"""add prediction status/time semantics and MatchStats provenance

Revision ID: 0005_prediction_status_and_stats_provenance
Revises: 0004_snapshot_and_constraints
Create Date: 2026-09-15

"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision: str = '0005_prediction_status_and_stats_provenance'
down_revision: Union[str, None] = '0004_snapshot_and_constraints'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # 1. Prediction 新增字段
    op.add_column('predictions', sa.Column('status', sa.String(length=20), nullable=False, server_default='success'))
    op.add_column('predictions', sa.Column('match_kickoff_at', sa.DateTime(timezone=True), nullable=True))
    op.add_column('predictions', sa.Column('prediction_created_at', sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()))
    op.add_column('predictions', sa.Column('prediction_cutoff_at', sa.DateTime(timezone=True), nullable=True))

    # 重命名 cutoff_at → 保留作为兼容,prediction_cutoff_at 为主字段
    # op.drop_column('predictions', 'cutoff_at')  # 暂不删除,避免破坏现有数据

    # 2. 新增 status CHECK 约束
    op.create_check_constraint('ck_status_enum', 'predictions', "status IN ('success', 'failed', 'degraded')")

    # 3. MatchStats 新增数据血缘字段
    op.add_column('match_stats', sa.Column('source', sa.String(length=30), nullable=True))
    op.add_column('match_stats', sa.Column('source_record_id', sa.String(length=100), nullable=True))
    op.add_column('match_stats', sa.Column('retrieved_at', sa.DateTime(timezone=True), nullable=True))
    op.add_column('match_stats', sa.Column('available_at', sa.DateTime(timezone=True), nullable=True))

    # 4. 索引
    op.create_index('ix_match_stats_available_at', 'match_stats', ['available_at'])
    op.create_index('ix_predictions_cutoff_at', 'predictions', ['prediction_cutoff_at'])


def downgrade() -> None:
    op.drop_index('ix_predictions_cutoff_at', table_name='predictions')
    op.drop_index('ix_match_stats_available_at', table_name='match_stats')

    op.drop_column('match_stats', 'available_at')
    op.drop_column('match_stats', 'retrieved_at')
    op.drop_column('match_stats', 'source_record_id')
    op.drop_column('match_stats', 'source')

    op.drop_constraint('ck_status_enum', 'predictions', type_='check')

    op.drop_column('predictions', 'prediction_cutoff_at')
    op.drop_column('predictions', 'prediction_created_at')
    op.drop_column('predictions', 'match_kickoff_at')
    op.drop_column('predictions', 'status')