"""
用户收藏模型
"""
from datetime import datetime
from config.database import db
from app.models.product import Product
from app.models.user import User


class UserFavorite(db.Model):
    __tablename__ = 'user_favorites'

    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'), nullable=False)
    product_id = db.Column(db.Integer, db.ForeignKey('products.id'), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.utcnow)

    # 关联关系
    user = db.relationship('User', backref='favorites')
    product = db.relationship('Product', backref='favorited_by')

    # 唯一约束
    __table_args__ = (db.UniqueConstraint('user_id', 'product_id', name='uk_user_product'),)

    def to_dict(self):
        """转换为字典"""
        return {
            'id': self.id,
            'user_id': self.user_id,
            'product_id': self.product_id,
            'created_at': self.created_at.isoformat() if self.created_at else None,
            'product': {
                'id': self.product.id,
                'name': self.product.name,
                'price': float(self.product.price),
                'main_image': self.product.main_image,
                'status': self.product.status,
                'sales_count': self.product.sales_count
            } if self.product else None
        }

    @classmethod
    def is_favorited(cls, user_id, product_id):
        """检查用户是否收藏了某商品"""
        return cls.query.filter_by(user_id=user_id, product_id=product_id).first() is not None

    @classmethod
    def add_favorite(cls, user_id, product_id):
        """添加收藏"""
        # 检查是否已存在
        existing = cls.query.filter_by(user_id=user_id, product_id=product_id).first()
        if existing:
            return False, "商品已在收藏夹中"

        # 检查商品是否存在
        product = Product.query.get(product_id)
        if not product:
            return False, "商品不存在"

        # 添加收藏
        favorite = cls(user_id=user_id, product_id=product_id)
        db.session.add(favorite)
        
        try:
            db.session.commit()
            return True, "收藏成功"
        except Exception as e:
            db.session.rollback()
            return False, f"收藏失败: {str(e)}"

    @classmethod
    def remove_favorite(cls, user_id, product_id):
        """取消收藏"""
        favorite = cls.query.filter_by(user_id=user_id, product_id=product_id).first()
        if not favorite:
            return False, "商品未收藏"

        db.session.delete(favorite)
        
        try:
            db.session.commit()
            return True, "取消收藏成功"
        except Exception as e:
            db.session.rollback()
            return False, f"取消收藏失败: {str(e)}"

    @classmethod
    def get_user_favorites(cls, user_id, page=1, per_page=20):
        """获取用户收藏列表"""
        return cls.query.filter_by(user_id=user_id) \
            .join(Product) \
            .filter(Product.status == 1) \
            .order_by(cls.created_at.desc()) \
            .paginate(page=page, per_page=per_page, error_out=False)

    @classmethod
    def get_user_favorites_count(cls, user_id):
        """获取用户收藏数量"""
        return cls.query.filter_by(user_id=user_id).count()

    def __repr__(self):
        return f'<UserFavorite {self.user_id}-{self.product_id}>'