from fastapi import HTTPException
from sqlalchemy import delete, select
from sqlalchemy.orm import Session, selectinload

from .models import DemandRecommendation, DemandRecommendationProduct, Product
from .serializers import model_dict


def demand_recommendation_error(status_code: int, message: str, code: str, details: dict | None = None) -> None:
    raise HTTPException(status_code=status_code, detail={"message": message, "code": code, "details": details or {}})


def demand_recommendation_dict(item: DemandRecommendation, *, public: bool = False) -> dict:
    links = sorted(item.products or [], key=lambda link: (link.sortOrder, link.productId))
    if public:
        links = [link for link in links if link.product and link.product.status == "published"]

    data = {
        "id": item.id,
        "title": item.title,
        "subtitle": item.subtitle,
        "productIds": [link.productId for link in links],
        "isActive": item.isActive,
    }
    if not public:
        base = model_dict(item)
        data.update(
            {
                "sortOrder": item.sortOrder,
                "createdAt": base["createdAt"],
                "updatedAt": base["updatedAt"],
            }
        )
    return data


def demand_recommendation_query():
    return (
        select(DemandRecommendation)
        .options(selectinload(DemandRecommendation.products).selectinload(DemandRecommendationProduct.product))
        .order_by(DemandRecommendation.sortOrder.asc())
    )


def validate_demand_recommendation_product_ids(db: Session, product_ids: list[str]) -> None:
    if len(set(product_ids)) != len(product_ids):
        demand_recommendation_error(422, "推荐线路商品不能重复", "DEMAND_RECOMMENDATION_PRODUCT_DUPLICATE")
    if not product_ids:
        return

    products = db.scalars(select(Product).where(Product.id.in_(product_ids))).all()
    found_ids = {product.id for product in products}
    missing_ids = [product_id for product_id in product_ids if product_id not in found_ids]
    if missing_ids:
        demand_recommendation_error(422, "推荐线路商品不存在", "DEMAND_RECOMMENDATION_PRODUCT_NOT_FOUND", {"productIds": missing_ids})


def replace_demand_recommendation_products(db: Session, recommendation: DemandRecommendation, product_ids: list[str]) -> None:
    validate_demand_recommendation_product_ids(db, product_ids)
    db.execute(delete(DemandRecommendationProduct).where(DemandRecommendationProduct.recommendationId == recommendation.id))
    db.flush()
    recommendation.products = []
    for index, product_id in enumerate(product_ids):
        link = DemandRecommendationProduct(recommendationId=recommendation.id, productId=product_id, sortOrder=index)
        recommendation.products.append(link)
        db.add(link)