"""matches.source_event_id 部分唯一索引

业务唯一键:同联赛同主客同自然天一条(ix_matches_unique,既有)。
source_event_id 是上游 bzzoiro 的比赛 id,用于统计回填与血缘追踪;
当它非空时应全局唯一(同一 upstream 比赛只对应一行 matches),
避免同一场比赛因自然键天级舍入差异产生重复。

partial unique(WHERE source_event_id IS NOT NULL):
  - 兼容存量空 source_event_id 的历史行(不强制回填);
  - 新采集行均带 source_event_id,从此具备 upstream 唯一性。

Revision ID: 0021_match_source_event_id_unique
Revises: 0020_team_aliases
Create Date: 2026-09-22
"""

from typing import Sequence, Union

from alembic import op

revision: str = '0021_match_source_event_id_unique'
down_revision: Union[str, None] = '0020_team_aliases'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_index(
        'ix_matches_source_event_id_unique',
        'matches',
        ['source_event_id'],
        unique=True,
        postgresql_where=op.text('source_event_id IS NOT NULL'),
    )


def downgrade() -> None:
    op.drop_index('ix_matches_source_event_id_unique', table_name='matches')