"""Add policyactionholds (break-glass desired-state suppression).

Backs the admin override: when an admin break-glasses past a policy denial on a
desired-mode action, a hold row suspends reconciliation of that action on that
endpoint until expiresat, so the override is not immediately undone by the next
drift-correcting enqueue.

Rows are never swept: expiry is evaluated at resolve time against expiresat, and
an expired row stays as the audit record of what was suppressed and why.

Idempotent: the create_table is skipped when the table already exists (e.g. a
test DB built by db.create_all()).

Revision ID: computers0005policyactionholds
Revises: computers0004policies
"""
from alembic import op
import sqlalchemy as sa


revision = 'computers0005policyactionholds'
down_revision = 'computers0004policies'
branch_labels = None
depends_on = None


def upgrade():
    bind = op.get_bind()
    insp = sa.inspect(bind)
    existing = set(insp.get_table_names())

    if 'policyactionholds' not in existing:
        op.create_table(
            'policyactionholds',
            sa.Column('policyactionholdid', sa.Integer(), nullable=False),
            sa.Column('assetid', sa.Integer(), nullable=False),
            sa.Column('action', sa.String(length=100), nullable=False),
            sa.Column('expiresat', sa.DateTime(), nullable=False),
            sa.Column('createdbyuserid', sa.Integer(), nullable=True),
            sa.Column('createdbyusername', sa.String(length=100), nullable=True),
            sa.Column('reason', sa.Text(), nullable=False),
            sa.Column('createddate', sa.DateTime(), nullable=False),
            sa.Column('modifieddate', sa.DateTime(), nullable=False),
            sa.Column('isactive', sa.Boolean(), nullable=False,
                      server_default=sa.true()),
            sa.PrimaryKeyConstraint('policyactionholdid'),
            sa.ForeignKeyConstraint(['assetid'], ['assets.assetid'],
                                    ondelete='CASCADE'),
            sa.ForeignKeyConstraint(['createdbyuserid'], ['users.userid'],
                                    ondelete='SET NULL'),
        )
        op.create_index('idx_policyactionhold_asset', 'policyactionholds',
                        ['assetid'])
        op.create_index('idx_policyactionhold_expiry', 'policyactionholds',
                        ['expiresat'])


def downgrade():
    bind = op.get_bind()
    insp = sa.inspect(bind)
    existing = set(insp.get_table_names())

    if 'policyactionholds' in existing:
        op.drop_index('idx_policyactionhold_expiry',
                      table_name='policyactionholds')
        op.drop_index('idx_policyactionhold_asset',
                      table_name='policyactionholds')
        op.drop_table('policyactionholds')