"""Deterministic replay backtester (toy) for MVP."""
from __future__ import annotations

from typing import List

from deltaforge_mvp.core import PlanDelta


class Backtester:
    def __init__(self, seed: int = 0):
        self.seed = seed

    def replay(self, plan: PlanDelta) -> dict:
        # Very small deterministic stub: compute a fake PnL based on number of deltas and a seed
        pnl = 0.0
        for d in plan.deltas:
            pnl += (d.delta * 0.5)  # arbitrary scaling for demo
        return {"pnl": pnl, "delta_count": len(plan.deltas), "seed": self.seed}