"""P0-01: 比分可信度——score_status + 允许完赛缺分(NULL,禁止伪造 0:0)

替换 ck_matches_finished_has_score:引入 score_status(known/missing/unknown),
完赛 + score_status=missing 时 home/away_goals 必须 NULL(不伪造比分)。

Revision ID: 0022_match_score_status
Revises: 0021_match_source_event_id_unique
Create Date: 2026-09-22
"""

from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa

revision: str = '0022_match_score_status'
down_revision: Union[str, None] = '0021_match_source_event_id_unique'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # 1) 新增 score_status 列(默认 unknown)
    op.add_column(
        'matches',
        sa.Column('score_status', sa.String(20), server_default='unknown', nullable=False),
    )

    # 2) 按现有数据回填 score_status(绝不写 goals=0):
    #    - 有比分(两列均非 NULL) → known
    #    - 无比分 + 完赛 → missing(缺分)
    #    - 其余 → unknown
    op.execute(
        "UPDATE matches SET score_status = 'known'"
        " WHERE home_goals IS NOT NULL AND away_goals IS NOT NULL"
    )
    op.execute(
        "UPDATE matches SET score_status = 'missing'"
        " WHERE match_status = 'finished' AND home_goals IS NULL AND away_goals IS NULL"
    )

    # 3) 删除旧约束,加新约束
    op.drop_constraint('ck_matches_finished_has_score', 'matches', type_='check')
    op.create_check_constraint(
        'ck_matches_score_status_enum', 'matches',
        "score_status IN ('known', 'missing', 'unknown')",
    )
    op.create_check_constraint(
        'ck_matches_score_integrity', 'matches',
        "match_status <> 'finished'"
        " OR (score_status = 'known' AND home_goals IS NOT NULL AND away_goals IS NOT NULL)"
        " OR (score_status IN ('missing', 'unknown') AND home_goals IS NULL AND away_goals IS NULL)",
    )


def downgrade() -> None:
    op.drop_constraint('ck_matches_score_integrity', 'matches', type_='check')
    op.drop_constraint('ck_matches_score_status_enum', 'matches', type_='check')
    op.create_check_constraint(
        'ck_matches_finished_has_score', 'matches',
        "match_status <> 'finished' OR (home_goals IS NOT NULL AND away_goals IS NOT NULL)",
    )
    op.remove_column('matches', 'score_status')