-		return nil
-	})
-
-	router.Handle("GET", "/:schema/:entity", func(w http.ResponseWriter, req bunrouter.Request) error {
-		params := map[string]string{
-			"schema": req.Param("schema"),
-			"entity": req.Param("entity"),
-		}
-		handler.HandleGet(w, req.Request, params)
-		return nil
-	})
-
-	router.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"),
-		}
-		handler.HandleGet(w, req.Request, params)
-		return nil
-	})
-}

pkg/common/adapters/router/mux.go

@@ -1,10 +1,11 @@
-package resolvespec
+package router
 
 import (
 	"encoding/json"
 	"io"
 	"net/http"
 
+	"github.com/Warky-Devs/ResolveSpec/pkg/common"
 	"github.com/gorilla/mux"
 )
 
@@ -18,7 +19,7 @@ func NewMuxAdapter(router *mux.Router) *MuxAdapter {
 	return &MuxAdapter{router: router}
 }
 
-func (m *MuxAdapter) HandleFunc(pattern string, handler HTTPHandlerFunc) RouteRegistration {
+func (m *MuxAdapter) HandleFunc(pattern string, handler common.HTTPHandlerFunc) common.RouteRegistration {
 	route := &MuxRouteRegistration{
 		router:  m.router,
 		pattern: pattern,
@@ -27,7 +28,7 @@ func (m *MuxAdapter) HandleFunc(pattern string, handler HTTPHandlerFunc) RouteRe
 	return route
 }
 
-func (m *MuxAdapter) ServeHTTP(w ResponseWriter, r Request) {
+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")
@@ -37,11 +38,11 @@ func (m *MuxAdapter) ServeHTTP(w ResponseWriter, r Request) {
 type MuxRouteRegistration struct {
 	router  *mux.Router
 	pattern string
-	handler HTTPHandlerFunc
+	handler common.HTTPHandlerFunc
 	route   *mux.Route
 }
 
-func (m *MuxRouteRegistration) Methods(methods ...string) RouteRegistration {
+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)}
@@ -53,7 +54,7 @@ func (m *MuxRouteRegistration) Methods(methods ...string) RouteRegistration {
 	return m
 }
 
-func (m *MuxRouteRegistration) PathPrefix(prefix string) RouteRegistration {
+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)}
@@ -115,10 +116,20 @@ 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      ResponseWriter
+	w      common.ResponseWriter
 	status int
 }
 
@@ -126,7 +137,6 @@ func NewHTTPResponseWriter(w http.ResponseWriter) *HTTPResponseWriter {
 	return &HTTPResponseWriter{resp: w}
 }
 
-
 func (h *HTTPResponseWriter) SetHeader(key, value string) {
 	h.resp.Header().Set(key, value)
 }
@@ -156,7 +166,7 @@ func NewStandardMuxAdapter() *StandardMuxAdapter {
 	}
 }
 
-// RegisterRoute registers a route that works with the existing APIHandler
+// 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)
@@ -169,18 +179,6 @@ func (s *StandardMuxAdapter) GetMuxRouter() *mux.Router {
 	return s.router
 }
 
-// GinAdapter for future Gin support
-type GinAdapter struct {
-	// This would be implemented when Gin support is needed
-	// engine *gin.Engine  
-}
-
-// EchoAdapter for future Echo support  
-type EchoAdapter struct {
-	// This would be implemented when Echo support is needed
-	// echo *echo.Echo
-}
-
 // PathParamExtractor extracts path parameters from different router types
 type PathParamExtractor interface {
 	ExtractParams(*http.Request) map[string]string
@@ -207,4 +205,4 @@ func DefaultRouterConfig() *RouterConfig {
 		Middleware:     make([]func(http.Handler) http.Handler, 0),
 		ParamExtractor: MuxParamExtractor{},
 	}
-}
+}

pkg/common/interfaces.go

@@ -1,4 +1,4 @@
-package resolvespec
+package common
 
 import "context"
 
