/**
 * Notifications Page
 *
 * Full page view for managing all user notifications
 */

'use client';

import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { useState } from 'react';
import { useRouter } from 'next/navigation';
import {
  listNotifications,
  markNotificationAsRead,
  markAllNotificationsAsRead,
  deleteNotification,
} from '@/lib/api';
import type { NotificationResponse } from '@/types/api';
import { Trash2, CheckCheck, Filter, Bell, ChevronLeft, ChevronRight } from 'lucide-react';

export default function NotificationsPage() {
  const [selectedFilter, setSelectedFilter] = useState<'all' | 'unread' | 'read'>('all');
  const [currentPage, setCurrentPage] = useState(1);
  const queryClient = useQueryClient();
  const router = useRouter();

  // Fetch notifications with pagination
  const { data, isLoading } = useQuery({
    queryKey: ['notifications', 'page', selectedFilter, currentPage],
    queryFn: () =>
      listNotifications({
        page: currentPage,
        limit: 20,
        isRead: selectedFilter === 'all' ? undefined : selectedFilter === 'read',
      }),
  });

  const notifications = data?.notifications || [];
  const total = data?.total || 0;
  const totalPages = Math.ceil(total / 20);
  const unreadCount = notifications.filter((n: NotificationResponse) => !n.read).length;

  // Mark single notification as read
  const markAsReadMutation = useMutation({
    mutationFn: markNotificationAsRead,
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['notifications'] });
    },
  });

  // Mark all as read
  const markAllAsReadMutation = useMutation({
    mutationFn: markAllNotificationsAsRead,
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['notifications'] });
    },
  });

  // Delete notification
  const deleteNotificationMutation = useMutation({
    mutationFn: deleteNotification,
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['notifications'] });
    },
  });

  const handleNotificationClick = (notification: NotificationResponse) => {
    if (!notification.read) {
      markAsReadMutation.mutate(notification.id);
    }

    // Navigate to actionUrl if available
    if (notification.actionUrl) {
      router.push(notification.actionUrl);
    }
  };

  const handleDelete = (e: React.MouseEvent, notificationId: string) => {
    e.stopPropagation();
    if (confirm('Are you sure you want to delete this notification?')) {
      deleteNotificationMutation.mutate(notificationId);
    }
  };

  const getPriorityColor = (priority: string) => {
    const colors = {
      urgent: 'border-l-4 border-red-500 bg-red-50 hover:bg-red-100',
      high: 'border-l-4 border-orange-500 bg-orange-50 hover:bg-orange-100',
      medium: 'border-l-4 border-yellow-500 bg-yellow-50 hover:bg-yellow-100',
      low: 'border-l-4 border-blue-500 bg-blue-50 hover:bg-blue-100',
    };
    return colors[priority as keyof typeof colors] || 'border-l-4 border-gray-300 hover:bg-gray-100';
  };

  const getNotificationIcon = (type: string) => {
    const icons: Record<string, string> = {
      booking_created: '📦',
      booking_updated: '🔄',
      booking_cancelled: '❌',
      booking_confirmed: '✅',
      csv_booking_accepted: '✅',
      csv_booking_rejected: '❌',
      csv_booking_request_sent: '📧',
      rate_quote_expiring: '⏰',
      document_uploaded: '📄',
      system_announcement: '📢',
      user_invited: '👤',
      organization_update: '🏢',
    };
    return icons[type.toLowerCase()] || '🔔';
  };

  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(diffMs / 3600000);
    const diffDays = Math.floor(diffMs / 86400000);

    if (diffMins < 1) return 'Just now';
    if (diffMins < 60) return `${diffMins}m ago`;
    if (diffHours < 24) return `${diffHours}h ago`;
    if (diffDays < 7) return `${diffDays}d ago`;
    return date.toLocaleDateString('en-US', {
      month: 'long',
      day: 'numeric',
      year: date.getFullYear() !== now.getFullYear() ? 'numeric' : undefined,
      hour: '2-digit',
      minute: '2-digit',
    });
  };

