"""策略 API（M8.3）：/api/strategies CRUD + 展开为 ResearchSpec。

POST /api/strategies   保存策略（name 唯一）
GET  /api/strategies   列表
GET  /api/strategies/{id}
DELETE /api/strategies/{id}
POST /api/strategies/{id}/expand  body: {period:[start,end], initial_capital?} → ResearchSpec
"""

from __future__ import annotations

from datetime import date

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

from app.api.deps import DbSession, StrategyRepoDep
from app.application.services.job_executor import new_id
from app.domain.entities.research import ResearchSpec
from app.domain.entities.strategy import StrategyDefinition

router = APIRouter(prefix="/strategies", tags=["strategies"])


class ExpandRequest(BaseModel):
    period: tuple[date, date]
    initial_capital: float = Field(default=1_000_000.0, gt=0)


@router.post("", response_model=StrategyDefinition, summary="保存策略")
def create_strategy(
    definition: StrategyDefinition,
    strategy_repo: StrategyRepoDep,
    session: DbSession,
) -> StrategyDefinition:
    try:
        saved = strategy_repo.save(definition.model_copy(update={"id": new_id("STG")}))
        session.commit()
        return saved
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@router.get("", response_model=list[StrategyDefinition], summary="策略列表")
def list_strategies(strategy_repo: StrategyRepoDep) -> list[StrategyDefinition]:
    return strategy_repo.list()


@router.get("/{strategy_id}", response_model=StrategyDefinition, summary="读取策略")
def get_strategy(strategy_id: str, strategy_repo: StrategyRepoDep) -> StrategyDefinition:
    row = strategy_repo.get(strategy_id)
    if row is None:
        raise HTTPException(status_code=404, detail=f"策略 {strategy_id} 不存在")
    return row


@router.delete("/{strategy_id}", summary="删除策略")
def delete_strategy(
    strategy_id: str,
    strategy_repo: StrategyRepoDep,
    session: DbSession,
) -> dict:
    if not strategy_repo.delete(strategy_id):
        raise HTTPException(status_code=404, detail=f"策略 {strategy_id} 不存在")
    session.commit()
    return {"deleted": strategy_id}


@router.post("/{strategy_id}/expand", response_model=ResearchSpec, summary="展开为研究 Spec")
def expand_strategy(
    strategy_id: str,
    req: ExpandRequest,
    strategy_repo: StrategyRepoDep,
) -> ResearchSpec:
    row = strategy_repo.get(strategy_id)
    if row is None:
        raise HTTPException(status_code=404, detail=f"策略 {strategy_id} 不存在")
    if req.period[0] >= req.period[1]:
        raise HTTPException(status_code=400, detail="period 必须满足 start < end")
    return row.to_research_spec(period=req.period, initial_capital=req.initial_capital)