module AwsResourceMixin

def catch_aws_errors
  yield
rescue Aws::Errors::MissingCredentialsError
  # The AWS error here is unhelpful:
  # "unable to sign request without credentials set"
  Inspec::Log.error "It appears that you have not set your AWS credentials.  You may set them using environment variables, or using the 'aws://region/aws_credentials_profile' target.  See https://www.inspec.io/docs/reference/platforms for details."
  fail_resource('No AWS credentials available')
rescue Aws::Errors::ServiceError => e
  fail_resource e.message
end

def check_resource_param_names(raw_params: {}, allowed_params: [], allowed_scalar_name: nil, allowed_scalar_type: nil)
  # Some resources allow passing in a single ID value.  Check and convert to hash if so.
  if allowed_scalar_name && !raw_params.is_a?(Hash)
    value_seen = raw_params
    if value_seen.is_a?(allowed_scalar_type)
      raw_params = { allowed_scalar_name => value_seen }
    else
      raise ArgumentError, 'If you pass a single value to the resource, it must ' \
                           "be a #{allowed_scalar_type}, not an #{value_seen.class}."
    end
  end
  # Remove all expected params from the raw param hash
  recognized_params = {}
  allowed_params.each do |expected_param|
    recognized_params[expected_param] = raw_params.delete(expected_param) if raw_params.key?(expected_param)
  end
  # Any leftovers are unwelcome
  unless raw_params.empty?
    raise ArgumentError, "Unrecognized resource param '#{raw_params.keys.first}'. Expected parameters: #{allowed_params.join(', ')}"
  end
  recognized_params
end

def initialize(resource_params = {})
  validate_params(resource_params).each do |param, value|
    instance_variable_set(:"@#{param}", value)
  end
  catch_aws_errors do
    fetch_from_api
  end
rescue ArgumentError => e
  # continue with ArgumentError if testing
  raise unless respond_to?(:inspec)
  raise Inspec::Exceptions::ResourceFailed, e.message
end

def inspec_runner
  # When running under inspec-cli, we have an 'inspec' method that
  # returns the runner. When running under unit tests, we don't
  # have that, but we still have to call this to pass something
  # (nil is OK) to the backend.
  # TODO: remove with https://github.com/chef/inspec-aws/issues/216
  inspec if respond_to?(:inspec)
end

def validate_params(resource_params)
  resource_params
end