// ServerPreferredNamespacedGroupVersionResources uses the specified client to discover the set of preferred groupVersionResources that are namespaced
func ServerPreferredNamespacedGroupVersionResources(discoveryClient discovery.DiscoveryInterface) ([]unversioned.GroupVersionResource, error) {
	results := []unversioned.GroupVersionResource{}
	serverGroupList, err := discoveryClient.ServerGroups()
	if err != nil {
		return results, err
	}

	allErrs := []error{}
	for _, apiGroup := range serverGroupList.Groups {
		preferredVersion := apiGroup.PreferredVersion
		apiResourceList, err := discoveryClient.ServerResourcesForGroupVersion(preferredVersion.GroupVersion)
		if err != nil {
			allErrs = append(allErrs, err)
			continue
		}
		groupVersion := unversioned.GroupVersion{Group: apiGroup.Name, Version: preferredVersion.Version}
		for _, apiResource := range apiResourceList.APIResources {
			if !apiResource.Namespaced {
				continue
			}
			if strings.Contains(apiResource.Name, "/") {
				continue
			}
			results = append(results, groupVersion.WithResource(apiResource.Name))
		}
	}
	return results, utilerrors.NewAggregate(allErrs)
}

// FindAllCanonicalResources returns all resource names that map directly to their kind (Kind -> Resource -> Kind)
// and are not subresources. This is the closest mapping possible from the client side to resources that can be
// listed and updated. Note that this may return some virtual resources (like imagestreamtags) that can be otherwise
// represented.
// TODO: add a field to APIResources for "virtual" (or that points to the canonical resource).
// TODO: fallback to the scheme when discovery is not possible.
func FindAllCanonicalResources(d discovery.DiscoveryInterface, m meta.RESTMapper) ([]unversioned.GroupResource, error) {
	set := make(map[unversioned.GroupResource]struct{})
	all, err := d.ServerResources()
	if err != nil {
		return nil, err
	}
	for apiVersion, v := range all {
		gv, err := unversioned.ParseGroupVersion(apiVersion)
		if err != nil {
			continue
		}
		for _, r := range v.APIResources {
			// ignore subresources
			if strings.Contains(r.Name, "/") {
				continue
			}
			// because discovery info doesn't tell us whether the object is virtual or not, perform a lookup
			// by the kind for resource (which should be the canonical resource) and then verify that the reverse
			// lookup (KindsFor) does not error.
			if mapping, err := m.RESTMapping(unversioned.GroupKind{Group: gv.Group, Kind: r.Kind}, gv.Version); err == nil {
				if _, err := m.KindsFor(mapping.GroupVersionKind.GroupVersion().WithResource(mapping.Resource)); err == nil {
					set[unversioned.GroupResource{Group: mapping.GroupVersionKind.Group, Resource: mapping.Resource}] = struct{}{}
				}
			}
		}
	}
	var groupResources []unversioned.GroupResource
	for k := range set {
		groupResources = append(groupResources, k)
	}
	sort.Sort(groupResourcesByName(groupResources))
	return groupResources, nil
}

func NewShortcutExpander(discoveryClient discovery.DiscoveryInterface, delegate meta.RESTMapper) ShortcutExpander {
	defaultMapper := ShortcutExpander{RESTMapper: delegate}

	// this assumes that legacy kube versions and legacy origin versions are the same, probably fair
	apiResources, err := discoveryClient.ServerResources()
	if err != nil {
		return defaultMapper
	}

	availableResources := []unversioned.GroupVersionResource{}
	for groupVersionString, resourceList := range apiResources {
		currVersion, err := unversioned.ParseGroupVersion(groupVersionString)
		if err != nil {
			return defaultMapper
		}

		for _, resource := range resourceList.APIResources {
			availableResources = append(availableResources, currVersion.WithResource(resource.Name))
		}
	}

