feat(reflection): ✨ add ExtractTagValue and GetRelationshipInfo functions

* Implement ExtractTagValue to handle struct tag parsing.
* Introduce GetRelationshipInfo for extracting relationship metadata.
* Update tests to validate new functionality.
* Refactor related code for improved clarity and maintainability.

pkg/common/handler_utils.go

@@ -3,6 +3,9 @@ package common
 import (
 	"fmt"
 	"reflect"
+	"strings"
+
+	"github.com/bitechdev/ResolveSpec/pkg/logger"
 )
 
 // ValidateAndUnwrapModelResult contains the result of model validation
@@ -45,3 +48,216 @@ func ValidateAndUnwrapModel(model interface{}) (*ValidateAndUnwrapModelResult, e
 		OriginalType: originalType,
 	}, nil
 }
+
+// ExtractTagValue extracts the value for a given key from a struct tag string.
+// It handles both semicolon and comma-separated tag formats (e.g., GORM and BUN tags).
+// For tags like "json:name;validate:required" it will extract "name" for key "json".
+// For tags like "rel:has-many,join:table" it will extract "table" for key "join".
+func ExtractTagValue(tag, key string) string {
+	// Split by both semicolons and commas to handle different tag formats
+	// We need to be smart about this - commas can be part of values
+	// So we'll try semicolon first, then comma if needed
+	separators := []string{";", ","}
+
+	for _, sep := range separators {
+		parts := strings.Split(tag, sep)
+		for _, part := range parts {
+			part = strings.TrimSpace(part)
+			if strings.HasPrefix(part, key+":") {
+				return strings.TrimPrefix(part, key+":")
+			}
+		}
+	}
+	return ""
+}
+
+// GetRelationshipInfo analyzes a model type and extracts relationship metadata
+// for a specific relation field identified by its JSON name.
+// Returns nil if the field is not found or is not a valid relationship.
+func GetRelationshipInfo(modelType reflect.Type, relationName string) *RelationshipInfo {
+	// Ensure we have a struct type
+	if modelType == nil || modelType.Kind() != reflect.Struct {
+		logger.Warn("Cannot get relationship info from non-struct type: %v", modelType)
+		return nil
+	}
+
+	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")
+			bunTag := field.Tag.Get("bun")
+			info := &RelationshipInfo{
+				FieldName: field.Name,
+				JSONName:  jsonName,
+			}
+
+			if strings.Contains(bunTag, "rel:") || strings.Contains(bunTag, "join:") {
+				//bun:"rel:has-many,join:rid_hub=rid_hub_division"
+				if strings.Contains(bunTag, "has-many") {
+					info.RelationType = "hasMany"
+				} else if strings.Contains(bunTag, "has-one") {
+					info.RelationType = "hasOne"
+				} else if strings.Contains(bunTag, "belongs-to") {
+					info.RelationType = "belongsTo"
+				} else if strings.Contains(bunTag, "many-to-many") {
+					info.RelationType = "many2many"
+				} else {
+					info.RelationType = "hasOne"
+				}
+
+				// Extract join info
+				joinPart := ExtractTagValue(bunTag, "join")
+				if joinPart != "" && info.RelationType == "many2many" {
+					// For many2many, the join part is the join table name
+					info.JoinTable = joinPart
+				} else if joinPart != "" {
+					// For other relations, parse foreignKey and references
+					joinParts := strings.Split(joinPart, "=")
+					if len(joinParts) == 2 {
+						info.ForeignKey = joinParts[0]
+						info.References = joinParts[1]
+					}
+				}
+
+				// Get related model type
+				if field.Type.Kind() == reflect.Slice {
+					elemType := field.Type.Elem()
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.RelatedModel = reflect.New(elemType).Elem().Interface()
+					}
+				} else if field.Type.Kind() == reflect.Ptr || field.Type.Kind() == reflect.Struct {
+					elemType := field.Type
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.RelatedModel = reflect.New(elemType).Elem().Interface()
+					}
+				}
+
+				return info
+			}
+
+			// Parse GORM tag to determine relationship type and keys
