"""${message}

Revision ID: ${up_revision}
Revises: ${down_revision | comma,n}
Create Date: ${create_date}

"""
from collections.abc import Sequence

from alembic import op
import sqlalchemy as sa
${imports if imports else ""}

# revision identifiers, used by Alembic.
revision: str = ${repr(up_revision)}
down_revision: str | Sequence[str] | None = ${repr(down_revision)}
branch_labels: str | Sequence[str] | None = ${repr(branch_labels)}
depends_on: str | Sequence[str] | None = ${repr(depends_on)}


def upgrade() -> None:
    """应用迁移。"""
    ${upgrades if upgrades else "pass"}


def downgrade() -> None:
    """回滚迁移。

    **注意（autogenerate 不会替你处理）**：生成的 `op.drop_index` 与
    `op.drop_table` 顺序需人工检查 —— 若某索引是外键的唯一支撑索引，
    单独 drop_index 会报 MySQL 1553（needed in a foreign key constraint）。
    **整表回滚应只保留 `op.drop_table`**，DROP TABLE 会连带删除索引与外键。
    """
    ${downgrades if downgrades else "pass"}