from __future__ import annotations

from datetime import date

import pytest

from app.services.backtesting.ui_service import BacktestPageService


def test_backtest_page_service_uses_fixture_window_for_deterministic_run() -> None:
    service = BacktestPageService()

    entry_spot = service.derive_entry_spot("GLD", date(2024, 1, 2), date(2024, 1, 8))
    result = service.run_read_only_scenario(
        symbol="GLD",
        start_date=date(2024, 1, 2),
        end_date=date(2024, 1, 8),
        template_slug="protective-put-atm-12m",
        underlying_units=1000.0,
        loan_amount=68000.0,
        margin_call_ltv=0.75,
    )

    assert entry_spot == 100.0
    assert result.scenario.initial_portfolio.entry_spot == 100.0
    assert result.run_result.template_results[0].summary_metrics.margin_threshold_breached_unhedged is True
    assert result.run_result.template_results[0].summary_metrics.margin_threshold_breached_hedged is False
    assert [point.date.isoformat() for point in result.run_result.template_results[0].daily_path] == [
        "2024-01-02",
        "2024-01-03",
        "2024-01-04",
        "2024-01-05",
        "2024-01-08",
    ]


def test_backtest_non_default_template_slug_runs_successfully() -> None:
    service = BacktestPageService()

    options = service.template_options("GLD")
    non_default_slug = str(options[1]["slug"])

    result = service.run_read_only_scenario(
        symbol="GLD",
        start_date=date(2024, 1, 2),
        end_date=date(2024, 1, 8),
        template_slug=non_default_slug,
        underlying_units=1000.0,
        loan_amount=68000.0,
        margin_call_ltv=0.75,
    )

    assert result.scenario.template_refs[0].slug == non_default_slug
    assert result.run_result.template_results[0].template_slug == non_default_slug


@pytest.mark.parametrize(
    ("kwargs", "message"),
    [
        (
            {
                "symbol": "",
                "start_date": date(2024, 1, 2),
                "end_date": date(2024, 1, 8),
                "template_slug": "protective-put-atm-12m",
                "underlying_units": 1000.0,
                "loan_amount": 68000.0,
                "margin_call_ltv": 0.75,
            },
            "Symbol is required",
        ),
        (
            {
                "symbol": "GLD",
                "start_date": date(2024, 1, 8),
                "end_date": date(2024, 1, 2),
                "template_slug": "protective-put-atm-12m",
                "underlying_units": 1000.0,
                "loan_amount": 68000.0,
                "margin_call_ltv": 0.75,
            },
            "Start date must be on or before end date",
        ),
        (
            {
                "symbol": "GLD",
                "start_date": date(2024, 1, 2),
                "end_date": date(2024, 1, 8),
                "template_slug": "protective-put-atm-12m",
                "underlying_units": 0.0,
                "loan_amount": 68000.0,
                "margin_call_ltv": 0.75,
            },
            "Underlying units must be positive",
        ),
        (
            {
                "symbol": "TLT",
                "start_date": date(2024, 1, 2),
                "end_date": date(2024, 1, 8),
                "template_slug": "protective-put-atm-12m",
                "underlying_units": 1000.0,
                "loan_amount": 68000.0,
                "margin_call_ltv": 0.75,
            },
            "BT-001A backtests are currently limited to GLD on this page",
        ),
    ],
)
def test_backtest_page_service_validation_errors_are_user_facing(kwargs: dict[str, object], message: str) -> None:
    service = BacktestPageService()

    with pytest.raises(ValueError, match=message):
        service.run_read_only_scenario(**kwargs)