"""add region to olt_devices

Revision ID: d4e5f6a7b8c9
Revises: c3d4e5f6a7b8
Create Date: 2026-04-05

"""
from alembic import op
import sqlalchemy as sa

revision = 'd4e5f6a7b8c9'
down_revision = 'c3d4e5f6a7b8'
branch_labels = None
depends_on = None


def upgrade():
    op.add_column('olt_devices', sa.Column('region', sa.String(100), nullable=True))
    op.create_index('ix_olt_devices_region', 'olt_devices', ['region'])
    # 默认将现有 OLT 设置为城区
    op.execute("UPDATE olt_devices SET region = '城区' WHERE region IS NULL")


def downgrade():
    op.drop_index('ix_olt_devices_region', 'olt_devices')
    op.drop_column('olt_devices', 'region')