from __future__ import annotations

from datetime import UTC, datetime, timedelta

import pytest

from arbitrade.risk.loss_limits import LossLimitGuard


def test_loss_limit_guard_tracks_daily_and_cumulative_pnl() -> None:
    guard = LossLimitGuard(daily_loss_limit=100.0, cumulative_loss_limit=200.0)
    t0 = datetime.now(UTC)

    guard.register_realized_pnl(-40.0, at=t0)
    guard.register_realized_pnl(10.0, at=t0)

    assert guard.cumulative_pnl == -30.0
    assert guard.daily_pnl(t0.date()) == -30.0
    assert not guard.is_halted


def test_loss_limit_guard_halts_on_daily_limit() -> None:
    guard = LossLimitGuard(daily_loss_limit=50.0)
    t0 = datetime.now(UTC)

    guard.register_realized_pnl(-30.0, at=t0)
    guard.register_realized_pnl(-25.0, at=t0)

    assert guard.is_halted
    assert guard.halted_reason == "daily_loss_limit_breached"


def test_loss_limit_guard_halts_on_cumulative_limit_across_days() -> None:
    guard = LossLimitGuard(cumulative_loss_limit=60.0)
    t0 = datetime.now(UTC)

    guard.register_realized_pnl(-40.0, at=t0)
    guard.register_realized_pnl(-25.0, at=t0 + timedelta(days=1))

    assert guard.is_halted
    assert guard.halted_reason == "cumulative_loss_limit_breached"


def test_loss_limit_guard_rejects_invalid_limits() -> None:
    with pytest.raises(ValueError, match="daily_loss_limit"):
        LossLimitGuard(daily_loss_limit=0.0)

    with pytest.raises(ValueError, match="cumulative_loss_limit"):
        LossLimitGuard(cumulative_loss_limit=-1.0)