\set ON_ERROR_STOP on

SELECT format('CREATE ROLE %I LOGIN PASSWORD %L', :'app_user', :'app_password')
WHERE NOT EXISTS (
  SELECT 1
  FROM pg_catalog.pg_roles
  WHERE rolname = :'app_user'
)\gexec

SELECT format('ALTER ROLE %I WITH LOGIN PASSWORD %L', :'app_user', :'app_password')\gexec

SELECT format('CREATE DATABASE %I OWNER %I', :'app_db', :'app_user')
WHERE NOT EXISTS (
  SELECT 1
  FROM pg_database
  WHERE datname = :'app_db'
)\gexec

SELECT format('ALTER DATABASE %I OWNER TO %I', :'app_db', :'app_user')\gexec
SELECT format('GRANT ALL PRIVILEGES ON DATABASE %I TO %I', :'app_db', :'app_user')\gexec