/**
 * 업비트 최근 체결 (호가창 좌측 체결 목록용)
 */
import { useState, useEffect, useRef, useCallback } from 'react';
import { subscribeUpbitWs } from '../utils/upbitWsBroker';

export interface RecentTrade {
  price:  number;
  volume: number;
  side:   'ask' | 'bid';
  time:   number;
}

const MAX_TRADES_DEFAULT = 12;

interface UpbitTradeRaw {
  market:       string;
  trade_price:  number;
  trade_volume: number;
  ask_bid:      'ASK' | 'BID';
  timestamp:    number;
}

interface UpbitTradeWs {
  type:          string;
  code:          string;
  trade_price:   number;
  trade_volume:  number;
  ask_bid:       'ASK' | 'BID';
  timestamp:     number;
}

export function useUpbitRecentTrades(market: string, enabled = true, maxTrades = MAX_TRADES_DEFAULT) {
  const [trades, setTrades] = useState<RecentTrade[]>([]);
  const [strength, setStrength] = useState<number | null>(null);
  const maxRef = useRef(maxTrades);
  maxRef.current = maxTrades;

  const mountedRef = useRef(true);
  const marketRef  = useRef(market);
  marketRef.current = market;

  const pushTrade = useCallback((t: RecentTrade) => {
    setTrades(prev => {
      const cap = maxRef.current;
      const next = [t, ...prev].slice(0, cap);
      const buyVol = next.filter(x => x.side === 'bid').reduce((s, x) => s + x.volume, 0);
      const sellVol = next.filter(x => x.side === 'ask').reduce((s, x) => s + x.volume, 0);
      if (sellVol > 0) setStrength((buyVol / sellVol) * 100);
      else if (buyVol > 0) setStrength(100);
      return next;
    });
  }, []);

  const fetchSnapshot = useCallback(async () => {
    try {
      const res = await fetch(`/upbit-api/v1/trades/ticks?market=${marketRef.current}&count=${maxRef.current}`);
      if (!res.ok) return;
      const data: UpbitTradeRaw[] = await res.json();
      const list: RecentTrade[] = data.map(d => ({
        price:  d.trade_price,
        volume: d.trade_volume,
        side:   d.ask_bid === 'ASK' ? 'ask' : 'bid',
        time:   d.timestamp,
      }));
      setTrades(list);
      const buyVol = list.filter(x => x.side === 'bid').reduce((s, x) => s + x.volume, 0);
      const sellVol = list.filter(x => x.side === 'ask').reduce((s, x) => s + x.volume, 0);
      if (sellVol > 0) setStrength((buyVol / sellVol) * 100);
    } catch { /* ignore */ }
  }, []);

  useEffect(() => {
    mountedRef.current = true;
    setTrades([]);
    setStrength(null);

    if (!enabled) {
      return () => { mountedRef.current = false; };
    }

    fetchSnapshot();

    const unsub = subscribeUpbitWs('trade', [market], raw => {
      if (!mountedRef.current) return;
      const msg = raw as unknown as UpbitTradeWs;
      if (msg.type === 'trade' && msg.code === marketRef.current) {
        pushTrade({
          price:  msg.trade_price,
          volume: msg.trade_volume,
          side:   msg.ask_bid === 'ASK' ? 'ask' : 'bid',
          time:   msg.timestamp,
        });
      }
    });

    return () => {
      mountedRef.current = false;
      unsub();
    };
  }, [market, enabled, fetchSnapshot, pushTrade]);

  return { trades, strength };
}