import React, { useState } from "react";
import { base44 } from "@/api/base44Client";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { useNavigate } from "react-router-dom";
import { createPageUrl } from "@/utils";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import { 
  X, 
  Bell, 
  Calendar, 
  UserPlus, 
  FileText, 
  MessageSquare, 
  AlertCircle, 
  CheckCircle,
  ArrowRight,
  MoreVertical,
  CheckSquare,
  Package
} from "lucide-react";
import { motion, AnimatePresence } from "framer-motion";
import { formatDistanceToNow, format, isToday, isYesterday, isThisWeek, startOfDay } from "date-fns";

const iconMap = {
  calendar: Calendar,
  user: UserPlus,
  invoice: FileText,
  message: MessageSquare,
  alert: AlertCircle,
  check: CheckCircle,
};

const colorMap = {
  blue: "bg-blue-100 text-blue-600",
  red: "bg-red-100 text-red-600",
  green: "bg-green-100 text-green-600",
  yellow: "bg-yellow-100 text-yellow-600",
  purple: "bg-purple-100 text-purple-600",
};

export default function NotificationPanel({ isOpen, onClose }) {
  const navigate = useNavigate();
  const queryClient = useQueryClient();
  const [activeFilter, setActiveFilter] = useState('all');

  const { data: user } = useQuery({
    queryKey: ['current-user-notifications'],
    queryFn: () => base44.auth.me(),
  });

  const { data: notifications = [] } = useQuery({
    queryKey: ['activity-logs', user?.id],
    queryFn: async () => {
      if (!user?.id) return [];
      
      // Create sample notifications if none exist
      const existing = await base44.entities.ActivityLog.filter({ user_id: user.id }, '-created_date', 50);
      
      if (existing.length === 0 && user?.id) {
        // Create initial sample notifications
        await base44.entities.ActivityLog.bulkCreate([
          {
            title: "Event Rescheduled",
            description: "Team Meeting was moved to July 15, 3:00 PM",
            activity_type: "event_rescheduled",
            related_entity_type: "event",
            action_label: "View Event",
            icon_type: "calendar",
            icon_color: "blue",
            is_read: false,
            user_id: user.id
          },
          {
            title: "Event Canceled",
            description: "Product Demo scheduled for May 20 has been canceled",
            activity_type: "event_canceled",
            related_entity_type: "event",
            action_label: "View Event",
            icon_type: "calendar",
            icon_color: "red",
            is_read: false,
            user_id: user.id
          },
          {
            title: "Invoice Paid",
            description: "You've been added to Client Kickoff on June 8, 10:00 AM",
            activity_type: "invoice_paid",
            related_entity_type: "invoice",
            action_label: "View Invoice",
            icon_type: "invoice",
            icon_color: "green",
            is_read: false,
            user_id: user.id
          },
          {
            title: "Staff Selected",
            description: "10 staff members selected to fill remaining 10 slots",
            activity_type: "staff_assigned",
            related_entity_type: "event",
            icon_type: "user",
            icon_color: "purple",
            is_read: true,
            user_id: user.id
          }
        ]);
        
        return await base44.entities.ActivityLog.filter({ user_id: user.id }, '-created_date', 50);
      }
      
      return existing;
    },
    enabled: !!user?.id,
    initialData: [],
  });

  const markAsReadMutation = useMutation({
    mutationFn: ({ id }) => base44.entities.ActivityLog.update(id, { is_read: true }),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['activity-logs'] });
    },
  });

  const deleteMutation = useMutation({
    mutationFn: ({ id }) => base44.entities.ActivityLog.delete(id),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['activity-logs'] });
    },
  });

  // Categorize by type
  const categorizeByType = (notif) => {
    const type = notif.activity_type || '';
    const title = (notif.title || '').toLowerCase();

    if (type.includes('message') || title.includes('message') || title.includes('comment') || title.includes('mentioned')) {
      return 'mentions';
    } else if (type.includes('staff_assigned') || type.includes('user') || title.includes('invited') || title.includes('followed')) {
      return 'invites';
    } else {
      return 'all';
    }
  };

  // Filter notifications based on active filter
  const filteredNotifications = notifications.filter(notif => {
    if (activeFilter === 'all') return true;
    return categorizeByType(notif) === activeFilter;
  });

  // Group by day
  const groupByDay = (notifList) => {
    const groups = {
      today: [],
      yesterday: [],
      thisWeek: [],
      older: []
    };

    notifList.forEach(notif => {
      const date = new Date(notif.created_date);
      if (isToday(date)) {
        groups.today.push(notif);
      } else if (isYesterday(date)) {
        groups.yesterday.push(notif);
      } else if (isThisWeek(date)) {
        groups.thisWeek.push(notif);
      } else {
        groups.older.push(notif);
      }
    });

    return groups;
  };

  const groupedNotifications = groupByDay(filteredNotifications);

