"""alter executions.schedule_id FK to ON DELETE SET NULL

Revision ID: 012_schedule_fk_set_null
Revises: 011_add_agent_market_fields
Create Date: 2026-05-07
"""
from alembic import op

revision = "012_schedule_fk_set_null"
down_revision = "011_add_agent_market_fields"
branch_labels = None
depends_on = None


def upgrade() -> None:
    """将 executions.schedule_id 外键改为 SET NULL，删除定时任务时自动保留执行记录。"""
    try:
        op.drop_constraint("executions_ibfk_3", "executions", type_="foreignkey")
    except Exception:
        # FK name may vary; try alternate patterns
        try:
            op.drop_constraint("executions_ibfk_4", "executions", type_="foreignkey")
        except Exception:
            pass
    op.create_foreign_key(
        "executions_ibfk_3",
        "executions", "agent_schedules",
        ["schedule_id"], ["id"],
        ondelete="SET NULL",
    )


def downgrade() -> None:
    try:
        op.drop_constraint("executions_ibfk_3", "executions", type_="foreignkey")
    except Exception:
        pass
    op.create_foreign_key(
        "executions_ibfk_3",
        "executions", "agent_schedules",
        ["schedule_id"], ["id"],
        ondelete="RESTRICT",
    )