"""backfill user_id for generated_videos from generation_tasks

Revision ID: 045_backfill_user_id_generated_videos
Revises: 044_user_id_generated_videos
Create Date: 2026-07-19 10:50:00.000000

"""

import sqlalchemy as sa

from alembic import op

# revision identifiers, used by Alembic.
revision = "045_backfill_user_id"
down_revision = "044_user_id_generated_videos"
branch_labels = None
depends_on = None


def upgrade() -> None:
    # 回填 generated_videos.user_id：通过 generation_task_id 关联 generation_tasks 表
    # 取 generation_tasks.created_by_user_id 作为 user_id
    # 回填不到的（无关联task的兜底记录）保持空字符串
    op.execute("""
        UPDATE generated_videos gv
        SET user_id = gt.created_by_user_id
        FROM generation_tasks gt
        WHERE gv.generation_task_id = gt.id
          AND gv.user_id = ''
          AND gt.created_by_user_id != ''
        """)


def downgrade() -> None:
    # 降级不做处理（无法精确区分哪些是回填的）
    pass