import uuid
from datetime import datetime, timezone

from sqlalchemy import Boolean, DateTime, ForeignKey, String, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database import Base


class Group(Base):
    __tablename__ = "groups"

    id: Mapped[str] = mapped_column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
    name: Mapped[str] = mapped_column(String(128), unique=True, nullable=False, index=True)
    description: Mapped[str | None] = mapped_column(String(512), nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        nullable=False,
    )

    memberships: Mapped[list["GroupMembership"]] = relationship(
        "GroupMembership", back_populates="group", cascade="all, delete-orphan"
    )


class GroupMembership(Base):
    __tablename__ = "group_memberships"
    __table_args__ = (UniqueConstraint("group_id", "user_id", name="uq_group_user"),)

    id: Mapped[str] = mapped_column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
    group_id: Mapped[str] = mapped_column(
        String, ForeignKey("groups.id", ondelete="CASCADE"), nullable=False, index=True
    )
    user_id: Mapped[str] = mapped_column(
        String, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    is_group_admin: Mapped[bool] = mapped_column(
        Boolean, nullable=False, default=False, server_default="false"
    )
    joined_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        nullable=False,
    )

    group: Mapped["Group"] = relationship("Group", back_populates="memberships")