"""Routes for backtesting strategies."""

import logging

from fastapi import APIRouter, HTTPException
from pydantic import BaseModel, Field

import backtest_service
from models import ApiResponse

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/v1/backtest", tags=["backtest"])


# ---------------------------------------------------------------------------
# Request models
# ---------------------------------------------------------------------------


class BacktestRequest(BaseModel):
    symbol: str = Field(..., min_length=1, max_length=20)
    days: int = Field(default=365, ge=30, le=3650)
    initial_capital: float = Field(default=10000.0, gt=0, le=1_000_000_000)


class SMARequest(BacktestRequest):
    short_window: int = Field(default=20, ge=5, le=100)
    long_window: int = Field(default=50, ge=10, le=400)


class RSIRequest(BacktestRequest):
    period: int = Field(default=14, ge=2, le=50)
    oversold: float = Field(default=30.0, ge=1, le=49)
    overbought: float = Field(default=70.0, ge=51, le=99)


class BuyAndHoldRequest(BacktestRequest):
    pass


class MomentumRequest(BaseModel):
    symbols: list[str] = Field(..., min_length=2, max_length=20)
    lookback: int = Field(default=60, ge=5, le=252)
    top_n: int = Field(default=2, ge=1)
    rebalance_days: int = Field(default=30, ge=5, le=252)
    days: int = Field(default=365, ge=60, le=3650)
    initial_capital: float = Field(default=10000.0, gt=0)


# ---------------------------------------------------------------------------
# Route handlers
# ---------------------------------------------------------------------------


@router.post("/sma-crossover", response_model=ApiResponse)
async def sma_crossover(req: SMARequest) -> ApiResponse:
    """SMA crossover strategy: buy when short SMA crosses above long SMA."""
    try:
        result = await backtest_service.backtest_sma_crossover(
            req.symbol,
            short_window=req.short_window,
            long_window=req.long_window,
            days=req.days,
            initial_capital=req.initial_capital,
        )
        return ApiResponse(data=result)
    except ValueError as exc:
        logger.warning("SMA crossover backtest validation error: %s", exc)
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except Exception as exc:
        logger.exception("SMA crossover backtest failed")
        raise HTTPException(
            status_code=502, detail="Data provider error. Check server logs."
        ) from exc


@router.post("/rsi", response_model=ApiResponse)
async def rsi_strategy(req: RSIRequest) -> ApiResponse:
    """RSI strategy: buy when RSI < oversold, sell when RSI > overbought."""
    try:
        result = await backtest_service.backtest_rsi(
            req.symbol,
            period=req.period,
            oversold=req.oversold,
            overbought=req.overbought,
            days=req.days,
            initial_capital=req.initial_capital,
        )
        return ApiResponse(data=result)
    except ValueError as exc:
        logger.warning("RSI backtest validation error: %s", exc)
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except Exception as exc:
        logger.exception("RSI backtest failed")
        raise HTTPException(
            status_code=502, detail="Data provider error. Check server logs."
        ) from exc


@router.post("/buy-and-hold", response_model=ApiResponse)
async def buy_and_hold(req: BuyAndHoldRequest) -> ApiResponse:
    """Buy-and-hold benchmark: buy on day 1, hold through end of period."""
    try:
        result = await backtest_service.backtest_buy_and_hold(
            req.symbol,
            days=req.days,
            initial_capital=req.initial_capital,
        )
        return ApiResponse(data=result)
    except ValueError as exc:
        logger.warning("Buy-and-hold backtest validation error: %s", exc)
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except Exception as exc:
        logger.exception("Buy-and-hold backtest failed")
        raise HTTPException(
            status_code=502, detail="Data provider error. Check server logs."
        ) from exc


@router.post("/momentum", response_model=ApiResponse)
async def momentum_strategy(req: MomentumRequest) -> ApiResponse:
    """Momentum strategy: every rebalance_days pick top_n symbols by lookback return."""
    try:
        result = await backtest_service.backtest_momentum(
            symbols=req.symbols,
            lookback=req.lookback,
            top_n=req.top_n,
            rebalance_days=req.rebalance_days,
            days=req.days,
            initial_capital=req.initial_capital,
        )
        return ApiResponse(data=result)
    except ValueError as exc:
        logger.warning("Momentum backtest validation error: %s", exc)
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    except Exception as exc:
        logger.exception("Momentum backtest failed")
        raise HTTPException(
            status_code=502, detail="Data provider error. Check server logs."
        ) from exc