  // Count by type
  const allCount = notifications.length;
  const mentionsCount = notifications.filter(n => categorizeByType(n) === 'mentions').length;
  const invitesCount = notifications.filter(n => categorizeByType(n) === 'invites').length;

  const handleAction = (notification) => {
    // Mark as read when clicking
    if (!notification.is_read) {
      markAsReadMutation.mutate({ id: notification.id });
    }

    const entityType = notification.related_entity_type;
    const entityId = notification.related_entity_id;
    const activityType = notification.activity_type || '';

    // Route based on entity type
    if (entityType === 'event' || activityType.includes('event') || activityType.includes('order')) {
      if (entityId) {
        navigate(createPageUrl(`EventDetail?id=${entityId}`));
      } else {
        navigate(createPageUrl('Events'));
      }
    } else if (entityType === 'task' || activityType.includes('task')) {
      navigate(createPageUrl('TaskBoard'));
    } else if (entityType === 'invoice' || activityType.includes('invoice')) {
      if (entityId) {
        navigate(createPageUrl(`Invoices?id=${entityId}`));
      } else {
        navigate(createPageUrl('Invoices'));
      }
    } else if (entityType === 'staff' || activityType.includes('staff')) {
      if (entityId) {
        navigate(createPageUrl(`EditStaff?id=${entityId}`));
      } else {
        navigate(createPageUrl('StaffDirectory'));
      }
    } else if (entityType === 'message' || activityType.includes('message')) {
      navigate(createPageUrl('Messages'));
    } else if (notification.action_link) {
      navigate(createPageUrl(notification.action_link));
    }

    onClose();
  };

  return (
    <AnimatePresence>
      {isOpen && (
        <>
          {/* Backdrop */}
          <motion.div
            initial={{ opacity: 0 }}
            animate={{ opacity: 1 }}
            exit={{ opacity: 0 }}
            onClick={onClose}
            className="fixed inset-0 bg-black/20 z-40"
          />

          {/* Panel */}
          <motion.div
            initial={{ opacity: 0, x: 300 }}
            animate={{ opacity: 1, x: 0 }}
            exit={{ opacity: 0, x: 300 }}
            transition={{ type: "spring", damping: 25 }}
            className="fixed right-0 top-0 h-full w-full sm:w-[440px] bg-white shadow-2xl z-50 flex flex-col"
          >
            {/* Header */}
            <div className="border-b border-slate-200">
              <div className="flex items-center justify-between p-6">
                <div className="flex items-center gap-3">
                  <Bell className="w-6 h-6 text-[#1C323E]" />
                  <h2 className="text-xl font-bold text-[#1C323E]">Notifications</h2>
                </div>
                <div className="flex items-center gap-2">
                  <Button variant="ghost" size="icon" onClick={onClose}>
                    <X className="w-5 h-5" />
                  </Button>
                </div>
              </div>
              
              {/* Filter Tabs */}
              <div className="flex items-center gap-2 px-6 pb-4">
                <button
                  onClick={() => setActiveFilter('all')}
                  className={`px-4 py-2 rounded-lg text-sm font-semibold transition-all ${
                    activeFilter === 'all' 
                      ? 'bg-blue-50 text-blue-600' 
                      : 'text-slate-600 hover:bg-slate-50'
                  }`}
                >
                  View all <span className="ml-1">{allCount}</span>
                </button>
                <button
                  onClick={() => setActiveFilter('mentions')}
                  className={`px-4 py-2 rounded-lg text-sm font-semibold transition-all ${
                    activeFilter === 'mentions' 
                      ? 'bg-blue-50 text-blue-600' 
                      : 'text-slate-600 hover:bg-slate-50'
                  }`}
                >
                  Mentions <span className="ml-1">{mentionsCount}</span>
                </button>
                <button
                  onClick={() => setActiveFilter('invites')}
                  className={`px-4 py-2 rounded-lg text-sm font-semibold transition-all ${
                    activeFilter === 'invites' 
                      ? 'bg-blue-50 text-blue-600' 
                      : 'text-slate-600 hover:bg-slate-50'
                  }`}
                >
                  Invites <span className="ml-1">{invitesCount}</span>
                </button>
              </div>
            </div>