+			if strings.Contains(gormTag, "foreignKey") {
+				info.ForeignKey = ExtractTagValue(gormTag, "foreignKey")
+				info.References = ExtractTagValue(gormTag, "references")
+
+				// Determine if it's belongsTo or hasMany/hasOne
+				if field.Type.Kind() == reflect.Slice {
+					info.RelationType = "hasMany"
+					// Get the element type for slice
+					elemType := field.Type.Elem()
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.RelatedModel = reflect.New(elemType).Elem().Interface()
+					}
+				} else if field.Type.Kind() == reflect.Ptr || field.Type.Kind() == reflect.Struct {
+					info.RelationType = "belongsTo"
+					elemType := field.Type
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.RelatedModel = reflect.New(elemType).Elem().Interface()
+					}
+				}
+			} else if strings.Contains(gormTag, "many2many") {
+				info.RelationType = "many2many"
+				info.JoinTable = ExtractTagValue(gormTag, "many2many")
+				// Get the element type for many2many (always slice)
+				if field.Type.Kind() == reflect.Slice {
+					elemType := field.Type.Elem()
+					if elemType.Kind() == reflect.Ptr {
+						elemType = elemType.Elem()
+					}
+					if elemType.Kind() == reflect.Struct {
+						info.RelatedModel = reflect.New(elemType).Elem().Interface()
+					}
+				}
+			} else {
+				// Field has no GORM relationship tags, so it's not a relation
+				return nil
+			}
+
+			return info
+		}
+	}
+	return nil
+}
+
+// RelationPathToBunAlias converts a relation path (e.g., "Order.Customer") to a Bun alias format.
+// It converts to lowercase and replaces dots with double underscores.
+// For example: "Order.Customer" -> "order__customer"
+func RelationPathToBunAlias(relationPath string) string {
+	if relationPath == "" {
+		return ""
+	}
+	// Convert to lowercase and replace dots with double underscores
+	alias := strings.ToLower(relationPath)
+	alias = strings.ReplaceAll(alias, ".", "__")
+	return alias
+}
+
+// ReplaceTableReferencesInSQL replaces references to a base table name in a SQL expression
+// with the appropriate alias for the current preload level.
+// For example, if baseTableName is "mastertaskitem" and targetAlias is "mal__mal",
+// it will replace "mastertaskitem.rid_mastertaskitem" with "mal__mal.rid_mastertaskitem"
+func ReplaceTableReferencesInSQL(sqlExpr, baseTableName, targetAlias string) string {
+	if sqlExpr == "" || baseTableName == "" || targetAlias == "" {
+		return sqlExpr
+	}
+
+	// Replace both quoted and unquoted table references
+	// Handle patterns like: tablename.column, "tablename".column, tablename."column", "tablename"."column"
+
+	// Pattern 1: tablename.column (unquoted)
+	result := strings.ReplaceAll(sqlExpr, baseTableName+".", targetAlias+".")
+
+	// Pattern 2: "tablename".column or "tablename"."column" (quoted table name)
+	result = strings.ReplaceAll(result, "\""+baseTableName+"\".", "\""+targetAlias+"\".")
+
+	return result
+}
+
+// GetTableNameFromModel extracts the table name from a model.
+// It checks the bun tag first, then falls back to converting the struct name to snake_case.
+func GetTableNameFromModel(model interface{}) string {
+	if model == nil {
+		return ""
+	}
+
+	modelType := reflect.TypeOf(model)
+
+	// Unwrap pointers
+	for modelType != nil && modelType.Kind() == reflect.Ptr {
+		modelType = modelType.Elem()
+	}
+
+	if modelType == nil || modelType.Kind() != reflect.Struct {
+		return ""
+	}
+
+	// Look for bun tag on embedded BaseModel
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+		if field.Anonymous {
+			bunTag := field.Tag.Get("bun")
+			if strings.HasPrefix(bunTag, "table:") {
+				return strings.TrimPrefix(bunTag, "table:")
+			}
+		}
+	}
+
+	// Fallback: convert struct name to lowercase (simple heuristic)
+	// This handles cases like "MasterTaskItem" -> "mastertaskitem"
+	return strings.ToLower(modelType.Name())
+}

