"""add_role_audit_fields

Revision ID: 4fa11836f7fd
Revises: 013_sync_permissions
Create Date: 2026-01-16 17:21:40.514605

"""
from typing import Sequence, Union

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


# revision identifiers, used by Alembic.
revision: str = '4fa11836f7fd'
down_revision: Union[str, None] = '013_sync_permissions'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # Add role audit trail columns
    op.add_column('users', sa.Column('role_changed_at', sa.DateTime(timezone=True), nullable=True))
    op.add_column('users', sa.Column('role_changed_by', UUID(as_uuid=True), nullable=True))

    # Create foreign key constraint to track who changed the role
    op.create_foreign_key(
        'fk_users_role_changed_by',
        'users', 'users',
        ['role_changed_by'], ['id'],
        ondelete='SET NULL'
    )

    # Create index for efficient querying by role change date
    op.create_index('idx_users_role_changed_at', 'users', ['role_changed_at'])


def downgrade() -> None:
    # Drop index first
    op.drop_index('idx_users_role_changed_at')

    # Drop foreign key constraint
    op.drop_constraint('fk_users_role_changed_by', 'users', type_='foreignkey')

    # Drop columns
    op.drop_column('users', 'role_changed_by')
    op.drop_column('users', 'role_changed_at')