"""为 predictions 表添加 match_id+provider+model 唯一约束

Revision ID: 0007_predictions_unique_constraint
Revises: 0007_injuries_constraint_naming_align
Create Date: 2026-09-16

背景(见代码审查报告 P1-6):
  同一 match_id + provider + model 组合不应产生重复预测。
  当前缺少数据库级唯一约束,回测多次运行或并发采集可能产生重复记录,
  导致统计偏差。

  先清理已存在的重复记录(保留最早创建的那条),再添加唯一约束。
"""

from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision: str = '0007_predictions_unique_constraint'
down_revision: Union[str, None] = '0007_injuries_constraint_naming_align'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # 1. 清理已存在的重复记录(保留 id 最小的)
    op.execute(
        """
        DELETE FROM predictions
        WHERE id NOT IN (
            SELECT MIN(id)
            FROM predictions
            GROUP BY match_id, provider, model
        )
        AND match_id IN (
            SELECT match_id
            FROM predictions
            GROUP BY match_id, provider, model
            HAVING COUNT(*) > 1
        )
        """
    )

    # 2. 添加唯一约束
    op.create_unique_constraint(
        "uq_predictions_match_provider_model",
        "predictions",
        ["match_id", "provider", "model"],
    )


def downgrade() -> None:
    op.drop_constraint(
        "uq_predictions_match_provider_model",
        "predictions",
        type_="unique",
    )