            {/* Notifications List */}
            <div className="flex-1 overflow-y-auto">
              {filteredNotifications.length === 0 ? (
                <div className="flex flex-col items-center justify-center h-full text-center p-8">
                  <Bell className="w-16 h-16 text-slate-300 mb-4" />
                  <h3 className="text-lg font-semibold text-slate-900 mb-2">No notifications</h3>
                  <p className="text-slate-600">You're all caught up!</p>
                </div>
              ) : (
                <>
                  {/* TODAY */}
                  {groupedNotifications.today.length > 0 && (
                    <div className="px-6 py-4">
                      <h3 className="text-xs font-bold text-slate-500 uppercase tracking-wider mb-4">TODAY</h3>
                      <div className="space-y-4">
                        {groupedNotifications.today.map((notification) => {
                          const Icon = iconMap[notification.icon_type] || AlertCircle;
                          const isUnread = !notification.is_read;
                          const notifDate = new Date(notification.created_date);

                          return (
                            <div key={notification.id} className="flex gap-3 group hover:bg-slate-50 p-3 rounded-lg transition-all -mx-3 relative">
                              {isUnread && (
                                <div className="flex-shrink-0 w-2 h-2 bg-blue-600 rounded-full mt-2" />
                              )}
                              <div 
                                onClick={() => handleAction(notification)}
                                className={`w-12 h-12 rounded-full flex items-center justify-center flex-shrink-0 cursor-pointer ${
                                  notification.icon_color === 'blue' ? 'bg-blue-100' :
                                  notification.icon_color === 'green' ? 'bg-green-100' :
                                  notification.icon_color === 'red' ? 'bg-red-100' :
                                  notification.icon_color === 'purple' ? 'bg-purple-100' :
                                  'bg-slate-100'
                                }`}>
                                <Icon className={`w-5 h-5 ${
                                  notification.icon_color === 'blue' ? 'text-blue-600' :
                                  notification.icon_color === 'green' ? 'text-green-600' :
                                  notification.icon_color === 'red' ? 'text-red-600' :
                                  notification.icon_color === 'purple' ? 'text-purple-600' :
                                  'text-slate-600'
                                }`} />
                              </div>
                              <div 
                                className="flex-1 min-w-0 cursor-pointer"
                                onClick={() => handleAction(notification)}
                              >
                                <div className="flex items-start justify-between mb-1">
                                  <p className="text-sm text-slate-900">
                                    <span className="font-semibold">{notification.title}</span> {notification.description}
                                  </p>
                                  <span className="text-xs text-slate-500 whitespace-nowrap ml-3">
                                    {formatDistanceToNow(notifDate, { addSuffix: true })}
                                  </span>
                                </div>
                                <div className="flex items-center gap-3 text-xs">
                                  {notification.action_link && (
                                    <span className="font-medium text-blue-600">{notification.action_label}</span>
                                  )}
                                  <span className="text-slate-500">{format(notifDate, 'h:mm a')}</span>
                                  {isUnread && (
                                    <button
                                      onClick={(e) => {
                                        e.stopPropagation();
                                        markAsReadMutation.mutate({ id: notification.id });
                                      }}
                                      className="text-blue-600 hover:text-blue-700 font-medium"
                                    >
                                      Mark as Read
                                    </button>
                                  )}
                                  <button
                                    onClick={(e) => {
                                      e.stopPropagation();
                                      deleteMutation.mutate({ id: notification.id });
                                    }}
                                    className="text-red-600 hover:text-red-700 font-medium"
                                  >
                                    Delete
                                  </button>
                                </div>
                              </div>
                            </div>
                          );
                        })}
                      </div>
                    </div>
                  )}

                  {/* YESTERDAY */}
                  {groupedNotifications.yesterday.length > 0 && (
                    <div className="px-6 py-4 border-t border-slate-100">
                      <h3 className="text-xs font-bold text-slate-500 uppercase tracking-wider mb-4">YESTERDAY</h3>
                      <div className="space-y-4">
                        {groupedNotifications.yesterday.map((notification) => {
                          const Icon = iconMap[notification.icon_type] || AlertCircle;
                          const isUnread = !notification.is_read;
                          const notifDate = new Date(notification.created_date);

