Adaptateur exchange (CCXT)

// src/broker/ccxt-adapter.ts
import ccxt from 'ccxt'

export type OrderParams = { symbol: string; side: 'buy' | 'sell'; amount: number; price?: number; type?: 'market'|'limit'; clientOrderId?: string }
export type OrderInfo = { id: string; status: string; filled: number; price?: number }

export class CcxtAdapter {
  private ex: ccxt.Exchange
  constructor(opts: { id: string; apiKey: string; secret: string; testnet?: boolean }) {
    const { id, apiKey, secret, testnet } = opts
    const cls = (ccxt as any)[id]
    if (!cls) throw new Error(`Exchange ${id} non supporté par CCXT`)
    this.ex = new cls({
      apiKey, secret,
      enableRateLimit: true,
      options: testnet ? { defaultType: 'future' } : {},
    })
    if (id.includes('binance') && testnet) {
      // endpoints testnet (ex: binance futures)
      ;(this.ex as any).urls['api'] = { public: 'https://testnet.binancefuture.com/fapi', private: 'https://testnet.binancefuture.com/fapi' }
    }
  }

  async fetchOHLCV(symbol: string, timeframe: string, limit = 200) {
    return this.ex.fetchOHLCV(symbol, timeframe, undefined, limit) // [t,o,h,l,c,v]
  }

  async balanceUSDT(): Promise<number> {
    const b = await this.ex.fetchBalance()
    return (b['USDT']?.free ?? 0) + (b['USDT']?.total ?? 0) - (b['USDT']?.used ?? 0)
  }

  async createOrder(p: OrderParams): Promise<OrderInfo> {
    const type = p.type || 'market'
    const order = await this.ex.createOrder(p.symbol, type, p.side, p.amount, p.price, { newClientOrderId: p.clientOrderId })
    return { id: order.id, status: order.status ?? 'open', filled: order.filled ?? 0, price: order.price }
  }
}