  return (
    <div className="min-h-screen bg-gray-50">
      {/* Header */}
      <div className="bg-white border-b shadow-sm">
        <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-6">
          <div className="flex items-center justify-between">
            <div className="flex items-center space-x-4">
              <div className="p-3 bg-blue-100 rounded-lg">
                <Bell className="w-8 h-8 text-blue-600" />
              </div>
              <div>
                <h1 className="text-3xl font-bold text-gray-900">Notifications</h1>
                <p className="text-sm text-gray-600 mt-1">
                  {total} notification{total !== 1 ? 's' : ''} total
                  {unreadCount > 0 && ` • ${unreadCount} unread`}
                </p>
              </div>
            </div>
            {unreadCount > 0 && (
              <button
                onClick={() => markAllAsReadMutation.mutate()}
                disabled={markAllAsReadMutation.isPending}
                className="flex items-center space-x-2 px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 disabled:opacity-50 transition-colors"
              >
                <CheckCheck className="w-5 h-5" />
                <span>Mark all as read</span>
              </button>
            )}
          </div>
        </div>
      </div>

      {/* Main Content */}
      <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
        {/* Filter Bar */}
        <div className="bg-white rounded-lg shadow-sm border p-4 mb-6">
          <div className="flex items-center space-x-3">
            <Filter className="w-5 h-5 text-gray-500" />
            <span className="text-sm font-medium text-gray-700">Filter:</span>
            <div className="flex space-x-2">
              {(['all', 'unread', 'read'] as const).map((filter) => (
                <button
                  key={filter}
                  onClick={() => {
                    setSelectedFilter(filter);
                    setCurrentPage(1);
                  }}
                  className={`px-4 py-2 text-sm font-medium rounded-lg transition-colors ${
                    selectedFilter === filter
                      ? 'bg-blue-600 text-white shadow-sm'
                      : 'bg-gray-100 text-gray-700 hover:bg-gray-200'
                  }`}
                >
                  {filter.charAt(0).toUpperCase() + filter.slice(1)}
                  {filter === 'unread' && unreadCount > 0 && (
                    <span className="ml-2 px-2 py-0.5 bg-white/20 rounded-full text-xs">
                      {unreadCount}
                    </span>
                  )}
                </button>
              ))}
            </div>
          </div>
        </div>

        {/* Notifications List */}
        <div className="bg-white rounded-lg shadow-sm border">
          {isLoading ? (
            <div className="flex items-center justify-center py-20">
              <div className="text-center">
                <div className="animate-spin rounded-full h-16 w-16 border-b-2 border-blue-600 mx-auto mb-4" />
                <p className="text-gray-500">Loading notifications...</p>
              </div>
            </div>
          ) : notifications.length === 0 ? (
            <div className="flex items-center justify-center py-20">
              <div className="text-center">
                <div className="text-7xl mb-4">🔔</div>
                <h3 className="text-xl font-semibold text-gray-900 mb-2">No notifications</h3>
                <p className="text-gray-500">
                  {selectedFilter === 'unread'
                    ? "You're all caught up! Great job!"
                    : 'No notifications to display'}
                </p>
              </div>
            </div>
          ) : (
            <div className="divide-y">
              {notifications.map((notification: NotificationResponse) => (
                <div
                  key={notification.id}
                  onClick={() => handleNotificationClick(notification)}
                  className={`p-6 transition-all cursor-pointer group ${
                    !notification.read ? 'bg-blue-50/50' : ''
                  } ${getPriorityColor(notification.priority || 'low')}`}
                >
                  <div className="flex items-start space-x-4">
                    {/* Icon */}
                    <div className="flex-shrink-0 text-4xl">
                      {getNotificationIcon(notification.type)}
                    </div>

                    {/* Content */}
                    <div className="flex-1 min-w-0">
                      <div className="flex items-start justify-between mb-2">
                        <div className="flex items-center space-x-3">
                          <h3 className="text-lg font-semibold text-gray-900">
                            {notification.title}
                          </h3>
                          {!notification.read && (
                            <span className="flex items-center space-x-1 px-2 py-1 bg-blue-600 text-white text-xs font-medium rounded-full">
                              <span className="w-2 h-2 bg-white rounded-full animate-pulse" />
                              <span>NEW</span>
                            </span>
                          )}
                        </div>
                        <button
                          onClick={(e) => handleDelete(e, notification.id)}
                          className="opacity-0 group-hover:opacity-100 transition-opacity p-2 hover:bg-red-100 rounded-lg"
                          title="Delete notification"
                        >
                          <Trash2 className="w-5 h-5 text-red-600" />
                        </button>
                      </div>

                      <p className="text-base text-gray-700 mb-4 leading-relaxed">
                        {notification.message}
                      </p>