	availableAll := []string{}
	for _, requestedResource := range userResources {
		for _, availableResource := range availableResources {
			if requestedResource == availableResource.Resource {
				availableAll = append(availableAll, requestedResource)
				break
			}
		}
	}

	return ShortcutExpander{All: availableAll, RESTMapper: delegate}
}

// GetServerSupportedSMPatchVersion takes a discoveryClient,
// returns the max StrategicMergePatch version supported
func GetServerSupportedSMPatchVersion(discoveryClient discovery.DiscoveryInterface) (StrategicMergePatchVersion, error) {
	serverVersion, err := discoveryClient.ServerVersion()
	if err != nil {
		return Unknown, err
	}
	serverGitVersion := serverVersion.GitVersion
	if serverGitVersion >= string(SMPatchVersion_1_5) {
		return SMPatchVersion_1_5, nil
	}
	if serverGitVersion >= string(SMPatchVersion_1_0) {
		return SMPatchVersion_1_0, nil
	}
	return Unknown, fmt.Errorf("The version is too old: %v\n", serverVersion)
}

// GetThirdPartyGroupVersions returns the thirdparty "group/versions"s and
// resources supported by the server. A user may delete a thirdparty resource
// when this function is running, so this function may return a "NotFound" error
// due to the race.
func GetThirdPartyGroupVersions(discovery discovery.DiscoveryInterface) ([]unversioned.GroupVersion, []unversioned.GroupVersionKind, error) {
	result := []unversioned.GroupVersion{}
	gvks := []unversioned.GroupVersionKind{}

	groupList, err := discovery.ServerGroups()
	if err != nil {
		// On forbidden or not found, just return empty lists.
		if kerrors.IsForbidden(err) || kerrors.IsNotFound(err) {
			return result, gvks, nil
		}

		return nil, nil, err
	}

	for ix := range groupList.Groups {
		group := &groupList.Groups[ix]
		for jx := range group.Versions {
			gv, err2 := unversioned.ParseGroupVersion(group.Versions[jx].GroupVersion)
			if err2 != nil {
				return nil, nil, err
			}
			// Skip GroupVersionKinds that have been statically registered.
			if registered.IsRegisteredVersion(gv) {
				continue
			}
			result = append(result, gv)

			resourceList, err := discovery.ServerResourcesForGroupVersion(group.Versions[jx].GroupVersion)
			if err != nil {
				return nil, nil, err
			}
			for kx := range resourceList.APIResources {
				gvks = append(gvks, gv.WithKind(resourceList.APIResources[kx].Kind))
			}
		}
	}
	return result, gvks, nil
}

// TODO: In general, any controller checking this needs to be dynamic so
//  users don't have to restart their controller manager if they change the apiserver.
func getAvailableResources(clientBuilder controller.ControllerClientBuilder) (map[schema.GroupVersionResource]bool, error) {
	var discoveryClient discovery.DiscoveryInterface

	// If apiserver is not running we should wait for some time and fail only then. This is particularly
	// important when we start apiserver and controller manager at the same time.
	err := wait.PollImmediate(time.Second, 10*time.Second, func() (bool, error) {
		client, err := clientBuilder.Client("controller-discovery")
		if err != nil {
			glog.Errorf("Failed to get api versions from server: %v", err)
			return false, nil
		}

		discoveryClient = client.Discovery()
		return true, nil
	})
	if err != nil {
		return nil, fmt.Errorf("failed to get api versions from server: %v", err)
	}

	resourceMap, err := discoveryClient.ServerResources()
	if err != nil {
		return nil, fmt.Errorf("failed to get supported resources from server: %v", err)
	}

	allResources := map[schema.GroupVersionResource]bool{}
	for _, apiResourceList := range resourceMap {
		version, err := schema.ParseGroupVersion(apiResourceList.GroupVersion)
		if err != nil {
			return nil, err
		}
		for _, apiResource := range apiResourceList.APIResources {
			allResources[version.WithResource(apiResource.Name)] = true
		}
	}

	return allResources, nil
}