pkg/common/handler_utils_test.go

@@ -0,0 +1,108 @@
+package common
+
+import (
+	"testing"
+)
+
+func TestExtractTagValue(t *testing.T) {
+	tests := []struct {
+		name     string
+		tag      string
+		key      string
+		expected string
+	}{
+		{
+			name:     "Extract existing key",
+			tag:      "json:name;validate:required",
+			key:      "json",
+			expected: "name",
+		},
+		{
+			name:     "Extract key with spaces",
+			tag:      "json:name ; validate:required",
+			key:      "validate",
+			expected: "required",
+		},
+		{
+			name:     "Extract key at end",
+			tag:      "json:name;validate:required;db:column_name",
+			key:      "db",
+			expected: "column_name",
+		},
+		{
+			name:     "Extract key at beginning",
+			tag:      "primary:true;json:id;db:user_id",
+			key:      "primary",
+			expected: "true",
+		},
+		{
+			name:     "Key not found",
+			tag:      "json:name;validate:required",
+			key:      "db",
+			expected: "",
+		},
+		{
+			name:     "Empty tag",
+			tag:      "",
+			key:      "json",
+			expected: "",
+		},
+		{
+			name:     "Single key-value pair",
+			tag:      "json:name",
+			key:      "json",
+			expected: "name",
+		},
+		{
+			name:     "Key with empty value",
+			tag:      "json:;validate:required",
+			key:      "json",
+			expected: "",
+		},
+		{
+			name:     "Key with complex value",
+			tag:      "json:user_name,omitempty;validate:required,min=3",
+			key:      "json",
+			expected: "user_name,omitempty",
+		},
+		{
+			name:     "Multiple semicolons",
+			tag:      "json:name;;validate:required",
+			key:      "validate",
+			expected: "required",
+		},
+		{
+			name:     "BUN Tag with comma separator",
+			tag:      "rel:has-many,join:rid_hub=rid_hub_child",
+			key:      "join",
+			expected: "rid_hub=rid_hub_child",
+		},
+		{
+			name:     "Extract foreignKey",
+			tag:      "foreignKey:UserID;references:ID",
+			key:      "foreignKey",
+			expected: "UserID",
+		},
+		{
+			name:     "Extract references",
+			tag:      "foreignKey:UserID;references:ID",
+			key:      "references",
+			expected: "ID",
+		},
+		{
+			name:     "Extract many2many",
+			tag:      "many2many:user_roles",
+			key:      "many2many",
+			expected: "user_roles",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ExtractTagValue(tt.tag, tt.key)
+			if result != tt.expected {
+				t.Errorf("ExtractTagValue(%q, %q) = %q; want %q", tt.tag, tt.key, result, tt.expected)
+			}
+		})
+	}
+}

pkg/common/recursive_crud.go

@@ -20,17 +20,6 @@ type RelationshipInfoProvider interface {
 	GetRelationshipInfo(modelType reflect.Type, relationName string) *RelationshipInfo
 }
 
-// RelationshipInfo contains information about a model relationship
-type RelationshipInfo struct {
-	FieldName    string
-	JSONName     string
-	RelationType string // "belongsTo", "hasMany", "hasOne", "many2many"
-	ForeignKey   string
-	References   string
-	JoinTable    string
-	RelatedModel interface{}
-}
-
 // NestedCUDProcessor handles recursive processing of nested object graphs
 type NestedCUDProcessor struct {
 	db                 Database

pkg/common/types.go

@@ -111,3 +111,14 @@ type TableMetadata struct {
 	Columns   []Column `json:"columns"`
 	Relations []string `json:"relations"`
 }
+
+// RelationshipInfo contains information about a model relationship
+type RelationshipInfo struct {
+	FieldName    string      `json:"field_name"`
+	JSONName     string      `json:"json_name"`
+	RelationType string      `json:"relation_type"` // "belongsTo", "hasMany", "hasOne", "many2many"
+	ForeignKey   string      `json:"foreign_key"`
+	References   string      `json:"references"`
+	JoinTable    string      `json:"join_table"`
+	RelatedModel interface{} `json:"related_model"`
+}

