"""支持用户软删除并保留历史任务归属"""

from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa


revision: str = "20260813_0023"
down_revision: Union[str, None] = "20260812_0022"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def _columns(bind, table_name: str) -> set[str]:
    return {column["name"] for column in sa.inspect(bind).get_columns(table_name)}


def upgrade() -> None:
    bind = op.get_bind()
    columns = _columns(bind, "users")
    if "deleted_at" not in columns:
        op.add_column("users", sa.Column("deleted_at", sa.DateTime(), nullable=True))
        op.create_index("ix_users_deleted_at", "users", ["deleted_at"])
    if "deleted_username" not in columns:
        op.add_column("users", sa.Column("deleted_username", sa.String(length=64), nullable=True))


def downgrade() -> None:
    bind = op.get_bind()
    columns = _columns(bind, "users")
    if "deleted_username" in columns:
        op.drop_column("users", "deleted_username")
    if "deleted_at" in columns:
        op.drop_index("ix_users_deleted_at", table_name="users")
        op.drop_column("users", "deleted_at")