                          return (
                            <div key={notification.id} className="flex gap-3 group hover:bg-slate-50 p-3 rounded-lg transition-all -mx-3 relative">
                              {isUnread && (
                                <div className="flex-shrink-0 w-2 h-2 bg-blue-600 rounded-full mt-2" />
                              )}
                              <div 
                                onClick={() => handleAction(notification)}
                                className={`w-12 h-12 rounded-full flex items-center justify-center flex-shrink-0 cursor-pointer ${
                                  notification.icon_color === 'blue' ? 'bg-blue-100' :
                                  notification.icon_color === 'green' ? 'bg-green-100' :
                                  notification.icon_color === 'red' ? 'bg-red-100' :
                                  notification.icon_color === 'purple' ? 'bg-purple-100' :
                                  'bg-slate-100'
                                }`}>
                                <Icon className={`w-5 h-5 ${
                                  notification.icon_color === 'blue' ? 'text-blue-600' :
                                  notification.icon_color === 'green' ? 'text-green-600' :
                                  notification.icon_color === 'red' ? 'text-red-600' :
                                  notification.icon_color === 'purple' ? 'text-purple-600' :
                                  'text-slate-600'
                                }`} />
                              </div>
                              <div 
                                className="flex-1 min-w-0"
                                onClick={() => notification.action_link && handleAction(notification)}
                              >
                                <div className={`flex items-start justify-between mb-1 ${notification.action_link ? 'cursor-pointer' : ''}`}>
                                  <p className="text-sm text-slate-900">
                                    <span className="font-semibold">{notification.title}</span> {notification.description}
                                  </p>
                                  <span className="text-xs text-slate-500 whitespace-nowrap ml-3">
                                    {formatDistanceToNow(notifDate, { addSuffix: true })}
                                  </span>
                                </div>
                                <div className="flex items-center gap-3 text-xs">
                                  {notification.action_link && (
                                    <span className="font-medium text-blue-600">{notification.action_label}</span>
                                  )}
                                  <span className="text-slate-500">{format(notifDate, 'MM/dd/yy • h:mm a')}</span>
                                  {isUnread && (
                                    <button
                                      onClick={(e) => {
                                        e.stopPropagation();
                                        markAsReadMutation.mutate({ id: notification.id });
                                      }}
                                      className="text-blue-600 hover:text-blue-700 font-medium"
                                    >
                                      Mark as Read
                                    </button>
                                  )}
                                  <button
                                    onClick={(e) => {
                                      e.stopPropagation();
                                      deleteMutation.mutate({ id: notification.id });
                                    }}
                                    className="text-red-600 hover:text-red-700 font-medium"
                                  >
                                    Delete
                                  </button>
                                </div>
                              </div>
                            </div>
                          );
                        })}
                      </div>
                    </div>
                  )}

                  {/* THIS WEEK */}
                  {groupedNotifications.thisWeek.length > 0 && (
                    <div className="px-6 py-4 border-t border-slate-100">
                      <h3 className="text-xs font-bold text-slate-500 uppercase tracking-wider mb-4">THIS WEEK</h3>
                      <div className="space-y-4">
                        {groupedNotifications.thisWeek.map((notification) => {
                          const Icon = iconMap[notification.icon_type] || AlertCircle;
                          const isUnread = !notification.is_read;
                          const notifDate = new Date(notification.created_date);

                          return (
                            <div key={notification.id} className="flex gap-3 group hover:bg-slate-50 p-3 rounded-lg transition-all -mx-3 opacity-80 hover:opacity-100">
                              {isUnread && (
                                <div className="flex-shrink-0 w-2 h-2 bg-blue-600 rounded-full mt-2" />
                              )}
                              <div 
                                onClick={() => handleAction(notification)}
                                className={`w-12 h-12 rounded-full flex items-center justify-center flex-shrink-0 cursor-pointer ${
                                  notification.icon_color === 'blue' ? 'bg-blue-100' :
                                  notification.icon_color === 'green' ? 'bg-green-100' :
                                  notification.icon_color === 'red' ? 'bg-red-100' :
                                  notification.icon_color === 'purple' ? 'bg-purple-100' :
                                  'bg-slate-100'
                                }`}>
                                <Icon className={`w-5 h-5 ${
                                  notification.icon_color === 'blue' ? 'text-blue-600' :
                                  notification.icon_color === 'green' ? 'text-green-600' :
                                  notification.icon_color === 'red' ? 'text-red-600' :
                                  notification.icon_color === 'purple' ? 'text-purple-600' :
                                  'text-slate-600'
                                }`} />
                              </div>
                              <div 
                                className="flex-1 min-w-0"
                                onClick={() => notification.action_link && handleAction(notification)}
                              >
                                <div className={`flex items-start justify-between mb-1 ${notification.action_link ? 'cursor-pointer' : ''}`}>
                                  <p className="text-sm text-slate-900">
                                    <span className="font-semibold">{notification.title}</span> {notification.description}
                                  </p>
                                  <span className="text-xs text-slate-500 whitespace-nowrap ml-3">
                                    {formatDistanceToNow(notifDate, { addSuffix: true })}
                                  </span>
                                </div>
                                <div className="flex items-center gap-3 text-xs">
                                  {notification.action_link && (
                                    <span className="font-medium text-blue-600">{notification.action_label}</span>
                                  )}
                                  <span className="text-slate-500">{format(notifDate, 'MM/dd/yy • h:mm a')}</span>
                                  {isUnread && (
                                    <button
                                      onClick={(e) => {
                                        e.stopPropagation();
                                        markAsReadMutation.mutate({ id: notification.id });
                                      }}
                                      className="text-blue-600 hover:text-blue-700 font-medium"
                                    >
                                      Mark as Read
                                    </button>
                                  )}
                                  <button
                                    onClick={(e) => {
                                      e.stopPropagation();
                                      deleteMutation.mutate({ id: notification.id });
                                    }}
                                    className="text-red-600 hover:text-red-700 font-medium"
                                  >
                                    Delete
                                  </button>
                                </div>
                              </div>
                            </div>
                          );
                        })}
                      </div>
                    </div>
                  )}

