"""TDD per :mod:`cerbero_bite.runtime.auto_pause` (§7-bis F)."""

from __future__ import annotations

from datetime import UTC, datetime, timedelta
from decimal import Decimal

import pytest

from cerbero_bite.config.schema import AutoPauseConfig
from cerbero_bite.runtime.auto_pause import (
    evaluate_drawdown_breach,
    is_paused,
    pause_until,
)
from cerbero_bite.state.models import SystemStateRecord


_NOW = datetime(2026, 5, 1, 14, 0, tzinfo=UTC)


def _state(**overrides: object) -> SystemStateRecord:
    base: dict[str, object] = {
        "kill_switch": 0,
        "last_health_check": _NOW,
        "config_version": "1.0.0",
        "started_at": _NOW - timedelta(hours=1),
    }
    base.update(overrides)
    return SystemStateRecord(**base)  # type: ignore[arg-type]


# ---------------------------------------------------------------------------
# is_paused
# ---------------------------------------------------------------------------


def test_is_paused_returns_false_when_state_is_none() -> None:
    status = is_paused(None, now=_NOW)
    assert status.paused is False


def test_is_paused_returns_false_when_until_is_none() -> None:
    status = is_paused(_state(), now=_NOW)
    assert status.paused is False


def test_is_paused_returns_true_when_until_in_future() -> None:
    status = is_paused(
        _state(auto_pause_until=_NOW + timedelta(weeks=2),
               auto_pause_reason="DD breach"),
        now=_NOW,
    )
    assert status.paused is True
    assert status.reason == "DD breach"


def test_is_paused_returns_false_when_until_in_past() -> None:
    status = is_paused(
        _state(auto_pause_until=_NOW - timedelta(seconds=1)),
        now=_NOW,
    )
    assert status.paused is False


# ---------------------------------------------------------------------------
# pause_until
# ---------------------------------------------------------------------------


def test_pause_until_adds_weeks() -> None:
    until = pause_until(_NOW, weeks=2)
    assert until == _NOW + timedelta(weeks=2)


def test_pause_until_clamps_to_one_week_minimum() -> None:
    # weeks <= 0 deve cmq dare almeno 1 settimana di pausa, altrimenti
    # la cron settimanale potrebbe scattare comunque.
    assert pause_until(_NOW, weeks=0) == _NOW + timedelta(weeks=1)
    assert pause_until(_NOW, weeks=-3) == _NOW + timedelta(weeks=1)


# ---------------------------------------------------------------------------
# evaluate_drawdown_breach
# ---------------------------------------------------------------------------


def _cfg(**overrides: object) -> AutoPauseConfig:
    base: dict[str, object] = {
        "enabled": True,
        "lookback_trades": 5,
        "max_drawdown_pct": Decimal("0.10"),
        "pause_weeks": 2,
    }
    base.update(overrides)
    return AutoPauseConfig(**base)  # type: ignore[arg-type]


def test_drawdown_breach_when_enabled_and_threshold_exceeded() -> None:
    decision = evaluate_drawdown_breach(
        cfg=_cfg(),
        recent_pnl_usd=[Decimal("-50"), Decimal("-60"), Decimal("-40"),
                        Decimal("-30"), Decimal("-20")],  # cum −200 USD
        capital_usd=Decimal("1500"),
    )
    # |200| / 1500 = 0.133 > 0.10
    assert decision.should_pause is True
    assert decision.reason is not None
    assert "rolling DD" in decision.reason


def test_no_breach_when_filter_disabled() -> None:
    decision = evaluate_drawdown_breach(
        cfg=_cfg(enabled=False),
        recent_pnl_usd=[Decimal("-200")] * 5,  # massacro
        capital_usd=Decimal("1500"),
    )
    assert decision.should_pause is False


def test_no_breach_when_lookback_insufficient() -> None:
    decision = evaluate_drawdown_breach(
        cfg=_cfg(lookback_trades=5),
        recent_pnl_usd=[Decimal("-100")] * 3,  # solo 3 trade, serve 5
        capital_usd=Decimal("1500"),
    )
    assert decision.should_pause is False


def test_no_breach_when_cumulative_positive() -> None:
    # Anche con tante perdite, se la somma è positiva non scattiamo.
    decision = evaluate_drawdown_breach(
        cfg=_cfg(),
        recent_pnl_usd=[Decimal("-100"), Decimal("-50"),
                        Decimal("300"), Decimal("-20"), Decimal("-10")],
        capital_usd=Decimal("1500"),
    )
    assert decision.should_pause is False


def test_no_breach_when_below_threshold() -> None:
    decision = evaluate_drawdown_breach(
        cfg=_cfg(),
        recent_pnl_usd=[Decimal("-30")] * 5,  # cum −150 / 1500 = 10% esatto
        capital_usd=Decimal("1500"),
    )
    # esattamente alla soglia (>=) ⇒ pausa armata
    assert decision.should_pause is True


def test_no_breach_when_capital_zero_or_negative() -> None:
    decision = evaluate_drawdown_breach(
        cfg=_cfg(),
        recent_pnl_usd=[Decimal("-100")] * 5,
        capital_usd=Decimal("0"),
    )
    assert decision.should_pause is False