func (lt *opsworksLayerType) Update(d *schema.ResourceData, client *opsworks.OpsWorks) error {

	req := &opsworks.UpdateLayerInput{
		LayerId:                     aws.String(d.Id()),
		AutoAssignElasticIps:        aws.Bool(d.Get("auto_assign_elastic_ips").(bool)),
		AutoAssignPublicIps:         aws.Bool(d.Get("auto_assign_public_ips").(bool)),
		CustomInstanceProfileArn:    aws.String(d.Get("custom_instance_profile_arn").(string)),
		CustomRecipes:               lt.CustomRecipes(d),
		CustomSecurityGroupIds:      makeAwsStringSet(d.Get("custom_security_group_ids").(*schema.Set)),
		EnableAutoHealing:           aws.Bool(d.Get("auto_healing").(bool)),
		InstallUpdatesOnBoot:        aws.Bool(d.Get("install_updates_on_boot").(bool)),
		LifecycleEventConfiguration: lt.LifecycleEventConfiguration(d),
		Name:                     aws.String(d.Get("name").(string)),
		Packages:                 makeAwsStringSet(d.Get("system_packages").(*schema.Set)),
		UseEbsOptimizedInstances: aws.Bool(d.Get("use_ebs_optimized_instances").(bool)),
		Attributes:               lt.AttributeMap(d),
		VolumeConfigurations:     lt.VolumeConfigurations(d),
	}

	if lt.CustomShortName {
		req.Shortname = aws.String(d.Get("short_name").(string))
	} else {
		req.Shortname = aws.String(lt.TypeName)
	}

	log.Printf("[DEBUG] Updating OpsWorks layer: %s", d.Id())

	_, err := client.UpdateLayer(req)
	if err != nil {
		return err
	}

	return lt.Read(d, client)
}

func OpsworksInstanceStateRefreshFunc(conn *opsworks.OpsWorks, instanceID string) resource.StateRefreshFunc {
	return func() (interface{}, string, error) {
		resp, err := conn.DescribeInstances(&opsworks.DescribeInstancesInput{
			InstanceIds: []*string{aws.String(instanceID)},
		})
		if err != nil {
			if awserr, ok := err.(awserr.Error); ok && awserr.Code() == "ResourceNotFoundException" {
				// Set this to nil as if we didn't find anything.
				resp = nil
			} else {
				log.Printf("Error on OpsworksInstanceStateRefresh: %s", err)
				return nil, "", err
			}
		}

		if resp == nil || len(resp.Instances) == 0 {
			// Sometimes AWS just has consistency issues and doesn't see
			// our instance yet. Return an empty state.
			return nil, "", nil
		}

		i := resp.Instances[0]
		return i, *i.Status, nil
	}
}

func (lt *opsworksLayerType) Delete(d *schema.ResourceData, client *opsworks.OpsWorks) error {
	req := &opsworks.DeleteLayerInput{
		LayerId: aws.String(d.Id()),
	}

	log.Printf("[DEBUG] Deleting OpsWorks layer: %s", d.Id())

	_, err := client.DeleteLayer(req)
	return err
}

func (lt *opsworksLayerType) Create(d *schema.ResourceData, client *opsworks.OpsWorks) error {

	req := &opsworks.CreateLayerInput{
		AutoAssignElasticIps:        aws.Bool(d.Get("auto_assign_elastic_ips").(bool)),
		AutoAssignPublicIps:         aws.Bool(d.Get("auto_assign_public_ips").(bool)),
		CustomInstanceProfileArn:    aws.String(d.Get("custom_instance_profile_arn").(string)),
		CustomRecipes:               lt.CustomRecipes(d),
		CustomSecurityGroupIds:      expandStringSet(d.Get("custom_security_group_ids").(*schema.Set)),
		EnableAutoHealing:           aws.Bool(d.Get("auto_healing").(bool)),
		InstallUpdatesOnBoot:        aws.Bool(d.Get("install_updates_on_boot").(bool)),
		LifecycleEventConfiguration: lt.LifecycleEventConfiguration(d),
		Name:                     aws.String(d.Get("name").(string)),
		Packages:                 expandStringSet(d.Get("system_packages").(*schema.Set)),
		Type:                     aws.String(lt.TypeName),
		StackId:                  aws.String(d.Get("stack_id").(string)),
		UseEbsOptimizedInstances: aws.Bool(d.Get("use_ebs_optimized_instances").(bool)),
		Attributes:               lt.AttributeMap(d),
		VolumeConfigurations:     lt.VolumeConfigurations(d),
	}

	if lt.CustomShortName {
		req.Shortname = aws.String(d.Get("short_name").(string))
	} else {
		req.Shortname = aws.String(lt.TypeName)
	}

	req.CustomJson = aws.String(d.Get("custom_json").(string))

	log.Printf("[DEBUG] Creating OpsWorks layer: %s", d.Id())

	resp, err := client.CreateLayer(req)
	if err != nil {
		return err
	}

	layerId := *resp.LayerId
	d.SetId(layerId)
	d.Set("id", layerId)

	loadBalancer := aws.String(d.Get("elastic_load_balancer").(string))
	if loadBalancer != nil && *loadBalancer != "" {
		log.Printf("[DEBUG] Attaching load balancer: %s", *loadBalancer)
		_, err := client.AttachElasticLoadBalancer(&opsworks.AttachElasticLoadBalancerInput{
			ElasticLoadBalancerName: loadBalancer,
			LayerId:                 &layerId,
		})
		if err != nil {
			return err
		}
	}

	return lt.Read(d, client)
}

func (lt *opsworksLayerType) Read(d *schema.ResourceData, client *opsworks.OpsWorks) error {

	req := &opsworks.DescribeLayersInput{
		LayerIds: []*string{
			aws.String(d.Id()),
		},
	}

	log.Printf("[DEBUG] Reading OpsWorks layer: %s", d.Id())

	resp, err := client.DescribeLayers(req)
	if err != nil {
		if awserr, ok := err.(awserr.Error); ok {
			if awserr.Code() == "ResourceNotFoundException" {
				d.SetId("")
				return nil
			}
		}
		return err
	}

	layer := resp.Layers[0]
	d.Set("id", layer.LayerId)
	d.Set("auto_assign_elastic_ips", layer.AutoAssignElasticIps)
	d.Set("auto_assign_public_ips", layer.AutoAssignPublicIps)
	d.Set("custom_instance_profile_arn", layer.CustomInstanceProfileArn)
	d.Set("custom_security_group_ids", unwrapAwsStringList(layer.CustomSecurityGroupIds))
	d.Set("auto_healing", layer.EnableAutoHealing)
	d.Set("install_updates_on_boot", layer.InstallUpdatesOnBoot)
	d.Set("name", layer.Name)
	d.Set("system_packages", unwrapAwsStringList(layer.Packages))
	d.Set("stack_id", layer.StackId)
	d.Set("use_ebs_optimized_instances", layer.UseEbsOptimizedInstances)

	if lt.CustomShortName {
		d.Set("short_name", layer.Shortname)
	}

	lt.SetAttributeMap(d, layer.Attributes)
	lt.SetLifecycleEventConfiguration(d, layer.LifecycleEventConfiguration)
	lt.SetCustomRecipes(d, layer.CustomRecipes)
	lt.SetVolumeConfigurations(d, layer.VolumeConfigurations)

	return nil
}