package handler

import (
	"encoding/json"
	"errors"
	"net/http"
	"strings"

	"5803025020/w04/internal/middleware"
	"5803025020/w04/internal/models"
	"5803025020/w04/internal/store"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

type SnippetHandler struct {
	snippetStore *store.SnippetStore
}

func NewSnippetHandler(snippetStore *store.SnippetStore) *SnippetHandler {
	return &SnippetHandler{snippetStore: snippetStore}
}

type snippetRequest struct {
	Title   string `json:"title"`
	Content string `json:"content"`
}

func (h *SnippetHandler) Snippets(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		h.List(w, r)
	case http.MethodPost:
		h.Create(w, r)
	default:
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
	}
}

func (h *SnippetHandler) SnippetByID(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		h.Get(w, r)
	case http.MethodDelete:
		h.Delete(w, r)
	default:
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
	}
}

func (h *SnippetHandler) Create(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
		return
	}

	userID := middleware.GetUserID(r.Context())
	if userID == "" {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	var req snippetRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Bad Request", http.StatusBadRequest)
		return
	}

	req.Title = strings.TrimSpace(req.Title)
	req.Content = strings.TrimSpace(req.Content)
	if req.Title == "" || req.Content == "" {
		http.Error(w, "Title and content are required", http.StatusBadRequest)
		return
	}

	snippet := &models.Snippet{
		ID:      uuid.New().String(),
		Title:   req.Title,
		Content: req.Content,
		UserID:  userID,
	}

	if err := h.snippetStore.Create(r.Context(), snippet); err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusCreated)
	_ = json.NewEncoder(w).Encode(snippet)
}

func (h *SnippetHandler) List(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
		return
	}

	snippets, err := h.snippetStore.GetAll(r.Context())
	if err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	_ = json.NewEncoder(w).Encode(snippets)
}

func (h *SnippetHandler) Get(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
		return
	}

	id := r.PathValue("id")
	if id == "" {
		path := strings.TrimPrefix(r.URL.Path, "/snippets/")
		id = strings.TrimSuffix(path, "/")
	}

	if id == "" {
		http.Error(w, "Bad Request", http.StatusBadRequest)
		return
	}

	snippet, err := h.snippetStore.GetByID(r.Context(), id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			http.Error(w, "Snippet not found", http.StatusNotFound)
			return
		}
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	_ = json.NewEncoder(w).Encode(snippet)
}

func (h *SnippetHandler) Delete(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodDelete {
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
		return
	}

	id := r.PathValue("id")
	if id == "" {
		path := strings.TrimPrefix(r.URL.Path, "/snippets/")
		id = strings.TrimSuffix(path, "/")
	}

	if id == "" {
		http.Error(w, "Bad Request", http.StatusBadRequest)
		return
	}

	if err := h.snippetStore.Delete(r.Context(), id); err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}