@@ -9,11 +9,11 @@ type Database interface {
 	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
@@ -30,12 +30,13 @@ type SelectQuery interface {
 	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)
@@ -49,7 +50,7 @@ type InsertQuery interface {
 	Value(column string, value interface{}) InsertQuery
 	OnConflict(action string) InsertQuery
 	Returning(columns ...string) InsertQuery
-	
+
 	// Execution
 	Exec(ctx context.Context) (Result, error)
 }
@@ -62,7 +63,7 @@ type UpdateQuery interface {
 	SetMap(values map[string]interface{}) UpdateQuery
 	Where(query string, args ...interface{}) UpdateQuery
 	Returning(columns ...string) UpdateQuery
-	
+
 	// Execution
 	Exec(ctx context.Context) (Result, error)
 }
@@ -72,7 +73,7 @@ type DeleteQuery interface {
 	Model(model interface{}) DeleteQuery
 	Table(table string) DeleteQuery
 	Where(query string, args ...interface{}) DeleteQuery
-	
+
 	// Execution
 	Exec(ctx context.Context) (Result, error)
 }
@@ -94,7 +95,7 @@ type ModelRegistry interface {
 // Router interface for HTTP router abstraction
 type Router interface {
 	HandleFunc(pattern string, handler HTTPHandlerFunc) RouteRegistration
-	ServeHTTP(w ResponseWriter, r *Request)
+	ServeHTTP(w ResponseWriter, r Request)
 }
 
 // RouteRegistration allows method chaining for route configuration
@@ -108,6 +109,7 @@ 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
@@ -121,7 +123,7 @@ type ResponseWriter interface {
 	WriteJSON(data interface{}) error
 }
 
-// HTTPHandlerFunc type for HTTP handlers  
+// HTTPHandlerFunc type for HTTP handlers
 type HTTPHandlerFunc func(ResponseWriter, Request)
 
 // TableNameProvider interface for models that provide table names
@@ -129,7 +131,7 @@ type TableNameProvider interface {
 	TableName() string
 }
 
-// SchemaProvider interface for models that provide schema names  
+// 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

@@ -1,4 +1,4 @@
-package resolvespec
+package modelregistry
 
 import (
 	"fmt"
@@ -11,6 +11,11 @@ type DefaultModelRegistry struct {
 	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{
@@ -59,7 +64,41 @@ func (r *DefaultModelRegistry) GetModelByEntity(schema, entity string) (interfac
 	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 LegacyAPIHandler struct {
-	db *gorm.DB
-}
-
-// NewLegacyAPIHandler creates a new legacy API handler instance
-func NewLegacyAPIHandler(db *gorm.DB) *LegacyAPIHandler {
-	return &LegacyAPIHandler{
-		db: db,
-	}
-}
-
-// Main handler method
-func (h *LegacyAPIHandler) 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 *LegacyAPIHandler) 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 *LegacyAPIHandler) 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/compatibility.go

@@ -1,72 +0,0 @@
-package resolvespec
-
-import (
-	"net/http"
-
-	"github.com/Warky-Devs/ResolveSpec/pkg/models"
-	"gorm.io/gorm"
-)
-
-// NewAPIHandler creates a new APIHandler instance (backward compatibility)
-// For now, this returns the legacy APIHandler to maintain full compatibility
-// including preloading functionality. Users can opt-in to new abstractions when ready.
-func NewAPIHandler(db *gorm.DB) *APIHandlerCompat {
-	legacyHandler := NewLegacyAPIHandler(db)
-	
-	// Initialize new abstractions for future use
-	gormAdapter := NewGormAdapter(db)
-	registry := NewModelRegistry()
-	
-	// Initialize registry with existing models
-	models.IterateModels(func(name string, model interface{}) {
-		registry.RegisterModel(name, model)
-	})
-	
-	newHandler := NewHandler(gormAdapter, registry)
-	
-	return &APIHandlerCompat{
-		legacyHandler: legacyHandler,
-		newHandler:    newHandler,
-		db:           db,
-	}
-}
-
-// APIHandlerCompat provides backward compatibility with the original APIHandler
-type APIHandlerCompat struct {
-	legacyHandler *LegacyAPIHandler // For full backward compatibility
-	newHandler    *Handler          // New abstracted handler (optional use)
-	db           *gorm.DB          // Legacy GORM reference
-}
-
-// Handle maintains the original signature for backward compatibility
-func (a *APIHandlerCompat) Handle(w http.ResponseWriter, r *http.Request, params map[string]string) {
-	// Use legacy handler to maintain full compatibility including preloading
-	a.legacyHandler.Handle(w, r, params)
-}
-
-// HandleGet maintains the original signature for backward compatibility
-func (a *APIHandlerCompat) HandleGet(w http.ResponseWriter, r *http.Request, params map[string]string) {
-	// Use legacy handler for metadata
-	a.legacyHandler.HandleGet(w, r, params)
-}
-
-// RegisterModel maintains the original signature for backward compatibility
-func (a *APIHandlerCompat) RegisterModel(schema, name string, model interface{}) error {
-	// Register with both legacy handler and new handler
-	err1 := a.legacyHandler.RegisterModel(schema, name, model)
-	err2 := a.newHandler.RegisterModel(schema, name, model)
-	if err1 != nil {
-		return err1
-	}
-	return err2
-}
-
-// GetNewHandler returns the new abstracted handler for advanced use cases
-func (a *APIHandlerCompat) GetNewHandler() *Handler {
-	return a.newHandler
-}
-
-// GetLegacyHandler returns the legacy handler for cases needing full GORM features
-func (a *APIHandlerCompat) GetLegacyHandler() *LegacyAPIHandler {
-	return a.legacyHandler
-}

