from __future__ import annotations

from dataclasses import dataclass
from datetime import date
from enum import StrEnum
from typing import Any

from app.services.backtesting.historical_provider import DailyClosePoint, SyntheticHistoricalProvider

SEEDED_GLD_2024_FIXTURE_HISTORY: tuple[DailyClosePoint, ...] = (
    DailyClosePoint(date=date(2024, 1, 2), close=100.0),
    DailyClosePoint(date=date(2024, 1, 3), close=96.0),
    DailyClosePoint(date=date(2024, 1, 4), close=92.0),
    DailyClosePoint(date=date(2024, 1, 5), close=88.0),
    DailyClosePoint(date=date(2024, 1, 8), close=85.0),
)


class WindowPolicy(StrEnum):
    EXACT = "exact"
    BOUNDED = "bounded"


@dataclass(frozen=True)
class SharedHistoricalFixtureSource:
    feature_label: str
    supported_symbol: str
    history: tuple[DailyClosePoint, ...]
    window_policy: WindowPolicy

    @property
    def start_date(self) -> date:
        return self.history[0].date

    @property
    def end_date(self) -> date:
        return self.history[-1].date

    def load_daily_closes(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
        if start_date > end_date:
            raise ValueError("start_date must be on or before end_date")
        normalized_symbol = symbol.strip().upper()
        if normalized_symbol != self.supported_symbol.strip().upper():
            raise ValueError(
                f"{self.feature_label} deterministic fixture data only supports {self.supported_symbol} on this page"
            )
        if self.window_policy is WindowPolicy.EXACT:
            if start_date != self.start_date or end_date != self.end_date:
                raise ValueError(
                    f"{self.feature_label} deterministic fixture data only supports {self.supported_symbol} "
                    f"on the seeded {self.start_date.isoformat()} through {self.end_date.isoformat()} window"
                )
        else:
            if start_date < self.start_date or end_date > self.end_date:
                raise ValueError(
                    f"{self.feature_label} deterministic fixture data only supports the seeded "
                    f"{self.start_date.isoformat()} through {self.end_date.isoformat()} window"
                )
        return [point for point in self.history if start_date <= point.date <= end_date]


class FixtureBoundSyntheticHistoricalProvider:
    def __init__(self, base_provider: SyntheticHistoricalProvider, source: SharedHistoricalFixtureSource) -> None:
        self.base_provider = base_provider
        self.source = source

    def load_history(self, symbol: str, start_date: date, end_date: date) -> list[DailyClosePoint]:
        rows = self.source.load_daily_closes(symbol, start_date, end_date)
        return sorted(rows, key=lambda row: row.date)

    def __getattr__(self, name: str) -> Any:
        return getattr(self.base_provider, name)


def build_backtest_ui_fixture_source() -> SharedHistoricalFixtureSource:
    return SharedHistoricalFixtureSource(
        feature_label="BT-001A",
        supported_symbol="GLD",
        history=SEEDED_GLD_2024_FIXTURE_HISTORY,
        window_policy=WindowPolicy.EXACT,
    )


def build_event_comparison_fixture_source() -> SharedHistoricalFixtureSource:
    return SharedHistoricalFixtureSource(
        feature_label="BT-003A",
        supported_symbol="GLD",
        history=SEEDED_GLD_2024_FIXTURE_HISTORY,
        window_policy=WindowPolicy.BOUNDED,
    )


def bind_fixture_source(
    base_provider: SyntheticHistoricalProvider,
    source: SharedHistoricalFixtureSource,
) -> FixtureBoundSyntheticHistoricalProvider:
    return FixtureBoundSyntheticHistoricalProvider(base_provider=base_provider, source=source)