"""Add admins table for platform admin access control.

Revision ID: 005
Revises: 004
Create Date: 2025-03-18

Platform admins are stored in a dedicated table. Presence grants admin privileges.
Replaces the is_admin column that was never migrated to the users table.
"""
from typing import Sequence, Union

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

revision: str = "005"
down_revision: Union[str, None] = "004"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        "admins",
        sa.Column("id", postgresql.UUID(as_uuid=True), primary_key=True, server_default=sa.text("gen_random_uuid()")),
        sa.Column("user_id", postgresql.UUID(as_uuid=True), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False),
        sa.Column("created_at", sa.TIMESTAMP(timezone=True), server_default=sa.func.now()),
        sa.Column("created_by", postgresql.UUID(as_uuid=True), sa.ForeignKey("users.id", ondelete="SET NULL")),
        sa.UniqueConstraint("user_id", name="uq_admins_user_id"),
    )
    op.create_index("idx_admins_user_id", "admins", ["user_id"])


def downgrade() -> None:
    op.drop_index("idx_admins_user_id", table_name="admins")
    op.drop_table("admins")