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 *LegacyAPIHandler) 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 *LegacyAPIHandler) 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 *LegacyAPIHandler) 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 *LegacyAPIHandler) 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

@@ -8,17 +8,18 @@ import (
 	"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       Database
+	db       common.Database
-	registry ModelRegistry
+	registry common.ModelRegistry
 }
 
 // NewHandler creates a new API handler with database and registry abstractions
-func NewHandler(db Database, registry ModelRegistry) *Handler {
+func NewHandler(db common.Database, registry common.ModelRegistry) *Handler {
 	return &Handler{
 		db:       db,
 		registry: registry,
@@ -26,9 +27,9 @@ func NewHandler(db Database, registry ModelRegistry) *Handler {
 }
 
 // Handle processes API requests through router-agnostic interface
-func (h *Handler) Handle(w ResponseWriter, r Request, params map[string]string) {
+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)
@@ -36,7 +37,7 @@ func (h *Handler) Handle(w ResponseWriter, r Request, params map[string]string)
 		return
 	}
 
-	var req RequestBody
+	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)
@@ -65,7 +66,7 @@ func (h *Handler) Handle(w ResponseWriter, r Request, params map[string]string)
 }
 
 // HandleGet processes GET requests for metadata
-func (h *Handler) HandleGet(w ResponseWriter, r Request, params map[string]string) {
+func (h *Handler) HandleGet(w common.ResponseWriter, r common.Request, params map[string]string) {
 	schema := params["schema"]
 	entity := params["entity"]
 
@@ -82,7 +83,7 @@ func (h *Handler) HandleGet(w ResponseWriter, r Request, params map[string]strin
 	h.sendResponse(w, metadata, nil)
 }
 
-func (h *Handler) handleRead(ctx context.Context, w ResponseWriter, schema, entity, id string, options RequestOptions) {
+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)
@@ -104,11 +105,9 @@ func (h *Handler) handleRead(ctx context.Context, w ResponseWriter, schema, enti
 		query = query.Column(options.Columns...)
 	}
 
-	// Note: Preloading is not implemented in the new database abstraction yet
+	// Apply preloading
-	// This is a limitation of the current interface design
-	// For now, preloading should use the legacy APIHandler
 	if len(options.Preload) > 0 {
-		logger.Warn("Preloading not yet implemented in new handler - use legacy APIHandler for preload functionality")
+		query = h.applyPreloads(model, query, options.Preload)
 	}
 
 	// Apply filters
@@ -172,18 +171,35 @@ func (h *Handler) handleRead(ctx context.Context, w ResponseWriter, schema, enti
 	}
 
 	logger.Info("Successfully retrieved records")
-	h.sendResponse(w, result, &Metadata{
+
+	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:    optionalInt(options.Limit),
+		Limit:    limit,
-		Offset:   optionalInt(options.Offset),
+		Offset:   offset,
 	})
 }
 
-func (h *Handler) handleCreate(ctx context.Context, w ResponseWriter, schema, entity string, data interface{}, options RequestOptions) {
+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)
 