pkg/reflection/model_utils.go

@@ -584,11 +584,23 @@ func ExtractSourceColumn(colName string) string {
 }
 
 // ToSnakeCase converts a string from CamelCase to snake_case
+// Handles consecutive uppercase letters (acronyms) correctly:
+// "HTTPServer" -> "http_server", "UserID" -> "user_id", "MyHTTPServer" -> "my_http_server"
 func ToSnakeCase(s string) string {
 	var result strings.Builder
-	for i, r := range s {
+	runes := []rune(s)
+
+	for i, r := range runes {
 		if i > 0 && r >= 'A' && r <= 'Z' {
-			result.WriteRune('_')
+			// Add underscore if:
+			// 1. Previous character is lowercase, OR
+			// 2. Next character is lowercase (transition from acronym to word)
+			prevIsLower := runes[i-1] >= 'a' && runes[i-1] <= 'z'
+			nextIsLower := i+1 < len(runes) && runes[i+1] >= 'a' && runes[i+1] <= 'z'
+
+			if prevIsLower || nextIsLower {
+				result.WriteRune('_')
+			}
 		}
 		result.WriteRune(r)
 	}
@@ -961,7 +973,7 @@ func MapToStruct(dataMap map[string]interface{}, target interface{}) error {
 		// 4. Field name variations
 		columnNames = append(columnNames, field.Name)
 		columnNames = append(columnNames, strings.ToLower(field.Name))
-		columnNames = append(columnNames, ToSnakeCase(field.Name))
+		// columnNames = append(columnNames, ToSnakeCase(field.Name))
 
 		// Map all column name variations to this field index
 		for _, colName := range columnNames {
@@ -1067,7 +1079,7 @@ func setFieldValue(field reflect.Value, value interface{}) error {
 			case string:
 				field.SetBytes([]byte(v))
 				return nil
-			case map[string]interface{}, []interface{}:
+			case map[string]interface{}, []interface{}, []*any, map[string]*any:
 				// Marshal complex types to JSON for SqlJSONB fields
 				jsonBytes, err := json.Marshal(v)
 				if err != nil {
@@ -1077,6 +1089,11 @@ func setFieldValue(field reflect.Value, value interface{}) error {
 				return nil
 			}
 		}
+
+		// Handle slice-to-slice conversions (e.g., []interface{} to []*SomeModel)
+		if valueReflect.Kind() == reflect.Slice {
+			return convertSlice(field, valueReflect)
+		}
 	}
 
 	// Handle struct types (like SqlTimeStamp, SqlDate, SqlTime which wrap SqlNull[time.Time])
@@ -1156,6 +1173,92 @@ func setFieldValue(field reflect.Value, value interface{}) error {
 	return fmt.Errorf("cannot convert %v to %v", valueReflect.Type(), field.Type())
 }
 
+// convertSlice converts a source slice to a target slice type, handling element-wise conversions
+// Supports converting []interface{} to slices of structs or pointers to structs
+func convertSlice(targetSlice reflect.Value, sourceSlice reflect.Value) error {
+	if sourceSlice.Kind() != reflect.Slice || targetSlice.Kind() != reflect.Slice {
+		return fmt.Errorf("both source and target must be slices")
+	}
+
+	// Get the element type of the target slice
+	targetElemType := targetSlice.Type().Elem()
+	sourceLen := sourceSlice.Len()
+
+	// Create a new slice with the same length as the source
+	newSlice := reflect.MakeSlice(targetSlice.Type(), sourceLen, sourceLen)
+
+	// Convert each element
+	for i := 0; i < sourceLen; i++ {
+		sourceElem := sourceSlice.Index(i)
+		targetElem := newSlice.Index(i)
+
+		// Get the actual value from the source element
+		var sourceValue interface{}
+		if sourceElem.CanInterface() {
+			sourceValue = sourceElem.Interface()
+		} else {
+			continue
+		}
+
+		// Handle nil elements
+		if sourceValue == nil {
+			// For pointer types, nil is valid
+			if targetElemType.Kind() == reflect.Ptr {
+				targetElem.Set(reflect.Zero(targetElemType))
+			}
+			continue
+		}
+
+		// If target element type is a pointer to struct, we need to create new instances
+		if targetElemType.Kind() == reflect.Ptr {
+			// Create a new instance of the pointed-to type
+			newElemPtr := reflect.New(targetElemType.Elem())
+
+			// Convert the source value to the struct
+			switch sv := sourceValue.(type) {
+			case map[string]interface{}:
+				// Source is a map, use MapToStruct to populate the new instance
+				if err := MapToStruct(sv, newElemPtr.Interface()); err != nil {
+					return fmt.Errorf("failed to convert element %d: %w", i, err)
+				}
+			default:
+				// Try direct conversion or setFieldValue
+				if err := setFieldValue(newElemPtr.Elem(), sourceValue); err != nil {
+					return fmt.Errorf("failed to convert element %d: %w", i, err)
+				}
+			}
+
+			targetElem.Set(newElemPtr)
+		} else if targetElemType.Kind() == reflect.Struct {
+			// Target element is a struct (not a pointer)
+			switch sv := sourceValue.(type) {
+			case map[string]interface{}:
+				// Use MapToStruct to populate the element
+				elemPtr := targetElem.Addr()
+				if elemPtr.CanInterface() {
+					if err := MapToStruct(sv, elemPtr.Interface()); err != nil {
+						return fmt.Errorf("failed to convert element %d: %w", i, err)
+					}
+				}
+			default:
+				// Try direct conversion
+				if err := setFieldValue(targetElem, sourceValue); err != nil {
+					return fmt.Errorf("failed to convert element %d: %w", i, err)
+				}
+			}
+		} else {
+			// For other types, use setFieldValue
+			if err := setFieldValue(targetElem, sourceValue); err != nil {
+				return fmt.Errorf("failed to convert element %d: %w", i, err)
+			}
+		}
+	}
+
+	// Set the converted slice to the target field
+	targetSlice.Set(newSlice)
+	return nil
+}
+
 // convertToInt64 attempts to convert various types to int64
 func convertToInt64(value interface{}) (int64, bool) {
 	switch v := value.(type) {

