"""研究执行 API：/api/factor-tests 与 /api/backtests。

Phase 3 为同步执行（样本有限）；Phase 4 将改为 Job + SSE 异步（接口契约不变）。
最近一次结果在内存中可读，便于前端展示；持久化实验归档在 Phase 4。
"""

from __future__ import annotations

from datetime import date

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

from app.api.deps import ResearchServiceDep
from app.domain.entities.research import (
    BacktestResult,
    FactorCorrelationReport,
    FactorSpec,
    FactorTestReport,
    ResearchSpec,
    SelectionSpec,
    UniverseSpec,
)
from app.quant.factors import FactorError

router = APIRouter(tags=["research"])

# 内存中的最近结果（Phase 4 迁移到 Experiment 表）
_LAST_BACKTEST: dict[str, BacktestResult] = {}
_LAST_FACTOR_TEST: dict[str, FactorTestReport] = {}


@router.post("/factor-tests", response_model=FactorTestReport, summary="运行单因子测试（同步）")
def run_factor_test(
    spec: ResearchSpec,
    service: ResearchServiceDep,
) -> FactorTestReport:
    try:
        report = service.run_factor_test(spec)
    except (ValueError, FactorError) as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    _LAST_FACTOR_TEST["default"] = report
    return report


@router.post("/backtests", response_model=BacktestResult, summary="运行回测（同步）")
def run_backtest(
    spec: ResearchSpec,
    service: ResearchServiceDep,
) -> BacktestResult:
    try:
        result = service.run_backtest(spec)
    except (ValueError, FactorError) as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    _LAST_BACKTEST["default"] = result
    return result


@router.get("/backtests/last", response_model=BacktestResult, summary="最近一次回测结果")
def last_backtest() -> BacktestResult:
    if "default" not in _LAST_BACKTEST:
        raise HTTPException(status_code=404, detail="尚无回测结果，请先 POST /api/backtests")
    return _LAST_BACKTEST["default"]


class FactorCorrelationRequest(BaseModel):
    """因子相关性分析请求（v3 §12）。"""

    universe: UniverseSpec = UniverseSpec()
    factors: list[FactorSpec] = Field(min_length=2)
    period: tuple[date, date]
    price_adjustment: str = Field(default="none", pattern="^(none|qfq)$")


@router.post(
    "/factor-correlations",
    response_model=FactorCorrelationReport,
    summary="多因子两两相关（横截面 Spearman）",
)
def run_factor_correlation(
    req: FactorCorrelationRequest,
    service: ResearchServiceDep,
) -> FactorCorrelationReport:
    if req.period[0] >= req.period[1]:
        raise HTTPException(status_code=400, detail="period 必须满足 start < end")
    spec = ResearchSpec(
        type="factor_test",
        universe=req.universe,
        price_adjustment=req.price_adjustment,
        factors=req.factors,
        selection=SelectionSpec(top_n=10),
        rebalance="monthly",
        period=req.period,
    )
    try:
        return service.run_factor_correlation(spec)
    except (ValueError, FactorError) as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc