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

from app.database import Base


class AssetCollection(Base):
    """A curated collection or pack of 3D models and assets."""
    __tablename__ = "asset_collections"

    id = Column(Integer, primary_key=True, index=True)
    title = Column(String(255), nullable=False, index=True)
    description = Column(Text, nullable=True)
    theme = Column(String(64), nullable=False, default="general", index=True)
    thumbnail_url = Column(String(512), nullable=True)
    owner_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
    is_public = Column(Boolean, default=True, nullable=False, index=True)
    tags = Column(String(512), nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

    owner = relationship("User", back_populates="asset_collections")
    items = relationship(
        "CollectionAsset",
        back_populates="collection",
        cascade="all, delete-orphan",
        order_by="CollectionAsset.sort_order",
    )


class CollectionAsset(Base):
    """Join entity linking an Asset to an AssetCollection with ordering."""
    __tablename__ = "collection_assets"

    id = Column(Integer, primary_key=True, index=True)
    collection_id = Column(
        Integer,
        ForeignKey("asset_collections.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    asset_id = Column(
        Integer,
        ForeignKey("assets.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    sort_order = Column(Integer, default=0, nullable=False)
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    collection = relationship("AssetCollection", back_populates="items")
    asset = relationship("Asset")