init

internal/handler/category_handler.go

@@ -0,0 +1,266 @@
+package handler
+
+import (
+	"errors"
+	"strconv"
+
+	"accounting-app/pkg/api"
+	"accounting-app/internal/models"
+	"accounting-app/internal/service"
+
+	"github.com/gin-gonic/gin"
+)
+
+// CategoryHandler handles HTTP requests for category operations
+type CategoryHandler struct {
+	categoryService *service.CategoryService
+}
+
+// NewCategoryHandler creates a new CategoryHandler instance
+func NewCategoryHandler(categoryService *service.CategoryService) *CategoryHandler {
+	return &CategoryHandler{
+		categoryService: categoryService,
+	}
+}
+
+// CreateCategory handles POST /api/v1/categories
+// Creates a new category with the provided data
+func (h *CategoryHandler) CreateCategory(c *gin.Context) {
+	var input service.CategoryInput
+	if err := c.ShouldBindJSON(&input); err != nil {
+		api.ValidationError(c, "Invalid request body: "+err.Error())
+		return
+	}
+
+	userId, exists := c.Get("user_id")
+	if !exists {
+		api.Unauthorized(c, "User not authenticated")
+		return
+	}
+	input.UserID = userId.(uint)
+
+	category, err := h.categoryService.CreateCategory(input)
+	if err != nil {
+		if errors.Is(err, service.ErrInvalidParentCategory) {
+			api.BadRequest(c, "Invalid parent category ID")
+			return
+		}
+		if errors.Is(err, service.ErrParentTypeMismatch) {
+			api.BadRequest(c, "Parent category type must match child category type")
+			return
+		}
+		if errors.Is(err, service.ErrParentIsChild) {
+			api.BadRequest(c, "Cannot set a child category as parent (only 2 levels allowed)")
+			return
+		}
+		api.InternalError(c, "Failed to create category: "+err.Error())
+		return
+	}
+
+	api.Created(c, category)
+}
+
+// GetCategories handles GET /api/v1/categories
+// Returns a list of all categories, optionally filtered by type
+func (h *CategoryHandler) GetCategories(c *gin.Context) {
+	// Check for type filter
+	categoryType := c.Query("type")
+	tree := c.Query("tree") == "true"
+
+	userId, exists := c.Get("user_id")
+	if !exists {
+		api.Unauthorized(c, "User not authenticated")
+		return
+	}
+
+	var categories []models.Category
+	var err error
+
+	if tree {
+		// Return hierarchical tree structure
+		if categoryType != "" {
+			categories, err = h.categoryService.GetCategoryTreeByType(userId.(uint), models.CategoryType(categoryType))
+		} else {
+			categories, err = h.categoryService.GetCategoryTree(userId.(uint))
+		}
+	} else {
+		// Return flat list
+		if categoryType != "" {
+			categories, err = h.categoryService.GetCategoriesByType(userId.(uint), models.CategoryType(categoryType))
+		} else {
+			categories, err = h.categoryService.GetAllCategories(userId.(uint))
+		}
+	}
+
+	if err != nil {
+		api.InternalError(c, "Failed to get categories: "+err.Error())
+		return
+	}
+
+	api.Success(c, categories)
+}
+
+// GetCategory handles GET /api/v1/categories/:id
+// Returns a single category by ID
+func (h *CategoryHandler) GetCategory(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		api.BadRequest(c, "Invalid category ID")
+		return
+	}
+
+	// Check if children should be included
+	withChildren := c.Query("children") == "true"
+
+	userId, exists := c.Get("user_id")
+	if !exists {
+		api.Unauthorized(c, "User not authenticated")
+		return
+	}
+
+	var category *models.Category
+	if withChildren {
+		category, err = h.categoryService.GetCategoryWithChildren(userId.(uint), uint(id))
+	} else {
+		category, err = h.categoryService.GetCategory(userId.(uint), uint(id))
+	}
+
+	if err != nil {
+		if errors.Is(err, service.ErrCategoryNotFound) {
+			api.NotFound(c, "Category not found")
+			return
+		}
+		api.InternalError(c, "Failed to get category: "+err.Error())
+		return
+	}
