"""Make admin_id nullable in admin_logs for system actions

Revision ID: 017_admin_logs_nullable_admin_id
Revises: 016_add_banned_until
Create Date: 2024-12-19

"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa
from sqlalchemy import inspect


# revision identifiers, used by Alembic.
revision: str = '017_admin_logs_nullable_admin_id'
down_revision: Union[str, None] = '016_add_banned_until'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def is_column_nullable(table_name: str, column_name: str) -> bool:
    """Check if a column is nullable."""
    bind = op.get_bind()
    inspector = inspect(bind)
    columns = inspector.get_columns(table_name)
    for col in columns:
        if col['name'] == column_name:
            return col.get('nullable', True)
    return True


def upgrade() -> None:
    # Make admin_id nullable for system actions (like auto-unban)
    # Only alter if currently not nullable
    if not is_column_nullable('admin_logs', 'admin_id'):
        op.alter_column('admin_logs', 'admin_id',
                        existing_type=sa.Integer(),
                        nullable=True)


def downgrade() -> None:
    # Revert to not nullable (will fail if there are NULL values)
    if is_column_nullable('admin_logs', 'admin_id'):
        op.alter_column('admin_logs', 'admin_id',
                        existing_type=sa.Integer(),
                        nullable=False)