import enum
from uuid import uuid4

from sqlalchemy import Boolean, Column, DateTime, Enum, Float, ForeignKey, Integer, String, Text
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func

from app.core.database import Base


class ProductStatus(enum.Enum):
    DRAFT = "draft"
    PUBLISHED = "published"
    OUT_OF_STOCK = "out_of_stock"
    DISCONTINUED = "discontinued"

class Product(Base):
    __tablename__ = "products"

    id = Column(String(36), primary_key=True, default=lambda: str(uuid4()))
    name = Column(String(255), nullable=False, index=True)
    description = Column(Text, nullable=True)
    price = Column(Float, nullable=False)
    sku = Column(String(100), unique=True, nullable=True)
    barcode = Column(String(100), unique=True, nullable=True)
    stock_quantity = Column(Integer, default=0)
    weight = Column(Float, nullable=True)  # In kg
    dimensions = Column(String(100), nullable=True)  # Format: LxWxH in cm
    status = Column(Enum(ProductStatus), default=ProductStatus.DRAFT)
    is_featured = Column(Boolean, default=False)
    is_digital = Column(Boolean, default=False)
    digital_download_link = Column(String(512), nullable=True)
    slug = Column(String(255), nullable=False, unique=True)
    tax_rate = Column(Float, default=0.0)  # As a percentage
    discount_price = Column(Float, nullable=True)
    discount_start_date = Column(DateTime(timezone=True), nullable=True)
    discount_end_date = Column(DateTime(timezone=True), nullable=True)
    category_id = Column(String(36), ForeignKey("categories.id"), nullable=True)
    seller_id = Column(String(36), ForeignKey("users.id"), nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

    # Relationships
    category = relationship("Category", back_populates="products")
    seller = relationship("User", back_populates="products")
    images = relationship("ProductImage", back_populates="product", cascade="all, delete-orphan")
    reviews = relationship("Review", back_populates="product", cascade="all, delete-orphan")
    order_items = relationship("OrderItem", back_populates="product")
    cart_items = relationship("CartItem", back_populates="product")

    # Tags relationship
    tags = relationship("Tag", secondary="product_tags")

    def __repr__(self):
        return f"<Product {self.name}>"

    @property
    def average_rating(self):
        if not self.reviews:
            return None
        return sum(review.rating for review in self.reviews) / len(self.reviews)

    @property
    def current_price(self):
        """Returns the current effective price (discount or regular)"""
        now = func.now()
        if (self.discount_price and self.discount_start_date and self.discount_end_date and
            self.discount_start_date <= now and now <= self.discount_end_date):
            return self.discount_price
        return self.price

class ProductImage(Base):
    __tablename__ = "product_images"

    id = Column(String(36), primary_key=True, default=lambda: str(uuid4()))
    product_id = Column(String(36), ForeignKey("products.id", ondelete="CASCADE"), nullable=False)
    image_url = Column(String(512), nullable=False)
    alt_text = Column(String(255), nullable=True)
    is_primary = Column(Boolean, default=False)
    display_order = Column(Integer, default=0)
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    # Relationship
    product = relationship("Product", back_populates="images")

    def __repr__(self):
        return f"<ProductImage {self.id} for Product {self.product_id}>"