pkg/resolvespec/handler.go

@@ -1453,30 +1453,7 @@ func isNullable(field reflect.StructField) bool {
 
 // GetRelationshipInfo implements common.RelationshipInfoProvider interface
 func (h *Handler) GetRelationshipInfo(modelType reflect.Type, relationName string) *common.RelationshipInfo {
-	info := h.getRelationshipInfo(modelType, relationName)
+	return common.GetRelationshipInfo(modelType, relationName)
-	if info == nil {
-		return nil
-	}
-	// Convert internal type to common type
-	return &common.RelationshipInfo{
-		FieldName:    info.fieldName,
-		JSONName:     info.jsonName,
-		RelationType: info.relationType,
-		ForeignKey:   info.foreignKey,
-		References:   info.references,
-		JoinTable:    info.joinTable,
-		RelatedModel: info.relatedModel,
-	}
-}
-
-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, error) {
@@ -1496,7 +1473,7 @@ func (h *Handler) applyPreloads(model interface{}, query common.SelectQuery, pre
 	for idx := range preloads {
 		preload := preloads[idx]
 		logger.Debug("Processing preload for relation: %s", preload.Relation)
-		relInfo := h.getRelationshipInfo(modelType, preload.Relation)
+		relInfo := common.GetRelationshipInfo(modelType, preload.Relation)
 		if relInfo == nil {
 			logger.Warn("Relation %s not found in model", preload.Relation)
 			continue
@@ -1504,7 +1481,7 @@ func (h *Handler) applyPreloads(model interface{}, query common.SelectQuery, pre
 
 		// 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
+		relationFieldName := relInfo.FieldName
 
 		// Validate and fix WHERE clause to ensure it contains the relation prefix
 		if len(preload.Where) > 0 {
@@ -1547,13 +1524,13 @@ func (h *Handler) applyPreloads(model interface{}, query common.SelectQuery, pre
 				copy(columns, preload.Columns)
 
 				// Add foreign key if not already present
-				if relInfo.foreignKey != "" {
+				if relInfo.ForeignKey != "" {
 					// Convert struct field name (e.g., DepartmentID) to snake_case (e.g., department_id)
-					foreignKeyColumn := toSnakeCase(relInfo.foreignKey)
+					foreignKeyColumn := toSnakeCase(relInfo.ForeignKey)
 
 					hasForeignKey := false
 					for _, col := range columns {
-						if col == foreignKeyColumn || col == relInfo.foreignKey {
+						if col == foreignKeyColumn || col == relInfo.ForeignKey {
 							hasForeignKey = true
 							break
 						}
@@ -1599,58 +1576,6 @@ func (h *Handler) applyPreloads(model interface{}, query common.SelectQuery, pre
 	return query, nil
 }
 