+
+	api.Success(c, category)
+}
+
+// GetCategoryChildren handles GET /api/v1/categories/:id/children
+// Returns all child categories of a given parent
+func (h *CategoryHandler) GetCategoryChildren(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		api.BadRequest(c, "Invalid category ID")
+		return
+	}
+
+	userId, exists := c.Get("user_id")
+	if !exists {
+		api.Unauthorized(c, "User not authenticated")
+		return
+	}
+
+	children, err := h.categoryService.GetChildCategories(userId.(uint), uint(id))
+	if err != nil {
+		if errors.Is(err, service.ErrCategoryNotFound) {
+			api.NotFound(c, "Category not found")
+			return
+		}
+		api.InternalError(c, "Failed to get child categories: "+err.Error())
+		return
+	}
+
+	api.Success(c, children)
+}
+
+// UpdateCategory handles PUT /api/v1/categories/:id
+// Updates an existing category with the provided data
+func (h *CategoryHandler) UpdateCategory(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		api.BadRequest(c, "Invalid category ID")
+		return
+	}
+
+	var input service.CategoryInput
+	if err := c.ShouldBindJSON(&input); err != nil {
+		api.ValidationError(c, "Invalid request body: "+err.Error())
+		return
+	}
+
+	userId, exists := c.Get("user_id")
+	if !exists {
+		api.Unauthorized(c, "User not authenticated")
+		return
+	}
+	input.UserID = userId.(uint)
+
+	category, err := h.categoryService.UpdateCategory(userId.(uint), uint(id), input)
+	if err != nil {
+		if errors.Is(err, service.ErrCategoryNotFound) {
+			api.NotFound(c, "Category not found")
+			return
+		}
+		if errors.Is(err, service.ErrInvalidParentCategory) {
+			api.BadRequest(c, "Invalid parent category ID")
+			return
+		}
+		if errors.Is(err, service.ErrParentTypeMismatch) {
+			api.BadRequest(c, "Parent category type must match child category type")
+			return
+		}
+		if errors.Is(err, service.ErrCircularReference) {
+			api.BadRequest(c, "Cannot create circular reference in category hierarchy")
+			return
+		}
+		if errors.Is(err, service.ErrParentIsChild) {
+			api.BadRequest(c, "Cannot set a child category as parent (only 2 levels allowed)")
+			return
+		}
+		api.InternalError(c, "Failed to update category: "+err.Error())
+		return
+	}
+
+	api.Success(c, category)
+}
+
+// DeleteCategory handles DELETE /api/v1/categories/:id
+// Deletes a category by ID
+func (h *CategoryHandler) DeleteCategory(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		api.BadRequest(c, "Invalid category ID")
+		return
+	}
+
+	userId, exists := c.Get("user_id")
+	if !exists {
+		api.Unauthorized(c, "User not authenticated")
+		return
+	}
+
+	err = h.categoryService.DeleteCategory(userId.(uint), uint(id))
+	if err != nil {
+		if errors.Is(err, service.ErrCategoryNotFound) {
+			api.NotFound(c, "Category not found")
+			return
+		}
+		if errors.Is(err, service.ErrCategoryInUse) {
+			api.Conflict(c, "Category is in use and cannot be deleted. Please remove associated transactions first.")
+			return
+		}
+		if errors.Is(err, service.ErrCategoryHasChildren) {
+			api.Conflict(c, "Category has child categories and cannot be deleted. Please remove child categories first.")
+			return
+		}
+		api.InternalError(c, "Failed to delete category: "+err.Error())
+		return
+	}
+
+	api.NoContent(c)
+}
+
+// RegisterRoutes registers all category routes to the given router group
+func (h *CategoryHandler) RegisterRoutes(rg *gin.RouterGroup) {
+	categories := rg.Group("/categories")
+	{
+		categories.POST("", h.CreateCategory)
+		categories.GET("", h.GetCategories)
+		categories.GET("/:id", h.GetCategory)
+		categories.GET("/:id/children", h.GetCategoryChildren)
+		categories.PUT("/:id", h.UpdateCategory)
+		categories.DELETE("/:id", h.DeleteCategory)
+	}
+}