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"""Increase length of email and username in ``ab_user`` and ``ab_register_user`` table to ``256`` characters

Revision ID: 5e3ec427fdd3
Revises: 587bdf053233
Create Date: 2021-12-01 11:49:26.390210

"""
from __future__ import annotations

import sqlalchemy as sa
from alembic import op

from airflow.migrations.utils import get_mssql_table_constraints

# revision identifiers, used by Alembic.
revision = '5e3ec427fdd3'
down_revision = '587bdf053233'
branch_labels = None
depends_on = None
airflow_version = '2.3.0'


def upgrade():
    """Increase length of email from 64 to 256 characters"""
    with op.batch_alter_table('ab_user') as batch_op:
        batch_op.alter_column('username', type_=sa.String(256))
        batch_op.alter_column('email', type_=sa.String(256))
    with op.batch_alter_table('ab_register_user') as batch_op:
        batch_op.alter_column('username', type_=sa.String(256))
        batch_op.alter_column('email', type_=sa.String(256))


def downgrade():
    """Revert length of email from 256 to 64 characters"""
    conn = op.get_bind()
    if conn.dialect.name != 'mssql':
        with op.batch_alter_table('ab_user') as batch_op:
            batch_op.alter_column('username', type_=sa.String(64), nullable=False)
            batch_op.alter_column('email', type_=sa.String(64))
        with op.batch_alter_table('ab_register_user') as batch_op:
            batch_op.alter_column('username', type_=sa.String(64))
            batch_op.alter_column('email', type_=sa.String(64))
    else:
        # MSSQL doesn't drop implicit unique constraints it created
        # We need to drop the two unique constraints explicitly
        with op.batch_alter_table('ab_user') as batch_op:
            # Drop the unique constraint on username and email
            constraints = get_mssql_table_constraints(conn, 'ab_user')
            unique_key, _ = constraints['UNIQUE'].popitem()
            batch_op.drop_constraint(unique_key, type_='unique')
            unique_key, _ = constraints['UNIQUE'].popitem()
            batch_op.drop_constraint(unique_key, type_='unique')
            batch_op.alter_column('username', type_=sa.String(64), nullable=False)
            batch_op.create_unique_constraint(None, ['username'])
            batch_op.alter_column('email', type_=sa.String(64))
            batch_op.create_unique_constraint(None, ['email'])

        with op.batch_alter_table('ab_register_user') as batch_op:
            # Drop the unique constraint on username and email
            constraints = get_mssql_table_constraints(conn, 'ab_register_user')
            for k, _ in constraints.get('UNIQUE').items():
                batch_op.drop_constraint(k, type_='unique')
            batch_op.alter_column('username', type_=sa.String(64))
            batch_op.create_unique_constraint(None, ['username'])
            batch_op.alter_column('email', type_=sa.String(64))
