from __future__ import annotations

import pytest

from arbitrade.risk.trade_limits import TradeLimitsGuard


def test_trade_limits_guard_blocks_when_max_concurrent_reached() -> None:
    guard = TradeLimitsGuard(max_concurrent_trades=1)

    guard.open_trade({"BTC": 10.0})

    assert not guard.is_trade_allowed({"BTC": 1.0})


def test_trade_limits_guard_blocks_when_asset_exposure_would_breach_cap() -> None:
    guard = TradeLimitsGuard(max_exposure_per_asset=100.0)

    guard.open_trade({"BTC": 80.0})

    assert not guard.is_trade_allowed({"BTC": 25.0})
    assert guard.is_trade_allowed({"ETH": 25.0})


def test_trade_limits_guard_releases_exposure_on_close() -> None:
    guard = TradeLimitsGuard(max_concurrent_trades=2, max_exposure_per_asset=100.0)

    guard.open_trade({"BTC": 80.0})
    guard.close_trade({"BTC": 80.0})

    assert guard.active_trades == 0
    assert guard.exposure_for_asset("BTC") == 0.0
    assert guard.is_trade_allowed({"BTC": 100.0})


def test_trade_limits_guard_rejects_invalid_configuration() -> None:
    with pytest.raises(ValueError, match="max_concurrent_trades"):
        TradeLimitsGuard(max_concurrent_trades=0)

    with pytest.raises(ValueError, match="max_exposure_per_asset"):
        TradeLimitsGuard(max_exposure_per_asset=0.0)