import uuid
from datetime import datetime, timezone
from sqlalchemy import DateTime, ForeignKey, Integer, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column
from sqlalchemy.dialects.postgresql import UUID
from app.core.database import Base


class UserPinnedTree(Base):
    """Tracks which trees a user has pinned to their sidebar."""
    __tablename__ = "user_pinned_trees"
    __table_args__ = (
        UniqueConstraint('user_id', 'tree_id', name='uq_user_pinned_tree'),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4
    )
    user_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("users.id", ondelete="CASCADE"),
        nullable=False,
        index=True
    )
    tree_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("trees.id", ondelete="CASCADE"),
        nullable=False,
        index=True
    )
    display_order: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    pinned_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc)
    )