"use client";

import { useCallback, useEffect, useState } from "react";
import { useSession } from "next-auth/react";
import { Bell, Check, AlertTriangle, TrendingDown, TrendingUp, Users, Globe } from "lucide-react";
import { Button } from "@/components/ui/button";
import { Badge } from "@/components/ui/badge";
import {
  Popover,
  PopoverContent,
  PopoverTrigger,
} from "@/components/ui/popover";
import { api } from "@/lib/api";

// ============================================================
// 类型定义
// ============================================================

interface AlertItem {
  id: string;
  brand_id: string;
  user_id: string;
  alert_type: string;
  severity: string;
  title: string;
  message: string;
  data: Record<string, unknown> | null;
  is_read: boolean;
  created_at: string;
}

interface AlertListResponse {
  items: AlertItem[];
  total: number;
}

interface UnreadCountResponse {
  unread_count: number;
}

// ============================================================
// 告警类型配置
// ============================================================

const ALERT_TYPE_CONFIG: Record<string, { label: string; icon: React.ElementType; color: string }> = {
  score_drop: { label: "评分下降", icon: TrendingDown, color: "text-red-500" },
  score_rise: { label: "评分上升", icon: TrendingUp, color: "text-emerald-500" },
  negative_sentiment: { label: "负面情感", icon: AlertTriangle, color: "text-orange-500" },
  competitor_overtake: { label: "竞品超越", icon: Users, color: "text-amber-500" },
  new_platform_mention: { label: "新平台提及", icon: Globe, color: "text-blue-500" },
};

const SEVERITY_CONFIG: Record<string, { label: string; className: string }> = {
  critical: { label: "严重", className: "bg-red-100 text-red-700 border-red-200" },
  warning: { label: "警告", className: "bg-orange-100 text-orange-700 border-orange-200" },
  info: { label: "信息", className: "bg-blue-100 text-blue-700 border-blue-200" },
};

// ============================================================
// 工具函数
// ============================================================

function formatTimeAgo(dateStr: string): string {
  const date = new Date(dateStr);
  const now = new Date();
  const diffMs = now.getTime() - date.getTime();
  const diffMinutes = Math.floor(diffMs / 60000);
  const diffHours = Math.floor(diffMs / 3600000);
  const diffDays = Math.floor(diffMs / 86400000);

  if (diffMinutes < 1) return "刚刚";
  if (diffMinutes < 60) return `${diffMinutes}分钟前`;
  if (diffHours < 24) return `${diffHours}小时前`;
  if (diffDays < 7) return `${diffDays}天前`;
  return date.toLocaleDateString("zh-CN");
}

// ============================================================
// 通知铃铛组件
// ============================================================

export function AlertBell() {
  const { data: session } = useSession();
  const [unreadCount, setUnreadCount] = useState(0);
  const [alerts, setAlerts] = useState<AlertItem[]>([]);
  const [isOpen, setIsOpen] = useState(false);
  const [loading, setLoading] = useState(false);

  const token = session?.accessToken;

  // 获取未读数量
  const fetchUnreadCount = useCallback(async () => {
    if (!token) return;
    try {
      const data = (await api.alerts.getUnreadCount(token)) as UnreadCountResponse;
      setUnreadCount(data.unread_count);
    } catch {
      // 静默失败
    }
  }, [token]);

  // 获取告警列表
  const fetchAlerts = useCallback(async () => {
    if (!token) return;
    setLoading(true);
    try {
      const data = (await api.alerts.getAlerts(token, {
        limit: 20,
      })) as AlertListResponse;
      setAlerts(data.items);
    } catch {
      // 静默失败
    } finally {
      setLoading(false);
    }
  }, [token]);

  // 标记单条已读
  const handleMarkRead = async (alertId: string) => {
    if (!token) return;
    try {
      await api.alerts.markRead(token, alertId);
      setAlerts((prev) =>
        prev.map((a) => (a.id === alertId ? { ...a, is_read: true } : a)),
      );
      setUnreadCount((prev) => Math.max(0, prev - 1));
    } catch {
      // 静默失败
    }
  };

  // 全部标记已读
  const handleMarkAllRead = async () => {
    if (!token) return;
    try {
      await api.alerts.markAllRead(token);
      setAlerts((prev) => prev.map((a) => ({ ...a, is_read: true })));
      setUnreadCount(0);
    } catch {
      // 静默失败
    }
  };

  // 打开面板时加载告警列表
  const handleOpenChange = (open: boolean) => {
    setIsOpen(open);
    if (open) {
      fetchAlerts();
    }
  };

