import Big from 'big.js';

// 定义流水参数结构
export interface TxRecord {
  date: string | Date;
  txType: 'BUY' | 'SELL' | 'DIVIDEND' | string;
  quantity: string | number;
  price: string | number;
  fee: string | number;
  totalValue?: string | number;
}

export function calculateAssetMetrics(transactions: TxRecord[], currentPrice: string | number) {
  let holdings = new Big(0);
  let totalInvested = new Big(0);
  let totalRealized = new Big(0);
  let averageCost = new Big(0);

  const sortedTx = [...transactions].sort((a, b) => new Date(a.date).getTime() - new Date(b.date).getTime());

  for (const tx of sortedTx) {
    const qty = new Big(tx.quantity || 0);
    const price = new Big(tx.price || 0);
    const fee = new Big(tx.fee || 0);

    if (tx.txType === 'BUY') {
      const cost = qty.times(price).plus(fee);
      totalInvested = totalInvested.plus(cost);

      if (holdings.plus(qty).gt(0)) {
        const oldTotalValue = holdings.times(averageCost);
        averageCost = oldTotalValue.plus(cost).div(holdings.plus(qty));
      }
      holdings = holdings.plus(qty);

    } else if (tx.txType === 'SELL') {
      const revenue = qty.times(price).minus(fee);
      totalRealized = totalRealized.plus(revenue);

      holdings = holdings.minus(qty);
      if (holdings.lte(0)) {
        holdings = new Big(0);
        averageCost = new Big(0);
      }

    } else if (tx.txType === 'DIVIDEND') {
      totalRealized = totalRealized.plus(tx.totalValue || 0);
    }
  }

  const currentMarketValue = holdings.times(new Big(currentPrice));

  const accumulatedPnl = currentMarketValue.plus(totalRealized).minus(totalInvested);

  const floatingPnl = holdings.gt(0) ? new Big(currentPrice).minus(averageCost).times(holdings) : new Big(0);

  const dilutedCost = holdings.gt(0) ? totalInvested.minus(totalRealized).div(holdings) : new Big(0);

  return {
    holdings: holdings.toString(),
    averageCost: averageCost.toString(),
    dilutedCost: dilutedCost.toString(),
    floatingPnl: floatingPnl.toString(),
    accumulatedPnl: accumulatedPnl.toString(),
    marketValue: currentMarketValue.toString()
  };
}