// lib/notification/NotificationContext.tsx
"use client";

import React, { createContext, useContext, useEffect, useState } from 'react';
import { useSession } from 'next-auth/react';
import { toast } from 'sonner'; // 또는 react-hot-toast

interface Notification {
  id: string;
  title: string;
  message: string;
  type: string;
  relatedRecordId?: string;
  relatedRecordType?: string;
  isRead: boolean;
  createdAt: string;
}

interface NotificationContextType {
  notifications: Notification[];
  unreadCount: number;
  markAsRead: (id: string) => Promise<void>;
  markAllAsRead: () => Promise<void>;
  refreshNotifications: () => Promise<void>;
}

const NotificationContext = createContext<NotificationContextType | null>(null);

export function NotificationProvider({ children }: { children: React.ReactNode }) {
  const { data: session } = useSession();
  const [notifications, setNotifications] = useState<Notification[]>([]);
  const [unreadCount, setUnreadCount] = useState(0);

  // 알림 목록 가져오기
  const refreshNotifications = async () => {
    if (!session?.user) return;

    try {
      const response = await fetch('/api/notifications');
      const data = await response.json();
      setNotifications(data.notifications);
      setUnreadCount(data.unreadCount);
    } catch (error) {
      console.error('Failed to fetch notifications:', error);
    }
  };

  // 읽음 처리
  const markAsRead = async (id: string) => {
    try {
      await fetch(`/api/notifications/${id}/read`, { method: 'PATCH' });
      setNotifications(prev => 
        prev.map(n => n.id === id ? { ...n, isRead: true } : n)
      );
      setUnreadCount(prev => prev - 1);
    } catch (error) {
      console.error('Failed to mark notification as read:', error);
    }
  };

  // 모든 알림 읽음 처리
  const markAllAsRead = async () => {
    try {
      await fetch('/api/notifications/read-all', { method: 'PATCH' });
      setNotifications(prev => prev.map(n => ({ ...n, isRead: true })));
      setUnreadCount(0);
    } catch (error) {
      console.error('Failed to mark all notifications as read:', error);
    }
  };

  // SSE 연결로 실시간 알림 수신
  useEffect(() => {
    if (!session?.user) return;

    // 초기 알림 로드
    refreshNotifications();

    // SSE 연결
    const eventSource = new EventSource('/api/notifications/stream');

    eventSource.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        
        if (data.type === 'heartbeat' || data.type === 'connected') {
          return; // 하트비트 및 연결 확인 메시지는 무시
        }
        
        if (data.type === 'new_notification') {
          const newNotification = data.data;
          
          // 새 알림을 기존 목록에 추가
          setNotifications(prev => [newNotification, ...prev]);
          setUnreadCount(prev => prev + 1);
          
          // Toast 알림 표시
          toast(newNotification.title, {
            description: newNotification.message,
            action: {
              label: "보기",
              onClick: () => {
                handleNotificationClick(newNotification);
              },
            },
          });
        } else if (data.type === 'notification_read') {
          const readData = data.data;
          
          // 읽음 상태 업데이트
          setNotifications(prev => 
            prev.map(n => n.id === readData.id ? { ...n, isRead: true, readAt: readData.read_at } : n)
          );
          
          if (!readData.is_read) {
            setUnreadCount(prev => Math.max(0, prev - 1));
          }
        }
      } catch (error) {
        console.error('Failed to parse SSE data:', error);
      }
    };

    eventSource.onopen = () => {
      console.log('SSE connection established');
    };

    eventSource.onerror = (error) => {
      console.error('SSE error:', error);
      // 자동 재연결은 EventSource가 처리
    };

    return () => {
      eventSource.close();
    };
  }, [session?.user]);

  const handleNotificationClick = (notification: Notification) => {
    // 알림 클릭 시 관련 페이지로 이동
    if (notification.relatedRecordId && notification.relatedRecordType) {
      const url = getNotificationUrl(notification.relatedRecordType, notification.relatedRecordId);
      window.location.href = url;
    }
    markAsRead(notification.id);
  };

  const getNotificationUrl = (type: string, id: string | null) => {
    const pathParts = window.location.pathname.split('/');
    const lng = pathParts[1];
    const domain = pathParts[2];
    
    // 도메인별 기본 URL 설정
    const baseUrls = {
      'partners': `/${lng}/partners`,
      'procurement': `/${lng}/procurement`, 
      'sales': `/${lng}/sales`,
      'engineering': `/${lng}/engineering`,
      'evcp': `/${lng}/evcp`
    };
    
    const baseUrl = baseUrls[domain as keyof typeof baseUrls] || `/${lng}/evcp`;
    
    if (!id) {
      // ID가 없는 경우 (시스템 공지, 일반 알림 등)
      switch (type) {
        case 'evaluation':
        case 'evaluation_request':
          return domain === 'partners' ? `${baseUrl}/evaluation` : `${baseUrl}/evaluations`;
        case 'announcement':
        case 'system':
          return `${baseUrl}/announcements`;
        default:
          return baseUrl;
      }
    }
    
    // ID가 있는 경우
    switch (type) {
      case 'project':
        return `${baseUrl}/projects/${id}`;
      case 'task':
        return `${baseUrl}/tasks/${id}`;
      case 'order':
        return `${baseUrl}/orders/${id}`;
      case 'evaluation_submission':
        return domain === 'partners' 
          ? `${baseUrl}/evaluation/${id}` 
          : `${baseUrl}/evaluations/submissions/${id}`;
      case 'document':
        return `${baseUrl}/documents/${id}`;
      case 'approval':
        return `${baseUrl}/approvals/${id}`;
      default:
        return baseUrl;
    }
  };

  return (
    <NotificationContext.Provider 
      value={{ 
        notifications, 
        unreadCount, 
        markAsRead, 
        markAllAsRead, 
        refreshNotifications 
      }}
    >
      {children}
    </NotificationContext.Provider>
  );
}

export function useNotifications() {
  const context = useContext(NotificationContext);
  if (!context) {
    throw new Error('useNotifications must be used within NotificationProvider');
  }
  return context;
}