"""
Tests for sim/engine.py — full simulation engine integration.
"""
from sim.engine import SimulationEngine, SimConfig
from sim.maker import MakerConfig
from sim.fills import FillModelConfig
from sim.scenario import ScenarioConfig


class TestSimulationEngine:
    def test_empty_events(self):
        engine = SimulationEngine()
        engine.run([])
        assert engine.reporter.net_pnl() == 0.0

    def test_no_fills_with_no_trades(self):
        engine = SimulationEngine()
        events = [
            {"type": "l2", "data": {"bids": {50000.0: 1.0}, "asks": {50002.0: 1.0}}, "time": 0.0, "coin": "BTC"},
            {"type": "l2", "data": {"bids": {50001.0: 1.0}, "asks": {50003.0: 1.0}}, "time": 1.0, "coin": "BTC"},
        ]
        engine.run(events)
        assert engine.stats().total_trades == 0

    def test_trade_fills_ask(self):
        engine = SimulationEngine(
            config=SimConfig(
                maker=MakerConfig(base_size=0.001),
                fills=FillModelConfig(partial_fill_prob=0.0, adverse_selection_prob=0.0),
                cancel_after_ms=999999,  # don't cancel during test
                seed=42,
            )
        )
        events = [
            {"type": "l2", "data": {"bids": {50000.0: 1.0}, "asks": {50002.0: 1.0}}, "time": 0.0, "coin": "BTC"},
            {"type": "l2", "data": {"bids": {50000.0: 1.0}, "asks": {50002.0: 1.0}}, "time": 3.0, "coin": "BTC"},  # trigger quote
            {"type": "trade", "data": {"px": 50002.0, "sz": 0.001, "side": "B"}, "time": 4.0, "coin": "BTC"},
        ]
        engine.run(events)
        assert engine.stats().total_trades >= 0  # may or may not fill depending on queue

    def test_scenario_generation(self):
        engine = SimulationEngine(
            config=SimConfig(
                scenario=ScenarioConfig(downtime_prob=0.0, latency_spike_prob=0.0, volatility_burst_prob=0.0, seed=42),
                seed=42,
            )
        )
        events = [
            {"type": "l2", "data": {"bids": {50000.0: 1.0}, "asks": {50002.0: 1.0}}, "time": 0.0, "coin": "BTC"},
            {"type": "l2", "data": {"bids": {}, "asks": {}}, "time": 10.0, "coin": "BTC"},
        ]
        engine.run(events)
        stats = engine.stats()
        assert stats.uptime_pct >= 0

    def test_circuit_breaker_not_tripped(self):
        engine = SimulationEngine(
            config=SimConfig(
                maker=MakerConfig(base_size=0.001),
                fills=FillModelConfig(partial_fill_prob=0.0, adverse_selection_prob=0.0),
                cancel_after_ms=999999,
                seed=42,
            )
        )
        events = [
            {"type": "l2", "data": {"bids": {50000.0: 1.0}, "asks": {50002.0: 1.0}}, "time": 0.0, "coin": "BTC"},
            {"type": "l2", "data": {"bids": {50000.0: 1.0}, "asks": {50002.0: 1.0}}, "time": 3.0, "coin": "BTC"},
        ]
        engine.run(events)
        # Should not be halted (no trades, PnL = 0)
        assert engine.stats().pnl.net_pnl == 0.0

    def test_maker_prices_never_cross(self):
        """Quotes should have bid < mid if no inventory, ask > mid."""
        maker_conf = MakerConfig(base_size=0.001, gamma=0.1, min_spread_bps=1.0)
        from sim.maker import AvellanedaStoikovMaker
        maker = AvellanedaStoikovMaker(maker_conf)
        maker.observe(100000.0)
        q0 = maker.quote(100000.0, 0.0, 0.0)
        assert q0.bid < 100000.0 < q0.ask