/**
 * 업비트 마켓 목록 + 실시간 시세 훅
 *
 *  1) /v1/market/all — 마켓 목록
 *  2) /v1/ticker — 우선 종목 즉시, 전 종목은 패널 열림·지연 후 (429 방지)
 *  3) upbitWsBroker ticker (우선 종목 위주)
 *  4) REST 보조 폴링 30초
 */
import { useState, useEffect, useRef, useCallback } from 'react';
import { setMarketNames } from '../utils/marketNameCache';
import { UPBIT_API } from '../utils/upbitApi';
import { fetchTickersThrottled, type UpbitTickerRaw } from '../utils/upbitTickerFetch';
import { subscribeUpbitWs } from '../utils/upbitWsBroker';

export type ChangeDir = 'RISE' | 'FALL' | 'EVEN';

export interface TickerData {
  market:          string;
  koreanName:      string;
  tradePrice:      number | null;
  changeRate:      number | null;
  changePrice:     number | null;
  accTradePrice24: number;
  accTradeVolume24: number | null;
  openingPrice:    number | null;
  highPrice:       number | null;
  lowPrice:        number | null;
  change:          ChangeDir;
}

export interface MarketInfo {
  market:      string;
  koreanName:  string;
  englishName: string;
}

export interface UseMarketTickerOptions {
  /** 우선 종목만 먼저 로드 (기본: 마켓 패널 닫힘) */
  lite?: boolean;
  priorityMarkets?: string[];
  getPriorityMarkets?: () => string[];
  /** true일 때만 전 종목 REST·폴링 (마켓 패널 열림) */
  loadFull?: boolean;
}

const REST_POLL_INTERVAL = 30_000;
const WS_BATCH_MS = 400;
const FULL_LOAD_DEFER_MS = 2_000;
const WS_TICKER_CAP = 80;
const LITE_BASE_MARKETS = ['KRW-BTC', 'KRW-USDT'];

function toChangeDir(raw: UpbitTickerRaw): ChangeDir {
  if (raw.change === 'RISE' || raw.change === 'FALL' || raw.change === 'EVEN') return raw.change;
  const r = raw.signed_change_rate ?? 0;
  return r > 0 ? 'RISE' : r < 0 ? 'FALL' : 'EVEN';
}

interface UpbitMarketAll {
  market:       string;
  korean_name:  string;
  english_name: string;
}

function getMarketCode(raw: UpbitTickerRaw): string {
  return (raw.code ?? raw.market ?? '') as string;
}

async function fetchAllMarkets(): Promise<MarketInfo[]> {
  const res = await fetch(`${UPBIT_API}/market/all?isDetails=true`);
  if (!res.ok) throw new Error(`market/all ${res.status}`);
  const data: UpbitMarketAll[] = await res.json();
  const krw = data.filter(m => m.market.startsWith('KRW-'));
  const nameMap: Record<string, string> = {};
  krw.forEach(m => { nameMap[m.market] = m.korean_name; });
  setMarketNames(nameMap);
  return krw.map(m => ({
    market:      m.market,
    koreanName:  m.korean_name,
    englishName: m.english_name,
  }));
}

function rawToTicker(raw: UpbitTickerRaw, koreanName: string): TickerData {
  return {
    market:          getMarketCode(raw),
    koreanName,
    tradePrice:      raw.trade_price         ?? null,
    changeRate:      raw.signed_change_rate  ?? null,
    changePrice:     raw.signed_change_price ?? null,
    accTradePrice24: raw.acc_trade_price_24h ?? 0,
    accTradeVolume24: raw.acc_trade_volume_24h ?? null,
    openingPrice:    raw.opening_price       ?? null,
    highPrice:       raw.high_price          ?? null,
    lowPrice:        raw.low_price           ?? null,
    change:          toChangeDir(raw),
  };
}

function mergePriorityMarkets(priorityMarkets?: string[]): string[] {
  const set = new Set(LITE_BASE_MARKETS);
  priorityMarkets?.forEach(m => { if (m?.startsWith('KRW-')) set.add(m); });
  return [...set];
}

function wsTickerMarkets(all: string[], priority: string[]): string[] {
  const set = new Set(priority);
  for (const m of all) {
    if (set.size >= WS_TICKER_CAP) break;
    set.add(m);
  }
  return [...set];
}

function subscribeTickerWs(
  markets: string[],
  onBatch: (rawList: UpbitTickerRaw[]) => void,
): () => void {
  if (markets.length === 0) return () => {};
  const batch = new Map<string, UpbitTickerRaw>();
  let batchTimer: ReturnType<typeof setTimeout> | null = null;

  const flushBatch = () => {
    batchTimer = null;
    if (batch.size === 0) return;
    onBatch(Array.from(batch.values()));
    batch.clear();
  };

  return subscribeUpbitWs('ticker', markets, raw => {
    if (raw.type !== 'ticker' && !raw.code) return;
    const msg = raw as unknown as UpbitTickerRaw;
    const code = getMarketCode(msg);
    if (!code) return;
    batch.set(code, msg);
    if (!batchTimer) batchTimer = setTimeout(flushBatch, WS_BATCH_MS);
  });
}