                  {/* OLDER */}
                  {groupedNotifications.older.length > 0 && (
                    <div className="px-6 py-4 border-t border-slate-100">
                      <h3 className="text-xs font-bold text-slate-500 uppercase tracking-wider mb-4">OLDER</h3>
                      <div className="space-y-4">
                        {groupedNotifications.older.map((notification) => {
                          const Icon = iconMap[notification.icon_type] || AlertCircle;
                          const isUnread = !notification.is_read;
                          const notifDate = new Date(notification.created_date);

                          return (
                            <div key={notification.id} className="flex gap-3 group hover:bg-slate-50 p-3 rounded-lg transition-all -mx-3 opacity-70 hover:opacity-100">
                              {isUnread && (
                                <div className="flex-shrink-0 w-2 h-2 bg-blue-600 rounded-full mt-2" />
                              )}
                              <div 
                                onClick={() => handleAction(notification)}
                                className={`w-12 h-12 rounded-full flex items-center justify-center flex-shrink-0 cursor-pointer ${
                                  notification.icon_color === 'blue' ? 'bg-blue-100' :
                                  notification.icon_color === 'green' ? 'bg-green-100' :
                                  notification.icon_color === 'red' ? 'bg-red-100' :
                                  notification.icon_color === 'purple' ? 'bg-purple-100' :
                                  'bg-slate-100'
                                }`}>
                                <Icon className={`w-5 h-5 ${
                                  notification.icon_color === 'blue' ? 'text-blue-600' :
                                  notification.icon_color === 'green' ? 'text-green-600' :
                                  notification.icon_color === 'red' ? 'text-red-600' :
                                  notification.icon_color === 'purple' ? 'text-purple-600' :
                                  'text-slate-600'
                                }`} />
                              </div>
                              <div 
                                className="flex-1 min-w-0"
                                onClick={() => notification.action_link && handleAction(notification)}
                              >
                                <div className={`flex items-start justify-between mb-1 ${notification.action_link ? 'cursor-pointer' : ''}`}>
                                  <p className="text-sm text-slate-900">
                                    <span className="font-semibold">{notification.title}</span> {notification.description}
                                  </p>
                                  <span className="text-xs text-slate-500 whitespace-nowrap ml-3">
                                    {formatDistanceToNow(notifDate, { addSuffix: true })}
                                  </span>
                                </div>
                                <div className="flex items-center gap-3 text-xs">
                                  {notification.action_link && (
                                    <span className="font-medium text-blue-600">{notification.action_label}</span>
                                  )}
                                  <span className="text-slate-500">{format(notifDate, 'MM/dd/yy • h:mm a')}</span>
                                  {isUnread && (
                                    <button
                                      onClick={(e) => {
                                        e.stopPropagation();
                                        markAsReadMutation.mutate({ id: notification.id });
                                      }}
                                      className="text-blue-600 hover:text-blue-700 font-medium"
                                    >
                                      Mark as Read
                                    </button>
                                  )}
                                  <button
                                    onClick={(e) => {
                                      e.stopPropagation();
                                      deleteMutation.mutate({ id: notification.id });
                                    }}
                                    className="text-red-600 hover:text-red-700 font-medium"
                                  >
                                    Delete
                                  </button>
                                </div>
                              </div>
                            </div>
                          );
                        })}
                      </div>
                    </div>
                  )}
                </>
              )}
            </div>
          </motion.div>
        </>
      )}
    </AnimatePresence>
  );
}