"""RBAC 003 - Create user_roles table

PRD-008 RBAC — Migration 3 of 7

Creates the user_roles table that maps a user to a single role within
a given merchant context. One row per user per merchant enforced by
a UNIQUE constraint on (user_id, merchant_id).

Revision ID: rbac003c4d5e6f
Revises: rbac002b3c4d5e
Create Date: 2026-03-19 00:00:03.000000

"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision: str = 'rbac003c4d5e6f'
down_revision: Union[str, Sequence[str], None] = 'rbac002b3c4d5e'
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    op.create_table(
        'user_roles',
        sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
        sa.Column('user_id', sa.Integer(), nullable=False),
        sa.Column('role_id', sa.Integer(), nullable=False),
        sa.Column('merchant_id', sa.Integer(), nullable=False),
        sa.Column(
            'is_primary',
            sa.Boolean(),
            nullable=False,
            server_default=sa.text('true'),
        ),
        sa.Column('created_at', sa.DateTime(), server_default=sa.func.now(), nullable=True),
        sa.ForeignKeyConstraint(['merchant_id'], ['merchants.id'], name='fk_user_roles_merchant_id'),
        sa.ForeignKeyConstraint(['role_id'], ['roles.id'], name='fk_user_roles_role_id'),
        sa.ForeignKeyConstraint(['user_id'], ['users.id'], name='fk_user_roles_user_id'),
        sa.PrimaryKeyConstraint('id'),
        sa.UniqueConstraint('user_id', 'merchant_id', name='uq_user_role_per_merchant'),
    )
    op.create_index('ix_user_roles_user_id', 'user_roles', ['user_id'], unique=False)
    op.create_index('ix_user_roles_merchant_id', 'user_roles', ['merchant_id'], unique=False)


def downgrade() -> None:
    op.drop_index('ix_user_roles_merchant_id', table_name='user_roles')
    op.drop_index('ix_user_roles_user_id', table_name='user_roles')
    op.drop_table('user_roles')