class Jets::Resource
  class Permission < Jets::Resource::Base
    def initialize(replacements, associated_resource)
      @replacements = replacements
      @associated_resource = associated_resource
    end

    def definition
      {
        permission_logical_id => {
          type: "AWS::Lambda::Permission",
          properties: {
            function_name: "!GetAtt {namespace}LambdaFunction.Arn",
            action: "lambda:InvokeFunction",
            principal: principal,
            source_arn: source_arn,
          }
        }
      }
    end

    def permission_logical_id
      logical_id = "{namespace}_permission"
      md = @associated_resource.logical_id.match(/(\d+)/)
      counter = md[1] if md
      [logical_id, counter].compact.join('').underscore
    end

    # Auto-detect principal from the associated resources.
    def principal
      Replacer.principal_map(@associated_resource.type)
    end

    def source_arn
      default_arn = "!GetAtt #{@associated_resource.logical_id}.Arn"
      Replacer.source_arn_map(@associated_resource.type) || default_arn
    end
  end
end