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"
)

// WordHandler handles HTTP requests for words.
type WordHandler struct {
	svc *services.WordService
}

// NewWordHandler creates a new WordHandler.
func NewWordHandler(svc *services.WordService) *WordHandler {
	return &WordHandler{svc: svc}
}

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

// List returns a paginated list of words.
func (h *WordHandler) List(w http.ResponseWriter, r *http.Request) {
	req := models.ListWordsRequest{}
	if v := r.URL.Query().Get("category_id"); v != "" {
		if id64, err := strconv.ParseInt(v, 10, 32); err == nil {
			id := int32(id64)
			req.CategoryID = &id
		}
	}
	req.Keyword = r.URL.Query().Get("keyword")
	if v := r.URL.Query().Get("page"); v != "" {
		if page, err := strconv.ParseInt(v, 10, 32); err == nil {
			req.Page = int32(page)
		}
	}
	if v := r.URL.Query().Get("page_size"); v != "" {
		if ps, err := strconv.ParseInt(v, 10, 32); err == nil {
			req.PageSize = int32(ps)
		}
	}

	resp, err := h.svc.List(r.Context(), req)
	if err != nil {
		status, code, msg := MapError(err)
		RespondError(w, status, code, msg)
		return
	}
	RespondSuccess(w, resp)
}

// Get returns a word by id.
func (h *WordHandler) 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 word.
func (h *WordHandler) Create(w http.ResponseWriter, r *http.Request) {
	var req models.CreateWordRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		RespondError(w, http.StatusBadRequest, 10003, "invalid request body")
		return
	}
	if req.Word == "" || req.Translation == "" || req.CategoryID == 0 {
		RespondError(w, http.StatusBadRequest, 10004, "word, translation and category_id are 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 word.
func (h *WordHandler) 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.UpdateWordRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		RespondError(w, http.StatusBadRequest, 10003, "invalid request body")
		return
	}
	if req.Word == "" || req.Translation == "" || req.CategoryID == 0 {
		RespondError(w, http.StatusBadRequest, 10004, "word, translation and category_id are 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 word.
func (h *WordHandler) 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)
}