-func (h *Handler) getRelationshipInfo(modelType reflect.Type, relationName string) *relationshipInfo {
-	// Ensure we have a struct type
-	if modelType == nil || modelType.Kind() != reflect.Struct {
-		logger.Warn("Cannot get relationship info from non-struct type: %v", modelType)
-		return nil
-	}
-
-	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 ""
-}
-
 // toSnakeCase converts a PascalCase or camelCase string to snake_case
 func toSnakeCase(s string) string {
 	var result strings.Builder

pkg/resolvespec/handler_test.go

@@ -269,8 +269,6 @@ func TestToSnakeCase(t *testing.T) {
 }
 
 func TestExtractTagValue(t *testing.T) {
-	handler := NewHandler(nil, nil)
-
 	tests := []struct {
 		name     string
 		tag      string
@@ -311,9 +309,9 @@ func TestExtractTagValue(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			result := handler.extractTagValue(tt.tag, tt.key)
+			result := common.ExtractTagValue(tt.tag, tt.key)
 			if result != tt.expected {
-				t.Errorf("extractTagValue(%q, %q) = %q, expected %q", tt.tag, tt.key, result, tt.expected)
+				t.Errorf("ExtractTagValue(%q, %q) = %q, expected %q", tt.tag, tt.key, result, tt.expected)
 			}
 		})
 	}

pkg/restheadspec/handler.go

@@ -766,7 +766,7 @@ func (h *Handler) applyPreloadWithRecursion(query common.SelectQuery, preload co
 			// Apply ComputedQL fields if any
 			if len(preload.ComputedQL) > 0 {
 				// Get the base table name from the related model
-				baseTableName := getTableNameFromModel(relatedModel)
+				baseTableName := common.GetTableNameFromModel(relatedModel)
 
 				// Convert the preload relation path to the appropriate alias format
 				// This is ORM-specific. Currently we only support Bun's format.
@@ -777,7 +777,7 @@ func (h *Handler) applyPreloadWithRecursion(query common.SelectQuery, preload co
 					underlyingType := fmt.Sprintf("%T", h.db.GetUnderlyingDB())
 					if strings.Contains(underlyingType, "bun.DB") {
 						// Use Bun's alias format: lowercase with double underscores
-						preloadAlias = relationPathToBunAlias(preload.Relation)
+						preloadAlias = common.RelationPathToBunAlias(preload.Relation)
 					}
 					// For GORM: GORM doesn't use the same alias format, and this fix
 					// may not be needed since GORM handles preloads differently
@@ -792,7 +792,7 @@ func (h *Handler) applyPreloadWithRecursion(query common.SelectQuery, preload co
 					// levels of recursive/nested preloads
 					adjustedExpr := colExpr
 					if baseTableName != "" && preloadAlias != "" {
-						adjustedExpr = replaceTableReferencesInSQL(colExpr, baseTableName, preloadAlias)
+						adjustedExpr = common.ReplaceTableReferencesInSQL(colExpr, baseTableName, preloadAlias)
 						if adjustedExpr != colExpr {
 							logger.Debug("Adjusted computed column expression for %s: '%s' -> '%s'",
 								colName, colExpr, adjustedExpr)
@@ -903,73 +903,6 @@ func (h *Handler) applyPreloadWithRecursion(query common.SelectQuery, preload co
 	return query
 }
 
