package handlers

import (
	"encoding/json"
	"net/http"
	"strconv"

	"github.com/fish/language/backend/internal/models"
	"github.com/fish/language/backend/internal/services"
	"github.com/go-chi/chi/v5"
)

// CategoryHandler handles HTTP requests for categories.
type CategoryHandler struct {
	svc *services.CategoryService
}

// NewCategoryHandler creates a new CategoryHandler.
func NewCategoryHandler(svc *services.CategoryService) *CategoryHandler {
	return &CategoryHandler{svc: svc}
}

// Register mounts category routes.
func (h *CategoryHandler) Register(r chi.Router) {
	r.Get("/categories", h.List)
	r.Post("/categories", h.Create)
	r.Get("/categories/{id}", h.Get)
	r.Put("/categories/{id}", h.Update)
	r.Delete("/categories/{id}", h.Delete)
}

// List returns all categories.
func (h *CategoryHandler) List(w http.ResponseWriter, r *http.Request) {
	items, err := h.svc.List(r.Context())
	if err != nil {
		status, code, msg := MapError(err)
		RespondError(w, status, code, msg)
		return
	}
	RespondSuccess(w, items)
}

// Get returns a category by id.
func (h *CategoryHandler) Get(w http.ResponseWriter, r *http.Request) {
	id, err := parseID(r)
	if err != nil {
		RespondError(w, http.StatusBadRequest, 10002, "invalid id")
		return
	}
	item, err := h.svc.Get(r.Context(), id)
	if err != nil {
		status, code, msg := MapError(err)
		RespondError(w, status, code, msg)
		return
	}
	RespondSuccess(w, item)
}

// Create creates a new category.
func (h *CategoryHandler) Create(w http.ResponseWriter, r *http.Request) {
	var req models.CreateCategoryRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		RespondError(w, http.StatusBadRequest, 10003, "invalid request body")
		return
	}
	if req.Name == "" {
		RespondError(w, http.StatusBadRequest, 10004, "name is required")
		return
	}
	item, err := h.svc.Create(r.Context(), req)
	if err != nil {
		status, code, msg := MapError(err)
		RespondError(w, status, code, msg)
		return
	}
	RespondJSON(w, http.StatusCreated, modelsAPIResponse{Code: 0, Message: "created", Data: item})
}

// Update updates a category.
func (h *CategoryHandler) Update(w http.ResponseWriter, r *http.Request) {
	id, err := parseID(r)
	if err != nil {
		RespondError(w, http.StatusBadRequest, 10002, "invalid id")
		return
	}
	var req models.UpdateCategoryRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		RespondError(w, http.StatusBadRequest, 10003, "invalid request body")
		return
	}
	if req.Name == "" {
		RespondError(w, http.StatusBadRequest, 10004, "name is required")
		return
	}
	item, err := h.svc.Update(r.Context(), id, req)
	if err != nil {
		status, code, msg := MapError(err)
		RespondError(w, status, code, msg)
		return
	}
	RespondSuccess(w, item)
}

// Delete removes a category.
func (h *CategoryHandler) Delete(w http.ResponseWriter, r *http.Request) {
	id, err := parseID(r)
	if err != nil {
		RespondError(w, http.StatusBadRequest, 10002, "invalid id")
		return
	}
	if err := h.svc.Delete(r.Context(), id); err != nil {
		status, code, msg := MapError(err)
		RespondError(w, status, code, msg)
		return
	}
	RespondSuccess(w, nil)
}

func parseID(r *http.Request) (int32, error) {
	idStr := chi.URLParam(r, "id")
	id64, err := strconv.ParseInt(idStr, 10, 32)
	if err != nil {
		return 0, err
	}
	return int32(id64), nil
}