"use client";

import { Bell } from "lucide-react";
import { useEffect, useRef, useState } from "react";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuTrigger,
} from "@/components/ui/dropdown-menu";
import { useSession } from "@/lib/hooks/use-session";
import { NotificationDropdown } from "./NotificationDropdown";

interface Notification {
  notification_id: number;
  notification_type: string;
  title: string;
  message: string;
  is_read: boolean;
  related_id: number | null;
  created_at: string;
}

interface NotificationBellProps {
  userId?: number;
  className?: string;
}

export function NotificationBell({ userId, className }: NotificationBellProps) {
  const { user } = useSession();
  const [unreadCount, setUnreadCount] = useState(0);
  const [notifications, setNotifications] = useState<Notification[]>([]);
  const [isOpen, setIsOpen] = useState(false);
  const [_loading, setLoading] = useState(false);
  const rawUnreadRef = useRef(0);
  const baselineUnreadRef = useRef(0);
  const baselineLoadedRef = useRef(false);
  const storageKeyRef = useRef<string | null>(null);

  const effectiveUserId = userId || user?.userId;

  // Buscar contagem de não lidas
  const persistBaseline = (value: number) => {
    baselineUnreadRef.current = value;
    if (typeof window !== "undefined" && storageKeyRef.current) {
      window.localStorage.setItem(storageKeyRef.current, String(value));
    }
  };

  const loadBaselineFromStorage = () => {
    if (typeof window === "undefined" || !storageKeyRef.current) {
      return undefined;
    }
    const stored = window.localStorage.getItem(storageKeyRef.current);
    if (!stored) return undefined;
    const parsed = Number.parseInt(stored, 10);
    if (Number.isNaN(parsed)) return undefined;
    return parsed;
  };

  const fetchUnreadCount = async () => {
    if (!effectiveUserId) return;

    try {
      const res = await fetch("/api/notifications/unread-count");
      if (res.ok) {
        const data = await res.json();
        if (data.success) {
          rawUnreadRef.current = data.count;
          if (!baselineLoadedRef.current) {
            const storedBaseline = loadBaselineFromStorage();
            if (storedBaseline !== undefined) {
              const normalized = Math.min(storedBaseline, data.count);
              persistBaseline(normalized);
            } else {
              persistBaseline(data.count);
            }
            baselineLoadedRef.current = true;
          } else if (data.count < baselineUnreadRef.current) {
            persistBaseline(data.count);
          }
          setUnreadCount(Math.max(0, data.count - baselineUnreadRef.current));
        }
      }
    } catch (error) {
      console.error("Erro ao buscar contagem de notificações:", error);
    }
  };

  // Buscar notificações recentes
  const fetchNotifications = async () => {
    if (!effectiveUserId) return;

    setLoading(true);
    try {
      const res = await fetch("/api/notifications?limit=10");
      if (res.ok) {
        const data = await res.json();
        if (data.success) {
          setNotifications(data.notifications || []);
        }
      }
    } catch (error) {
      console.error("Erro ao buscar notificações:", error);
    } finally {
      setLoading(false);
    }
  };

  // Polling automático a cada 30 segundos
  useEffect(() => {
    if (!effectiveUserId) {
      return;
    }
    storageKeyRef.current = `notifications:lastBaseline:${effectiveUserId}`;
    const storedBaseline = loadBaselineFromStorage();
    if (storedBaseline !== undefined) {
      baselineUnreadRef.current = storedBaseline;
      baselineLoadedRef.current = true;
    } else {
      baselineUnreadRef.current = 0;
      baselineLoadedRef.current = false;
    }
  }, [effectiveUserId, loadBaselineFromStorage]);

  useEffect(() => {
    if (!effectiveUserId) return;

    fetchUnreadCount();
    fetchNotifications();

    const interval = setInterval(() => {
      fetchUnreadCount();
      if (isOpen) {
        fetchNotifications();
      }
    }, 30000); // 30 segundos

    return () => clearInterval(interval);
  }, [effectiveUserId, isOpen, fetchNotifications, fetchUnreadCount]);

  // Atualizar quando abrir popover
  useEffect(() => {
    if (isOpen) {
      fetchNotifications();
      persistBaseline(rawUnreadRef.current);
      setUnreadCount(0);
    }
  }, [isOpen, fetchNotifications, persistBaseline]);

  const handleMarkAsRead = async (notificationId: number) => {
    try {
      const res = await fetch(`/api/notifications/${notificationId}/read`, {
        method: "POST",
      });

      if (res.ok) {
        // Atualizar estado local
        setNotifications((prev) =>
          prev.map((n) =>
            n.notification_id === notificationId ? { ...n, is_read: true } : n,
          ),
        );
        // Atualizar contagem
        rawUnreadRef.current = Math.max(0, rawUnreadRef.current - 1);
        const newBaseline = Math.min(
          baselineUnreadRef.current,
          rawUnreadRef.current,
        );
        persistBaseline(newBaseline);
        setUnreadCount((prev) => Math.max(0, prev - 1));
      }
    } catch (error) {
      console.error("Erro ao marcar notificação como lida:", error);
    }
  };

  if (!effectiveUserId) {
    return null;
  }

  return (
    <DropdownMenu open={isOpen} onOpenChange={setIsOpen}>
      <DropdownMenuTrigger asChild>
        <Button variant="ghost" size="icon" className={`relative ${className}`}>
          <Bell className="h-5 w-5" />
          {unreadCount > 0 && (
            <Badge
              variant="destructive"
              className="absolute -top-1 -right-1 h-5 w-5 flex items-center justify-center p-0 text-xs rounded-full animate-pulse"
            >
              {unreadCount > 99 ? "99+" : unreadCount}
            </Badge>
          )}
        </Button>
      </DropdownMenuTrigger>
      <DropdownMenuContent className="w-80 p-0" align="end">
        <NotificationDropdown
          notifications={notifications}
          onMarkAsRead={handleMarkAsRead}
          onViewAll={() => {
            setIsOpen(false);
            // Navegar para página de notificações (implementar depois)
            window.location.href = "/notifications";
          }}
        />
      </DropdownMenuContent>
    </DropdownMenu>
  );
}