"use client";

import { useEffect, useRef } from "react";
import {
  createChart,
  type CandlestickData,
  type IChartApi,
  type ISeriesApi,
  type UTCTimestamp,
} from "lightweight-charts";
import type { ChartPayload, LatestPredictionResponse } from "../lib/api";

type Props = {
  chart: ChartPayload;
  prediction?: LatestPredictionResponse | null;
};

// KST naive ISO ('YYYY-MM-DD' 또는 'YYYY-MM-DDTHH:MM:SS') 를 UTCTimestamp 로.
// lightweight-charts 는 UTC 라고 가정하지만 KST wall-clock 을 UTC 처럼 넣어
// timeScale 표시가 한국 사용자에게 자연스럽게 KST 그대로 나오도록 함.
function isoToUtcTs(s: string): UTCTimestamp {
  if (s.length <= 10) {
    return (Date.UTC(
      Number(s.slice(0, 4)),
      Number(s.slice(5, 7)) - 1,
      Number(s.slice(8, 10)),
    ) / 1000) as UTCTimestamp;
  }
  return (Date.UTC(
    Number(s.slice(0, 4)),
    Number(s.slice(5, 7)) - 1,
    Number(s.slice(8, 10)),
    Number(s.slice(11, 13)),
    Number(s.slice(14, 16)),
    Number(s.slice(17, 19) || "0"),
  ) / 1000) as UTCTimestamp;
}

// 한국 거래소 관행: 상승=빨강, 하락=파랑.
const COLOR_UP = "#ef4444";
const COLOR_DOWN = "#3b82f6";
// 예측 캔들은 같은 up/down 색 옅은 톤. "어우러지되 미래 데이터임이 명확" 한 시각 신호.
const PRED_UP = "#fda4af";
const PRED_DOWN = "#93c5fd";

export function StockChart({ chart, prediction }: Props) {
  const containerRef = useRef<HTMLDivElement | null>(null);
  const chartRef = useRef<IChartApi | null>(null);
  const candleRef = useRef<ISeriesApi<"Candlestick"> | null>(null);
  const predRef = useRef<ISeriesApi<"Candlestick"> | null>(null);

  const isIntraday = chart.interval === "10m";

  // chart 생성 — interval 바뀌면 timeVisible 토글을 위해 재생성.
  useEffect(() => {
    if (!containerRef.current) return;
    const c = createChart(containerRef.current, {
      layout: {
        background: { color: "transparent" },
        textColor: "#cbd5e1",
      },
      grid: {
        vertLines: { color: "#1f2937" },
        horzLines: { color: "#1f2937" },
      },
      rightPriceScale: { borderColor: "#374151" },
      timeScale: {
        borderColor: "#374151",
        timeVisible: isIntraday,
        secondsVisible: false,
      },
      autoSize: true,
      crosshair: { mode: 1 },
    });
    const candle = c.addCandlestickSeries({
      upColor: COLOR_UP,
      downColor: COLOR_DOWN,
      borderUpColor: COLOR_UP,
      borderDownColor: COLOR_DOWN,
      wickUpColor: COLOR_UP,
      wickDownColor: COLOR_DOWN,
    });
    chartRef.current = c;
    candleRef.current = candle;
    return () => {
      c.remove();
      chartRef.current = null;
      candleRef.current = null;
      predRef.current = null;
    };
  }, [isIntraday]);

  // 실 데이터 push.
  useEffect(() => {
    if (!candleRef.current) return;
    const data: CandlestickData[] = chart.ohlcv
      .filter((p) => p.open !== null && p.high !== null && p.low !== null && p.close !== null)
      .map((p) => ({
        time: isoToUtcTs(p.date),
        open: p.open as number,
        high: p.high as number,
        low: p.low as number,
        close: p.close as number,
      }));
    candleRef.current.setData(data);
    chartRef.current?.timeScale().fitContent();
  }, [chart, isIntraday]);

  // 예측 오버레이를 캔들 시리즈로 렌더.
  // 합성 OHLC:
  //   open[i]  = i==0 ? base_close : prev.point_close
  //   close[i] = point_close
  //   high[i]  = max(ci_high, open, close)
  //   low[i]   = min(ci_low,  open, close)
  // → 몸통 = 기간 사이 예상 변동, 위/아래 꼬리 = 신뢰구간 폭 (불확실성).
  // 10분봉(intraday) 에서는 예측 표시 안 함 — 모델은 일봉 기반.
  useEffect(() => {
    if (!chartRef.current) return;
    if (predRef.current) {
      chartRef.current.removeSeries(predRef.current);
      predRef.current = null;
    }
    if (isIntraday) return;
    if (!prediction?.found || !prediction.steps?.length) return;
    const baseDate = prediction.base_date;
    const baseClose = prediction.base_close;
    if (!baseDate || baseClose == null) return;

    const sorted = [...prediction.steps]
      .filter(
        (s) =>
          s.point_close != null && s.ci_low != null && s.ci_high != null && s.target_date,
      )
      .sort((a, b) => a.horizon - b.horizon);
    if (!sorted.length) return;

    const data: CandlestickData[] = [];
    let prevClose = baseClose;
    for (const s of sorted) {
      const open = prevClose;
      const close = s.point_close as number;
      const ciHi = s.ci_high as number;
      const ciLo = s.ci_low as number;
      data.push({
        time: isoToUtcTs(s.target_date),
        open,
        close,
        high: Math.max(ciHi, open, close),
        low: Math.min(ciLo, open, close),
      });
      prevClose = close;
    }

    const pred = chartRef.current.addCandlestickSeries({
      upColor: PRED_UP,
      downColor: PRED_DOWN,
      borderUpColor: PRED_UP,
      borderDownColor: PRED_DOWN,
      wickUpColor: PRED_UP,
      wickDownColor: PRED_DOWN,
      priceLineVisible: false,
      lastValueVisible: true,
      title: "예측",
    });
    pred.setData(data);
    predRef.current = pred;
    chartRef.current.timeScale().fitContent();
  }, [prediction, isIntraday]);

  return (
    <div className="w-full rounded-lg border border-zinc-800 bg-zinc-900/30 p-2">
      <div className="h-[460px] w-full">
        <div ref={containerRef} className="h-full w-full" />
      </div>
      {prediction?.found && !isIntraday && (
        <div className="mt-1 flex items-center justify-end gap-2 px-2 text-[11px] text-zinc-500">
          <span className="inline-block h-2 w-2 rounded-sm bg-rose-300" />
          <span className="inline-block h-2 w-2 rounded-sm bg-sky-300" />
          <span>예측 (꼬리 = q10~q90 신뢰구간)</span>
        </div>
      )}
    </div>
  );
}