// GetCloudNodesWithSpec constructs and returns api.NodeList from cloudprovider. If error
// occurs, an empty NodeList will be returned with a non-nil error info. The
// method only constructs spec fields for nodes.
func (s *NodeController) GetCloudNodesWithSpec() (*api.NodeList, error) {
	result := &api.NodeList{}
	instances, ok := s.cloud.Instances()
	if !ok {
		return result, ErrCloudInstance
	}
	matches, err := instances.List(s.matchRE)
	if err != nil {
		return result, err
	}
	for i := range matches {
		node := api.Node{}
		node.Name = matches[i]
		resources, err := instances.GetNodeResources(matches[i])
		if err != nil {
			return nil, err
		}
		if resources == nil {
			resources = s.staticResources
		}
		if resources != nil {
			node.Spec.Capacity = resources.Capacity
		}
		instanceID, err := instances.ExternalID(node.Name)
		if err != nil {
			glog.Errorf("error getting instance id for %s: %v", node.Name, err)
		} else {
			node.Spec.ExternalID = instanceID
		}
		result.Items = append(result.Items, node)
	}
	return result, nil
}

// ValidateMinionUpdate tests to make sure a minion update can be applied.  Modifies oldMinion.
func ValidateMinionUpdate(oldMinion *api.Node, minion *api.Node) errs.ValidationErrorList {
	allErrs := errs.ValidationErrorList{}
	allErrs = append(allErrs, ValidateObjectMetaUpdate(&oldMinion.ObjectMeta, &minion.ObjectMeta).Prefix("metadata")...)

	// TODO: Enable the code once we have better api object.status update model. Currently,
	// anyone can update node status.
	// if !api.Semantic.DeepEqual(minion.Status, api.NodeStatus{}) {
	// 	allErrs = append(allErrs, errs.NewFieldInvalid("status", minion.Status, "status must be empty"))
	// }

	// TODO: move reset function to its own location
	// Ignore metadata changes now that they have been tested
	oldMinion.ObjectMeta = minion.ObjectMeta
	// Allow users to update capacity
	oldMinion.Spec.Capacity = minion.Spec.Capacity
	// Clear status
	oldMinion.Status = minion.Status

	// TODO: Add a 'real' ValidationError type for this error and provide print actual diffs.
	if !api.Semantic.DeepEqual(oldMinion, minion) {
		glog.V(4).Infof("Update failed validation %#v vs %#v", oldMinion, minion)
		allErrs = append(allErrs, fmt.Errorf("update contains more than labels or capacity changes"))
	}

	// TODO: validate Spec.Capacity
	return allErrs
}

// ValidateMinionUpdate tests to make sure a minion update can be applied.  Modifies oldMinion.
func ValidateMinionUpdate(oldMinion *api.Node, minion *api.Node) errs.ValidationErrorList {
	allErrs := errs.ValidationErrorList{}

	if !api.Semantic.DeepEqual(minion.Status, api.NodeStatus{}) {
		allErrs = append(allErrs, errs.NewFieldInvalid("status", minion.Status, "status must be empty"))
	}

	// Allow users to update labels and capacity
	oldMinion.Labels = minion.Labels
	oldMinion.Spec.Capacity = minion.Spec.Capacity
	// Clear status
	oldMinion.Status = minion.Status

	if !api.Semantic.DeepEqual(oldMinion, minion) {
		glog.V(4).Infof("Update failed validation %#v vs %#v", oldMinion, minion)
		allErrs = append(allErrs, fmt.Errorf("update contains more than labels or capacity changes"))
	}
	return allErrs
}