from __future__ import annotations
import time
from typing import List
from ..dsl import OrderEvent, FillEvent

class ExchangeGatewaySimulator:
  """
  Simple exchange gateway simulator that converts PlanDelta hits into FillEvent outputs deterministically.
  """
  def __init__(self, latency_ms: int = 5):
    self.latency_ms = latency_ms

  def simulate_fills(self, orders: List[OrderEvent]) -> List[FillEvent]:
    t = time.time()
    fills: List[FillEvent] = []
    for o in orders:
      f = FillEvent(fill_id=f"fill-{o.order_id}", timestamp=t, order_id=o.order_id, quantity=o.quantity, price=o.price, venue="SIM_EX", delta_id=o.delta_id)
      fills.append(f)
    return fills