from fastapi import APIRouter, HTTPException
from typing import Optional
from decimal import Decimal

from database import get_session
from models import Cost, Vehicle
from schemas import (
    CostCreate,
    CostUpdate,
    CostDelete,
    CostResponse,
)


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


def _to_cost_response(cost: Cost) -> CostResponse:
    """将 Cost 模型转换为 CostResponse"""
    return CostResponse(
        id=cost.id,
        vehicle_id=cost.vehicle_id,
        date=cost.date,
        type=cost.type,
        amount=float(cost.amount),
        mileage=cost.mileage,
        notes=cost.notes,
        is_installment=cost.is_installment,
        installment_months=cost.installment_months,
        is_deleted=cost.is_deleted,
        created_at=cost.created_at,
        updated_at=cost.updated_at,
    )


@router.get("/list", response_model=list[CostResponse])
def get_costs(
    vehicle_id: Optional[int] = None,
    cost_type: Optional[str] = None,
):
    """获取费用记录列表（排除已删除），返回全部数据"""
    session = get_session()
    try:
        query = session.query(Cost).filter(Cost.is_deleted == False)
        if vehicle_id:
            query = query.filter(Cost.vehicle_id == vehicle_id)
        if cost_type:
            query = query.filter(Cost.type == cost_type)

        costs = query.order_by(Cost.date.desc()).all()
        return [_to_cost_response(c) for c in costs]
    finally:
        session.close()


@router.post("/create", response_model=CostResponse)
def create_cost(cost: CostCreate):
    """添加费用记录"""
    session = get_session()
    try:
        # 验证车辆存在
        vehicle = session.query(Vehicle).filter(Vehicle.id == cost.vehicle_id).first()
        if not vehicle:
            raise HTTPException(status_code=404, detail="Vehicle not found")

        db_cost = Cost(
            vehicle_id=cost.vehicle_id,
            date=cost.date,
            type=cost.type,
            amount=Decimal(str(cost.amount)),
            mileage=cost.mileage,
            notes=cost.notes or "",
            is_installment=cost.is_installment or False,
            installment_months=cost.installment_months or 12,
        )
        session.add(db_cost)
        session.commit()
        session.refresh(db_cost)

        return _to_cost_response(db_cost)
    finally:
        session.close()


@router.post("/update", response_model=CostResponse)
def update_cost(cost_update: CostUpdate):
    """更新费用记录"""
    session = get_session()
    try:
        cost = session.query(Cost).filter(Cost.id == cost_update.id).first()
        if not cost:
            raise HTTPException(status_code=404, detail="Cost record not found")

        if cost_update.date is not None:
            cost.date = cost_update.date
        if cost_update.type is not None:
            cost.type = cost_update.type
        if cost_update.amount is not None:
            cost.amount = Decimal(str(cost_update.amount))
        if cost_update.mileage is not None:
            cost.mileage = cost_update.mileage
        if cost_update.notes is not None:
            cost.notes = cost_update.notes or ""
        if cost_update.is_installment is not None:
            cost.is_installment = cost_update.is_installment
        if cost_update.installment_months is not None:
            cost.installment_months = cost_update.installment_months

        session.commit()
        session.refresh(cost)

        return _to_cost_response(cost)
    finally:
        session.close()


@router.post("/delete")
def delete_cost(cost: CostDelete):
    """软删除费用记录"""
    session = get_session()
    try:
        db_cost = (
            session.query(Cost)
            .filter(Cost.id == cost.id, Cost.is_deleted == False)
            .first()
        )
        if not db_cost:
            raise HTTPException(status_code=404, detail="Cost record not found")

        db_cost.is_deleted = True
        session.commit()
        return {"message": "Cost record deleted successfully"}
    finally:
        session.close()