# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.  The
# ASF licenses this file to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance with the
# License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
# License for the specific language governing permissions and limitations
# under the License.

module Deltacloud::Helpers

  module Drivers

    def driver_symbol
      driver_name.to_sym
    end

    def driver_name
      Thread.current[:driver] ||= ENV['API_DRIVER']
    end

    def driver_class_name
      driver_name.camelize
    end

    def driver_source_name
      File.join('..', 'drivers', driver_name, driver_name + '_driver.rb')
    end

    def driver_class
      begin
        m = Deltacloud::Drivers.const_get(driver_class_name)
        m.const_get(driver_class_name + "Driver").new
      rescue NameError
        raise "[ERROR] The driver class name is not defined as #{driver_class_name}Driver"
      end
    end

    def driver
      $:.unshift File.join(File.dirname(__FILE__), '..', '..')
      begin
        require_relative driver_source_name
        driver_class
      rescue LoadError => e
        raise "[ERROR] The driver '#{driver_name}' is unknown or not installed (#{driver_source_name})\n" +
          "\n#{e.message}\n"
      end
    end

  end

end