"use client";

import { useEffect, useState, useCallback } from "react";
import { api, RatesResponse, StatsResponse, HistoryResponse } from "@/lib/api";
import RateCard from "@/components/RateCard";
import StatsCard from "@/components/StatsCard";
import FundingChart from "@/components/FundingChart";

export default function Dashboard() {
  const [rates, setRates] = useState<RatesResponse | null>(null);
  const [stats, setStats] = useState<StatsResponse | null>(null);
  const [history, setHistory] = useState<HistoryResponse | null>(null);
  const [status, setStatus] = useState<"loading" | "running" | "error">("loading");
  const [lastUpdate, setLastUpdate] = useState<string>("");

  const fetchRates = useCallback(async () => {
    try {
      const r = await api.rates();
      setRates(r);
      setStatus("running");
      setLastUpdate(new Date().toLocaleTimeString("zh-CN"));
    } catch {
      setStatus("error");
    }
  }, []);

  const fetchAll = useCallback(async () => {
    try {
      const [s, h] = await Promise.all([api.stats(), api.history()]);
      setStats(s);
      setHistory(h);
    } catch {
      // stats/history 失败不影响主界面
    }
  }, []);

  useEffect(() => {
    fetchRates();
    fetchAll();
    const rateInterval = setInterval(fetchRates, 2_000);   // 价格 2秒刷新
    const slowInterval = setInterval(fetchAll, 120_000);   // 统计 2分钟刷新
    return () => { clearInterval(rateInterval); clearInterval(slowInterval); };
  }, [fetchRates, fetchAll]);

  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold text-slate-100">资金费率套利监控</h1>
          <p className="text-slate-400 text-sm mt-1">实时监控 BTC / ETH 永续合约资金费率</p>
        </div>
        <div className="flex items-center gap-2 text-sm">
          <span
            className={`w-2 h-2 rounded-full ${
              status === "running"
                ? "bg-emerald-400 animate-pulse"
                : status === "error"
                ? "bg-red-400"
                : "bg-slate-500"
            }`}
          />
          <span className={status === "running" ? "text-emerald-400" : status === "error" ? "text-red-400" : "text-slate-400"}>
            {status === "running" ? "运行中" : status === "error" ? "连接失败" : "加载中..."}
          </span>
          {lastUpdate && (
            <span className="text-slate-500 ml-2">更新于 {lastUpdate}</span>
          )}
        </div>
      </div>

      {/* Rate Cards */}
      <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
        <RateCard asset="BTC" data={rates?.BTC ?? null} />
        <RateCard asset="ETH" data={rates?.ETH ?? null} />
      </div>

      {/* Stats Cards */}
      {stats && (
        <div className="grid grid-cols-1 sm:grid-cols-3 gap-4">
          <StatsCard
            title="BTC 套利"
            mean7d={stats.BTC.mean7d}
            annualized={stats.BTC.annualized}
            accent="cyan"
          />
          <StatsCard
            title="ETH 套利"
            mean7d={stats.ETH.mean7d}
            annualized={stats.ETH.annualized}
            accent="violet"
          />
          <StatsCard
            title="50/50 组合"
            mean7d={stats.combo.mean7d}
            annualized={stats.combo.annualized}
            accent="emerald"
          />
        </div>
      )}

      {/* History Chart */}
      {history && (
        <div className="rounded-xl border border-slate-700 bg-slate-800/50 p-6">
          <h2 className="text-slate-200 font-semibold mb-4">过去7天资金费率走势</h2>
          <FundingChart history={history} />
        </div>
      )}

      {/* Strategy note */}
      <div className="rounded-lg border border-slate-700 bg-slate-800/30 px-5 py-3 text-sm text-slate-400">
        <span className="text-cyan-400 font-medium">策略原理：</span>
        持有现货多头 + 永续空头，每8小时收取资金费率，赚取无方向风险的稳定收益。
      </div>
    </div>
  );
}