package handlers

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

	"github.com/rede5/gohorsejobs/backend/internal/services"
)

type NotificationHandler struct {
	service *services.NotificationService
}

func NewNotificationHandler(service *services.NotificationService) *NotificationHandler {
	return &NotificationHandler{service: service}
}

// GetNotifications lists notifications
func (h *NotificationHandler) GetNotifications(w http.ResponseWriter, r *http.Request) {
	userID := getUserIDFromContext(r)
	if userID == "" {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	notifications, err := h.service.ListNotifications(r.Context(), userID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(notifications) // Returns []models.Notification
}

// MarkAsRead marks a notification as read
func (h *NotificationHandler) MarkAsRead(w http.ResponseWriter, r *http.Request) {
	userID := getUserIDFromContext(r)
	if userID == "" {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	id := r.PathValue("id")
	if id == "" {
		http.Error(w, "Invalid notification ID", http.StatusBadRequest)
		return
	}

	if err := h.service.MarkAsRead(r.Context(), userID, id); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusOK)
}

// MarkAllAsRead marks all as read
func (h *NotificationHandler) MarkAllAsRead(w http.ResponseWriter, r *http.Request) {
	userID := getUserIDFromContext(r)
	if userID == "" {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	if err := h.service.MarkAllAsRead(r.Context(), userID); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusOK)
}

// RegisterFCMToken registers a device token
func (h *NotificationHandler) RegisterFCMToken(w http.ResponseWriter, r *http.Request) {
	userID := getUserIDFromContext(r)
	if userID == "" {
		http.Error(w, "Unauthorized", http.StatusUnauthorized)
		return
	}

	var req struct {
		Token      string `json:"token"`
		DeviceType string `json:"deviceType"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request", http.StatusBadRequest)
		return
	}

	if req.Token == "" {
		http.Error(w, "Token is required", http.StatusBadRequest)
		return
	}

	if err := h.service.SaveFCMToken(r.Context(), userID, req.Token, req.DeviceType); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusOK)
}

// Helper: Extract UserID (String)
func getUserIDFromContext(r *http.Request) string {
	// 1. Check Context (set by correct middleware)
	if userID, ok := r.Context().Value("userID").(string); ok && userID != "" {
		return userID
	}
	// 2. Check Header (testing/dev)
	if userID := r.Header.Get("X-User-ID"); userID != "" {
		return userID
	}
	return ""
}