from decimal import Decimal

import pytest

from llm_trade_bot.config import RiskConfig
from llm_trade_bot.models import (
    AccountSnapshot,
    Category,
    InstrumentRules,
    OpenTradeRequest,
    OrderType,
    Side,
)
from llm_trade_bot.risk import RiskEngine, RiskRejected


@pytest.fixture
def engine() -> RiskEngine:
    return RiskEngine(RiskConfig())


@pytest.fixture
def account() -> AccountSnapshot:
    return AccountSnapshot(Decimal(10000), Decimal(10000), Decimal(0), 0)


@pytest.fixture
def rules() -> InstrumentRules:
    return InstrumentRules(Decimal("0.1"), Decimal("0.001"), Decimal("0.001"), Decimal(5), Decimal(100))


def request(**overrides) -> OpenTradeRequest:
    values = {
        "category": Category.LINEAR,
        "symbol": "BTCUSDT",
        "side": Side.BUY,
        "order_type": OrderType.MARKET,
        "reference_price": Decimal(100),
        "limit_price": None,
        "stop_loss": Decimal(90),
        "take_profit": Decimal(120),
        "trailing_distance": None,
        "risk_pct": Decimal(2),
        "leverage": Decimal(3),
        "rationale": "test",
    }
    values.update(overrides)
    return OpenTradeRequest(**values)


def test_sizes_by_risk_and_exposure(engine, account, rules):
    result = engine.validate_open(request(), account, rules)
    assert result.quantity == Decimal(20)
    assert result.notional == Decimal(2000)


def test_remaining_exposure_caps_position(engine, rules):
    account = AccountSnapshot(Decimal(10000), Decimal(10000), Decimal(3900), 2)
    result = engine.validate_open(request(), account, rules)
    assert result.quantity == Decimal(1)
    assert result.notional == Decimal(100)


@pytest.mark.parametrize(
    "overrides, message",
    [
        ({"risk_pct": Decimal("2.1")}, "risk_pct"),
        ({"leverage": Decimal(4)}, "Leverage"),
        ({"stop_loss": Decimal(101)}, "stop-loss"),
        ({"take_profit": None, "trailing_distance": None}, "take-profit or trailing"),
        ({"category": Category.SPOT, "order_type": OrderType.MARKET}, "Spot entries"),
        ({"category": Category.SPOT, "order_type": OrderType.LIMIT, "limit_price": Decimal(100), "take_profit": None}, "Spot entry requires"),
    ],
)
def test_rejects_unsafe_requests(engine, account, rules, overrides, message):
    with pytest.raises(RiskRejected, match=message):
        engine.validate_open(request(**overrides), account, rules)


def test_rejects_max_positions(engine, rules):
    account = AccountSnapshot(Decimal(10000), Decimal(10000), Decimal(0), 5)
    with pytest.raises(RiskRejected, match="Maximum"):
        engine.validate_open(request(), account, rules)