-	tableName := fmt.Sprintf("%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) {
@@ -201,7 +217,7 @@ func (h *Handler) handleCreate(ctx context.Context, w ResponseWriter, schema, en
 		h.sendResponse(w, v, nil)
 
 	case []map[string]interface{}:
-		err := h.db.RunInTransaction(ctx, func(tx Database) error {
+		err := h.db.RunInTransaction(ctx, func(tx common.Database) error {
 			for _, item := range v {
 				txQuery := tx.NewInsert().Table(tableName)
 				for key, value := range item {
@@ -224,7 +240,7 @@ func (h *Handler) handleCreate(ctx context.Context, w ResponseWriter, schema, en
 	case []interface{}:
 		// Handle []interface{} type from JSON unmarshaling
 		list := make([]interface{}, 0)
-		err := h.db.RunInTransaction(ctx, func(tx Database) error {
+		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)
@@ -253,10 +269,18 @@ func (h *Handler) handleCreate(ctx context.Context, w ResponseWriter, schema, en
 	}
 }
 
-func (h *Handler) handleUpdate(ctx context.Context, w ResponseWriter, schema, entity, urlID string, reqID interface{}, data interface{}, options RequestOptions) {
+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)
 
-	tableName := fmt.Sprintf("%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) {
@@ -289,18 +313,18 @@ func (h *Handler) handleUpdate(ctx context.Context, w ResponseWriter, schema, en
 		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 ResponseWriter, schema, entity, id string) {
+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 == "" {
@@ -309,7 +333,14 @@ func (h *Handler) handleDelete(ctx context.Context, w ResponseWriter, schema, en
 		return
 	}
 
-	tableName := fmt.Sprintf("%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.NewDelete().Table(tableName).Where("id = ?", id)
 
 	result, err := query.Exec(ctx)
@@ -318,7 +349,7 @@ func (h *Handler) handleDelete(ctx context.Context, w ResponseWriter, schema, en
 		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)
@@ -329,7 +360,7 @@ func (h *Handler) handleDelete(ctx context.Context, w ResponseWriter, schema, en
 	h.sendResponse(w, nil, nil)
 }
 
-func (h *Handler) applyFilter(query SelectQuery, filter FilterOption) SelectQuery {
+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)
@@ -355,22 +386,22 @@ func (h *Handler) applyFilter(query SelectQuery, filter FilterOption) SelectQuer
 }
 
 func (h *Handler) getTableName(schema, entity string, model interface{}) string {
-	if provider, ok := model.(TableNameProvider); ok {
+	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{}) TableMetadata {
+func (h *Handler) generateMetadata(schema, entity string, model interface{}) *common.TableMetadata {
 	modelType := reflect.TypeOf(model)
 	if modelType.Kind() == reflect.Ptr {
 		modelType = modelType.Elem()
 	}
 
-	metadata := TableMetadata{
+	metadata := &common.TableMetadata{
 		Schema:    schema,
 		Table:     entity,
-		Columns:   make([]Column, 0),
+		Columns:   make([]common.Column, 0),
 		Relations: make([]string, 0),
 	}
 
@@ -400,7 +431,7 @@ func (h *Handler) generateMetadata(schema, entity string, model interface{}) Tab
 			continue
 		}
 
-		column := Column{
+		column := common.Column{
 			Name:       jsonName,
 			Type:       getColumnType(field),
 			IsNullable: isNullable(field),
@@ -415,21 +446,21 @@ func (h *Handler) generateMetadata(schema, entity string, model interface{}) Tab
 	return metadata
 }
 
-func (h *Handler) sendResponse(w ResponseWriter, data interface{}, metadata *Metadata) {
+func (h *Handler) sendResponse(w common.ResponseWriter, data interface{}, metadata *common.Metadata) {
 	w.SetHeader("Content-Type", "application/json")
-	w.WriteJSON(Response{
+	w.WriteJSON(common.Response{
 		Success:  true,
 		Data:     data,
 		Metadata: metadata,
 	})
 }
 
-func (h *Handler) sendError(w ResponseWriter, status int, code, message string, details interface{}) {
+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(Response{
+	w.WriteJSON(common.Response{
 		Success: false,
-		Error: &APIError{
+		Error: &common.APIError{
 			Code:    code,
 			Message: message,
 			Details: details,
@@ -442,4 +473,142 @@ func (h *Handler) sendError(w ResponseWriter, status int, code, message string,
 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/meta.go

