"use client";

import { useEffect, useRef, useState, useCallback } from "react";
import { createChart, ColorType, CandlestickSeries } from "lightweight-charts";

const INTERVALS = [
  { label: "1m", value: "1m" },
  { label: "5m", value: "5m" },
  { label: "30m", value: "30m" },
  { label: "1h", value: "1h" },
  { label: "4h", value: "4h" },
  { label: "8h", value: "8h" },
  { label: "日", value: "1d" },
  { label: "周", value: "1w" },
  { label: "月", value: "1M" },
];

interface KBar {
  time: number;
  open: number; high: number; low: number; close: number;
  price_open: number; price_high: number; price_low: number; price_close: number;
}

function baseChartOptions(height: number) {
  return {
    layout: {
      background: { type: ColorType.Solid, color: "#ffffff" },
      textColor: "#64748b", fontSize: 11,
    },
    grid: { vertLines: { color: "#f1f5f9" }, horzLines: { color: "#f1f5f9" } },
    localization: {
      timeFormatter: (ts: number) => {
        const d = new Date((ts + 8 * 3600) * 1000);
        const Y = d.getUTCFullYear();
        const M = String(d.getUTCMonth() + 1).padStart(2, "0");
        const D = String(d.getUTCDate()).padStart(2, "0");
        const h = String(d.getUTCHours()).padStart(2, "0");
        const m = String(d.getUTCMinutes()).padStart(2, "0");
        return `${Y}-${M}-${D} ${h}:${m}`;
      },
    },
    timeScale: {
      borderColor: "#e2e8f0", timeVisible: true, secondsVisible: false,
      tickMarkFormatter: (ts: number) => {
        const d = new Date((ts + 8 * 3600) * 1000);
        return `${String(d.getUTCHours()).padStart(2,"0")}:${String(d.getUTCMinutes()).padStart(2,"0")}`;
      },
    },
    rightPriceScale: { borderColor: "#e2e8f0" },
    height,
  };
}

function IntervalBar({ value, onChange }: { value: string; onChange: (v: string) => void }) {
  return (
    <div className="flex flex-wrap gap-1.5 text-xs">
      {INTERVALS.map(iv => (
        <button key={iv.value} onClick={() => onChange(iv.value)}
          className={`px-2.5 py-1 rounded border transition-colors ${value === iv.value ? "bg-slate-800 text-white border-slate-800" : "border-slate-200 text-slate-500 hover:border-slate-400"}`}>
          {iv.label}
        </button>
      ))}
    </div>
  );
}

function KChart({
  symbol, interval, mode, color,
}: {
  symbol: string; interval: string; mode: "rate" | "price";
  color: { up: string; down: string };
}) {
  const containerRef = useRef<HTMLDivElement>(null);
  const chartRef = useRef<ReturnType<typeof createChart> | null>(null);
  const [count, setCount] = useState(0);

  const render = useCallback(async () => {
    try {
      const r = await fetch(`/api/kline?symbol=${symbol}&interval=${interval}&limit=500`);
      const json = await r.json();
      const bars: KBar[] = json.data || [];
      setCount(json.count || 0);
      if (!containerRef.current) return;
      chartRef.current?.remove();
      const chart = createChart(containerRef.current, baseChartOptions(260));
      chartRef.current = chart;
      const series = chart.addSeries(CandlestickSeries, {
        upColor: color.up, downColor: color.down,
        borderUpColor: color.up, borderDownColor: color.down,
        wickUpColor: color.up, wickDownColor: color.down,
      });
      if (mode === "rate") {
        series.setData(bars.map(b => ({ time: b.time as any, open: b.open, high: b.high, low: b.low, close: b.close })));
      } else {
        series.setData(bars.map(b => ({ time: b.time as any, open: b.price_open, high: b.price_high, low: b.price_low, close: b.price_close })));
      }
      chart.timeScale().fitContent();
      containerRef.current.querySelectorAll("a").forEach(a => (a as HTMLElement).style.display = "none");
    } catch (e) { console.error(e); }
  }, [symbol, interval, mode, color.up, color.down]);

  useEffect(() => {
    render();
    const iv = window.setInterval(render, 30_000);
    return () => {
      window.clearInterval(iv);
      chartRef.current?.remove();
      chartRef.current = null;
    };
  }, [render]);

  return (
    <div>
      <p className="text-xs text-slate-400 mb-1">{count} 根K线</p>
      <div ref={containerRef} className="w-full" style={{ height: 260 }} />
    </div>
  );
}

export default function KlinePage() {
  const [symbol, setSymbol] = useState<"BTC" | "ETH">("BTC");
  const [rateInterval, setRateInterval] = useState("1h");
  const [priceInterval, setPriceInterval] = useState("1h");

  return (
    <div className="space-y-5">
      {/* 标题+币种 */}
      <div className="flex items-center justify-between flex-wrap gap-3">
        <h1 className="text-2xl font-bold text-slate-900">费率 K 线</h1>
        <div className="flex gap-2 text-sm">
          {(["BTC", "ETH"] as const).map(s => (
            <button key={s} onClick={() => setSymbol(s)}
              className={`px-4 py-1.5 rounded-lg border font-medium transition-colors ${symbol === s ? "bg-blue-600 text-white border-blue-600" : "border-slate-200 text-slate-600 hover:border-blue-400"}`}>
              {s}
            </button>
          ))}
        </div>
      </div>

      {/* 费率K线 */}
      <div className="rounded-xl border border-slate-200 bg-white shadow-sm p-4 space-y-3">
        <div className="flex items-center justify-between flex-wrap gap-2">
          <div>
            <h2 className="text-slate-700 font-semibold text-sm">{symbol} 资金费率（万分之）</h2>
            <p className="text-xs text-slate-400">原始值×10000 · 绿涨红跌 · 代表多头情绪</p>
          </div>
          <IntervalBar value={rateInterval} onChange={setRateInterval} />
        </div>
        <KChart symbol={symbol} interval={rateInterval} mode="rate" color={{ up: "#16a34a", down: "#dc2626" }} />
      </div>

      {/* 价格K线 */}
      <div className="rounded-xl border border-slate-200 bg-white shadow-sm p-4 space-y-3">
        <div className="flex items-center justify-between flex-wrap gap-2">
          <div>
            <h2 className="text-slate-700 font-semibold text-sm">{symbol} 标记价格（USD）</h2>
            <p className="text-xs text-slate-400">蓝涨紫跌 · 与费率对比观察趋势</p>
          </div>
          <IntervalBar value={priceInterval} onChange={setPriceInterval} />
        </div>
        <KChart symbol={symbol} interval={priceInterval} mode="price" color={{ up: "#2563eb", down: "#7c3aed" }} />
      </div>

      <div className="rounded-lg border border-blue-100 bg-blue-50 px-5 py-3 text-sm text-slate-600">
        <span className="text-blue-600 font-medium">说明：</span>
        数据来自本地rate_snapshots表（每2秒一条），后端自动采集，永久保留。每30秒刷新。
      </div>
    </div>
  );
}