"""add suspended_intent / resumable_step_code / resumable_slots_json (Спринт 6a, блок C)

Revision ID: e1a4f7c83b29
Revises: d9b612a04e75
Create Date: 2026-04-25 12:30:00.000000

При hard-handoff из ветки со state machine (через `[INTENT_CHANGE: ...]`) текущий
сценарий запоминается в `suspended_intent` + `resumable_step_code` + `resumable_slots_json`.
Если на следующих репликах роутер возвращает intent = suspended_intent — восстанавливаем
state и очищаем эти поля. v2 §4.4.
"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa


revision: str = 'e1a4f7c83b29'
down_revision: Union[str, None] = 'd9b612a04e75'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    with op.batch_alter_table('thread_state', recreate='always') as batch:
        batch.add_column(sa.Column('suspended_intent', sa.String(length=50), nullable=True))
        batch.add_column(sa.Column('resumable_step_code', sa.String(length=50), nullable=True))
        batch.add_column(sa.Column('resumable_slots_json', sa.Text(), nullable=True))


def downgrade() -> None:
    with op.batch_alter_table('thread_state', recreate='always') as batch:
        batch.drop_column('resumable_slots_json')
        batch.drop_column('resumable_step_code')
        batch.drop_column('suspended_intent')