"""add group tables (groups, group_members)

Revision ID: 0009_add_group_tables
Revises: 0008_add_chat_tables
Create Date: 2026-09-15 00:00:00.000000

docs/planning/social.md US-5 / app/models/groups.py. Models + migration only
-- create/join/leave, role authorization, and the group page endpoint live
in a sibling task ("Groups API") that depends on this one.
"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa
from sqlalchemy.dialects import postgresql

# revision identifiers, used by Alembic.
revision: str = "0009_add_group_tables"
down_revision: Union[str, None] = "0008_add_chat_tables"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    group_role = postgresql.ENUM("owner", "admin", "member", name="group_role")
    group_role.create(op.get_bind(), checkfirst=True)

    op.create_table(
        "groups",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column("name", sa.String(length=100), nullable=False),
        sa.Column("description", sa.Text(), nullable=True),
        sa.Column(
            "owner_id",
            sa.Integer(),
            sa.ForeignKey("users.id", ondelete="SET NULL"),
            nullable=True,
        ),
        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
    )
    op.create_index("ix_groups_owner_id", "groups", ["owner_id"])

    op.create_table(
        "group_members",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column(
            "group_id",
            sa.Integer(),
            sa.ForeignKey("groups.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column(
            "user_id",
            sa.Integer(),
            sa.ForeignKey("users.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column(
            "role",
            postgresql.ENUM("owner", "admin", "member", name="group_role", create_type=False),
            nullable=False,
            server_default="member",
        ),
        sa.Column("joined_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
        sa.UniqueConstraint("group_id", "user_id", name="uq_group_members_pair"),
    )
    op.create_index("ix_group_members_group_id", "group_members", ["group_id"])
    op.create_index("ix_group_members_user_id", "group_members", ["user_id"])


def downgrade() -> None:
    op.drop_index("ix_group_members_user_id", table_name="group_members")
    op.drop_index("ix_group_members_group_id", table_name="group_members")
    op.drop_table("group_members")

    op.drop_index("ix_groups_owner_id", table_name="groups")
    op.drop_table("groups")

    postgresql.ENUM(name="group_role").drop(op.get_bind(), checkfirst=True)