feat: Refactor activity and project handlers to use utility functions for ID parsing and response handling

backend/internal/api/utils/handler_utils.go

@@ -0,0 +1,136 @@
+package utils
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/gin-gonic/gin"
+	"github.com/timetracker/backend/internal/types"
+)
+
+// ParseID parses an ID from the URL parameter and converts it to a types.ULID
+func ParseID(c *gin.Context, paramName string) (types.ULID, error) {
+	idStr := c.Param(paramName)
+	return types.ULIDFromString(idStr)
+}
+
+// BindJSON binds the request body to the provided struct
+func BindJSON(c *gin.Context, obj interface{}) error {
+	if err := c.ShouldBindJSON(obj); err != nil {
+		return fmt.Errorf("invalid request body: %w", err)
+	}
+	return nil
+}
+
+// ConvertToDTO converts a slice of models to a slice of DTOs using the provided conversion function
+func ConvertToDTO[M any, D any](models []M, convertFn func(*M) D) []D {
+	dtos := make([]D, len(models))
+	for i, model := range models {
+		// Create a copy of the model to avoid issues with loop variable capture
+		modelCopy := model
+		dtos[i] = convertFn(&modelCopy)
+	}
+	return dtos
+}
+
+// HandleGetAll is a generic function to handle GET all entities endpoints
+func HandleGetAll[M any, D any](
+	c *gin.Context,
+	getAllFn func(ctx context.Context) ([]M, error),
+	convertFn func(*M) D,
+	entityName string,
+) {
+	// Get entities from the database
+	entities, err := getAllFn(c.Request.Context())
+	if err != nil {
+		InternalErrorResponse(c, fmt.Sprintf("Error retrieving %s: %s", entityName, err.Error()))
+		return
+	}
+
+	// Convert to DTOs
+	dtos := ConvertToDTO(entities, convertFn)
+
+	SuccessResponse(c, 200, dtos)
+}
+
+// HandleGetByID is a generic function to handle GET entity by ID endpoints
+func HandleGetByID[M any, D any](
+	c *gin.Context,
+	getByIDFn func(ctx context.Context, id types.ULID) (*M, error),
+	convertFn func(*M) D,
+	entityName string,
+) {
+	// Parse ID from URL
+	id, err := ParseID(c, "id")
+	if err != nil {
+		BadRequestResponse(c, fmt.Sprintf("Invalid %s ID format", entityName))
+		return
+	}
+
+	// Get entity from the database
+	entity, err := getByIDFn(c.Request.Context(), id)
+	if err != nil {
+		InternalErrorResponse(c, fmt.Sprintf("Error retrieving %s: %s", entityName, err.Error()))
+		return
+	}
+
+	if entity == nil {
+		NotFoundResponse(c, fmt.Sprintf("%s not found", entityName))
+		return
+	}
+
+	// Convert to DTO
+	dto := convertFn(entity)
+
+	SuccessResponse(c, 200, dto)
+}
+
+// HandleCreate is a generic function to handle POST entity endpoints
+func HandleCreate[C any, M any, D any](
+	c *gin.Context,
+	createFn func(ctx context.Context, create C) (*M, error),
+	convertFn func(*M) D,
+	entityName string,
+) {
+	// Parse request body
+	var createDTO C
+	if err := BindJSON(c, &createDTO); err != nil {
+		BadRequestResponse(c, err.Error())
+		return
+	}
+
+	// Create entity in the database
+	entity, err := createFn(c.Request.Context(), createDTO)
+	if err != nil {
+		InternalErrorResponse(c, fmt.Sprintf("Error creating %s: %s", entityName, err.Error()))
+		return
+	}
+
+	// Convert to DTO
+	dto := convertFn(entity)
+
+	SuccessResponse(c, 201, dto)
+}
+
+// HandleDelete is a generic function to handle DELETE entity endpoints
+func HandleDelete(
+	c *gin.Context,
+	deleteFn func(ctx context.Context, id types.ULID) error,
+	entityName string,
+) {
+	// Parse ID from URL
+	id, err := ParseID(c, "id")
+	if err != nil {
+		BadRequestResponse(c, fmt.Sprintf("Invalid %s ID format", entityName))
+		return
+	}
+
+	// Delete entity from the database
+	err = deleteFn(c.Request.Context(), id)
+	if err != nil {
+		InternalErrorResponse(c, fmt.Sprintf("Error deleting %s: %s", entityName, err.Error()))
+		return
+	}
+
+	SuccessResponse(c, 204, nil)
+}