"use client";

import { useEffect, useRef, useState } from "react";
import { Link } from "@/i18n/navigation";
import { apiFetch } from "@/app/lib/api-client";

interface NotificationPreview {
  id: string;
  title: string;
  body: string;
  category: string;
  icon?: string;
  read: boolean;
  muted?: boolean;
  created?: string;
  actionUrl?: string;
}

const CATEGORY_LABELS: Record<string, string> = {
  system: "系统",
  meetup: "活动",
  gig: "赏金",
  match: "匹配",
  service: "服务",
  community: "社区",
  city: "城市",
};

function formatTime(value?: string): string {
  if (!value) return "刚刚";
  const date = new Date(value);
  if (Number.isNaN(date.getTime())) return "刚刚";
  const diff = Date.now() - date.getTime();
  const minutes = Math.floor(diff / 60000);
  if (minutes < 1) return "刚刚";
  if (minutes < 60) return `${minutes} 分钟前`;
  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `${hours} 小时前`;
  return `${date.getMonth() + 1}月${date.getDate()}日`;
}

export default function NotificationBell() {
  const [open, setOpen] = useState(false);
  const [unread, setUnread] = useState(0);
  const [items, setItems] = useState<NotificationPreview[]>([]);
  const ref = useRef<HTMLDivElement>(null);

  const load = () => {
    apiFetch<{ items: NotificationPreview[]; unread: number }>("/api/notifications?status=active&muted=exclude")
      .then((data) => {
        setItems((data.items || []).slice(0, 5));
        setUnread(Number(data.unread || 0));
      })
      .catch(() => {
        setItems([]);
        setUnread(0);
      });
  };

  useEffect(() => {
    load();
    const timer = window.setInterval(load, 30000);
    return () => window.clearInterval(timer);
  }, []);

  useEffect(() => {
    if (!open) return;
    const onClick = (event: MouseEvent) => {
      if (ref.current && !ref.current.contains(event.target as Node)) setOpen(false);
    };
    document.addEventListener("mousedown", onClick);
    return () => document.removeEventListener("mousedown", onClick);
  }, [open]);

  const markAllRead = async () => {
    await apiFetch("/api/notifications/mark-all-read", { method: "POST" });
    load();
  };

  const markRead = (id: string) => {
    apiFetch(`/api/notifications/${id}/read`, { method: "POST" })
      .then(load)
      .catch(() => undefined);
  };

  return (
    <div ref={ref} className="relative">
      <button
        type="button"
        onClick={() => setOpen((prev) => !prev)}
        className="relative inline-flex h-10 w-10 items-center justify-center rounded-full text-gray-600 transition-colors hover:bg-gray-100 dark:text-gray-300 dark:hover:bg-gray-800"
        aria-label="站内消息"
        title="站内消息"
      >
        <span className="text-lg">🔔</span>
        {unread > 0 && (
          <span className="absolute right-1.5 top-1.5 flex min-w-5 items-center justify-center rounded-full bg-[#ff4d4f] px-1 text-[10px] font-bold leading-5 text-white shadow-sm">
            {unread > 99 ? "99+" : unread}
          </span>
        )}
      </button>

      {open && (
        <div className="absolute right-0 top-12 z-50 w-[360px] overflow-hidden rounded-2xl border border-gray-200 bg-white shadow-2xl dark:border-gray-800 dark:bg-gray-900 sm:w-[420px]">
          <div className="flex items-center justify-between border-b border-gray-100 px-4 py-3 dark:border-gray-800">
            <div>
              <p className="font-semibold text-gray-950 dark:text-gray-50">站内消息</p>
              <p className="text-xs text-gray-400">{unread} 条未读</p>
            </div>
            <button
              type="button"
              onClick={markAllRead}
              className="rounded-lg px-2.5 py-1.5 text-xs font-medium text-[#ff4d4f] hover:bg-[#ff4d4f]/10"
            >
              全部已读
            </button>
          </div>

          <div className="max-h-[420px] overflow-y-auto">
            {items.map((item) => (
              <Link
                key={item.id}
                href={item.actionUrl || "/messages"}
                onClick={() => {
                  markRead(item.id);
                  setOpen(false);
                }}
                className="block border-b border-gray-100 px-4 py-3 transition-colors hover:bg-gray-50 dark:border-gray-800 dark:hover:bg-gray-800"
              >
                <div className="flex items-start gap-3">
                  <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-2xl bg-[#ff4d4f]/10 text-lg">
                    {item.icon || "🔔"}
                  </div>
                  <div className="min-w-0 flex-1">
                    <div className="flex items-center gap-2">
                      <p className={`line-clamp-1 text-sm font-semibold ${item.read ? "text-gray-600 dark:text-gray-300" : "text-gray-950 dark:text-gray-50"}`}>
                        {item.title}
                      </p>
                      {!item.read && <span className="h-2 w-2 shrink-0 rounded-full bg-[#ff4d4f]" />}
                    </div>
                    <p className="mt-1 line-clamp-2 text-xs leading-5 text-gray-500 dark:text-gray-400">{item.body}</p>
                    <p className="mt-1 text-[11px] text-gray-400">
                      {CATEGORY_LABELS[item.category] || item.category} · {formatTime(item.created)}
                    </p>
                  </div>
                </div>
              </Link>
            ))}
          </div>

          {items.length === 0 && (
            <div className="px-4 py-10 text-center">
              <div className="mx-auto flex h-12 w-12 items-center justify-center rounded-2xl bg-gray-100 text-2xl dark:bg-gray-800">📭</div>
              <p className="mt-3 text-sm text-gray-500 dark:text-gray-400">暂时没有新消息</p>
            </div>
          )}

          <Link
            href="/messages"
            onClick={() => setOpen(false)}
            className="block bg-gray-50 px-4 py-3 text-center text-sm font-semibold text-gray-800 hover:bg-gray-100 dark:bg-gray-950 dark:text-gray-200 dark:hover:bg-gray-800"
          >
            打开消息中心 →
          </Link>
        </div>
      )}
    </div>
  );
}