  // 轮询检查新告警（每60秒）
  useEffect(() => {
    fetchUnreadCount();
    const interval = setInterval(fetchUnreadCount, 60000);
    return () => clearInterval(interval);
  }, [fetchUnreadCount]);

  return (
    <Popover open={isOpen} onOpenChange={handleOpenChange}>
      <PopoverTrigger asChild>
        <Button variant="ghost" size="icon" className="relative">
          <Bell className="h-5 w-5" />
          {unreadCount > 0 && (
            <Badge
              className="absolute -right-1 -top-1 flex h-5 min-w-5 items-center justify-center rounded-full px-1 text-xs text-white"
              style={{
                backgroundColor:
                  unreadCount >= 5 ? "#ef4444" : unreadCount >= 2 ? "#f97316" : "#3b82f6",
              }}
            >
              {unreadCount > 99 ? "99+" : unreadCount}
            </Badge>
          )}
        </Button>
      </PopoverTrigger>
      <PopoverContent className="w-96 p-0" align="end">
        {/* 头部 */}
        <div className="flex items-center justify-between border-b px-4 py-3">
          <h3 className="text-sm font-semibold">通知</h3>
          {unreadCount > 0 && (
            <Button
              variant="ghost"
              size="sm"
              className="h-auto p-0 text-xs text-muted-foreground hover:text-foreground"
              onClick={handleMarkAllRead}
            >
              全部已读
            </Button>
          )}
        </div>

        {/* 告警列表 */}
        <div className="max-h-96 overflow-y-auto">
          {loading ? (
            <div className="flex items-center justify-center py-8">
              <p className="text-sm text-muted-foreground">加载中...</p>
            </div>
          ) : alerts.length === 0 ? (
            <div className="flex flex-col items-center justify-center py-8">
              <Bell className="mb-2 h-8 w-8 text-muted-foreground/40" />
              <p className="text-sm text-muted-foreground">暂无告警通知</p>
            </div>
          ) : (
            <div className="divide-y">
              {alerts.map((alert) => {
                const typeConfig = ALERT_TYPE_CONFIG[alert.alert_type] || {
                  label: alert.alert_type,
                  icon: Bell,
                  color: "text-gray-500",
                };
                const severityConfig = SEVERITY_CONFIG[alert.severity] || {
                  label: alert.severity,
                  className: "bg-gray-100 text-gray-700 border-gray-200",
                };
                const IconComponent = typeConfig.icon;

                return (
                  <div
                    key={alert.id}
                    className={`flex gap-3 px-4 py-3 transition-colors hover:bg-muted/50 ${
                      !alert.is_read ? "bg-blue-50/50 dark:bg-blue-950/20" : ""
                    }`}
                    onClick={() => {
                      if (!alert.is_read) {
                        handleMarkRead(alert.id);
                      }
                    }}
                  >
                    {/* 图标 */}
                    <div className="mt-0.5 flex-shrink-0">
                      <IconComponent className={`h-5 w-5 ${typeConfig.color}`} />
                    </div>

                    {/* 内容 */}
                    <div className="min-w-0 flex-1">
                      <div className="flex items-start justify-between gap-2">
                        <p
                          className={`text-sm leading-tight ${
                            !alert.is_read ? "font-medium" : "text-muted-foreground"
                          }`}
                        >
                          {alert.title}
                        </p>
                        <span
                          className={`inline-flex flex-shrink-0 items-center rounded border px-1.5 py-0.5 text-[10px] font-medium ${
                            severityConfig.className
                          }`}
                        >
                          {severityConfig.label}
                        </span>
                      </div>
                      <p className="mt-1 line-clamp-2 text-xs text-muted-foreground">
                        {alert.message}
                      </p>
                      <p className="mt-1 text-[10px] text-muted-foreground/60">
                        {formatTimeAgo(alert.created_at)}
                      </p>
                    </div>

                    {/* 未读标记 */}
                    {!alert.is_read && (
                      <div className="mt-1.5 flex-shrink-0">
                        <div className="h-2 w-2 rounded-full bg-blue-500" />
                      </div>
                    )}
                  </div>
                );
              })}
            </div>
          )}
        </div>

        {/* 底部 */}
        {alerts.length > 0 && (
          <div className="border-t px-4 py-2">
            <Button
              variant="ghost"
              size="sm"
              className="w-full text-xs text-muted-foreground"
              onClick={() => {
                setIsOpen(false);
                window.location.href = "/dashboard/settings";
              }}
            >
              <Check className="mr-1 h-3 w-3" />
              告警设置
            </Button>
          </div>
        )}
      </PopoverContent>
    </Popover>
  );
}
