'use client';

import { useState, useEffect } from 'react';
import { useRouter } from 'next/navigation';
import Link from 'next/link';
import { useTranslation } from '@/lib/i18n';
import { useAuthStore } from '@/lib/store';
import { notificationApi, Notification } from '@/lib/api';

export default function NotificationsPage() {
  const router = useRouter();
  const { t } = useTranslation();
  const { user } = useAuthStore();

  const [notifications, setNotifications] = useState<Notification[]>([]);
  const [loading, setLoading] = useState(true);
  const [page, setPage] = useState(1);
  const [total, setTotal] = useState(0);
  const [unreadCount, setUnreadCount] = useState(0);
  const [filter, setFilter] = useState<'all' | 'unread'>('all');

  const pageSize = 20;

  // Redirect if not logged in
  useEffect(() => {
    if (!user) {
      router.push('/login?redirect=/notifications');
    }
  }, [user, router]);

  // Fetch notifications
  useEffect(() => {
    if (!user) return;

    const fetchNotifications = async () => {
      setLoading(true);
      try {
        const response = await notificationApi.getNotifications(
          page,
          pageSize,
          filter === 'unread'
        );
        setNotifications(response.notifications);
        setTotal(response.total);
        setUnreadCount(response.unread_count);
      } catch (error) {
        console.error('Failed to fetch notifications:', error);
      } finally {
        setLoading(false);
      }
    };

    fetchNotifications();
  }, [user, page, filter]);

  // Mark as read and navigate
  const handleNotificationClick = async (notification: Notification) => {
    if (!notification.is_read) {
      try {
        await notificationApi.markAsRead([notification.id]);
        setNotifications(prev =>
          prev.map(n => n.id === notification.id ? { ...n, is_read: true } : n)
        );
        setUnreadCount(prev => Math.max(0, prev - 1));
      } catch (error) {
        console.error('Failed to mark as read:', error);
      }
    }

    if (notification.link) {
      router.push(notification.link);
    }
  };

  // Mark all as read
  const handleMarkAllRead = async () => {
    try {
      await notificationApi.markAllAsRead();
      setNotifications(prev => prev.map(n => ({ ...n, is_read: true })));
      setUnreadCount(0);
    } catch (error) {
      console.error('Failed to mark all as read:', error);
    }
  };

  // Delete notification
  const handleDelete = async (e: React.MouseEvent, notificationId: number) => {
    e.stopPropagation();
    try {
      await notificationApi.deleteNotification(notificationId);
      setNotifications(prev => prev.filter(n => n.id !== notificationId));
      setTotal(prev => prev - 1);
    } catch (error) {
      console.error('Failed to delete notification:', error);
    }
  };

  // Format time
  const formatTime = (dateString: string) => {
    const date = new Date(dateString);
    const now = new Date();
    const diffMs = now.getTime() - date.getTime();
    const diffMins = Math.floor(diffMs / 60000);
    const diffHours = Math.floor(diffMins / 60);
    const diffDays = Math.floor(diffHours / 24);

    if (diffMins < 1) return '방금 전';
    if (diffMins < 60) return `${diffMins}분 전`;
    if (diffHours < 24) return `${diffHours}시간 전`;
    if (diffDays < 7) return `${diffDays}일 전`;
    return date.toLocaleDateString('ko-KR', {
      year: 'numeric',
      month: 'long',
      day: 'numeric',
      hour: '2-digit',
      minute: '2-digit'
    });
  };

  // Get notification icon
  const getNotificationIcon = (type: string) => {
    switch (type) {
      case 'vehicle_recommended': return '🚗';
      case 'shipping_update': return '🚚';
      case 'withdrawal_processed': return '💰';
      case 'referral_reward': return '🎁';
      case 'dealer_approved': return '✅';
      case 'dealer_rejected': return '❌';
      case 'share_purchased': return '🎉';
      case 'system': return '📢';
      default: return '🔔';
    }
  };

  // Get notification type label
  const getTypeLabel = (type: string) => {
    switch (type) {
      case 'vehicle_recommended': return '차량 추천';
      case 'shipping_update': return '배송 업데이트';
      case 'withdrawal_processed': return '출금 처리';
      case 'referral_reward': return '레퍼럴 보상';
      case 'dealer_approved': return '딜러 승인';
      case 'dealer_rejected': return '딜러 거부';
      case 'share_purchased': return '공유 판매';
      case 'system': return '시스템 알림';
      default: return '알림';
    }
  };

  const totalPages = Math.ceil(total / pageSize);

  if (!user) {
    return null;
  }

  return (
    <div className="min-h-screen bg-gray-50 py-8">
      <div className="container mx-auto px-4 max-w-3xl">
        {/* Header */}
        <div className="flex items-center justify-between mb-6">
          <div>
            <h1 className="text-2xl font-bold text-gray-800">
              {t.notifications || '알림'}
            </h1>
            <p className="text-gray-600 mt-1">
              {unreadCount > 0 ? (
                <span className="text-primary-600 font-medium">
                  읽지 않은 알림 {unreadCount}개
                </span>
              ) : (
                '모든 알림을 확인했습니다'
              )}
            </p>
          </div>

