import type { PaperTrade } from './types';

export interface TradePnl {
  /** Reference price: live close for open trades, exit price for closed. */
  ref: number;
  perShare: number;
  pnl: number;
  pct: number;
  /** Profit in R-multiples (relative to the per-share risk), null if no risk. */
  r: number | null;
}

export function tradePnl(t: PaperTrade): TradePnl | null {
  const ref = t.current_price;
  if (ref == null || !t.entry_price) return null;
  const perShare = t.direction === 'long' ? ref - t.entry_price : t.entry_price - ref;
  const risk = Math.abs(t.entry_price - t.stop_loss);
  return {
    ref,
    perShare,
    pnl: perShare * t.shares,
    pct: (perShare / t.entry_price) * 100,
    r: risk > 0 ? perShare / risk : null,
  };
}