-// relationPathToBunAlias converts a relation path like "MAL.MAL.DEF" to the Bun alias format "mal__mal__def"
-// Bun generates aliases for nested relations by lowercasing and replacing dots with double underscores
-func relationPathToBunAlias(relationPath string) string {
-	if relationPath == "" {
-		return ""
-	}
-	// Convert to lowercase and replace dots with double underscores
-	alias := strings.ToLower(relationPath)
-	alias = strings.ReplaceAll(alias, ".", "__")
-	return alias
-}
-
-// replaceTableReferencesInSQL replaces references to a base table name in a SQL expression
-// with the appropriate alias for the current preload level
-// For example, if baseTableName is "mastertaskitem" and targetAlias is "mal__mal",
-// it will replace "mastertaskitem.rid_mastertaskitem" with "mal__mal.rid_mastertaskitem"
-func replaceTableReferencesInSQL(sqlExpr, baseTableName, targetAlias string) string {
-	if sqlExpr == "" || baseTableName == "" || targetAlias == "" {
-		return sqlExpr
-	}
-
-	// Replace both quoted and unquoted table references
-	// Handle patterns like: tablename.column, "tablename".column, tablename."column", "tablename"."column"
-
-	// Pattern 1: tablename.column (unquoted)
-	result := strings.ReplaceAll(sqlExpr, baseTableName+".", targetAlias+".")
-
-	// Pattern 2: "tablename".column or "tablename"."column" (quoted table name)
-	result = strings.ReplaceAll(result, "\""+baseTableName+"\".", "\""+targetAlias+"\".")
-
-	return result
-}
-
-// getTableNameFromModel extracts the table name from a model
-// It checks the bun tag first, then falls back to converting the struct name to snake_case
-func getTableNameFromModel(model interface{}) string {
-	if model == nil {
-		return ""
-	}
-
-	modelType := reflect.TypeOf(model)
-
-	// Unwrap pointers
-	for modelType != nil && modelType.Kind() == reflect.Ptr {
-		modelType = modelType.Elem()
-	}
-
-	if modelType == nil || modelType.Kind() != reflect.Struct {
-		return ""
-	}
-
-	// Look for bun tag on embedded BaseModel
-	for i := 0; i < modelType.NumField(); i++ {
-		field := modelType.Field(i)
-		if field.Anonymous {
-			bunTag := field.Tag.Get("bun")
-			if strings.HasPrefix(bunTag, "table:") {
-				return strings.TrimPrefix(bunTag, "table:")
-			}
-		}
-	}
-
-	// Fallback: convert struct name to lowercase (simple heuristic)
-	// This handles cases like "MasterTaskItem" -> "mastertaskitem"
-	return strings.ToLower(modelType.Name())
-}
-
 func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, data interface{}, options ExtendedRequestOptions) {
 	// Capture panics and return error response
 	defer func() {
@@ -2570,10 +2503,10 @@ func (h *Handler) filterExtendedOptions(validator *common.ColumnValidator, optio
 		filteredExpand := expand
 
 		// Get the relationship info for this expand relation
-		relInfo := h.getRelationshipInfo(modelType, expand.Relation)
+		relInfo := common.GetRelationshipInfo(modelType, expand.Relation)
-		if relInfo != nil && relInfo.relatedModel != nil {
+		if relInfo != nil && relInfo.RelatedModel != nil {
 			// Create a validator for the related model
-			expandValidator := common.NewColumnValidator(relInfo.relatedModel)
+			expandValidator := common.NewColumnValidator(relInfo.RelatedModel)
 			// Filter columns using the related model's validator
 			filteredExpand.Columns = expandValidator.FilterValidColumns(expand.Columns)
 
@@ -2650,110 +2583,7 @@ func (h *Handler) shouldUseNestedProcessor(data map[string]interface{}, model in
 