export function useMarketTicker(opts: UseMarketTickerOptions = {}) {
  const loadFull = opts.loadFull ?? false;
  const priorityList = mergePriorityMarkets(opts.getPriorityMarkets?.() ?? opts.priorityMarkets);
  const priorityKey = priorityList.join(',');

  const [tickers, setTickers] = useState<Map<string, TickerData>>(new Map());
  const [marketInfos, setMarketInfos] = useState<MarketInfo[]>([]);
  const [loading, setLoading] = useState(true);
  const [usdRate, setUsdRate] = useState(1_300);

  const mountedRef = useRef(true);
  const marketListRef = useRef<string[]>([]);
  const marketInfoMapRef = useRef<Map<string, MarketInfo>>(new Map());
  const destroyWsRef = useRef<(() => void) | null>(null);
  const pollTimerRef = useRef<ReturnType<typeof setInterval> | null>(null);
  const fullLoadedRef = useRef(false);
  const initDoneRef = useRef(false);

  const applyRawList = useCallback((rawList: UpbitTickerRaw[]) => {
    if (!mountedRef.current || rawList.length === 0) return;

    setTickers(prev => {
      const next = new Map(prev);
      rawList.forEach(raw => {
        const code = getMarketCode(raw);
        if (!code) return;
        const info = marketInfoMapRef.current.get(code);
        const name = info?.koreanName ?? next.get(code)?.koreanName ?? code.replace(/^KRW-/, '');
        next.set(code, rawToTicker(raw, name));
      });
      return next;
    });

    const usdt = rawList.find(t => getMarketCode(t) === 'KRW-USDT');
    if (usdt?.trade_price) setUsdRate(usdt.trade_price);
  }, []);

  const clearPoll = useCallback(() => {
    if (pollTimerRef.current) {
      clearInterval(pollTimerRef.current);
      pollTimerRef.current = null;
    }
  }, []);

  const attachWs = useCallback((markets: string[]) => {
    destroyWsRef.current?.();
    destroyWsRef.current = subscribeTickerWs(markets, applyRawList);
  }, [applyRawList]);

  const startPoll = useCallback((markets: string[]) => {
    clearPoll();
    if (markets.length === 0) return;
    pollTimerRef.current = setInterval(() => {
      if (!mountedRef.current) return;
      void fetchTickersThrottled(markets).then(raw => {
        if (raw.length > 0) applyRawList(raw);
      });
    }, REST_POLL_INTERVAL);
  }, [applyRawList, clearPoll]);

  const loadTickersFor = useCallback(async (markets: string[]) => {
    const rawList = await fetchTickersThrottled(markets);
    if (mountedRef.current && rawList.length > 0) applyRawList(rawList);
    return rawList;
  }, [applyRawList]);

  const runFullTickerLoad = useCallback(async () => {
    const all = marketListRef.current;
    if (all.length === 0 || fullLoadedRef.current) return;
    await loadTickersFor(all);
    if (!mountedRef.current) return;
    fullLoadedRef.current = true;
    attachWs(wsTickerMarkets(all, priorityList));
    startPoll(all);
  }, [loadTickersFor, attachWs, startPoll, priorityList]);

  // 1) 마켓 목록 + 우선 종목 ticker (마운트 1회)
  useEffect(() => {
    mountedRef.current = true;
    fullLoadedRef.current = false;
    initDoneRef.current = false;

    (async () => {
      let infos: MarketInfo[] = [];
      try { infos = await fetchAllMarkets(); }
      catch { /* ignore */ }
      if (!mountedRef.current) return;

      infos.forEach(m => marketInfoMapRef.current.set(m.market, m));
      setMarketInfos(infos);

      const allMarkets = infos.map(m => m.market);
      if (!allMarkets.includes('KRW-USDT')) allMarkets.push('KRW-USDT');
      marketListRef.current = allMarkets;

      await loadTickersFor(priorityList);
      if (!mountedRef.current) return;

      setLoading(false);
      initDoneRef.current = true;
      attachWs(wsTickerMarkets(allMarkets, priorityList));

      if (loadFull) {
        setTimeout(() => { void runFullTickerLoad(); }, FULL_LOAD_DEFER_MS);
      }
    })();

    return () => {
      mountedRef.current = false;
      destroyWsRef.current?.();
      destroyWsRef.current = null;
      clearPoll();
    };
  // eslint-disable-next-line react-hooks/exhaustive-deps -- init only
  }, []);

  // 2) 마켓 패널 열림 → 전 종목 (지연·스로틀)
  useEffect(() => {
    if (!loadFull || !initDoneRef.current) return;
    if (fullLoadedRef.current) return;

    const t = setTimeout(() => { void runFullTickerLoad(); }, FULL_LOAD_DEFER_MS);
    return () => clearTimeout(t);
  }, [loadFull, runFullTickerLoad]);

  // 3) 우선 종목 변경 (lite) — 전체 재시작 없이 보강
  useEffect(() => {
    if (!initDoneRef.current || fullLoadedRef.current) return;
    void loadTickersFor(priorityList);
    const all = marketListRef.current;
    if (all.length > 0) attachWs(wsTickerMarkets(all, priorityList));
  }, [priorityKey, loadTickersFor, attachWs, priorityList]);

  return { tickers, marketInfos, loading, usdRate };
}