module AwsClient
  class CfWrapper < Wrapper

    STACK_COMPLETE_STATUS = "CREATE_COMPLETE"
    STACK_UPDATE_COMPLETE_STATUS = "UPDATE_COMPLETE"
    STACK_ROLLLBACK_STATUS = "ROLLBACK_IN_PROGRESS"
    STACK_WAIT_SLEEP_TIME = 3

    def create_stack(stack_params)
      puts "Creating stack with the following parameters: #{stack_params.inspect}"
      response = client.create_stack(stack_params)
      wait_for_stack(stack_params[:stack_name])
    end

    # http://docs.aws.amazon.com/sdkforruby/api/Aws/CloudFormation/Client.html#update_stack-instance_method
    def update_stack(stack_params)
      puts "Updating stack with the following parameters: #{stack_params.inspect}"
      response = client.update_stack(stack_params)
      is_update = true
      wait_for_stack(stack_params[:stack_name], is_update)
    end

    def stack_status_for(stack_name)
      stack_info = stack_info_for(stack_name)
      return stack_info_for(stack_name).stack_status
    end

    def stack_info_for(stack_name)
      page = client.describe_stacks  
      stack_info = page.data.stacks.select{|stack| stack["stack_name"] == stack_name }
      raise "Cannot find CF stack named '#{stack_name}'" unless stack_info.any?
      return stack_info.last
    end

    def stack_resources_by_stack_name_and_resource_type(stack_name, resource_type)
      return stack_resources_for_stack(stack_name).select{|r| r.resource_type == resource_type }  
    end

    def ec2_server_stack_resource_for_node_name(stack_name, node_name)
      server_resources = ec2_server_stack_resources(stack_name)
      server_resource = server_resources.select{|s| s.logical_resource_id == node_name}
      return server_resource
    end

    def ec2_server_stack_resources(stack_name)
      stack_resources_by_stack_name_and_resource_type(stack_name, "AWS::EC2::Instance")
    end

    def stack_resources_for_stack(stack_name)
      @resources ||= client.describe_stack_resources("stack_name" => stack_name).data[:stack_resources]
    end 

    def resource_data_for_resource_name(stack_name, resource_name)
      stack_resources_for_stack(stack_name).select{|r| r.logical_resource_id == resource_name }.first
    end 

    def physical_resource_id_for(stack_name, resource_name)
      resource_data_for_resource_name(stack_name, resource_name).physical_resource_id
    end

    def wait_for_stack(stack_name, is_update = false)
      puts "Waiting for stack"
      status = ""
      end_status = is_update ? STACK_UPDATE_COMPLETE_STATUS : STACK_COMPLETE_STATUS

      while status != end_status
        status = stack_status_for(stack_name)
        puts "'#{stack_name}' stack status: #{status}"
 
        raise "Rollback in progress - CF build failed" if status == STACK_ROLLLBACK_STATUS 
        sleep(STACK_WAIT_SLEEP_TIME)     
      end
      puts "Stack is ready."
    end

  end
end