          {unreadCount > 0 && (
            <button
              onClick={handleMarkAllRead}
              className="text-primary-600 hover:text-primary-700 text-sm font-medium"
            >
              {t.markAllRead || '모두 읽음 처리'}
            </button>
          )}
        </div>

        {/* Filter Tabs */}
        <div className="flex gap-2 mb-4">
          <button
            onClick={() => { setFilter('all'); setPage(1); }}
            className={`px-4 py-2 rounded-lg text-sm font-medium transition ${
              filter === 'all'
                ? 'bg-primary-600 text-white'
                : 'bg-white text-gray-700 hover:bg-gray-100'
            }`}
          >
            전체
          </button>
          <button
            onClick={() => { setFilter('unread'); setPage(1); }}
            className={`px-4 py-2 rounded-lg text-sm font-medium transition ${
              filter === 'unread'
                ? 'bg-primary-600 text-white'
                : 'bg-white text-gray-700 hover:bg-gray-100'
            }`}
          >
            읽지 않음 ({unreadCount})
          </button>
        </div>

        {/* Notification List */}
        <div className="bg-white rounded-lg shadow-md overflow-hidden">
          {loading ? (
            <div className="p-8 text-center">
              <div className="animate-spin w-8 h-8 border-4 border-primary-600 border-t-transparent rounded-full mx-auto"></div>
              <p className="mt-4 text-gray-500">알림을 불러오는 중...</p>
            </div>
          ) : notifications.length === 0 ? (
            <div className="p-12 text-center">
              <div className="text-6xl mb-4">🔔</div>
              <p className="text-gray-500 text-lg">
                {filter === 'unread' ? '읽지 않은 알림이 없습니다' : '알림이 없습니다'}
              </p>
            </div>
          ) : (
            <div className="divide-y">
              {notifications.map((notification) => (
                <div
                  key={notification.id}
                  onClick={() => handleNotificationClick(notification)}
                  className={`p-4 hover:bg-gray-50 cursor-pointer transition ${
                    !notification.is_read ? 'bg-blue-50' : ''
                  }`}
                >
                  <div className="flex items-start gap-4">
                    {/* Icon */}
                    <div className="text-3xl flex-shrink-0">
                      {getNotificationIcon(notification.notification_type)}
                    </div>

                    {/* Content */}
                    <div className="flex-1 min-w-0">
                      <div className="flex items-center gap-2 mb-1">
                        <span className="text-xs text-gray-500 bg-gray-100 px-2 py-0.5 rounded">
                          {getTypeLabel(notification.notification_type)}
                        </span>
                        {!notification.is_read && (
                          <span className="w-2 h-2 bg-blue-500 rounded-full"></span>
                        )}
                      </div>

                      <h3 className={`text-base ${!notification.is_read ? 'font-semibold' : 'font-medium'} text-gray-800`}>
                        {notification.title}
                      </h3>

                      <p className="text-sm text-gray-600 mt-1">
                        {notification.message}
                      </p>

                      <p className="text-xs text-gray-400 mt-2">
                        {formatTime(notification.created_at)}
                      </p>
                    </div>

                    {/* Actions */}
                    <div className="flex-shrink-0">
                      <button
                        onClick={(e) => handleDelete(e, notification.id)}
                        className="p-2 text-gray-400 hover:text-red-500 hover:bg-red-50 rounded-full transition"
                        title="삭제"
                      >
                        <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16" />
                        </svg>
                      </button>
                    </div>
                  </div>
                </div>
              ))}
            </div>
          )}
        </div>

        {/* Pagination */}
        {totalPages > 1 && (
          <div className="flex justify-center items-center gap-2 mt-6">
            <button
              onClick={() => setPage(p => Math.max(1, p - 1))}
              disabled={page === 1}
              className="px-4 py-2 bg-white rounded-lg shadow disabled:opacity-50 disabled:cursor-not-allowed hover:bg-gray-50"
            >
              이전
            </button>

            <span className="px-4 py-2 text-gray-600">
              {page} / {totalPages}
            </span>

            <button
              onClick={() => setPage(p => Math.min(totalPages, p + 1))}
              disabled={page === totalPages}
              className="px-4 py-2 bg-white rounded-lg shadow disabled:opacity-50 disabled:cursor-not-allowed hover:bg-gray-50"
            >
              다음
            </button>
          </div>
        )}

        {/* Back Link */}
        <div className="mt-8 text-center">
          <Link href="/" className="text-primary-600 hover:text-primary-700">
            ← 홈으로 돌아가기
          </Link>
        </div>
      </div>
    </div>
  );
}