@@ -1,131 +0,0 @@
-package resolvespec
-
-import (
-	"net/http"
-	"reflect"
-	"strings"
-
-	"github.com/Warky-Devs/ResolveSpec/pkg/logger"
-)
-
-func (h *LegacyAPIHandler) 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

@@ -3,145 +3,179 @@ 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"
 )
 
-// NewAPIHandler creates a new APIHandler with GORM (backward compatibility)
-func NewAPIHandlerWithGORM(db *gorm.DB) *APIHandlerCompat {
-	return NewAPIHandler(db)
-}
-
 // NewHandlerWithGORM creates a new Handler with GORM adapter
 func NewHandlerWithGORM(db *gorm.DB) *Handler {
-	gormAdapter := NewGormAdapter(db)
+	gormAdapter := database.NewGormAdapter(db)
-	registry := NewModelRegistry()
+	registry := modelregistry.NewModelRegistry()
 	return NewHandler(gormAdapter, registry)
 }
 
-// NewStandardRouter creates a router with standard HTTP handlers
+// NewHandlerWithBun creates a new Handler with Bun adapter
-func NewStandardRouter() *StandardMuxAdapter {
+func NewHandlerWithBun(db *bun.DB) *Handler {
-	return NewStandardMuxAdapter()
+	bunAdapter := database.NewBunAdapter(db)
+	registry := modelregistry.NewModelRegistry()
+	return NewHandler(bunAdapter, registry)
 }
 
-// SetupRoutes sets up routes for the ResolveSpec API with backward compatibility
+// NewStandardMuxRouter creates a router with standard Mux HTTP handlers
-func SetupRoutes(router *mux.Router, handler *APIHandlerCompat) {
+func NewStandardMuxRouter() *router.StandardMuxAdapter {
-	router.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+	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)
-		handler.Handle(w, r, vars)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, vars)
 	}).Methods("POST")
 
-	router.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
+	muxRouter.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
 		vars := mux.Vars(r)
-		handler.Handle(w, r, vars)
+		reqAdapter := router.NewHTTPRequest(r)
+		respAdapter := router.NewHTTPResponseWriter(w)
+		handler.Handle(respAdapter, reqAdapter, vars)
 	}).Methods("POST")
 
-	router.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
+	muxRouter.HandleFunc("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request) {
 		vars := mux.Vars(r)
-		handler.HandleGet(w, r, vars)
+		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 (current default)
+// ExampleWithGORM shows how to use ResolveSpec with GORM
 func ExampleWithGORM(db *gorm.DB) {
-	// Create handler using GORM (backward compatible)
+	// Create handler using GORM
-	handler := NewAPIHandlerWithGORM(db)
+	handler := NewHandlerWithGORM(db)
-	
+
 	// Setup router
-	router := mux.NewRouter()
+	muxRouter := mux.NewRouter()
-	SetupRoutes(router, handler)
+	SetupMuxRoutes(muxRouter, handler)
-	
+
 	// Register models
 	// handler.RegisterModel("public", "users", &User{})
 }
 
