from __future__ import annotations

from datetime import date

import pytest

from app.services.backtesting.historical_provider import SyntheticHistoricalProvider
from app.services.backtesting.service import BacktestService
from app.services.backtesting.ui_service import BacktestPageService
from tests.helpers_backtest_sources import StaticBacktestSource


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


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

    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=9680.0,
        loan_amount=222000.0,
        margin_call_ltv=0.80,
    )

    assert result.entry_spot == 100.0
    assert result.scenario.initial_portfolio.underlying_units == 9680.0
    assert result.scenario.initial_portfolio.loan_amount == 222000.0
    assert result.scenario.initial_portfolio.margin_call_ltv == 0.80
    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",
    ]


@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",
        ),
        (
            {
                "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": 145000.0,
                "margin_call_ltv": 0.75,
            },
            "Historical scenario starts undercollateralized",
        ),
    ],
)
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)


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

    with pytest.raises(ValueError, match="deterministic fixture data only supports GLD"):
        service.derive_entry_spot("GLD", date(2024, 1, 3), date(2024, 1, 8))

    with pytest.raises(ValueError, match="deterministic fixture data only supports GLD"):
        service.run_read_only_scenario(
            symbol="GLD",
            start_date=date(2024, 1, 3),
            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,
        )


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

    with pytest.raises(ValueError, match="deterministic fixture data only supports GLD"):
        service.validate_preview_inputs(
            symbol="GLD",
            start_date=date(2024, 1, 3),
            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,
            entry_spot=100.0,
        )


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

    entry_spot = service.validate_preview_inputs(
        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,
        entry_spot=100.005,
    )

    assert entry_spot == 100.0


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

    with pytest.raises(ValueError, match="does not match derived historical entry spot"):
        service.validate_preview_inputs(
            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,
            entry_spot=99.0,
        )


def test_backtest_page_service_does_not_mutate_injected_backtest_service() -> None:
    provider = SyntheticHistoricalProvider(
        source=StaticBacktestSource(),
        implied_volatility=0.2,
        risk_free_rate=0.01,
    )
    injected_service = BacktestService(provider=provider)

    page_service = BacktestPageService(backtest_service=injected_service)

    history = injected_service.provider.load_history("GLD", date(2024, 1, 3), date(2024, 1, 3))
    assert history[0].close == 123.0
    assert page_service.template_service is injected_service.template_service
    assert page_service.backtest_service is not injected_service
    assert page_service.backtest_service.provider.implied_volatility == 0.2
    assert page_service.backtest_service.provider.risk_free_rate == 0.01
    seeded_history = page_service.backtest_service.provider.load_history("GLD", date(2024, 1, 2), date(2024, 1, 8))
    assert seeded_history[0].close == 100.0


def test_backtest_page_service_uses_injected_provider_identity_in_provider_ref() -> None:
    class CustomProvider(SyntheticHistoricalProvider):
        provider_id = "custom_v1"
        pricing_mode = "custom_mode"

    provider = CustomProvider(source=StaticBacktestSource(), implied_volatility=0.2, risk_free_rate=0.01)
    injected_service = BacktestService(provider=provider)
    page_service = BacktestPageService(backtest_service=injected_service)

    result = page_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 result.scenario.provider_ref.provider_id == "custom_v1"
    assert result.scenario.provider_ref.pricing_mode == "custom_mode"