 // GetRelationshipInfo implements common.RelationshipInfoProvider interface
 func (h *Handler) GetRelationshipInfo(modelType reflect.Type, relationName string) *common.RelationshipInfo {
-	info := h.getRelationshipInfo(modelType, relationName)
+	return common.GetRelationshipInfo(modelType, relationName)
-	if info == nil {
-		return nil
-	}
-	// Convert internal type to common type
-	return &common.RelationshipInfo{
-		FieldName:    info.fieldName,
-		JSONName:     info.jsonName,
-		RelationType: info.relationType,
-		ForeignKey:   info.foreignKey,
-		References:   info.references,
-		JoinTable:    info.joinTable,
-		RelatedModel: info.relatedModel,
-	}
-}
-
-type relationshipInfo struct {
-	fieldName    string
-	jsonName     string
-	relationType string // "belongsTo", "hasMany", "hasOne", "many2many"
-	foreignKey   string
-	references   string
-	joinTable    string
-	relatedModel interface{}
-}
-
-func (h *Handler) getRelationshipInfo(modelType reflect.Type, relationName string) *relationshipInfo {
-	// Ensure we have a struct type
-	if modelType == nil || modelType.Kind() != reflect.Struct {
-		logger.Warn("Cannot get relationship info from non-struct type: %v", modelType)
-		return nil
-	}
-
-	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"
-					// Get the element type for slice
-					elemType := field.Type.Elem()
-					if elemType.Kind() == reflect.Ptr {
-						elemType = elemType.Elem()
-					}
-					if elemType.Kind() == reflect.Struct {
-						info.relatedModel = reflect.New(elemType).Elem().Interface()
-					}
-				} else if field.Type.Kind() == reflect.Ptr || field.Type.Kind() == reflect.Struct {
-					info.relationType = "belongsTo"
-					elemType := field.Type
-					if elemType.Kind() == reflect.Ptr {
-						elemType = elemType.Elem()
-					}
-					if elemType.Kind() == reflect.Struct {
-						info.relatedModel = reflect.New(elemType).Elem().Interface()
-					}
-				}
-			} else if strings.Contains(gormTag, "many2many") {
-				info.relationType = "many2many"
-				info.joinTable = h.extractTagValue(gormTag, "many2many")
-				// Get the element type for many2many (always slice)
-				if field.Type.Kind() == reflect.Slice {
-					elemType := field.Type.Elem()
-					if elemType.Kind() == reflect.Ptr {
-						elemType = elemType.Elem()
-					}
-					if elemType.Kind() == reflect.Struct {
-						info.relatedModel = reflect.New(elemType).Elem().Interface()
-					}
-				}
-			} else {
-				// Field has no GORM relationship tags, so it's not a relation
-				return nil
-			}
-
-			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 ""
 }
 
 // HandleOpenAPI generates and returns the OpenAPI specification

pkg/restheadspec/restheadspec_test.go

@@ -2,6 +2,8 @@ package restheadspec
 
 import (
 	"testing"
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
 )
 
 func TestParseModelName(t *testing.T) {
@@ -112,3 +114,88 @@ func TestNewStandardBunRouter(t *testing.T) {
 		t.Error("Expected router to be created, got nil")
 	}
 }
+
+func TestExtractTagValue(t *testing.T) {
+	tests := []struct {
+		name     string
+		tag      string
+		key      string
+		expected string
+	}{
+		{
+			name:     "Extract existing key",
+			tag:      "json:name;validate:required",
+			key:      "json",
+			expected: "name",
+		},
+		{
+			name:     "Extract key with spaces",
+			tag:      "json:name ; validate:required",
+			key:      "validate",
+			expected: "required",
+		},
+		{
+			name:     "Extract key at end",
+			tag:      "json:name;validate:required;db:column_name",
+			key:      "db",
+			expected: "column_name",
+		},
+		{
+			name:     "Extract key at beginning",
+			tag:      "primary:true;json:id;db:user_id",
+			key:      "primary",
+			expected: "true",
+		},
+		{
+			name:     "Key not found",
+			tag:      "json:name;validate:required",
+			key:      "db",
+			expected: "",
+		},
+		{
+			name:     "Empty tag",
+			tag:      "",
+			key:      "json",
+			expected: "",
+		},
+		{
+			name:     "Single key-value pair",
+			tag:      "json:name",
+			key:      "json",
+			expected: "name",
+		},
+		{
+			name:     "Key with empty value",
+			tag:      "json:;validate:required",
+			key:      "json",
+			expected: "",
+		},
+		{
+			name:     "Key with complex value",
+			tag:      "json:user_name,omitempty;validate:required,min=3",
+			key:      "json",
+			expected: "user_name,omitempty",
+		},
+		{
+			name:     "Multiple semicolons",
+			tag:      "json:name;;validate:required",
+			key:      "validate",
+			expected: "required",
+		},
+		{
+			name:     "BUN Tag",
+			tag:      "rel:has-many,join:rid_hub=rid_hub_child",
+			key:      "join",
+			expected: "rid_hub=rid_hub_child",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := common.ExtractTagValue(tt.tag, tt.key)
+			if result != tt.expected {
+				t.Errorf("ExtractTagValue(%q, %q) = %q; want %q", tt.tag, tt.key, result, tt.expected)
+			}
+		})
+	}
+}