-// ExampleWithNewAPI shows how to use the new abstracted API
-func ExampleWithNewAPI(db *gorm.DB) {
-	// Create database adapter
-	dbAdapter := NewGormAdapter(db)
-	
-	// Create model registry
-	registry := NewModelRegistry()
-	// registry.RegisterModel("public.users", &User{})
-	
-	// Create handler with new API
-	handler := NewHandler(dbAdapter, registry)
-	
-	// Create router adapter
-	routerAdapter := NewStandardRouter()
-	
-	// Register routes using new API
-	routerAdapter.RegisterRoute("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request, params map[string]string) {
-		reqAdapter := NewHTTPRequest(r)
-		respAdapter := NewHTTPResponseWriter(w)
-		handler.Handle(respAdapter, reqAdapter, params)
-	})
-}
-
 // ExampleWithBun shows how to switch to Bun ORM
 func ExampleWithBun(bunDB *bun.DB) {
 	// Create Bun adapter
-	dbAdapter := NewBunAdapter(bunDB)
+	dbAdapter := database.NewBunAdapter(bunDB)
-	
+
 	// Create model registry
-	registry := NewModelRegistry()
+	registry := modelregistry.NewModelRegistry()
 	// registry.RegisterModel("public.users", &User{})
-	
+
 	// Create handler
 	handler := NewHandler(dbAdapter, registry)
-	
+
-	// Setup routes same as with GORM
+	// Setup routes
-	router := NewStandardRouter()
+	muxRouter := mux.NewRouter()
-	router.RegisterRoute("/{schema}/{entity}", func(w http.ResponseWriter, r *http.Request, params map[string]string) {
+	SetupMuxRoutes(muxRouter, handler)
-		reqAdapter := NewHTTPRequest(r)
+}
-		respAdapter := NewHTTPResponseWriter(w)
+
+// 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(db *gorm.DB) {
+func ExampleWithBunRouter(bunDB *bun.DB) {
-	// Create handler (can use any database adapter)
+	// Create handler with Bun adapter
-	handler := NewAPIHandler(db)
+	handler := NewHandlerWithBun(bunDB)
-	
+
 	// Create bunrouter
-	router := NewStandardBunRouterAdapter()
+	bunRouter := router.NewStandardBunRouterAdapter()
-	
+
 	// Setup ResolveSpec routes with bunrouter
-	SetupBunRouterWithResolveSpec(router.GetBunRouter(), handler)
+	SetupBunRouterRoutes(bunRouter, handler)
-	
+
 	// Start server
-	// http.ListenAndServe(":8080", router.GetBunRouter())
+	// http.ListenAndServe(":8080", bunRouter.GetBunRouter())
 }
 
 // ExampleBunRouterWithBunDB shows the full uptrace stack (bunrouter + Bun ORM)
 func ExampleBunRouterWithBunDB(bunDB *bun.DB) {
 	// Create Bun database adapter
-	dbAdapter := NewBunAdapter(bunDB)
+	dbAdapter := database.NewBunAdapter(bunDB)
-	
+
 	// Create model registry
-	registry := NewModelRegistry()
+	registry := modelregistry.NewModelRegistry()
 	// registry.RegisterModel("public.users", &User{})
-	
+
 	// Create handler with Bun
 	handler := NewHandler(dbAdapter, registry)
-	
+
-	// Create compatibility wrapper for existing APIs
-	compatHandler := &APIHandlerCompat{
-		legacyHandler: nil, // No legacy handler needed
-		newHandler:    handler,
-		db:           nil, // No GORM dependency
-	}
-	
 	// Create bunrouter
-	router := NewStandardBunRouterAdapter()
+	bunRouter := router.NewStandardBunRouterAdapter()
-	
+
 	// Setup ResolveSpec routes
-	SetupBunRouterWithResolveSpec(router.GetBunRouter(), compatHandler)
+	SetupBunRouterRoutes(bunRouter, handler)
-	
+
 	// This gives you the full uptrace stack: bunrouter + Bun ORM
-	// http.ListenAndServe(":8080", router.GetBunRouter())
+	// 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 *LegacyAPIHandler, 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 *LegacyAPIHandler) 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 *LegacyAPIHandler) 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 *LegacyAPIHandler) 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() {
+// RegisterTestModels registers all test models with the provided registry
-	models.RegisterModel(&Department{}, "departments")
+func RegisterTestModels(registry *modelregistry.DefaultModelRegistry) {
-	models.RegisterModel(&Employee{}, "employees")
+	registry.RegisterModel("departments", &Department{})
-	models.RegisterModel(&Project{}, "projects")
+	registry.RegisterModel("employees", &Employee{})
-	models.RegisterModel(&ProjectTask{}, "project_tasks")
+	registry.RegisterModel("projects", &Project{})
-	models.RegisterModel(&Document{}, "documents")
+	registry.RegisterModel("project_tasks", &ProjectTask{})
-	models.RegisterModel(&Comment{}, "comments")
+	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) {
+	// Create a new registry instance
-		vars := mux.Vars(r)
+	registry := modelregistry.NewModelRegistry()
-		handler.Handle(w, r, vars)
-	}).Methods("POST")
 
-	r.HandleFunc("/{schema}/{entity}/{id}", func(w http.ResponseWriter, r *http.Request) {
+	// Register test models with the registry
-		vars := mux.Vars(r)
+	testmodels.RegisterTestModels(registry)
-		handler.Handle(w, r, vars)
+
-	}).Methods("POST")
+	// 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...)
 }