                      {/* Metadata */}
                      <div className="flex items-center justify-between">
                        <div className="flex items-center flex-wrap gap-3 text-xs">
                          <span className="flex items-center space-x-1 text-gray-600">
                            <svg
                              className="w-4 h-4"
                              fill="none"
                              stroke="currentColor"
                              viewBox="0 0 24 24"
                            >
                              <path
                                strokeLinecap="round"
                                strokeLinejoin="round"
                                strokeWidth={2}
                                d="M12 8v4l3 3m6-3a9 9 0 11-18 0 9 9 0 0118 0z"
                              />
                            </svg>
                            <span className="font-medium">{formatTime(notification.createdAt)}</span>
                          </span>
                          <span className="px-3 py-1 bg-gray-100 rounded-full text-gray-700 font-medium">
                            {notification.type.replace(/_/g, ' ').toUpperCase()}
                          </span>
                          {notification.priority && (
                            <span
                              className={`px-3 py-1 rounded-full font-medium ${
                                notification.priority === 'urgent'
                                  ? 'bg-red-100 text-red-700'
                                  : notification.priority === 'high'
                                  ? 'bg-orange-100 text-orange-700'
                                  : notification.priority === 'medium'
                                  ? 'bg-yellow-100 text-yellow-700'
                                  : 'bg-blue-100 text-blue-700'
                              }`}
                            >
                              {notification.priority.toUpperCase()}
                            </span>
                          )}
                        </div>
                        {notification.actionUrl && (
                          <span className="text-sm text-blue-600 font-medium group-hover:underline flex items-center space-x-1">
                            <span>View details</span>
                            <svg
                              className="w-4 h-4"
                              fill="none"
                              stroke="currentColor"
                              viewBox="0 0 24 24"
                            >
                              <path
                                strokeLinecap="round"
                                strokeLinejoin="round"
                                strokeWidth={2}
                                d="M9 5l7 7-7 7"
                              />
                            </svg>
                          </span>
                        )}
                      </div>
                    </div>
                  </div>
                </div>
              ))}
            </div>
          )}
        </div>

        {/* Pagination */}
        {totalPages > 1 && (
          <div className="mt-6 bg-white rounded-lg shadow-sm border p-4">
            <div className="flex items-center justify-between">
              <div className="text-sm text-gray-600">
                Showing page <span className="font-semibold">{currentPage}</span> of{' '}
                <span className="font-semibold">{totalPages}</span>
                {' • '}
                <span className="font-semibold">{total}</span> total notification
                {total !== 1 ? 's' : ''}
              </div>
              <div className="flex items-center space-x-2">
                <button
                  onClick={() => setCurrentPage((p) => Math.max(1, p - 1))}
                  disabled={currentPage === 1}
                  className="flex items-center space-x-1 px-4 py-2 text-sm font-medium bg-white border border-gray-300 rounded-lg hover:bg-gray-50 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
                >
                  <ChevronLeft className="w-4 h-4" />
                  <span>Previous</span>
                </button>
                <div className="flex items-center space-x-1">
                  {Array.from({ length: Math.min(5, totalPages) }, (_, i) => {
                    let pageNum;
                    if (totalPages <= 5) {
                      pageNum = i + 1;
                    } else if (currentPage <= 3) {
                      pageNum = i + 1;
                    } else if (currentPage >= totalPages - 2) {
                      pageNum = totalPages - 4 + i;
                    } else {
                      pageNum = currentPage - 2 + i;
                    }

                    return (
                      <button
                        key={pageNum}
                        onClick={() => setCurrentPage(pageNum)}
                        className={`w-10 h-10 text-sm font-medium rounded-lg transition-colors ${
                          currentPage === pageNum
                            ? 'bg-blue-600 text-white'
                            : 'bg-white text-gray-700 hover:bg-gray-100 border border-gray-300'
                        }`}
                      >
                        {pageNum}
                      </button>
                    );
                  })}
                </div>
                <button
                  onClick={() => setCurrentPage((p) => Math.min(totalPages, p + 1))}
                  disabled={currentPage === totalPages}
                  className="flex items-center space-x-1 px-4 py-2 text-sm font-medium bg-white border border-gray-300 rounded-lg hover:bg-gray-50 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
                >
                  <span>Next</span>
                  <ChevronRight className="w-4 h-4" />
                </button>
              </div>
            </div>
          </div>
        )}
      </div>
    </div>
  );
}
