package dish

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

	"github.com/go-chi/chi/v5"
	"github.com/food-ai/backend/internal/infra/middleware"
)

// Handler handles HTTP requests for dishes.
type Handler struct {
	repo *Repository
}

// NewHandler creates a new Handler.
func NewHandler(repo *Repository) *Handler {
	return &Handler{repo: repo}
}

// Search handles GET /dishes/search?q=<query>&limit=<n>
func (h *Handler) Search(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query().Get("q")
	if query == "" {
		writeJSON(w, http.StatusOK, []*DishSearchResult{})
		return
	}
	limit := 10
	if limitStr := r.URL.Query().Get("limit"); limitStr != "" {
		if parsed, parseError := strconv.Atoi(limitStr); parseError == nil && parsed > 0 && parsed <= 50 {
			limit = parsed
		}
	}
	results, searchError := h.repo.Search(r.Context(), query, limit)
	if searchError != nil {
		slog.ErrorContext(r.Context(), "search dishes", "err", searchError)
		writeError(w, r, http.StatusInternalServerError, "failed to search dishes")
		return
	}
	if results == nil {
		results = []*DishSearchResult{}
	}
	writeJSON(w, http.StatusOK, results)
}

// List handles GET /dishes — returns all dishes (no recipe variants).
func (h *Handler) List(w http.ResponseWriter, r *http.Request) {
	dishes, err := h.repo.List(r.Context())
	if err != nil {
		slog.ErrorContext(r.Context(), "list dishes", "err", err)
		writeError(w, r, http.StatusInternalServerError, "failed to list dishes")
		return
	}
	if dishes == nil {
		dishes = []*Dish{}
	}
	writeJSON(w, http.StatusOK, map[string]any{"dishes": dishes})
}

// GetByID handles GET /dishes/{id} — returns a dish with all recipe variants.
func (h *Handler) GetByID(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	dish, err := h.repo.GetByID(r.Context(), id)
	if err != nil {
		slog.ErrorContext(r.Context(), "get dish", "id", id, "err", err)
		writeError(w, r, http.StatusInternalServerError, "failed to get dish")
		return
	}
	if dish == nil {
		writeError(w, r, http.StatusNotFound, "dish not found")
		return
	}
	writeJSON(w, http.StatusOK, dish)
}

// --- helpers ---

type errorResponse struct {
	Error     string `json:"error"`
	RequestID string `json:"request_id,omitempty"`
}

func writeError(w http.ResponseWriter, r *http.Request, status int, msg string) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(errorResponse{
		Error:     msg,
		RequestID: middleware.RequestIDFromCtx(r.Context()),
	})
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}