"""kr_backtest_engine: 원주가 불연속 역보정 + regime='AUTO' 거부."""
import asyncio
from datetime import date, timedelta

import pytest

from app.core.config import settings
from app.services.kr_backtest_engine import (
    BarData, KrBacktestEngine, MeanReversionBacktest, back_adjust_price_events_v2,
)

D0 = date(2026, 1, 5)


def _b(i, px, vol=1000):
    return BarData(trade_date=D0 + timedelta(days=i), open_price=px, high_price=px,
                   low_price=px, close_price=px, volume=vol, stock_code="A")


def test_split_back_adjusted():
    bars = [_b(0, 1000), _b(1, 1000), _b(2, 500), _b(3, 505)]
    n = back_adjust_price_events_v2(bars, [None, 0.0, 0.0, 0.01])
    assert n == 1
    assert [b.close_price for b in bars] == [500, 500, 500, 505]
    assert bars[0].volume == 2000 and bars[2].volume == 1000


def test_normal_move_untouched_and_no_rate_skipped():
    bars = [_b(0, 1000), _b(1, 900)]
    assert back_adjust_price_events_v2(bars, [None, -0.10]) == 0
    assert back_adjust_price_events_v2([_b(0, 1000), _b(1, 400)], [None, None]) == 0
    assert bars[0].close_price == 1000


def test_genuine_crash_not_adjusted():
    bars = [_b(0, 1000), _b(1, 700)]
    assert back_adjust_price_events_v2(bars, [None, -0.30]) == 0


def test_gap_not_event():
    bars = [_b(0, 1000), _b(10, 400)]
    assert back_adjust_price_events_v2(bars, [None, 0.0]) == 0


def test_auto_regime_rejected():
    with pytest.raises(ValueError):
        MeanReversionBacktest._get_regime({"regime": "auto"})
    with pytest.raises(ValueError):
        MeanReversionBacktest._get_regime({"regime": "???"})
    assert MeanReversionBacktest._get_regime({"regime": "bear"}).name == "BEAR"


def test_run_rejects_auto_before_loading(monkeypatch):
    async def boom(*a, **k):
        raise AssertionError("데이터 로드까지 가면 안 됨")
    monkeypatch.setattr("app.services.kr_backtest_engine.load_daily_bars", boom)
    with pytest.raises(ValueError):
        asyncio.run(KrBacktestEngine().run(["A"], D0, D0, params={"regime": "AUTO"}))


def test_default_regime_valid():
    assert MeanReversionBacktest().default_params()["regime"] == "BULL"
    assert settings.MAX_POSITION_SIZE > 0