"""Block model: a hard deny that also hides content and prevents DMs."""

from sqlalchemy import CheckConstraint, Column, DateTime, ForeignKey, Integer, UniqueConstraint
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func

from app.database import Base


class Block(Base):
    __tablename__ = "blocks"
    __table_args__ = (
        UniqueConstraint(
            "blocker_id",
            "blocked_id",
            name="uq_blocks_blocker_blocked",
        ),
        CheckConstraint(
            "blocker_id <> blocked_id",
            name="ck_blocks_no_self",
        ),
    )

    id = Column(Integer, primary_key=True, index=True)
    blocker_id = Column(
        Integer,
        ForeignKey("users.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    blocked_id = Column(
        Integer,
        ForeignKey("users.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    created_at = Column(DateTime(timezone=True), server_default=func.now())

    blocker = relationship(
        "User",
        foreign_keys=[blocker_id],
        back_populates="blocks_given",
    )
    blocked = relationship(
        "User",
        foreign_keys=[blocked_id],
        back_populates="blocks_received",
    )