from decimal import Decimal

import pytest

from llm_trade_bot.models import (
    AccountSnapshot,
    Category,
    InstrumentRules,
    OpenTradeRequest,
    OrderType,
    Side,
)
from llm_trade_bot.risk import OrderRejected, OrderValidator


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


@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,
        "leverage": Decimal(3),
        "rationale": "test",
    }
    values.update(overrides)
    return OpenTradeRequest(**values)


def test_uses_all_available_buying_power(engine, account, rules):
    result = engine.validate_open(request(), account, rules)
    assert result.quantity == Decimal(300)
    assert result.notional == Decimal(30000)


def test_existing_exposure_does_not_cap_position(engine, rules):
    account = AccountSnapshot(Decimal(10000), Decimal(10000), Decimal(3900), 2)
    result = engine.validate_open(request(), account, rules)
    assert result.quantity == Decimal(300)
    assert result.notional == Decimal(30000)


def test_explicit_quote_notional_sizes_order(engine, account, rules):
    result = engine.validate_open(request(), account, rules, quote_notional=Decimal("5000"))
    assert result.quantity == Decimal(50)
    assert result.notional == Decimal(5000)


def test_available_balance_percent_sizes_margin_before_leverage(engine, account, rules):
    result = engine.validate_open(
        request(), account, rules, available_balance_percent=Decimal("25")
    )
    assert result.quantity == Decimal(75)
    assert result.notional == Decimal(7500)


@pytest.mark.parametrize(
    "quote_notional, available_balance_percent, message",
    [
        (Decimal("1"), Decimal("50"), "either"),
        (Decimal("0"), None, "quote_notional"),
        (None, Decimal("101"), "available_balance_percent"),
        (Decimal("30001"), None, "exceeds available buying power"),
    ],
)
def test_rejects_invalid_explicit_sizing(
    engine, account, rules, quote_notional, available_balance_percent, message
):
    with pytest.raises(OrderRejected, match=message):
        engine.validate_open(
            request(),
            account,
            rules,
            quote_notional=quote_notional,
            available_balance_percent=available_balance_percent,
        )


def test_minimum_quantity_error_reports_sizing_inputs(engine, rules):
    empty_account = AccountSnapshot(Decimal(10000), Decimal(0), Decimal(0), 0)

    with pytest.raises(
        OrderRejected,
        match=r"quantity 0.*minimum 0\.001.*available_balance=0.*leverage=3.*entry_price=100",
    ):
        engine.validate_open(request(), empty_account, rules)


@pytest.mark.parametrize(
    "overrides, message",
    [
        ({"leverage": Decimal(101)}, "Leverage"),
        ({"stop_loss": Decimal(101)}, "stop-loss"),
        ({"take_profit": None, "trailing_distance": None}, "take-profit or trailing"),
        ({"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(OrderRejected, match=message):
        engine.validate_open(request(**overrides), account, rules)