/*
Copyright 2019 The KubeSphere Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package workspacetemplate

import (
	"bytes"
	"encoding/json"
	"fmt"
	corev1 "k8s.io/api/core/v1"
	rbacv1 "k8s.io/api/rbac/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/apimachinery/pkg/util/yaml"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/kubernetes/scheme"
	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/record"
	"k8s.io/client-go/util/workqueue"
	"k8s.io/klog"
	iamv1alpha2 "kubesphere.io/kubesphere/pkg/apis/iam/v1alpha2"
	tenantv1alpha1 "kubesphere.io/kubesphere/pkg/apis/tenant/v1alpha1"
	tenantv1alpha2 "kubesphere.io/kubesphere/pkg/apis/tenant/v1alpha2"
	kubesphere "kubesphere.io/kubesphere/pkg/client/clientset/versioned"
	iamv1alpha2informers "kubesphere.io/kubesphere/pkg/client/informers/externalversions/iam/v1alpha2"
	tenantv1alpha1informers "kubesphere.io/kubesphere/pkg/client/informers/externalversions/tenant/v1alpha1"
	tenantv1alpha2informers "kubesphere.io/kubesphere/pkg/client/informers/externalversions/tenant/v1alpha2"
	iamv1alpha2listers "kubesphere.io/kubesphere/pkg/client/listers/iam/v1alpha2"
	tenantv1alpha1listers "kubesphere.io/kubesphere/pkg/client/listers/tenant/v1alpha1"
	tenantv1alpha2listers "kubesphere.io/kubesphere/pkg/client/listers/tenant/v1alpha2"
	"reflect"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"time"
)

const (
	// SuccessSynced is used as part of the Event 'reason' when a Foo is synced
	successSynced = "Synced"
	// is synced successfully
	messageResourceSynced = "WorkspaceTemplate synced successfully"
	controllerName        = "workspacetemplate-controller"
)

type Controller struct {
	k8sClient                   kubernetes.Interface
	ksClient                    kubesphere.Interface
	workspaceTemplateInformer   tenantv1alpha2informers.WorkspaceTemplateInformer
	workspaceTemplateLister     tenantv1alpha2listers.WorkspaceTemplateLister
	workspaceTemplateSynced     cache.InformerSynced
	workspaceRoleInformer       iamv1alpha2informers.WorkspaceRoleInformer
	workspaceRoleLister         iamv1alpha2listers.WorkspaceRoleLister
	workspaceRoleSynced         cache.InformerSynced
	roleBaseInformer            iamv1alpha2informers.RoleBaseInformer
	roleBaseLister              iamv1alpha2listers.RoleBaseLister
	roleBaseSynced              cache.InformerSynced
	workspaceInformer           tenantv1alpha1informers.WorkspaceInformer
	workspaceLister             tenantv1alpha1listers.WorkspaceLister
	workspaceSynced             cache.InformerSynced
	fedWorkspaceCache           cache.Store
	fedWorkspaceCacheController cache.Controller
	multiClusterEnabled         bool
	// workqueue is a rate limited work queue. This is used to queue work to be
	// processed instead of performing it as soon as a change happens. This
	// means we can ensure we only process a fixed amount of resources at a
	// time, and makes it easy to ensure we are never processing the same item
	// simultaneously in two different workers.
	workqueue workqueue.RateLimitingInterface
	// recorder is an event recorder for recording Event resources to the
	// Kubernetes API.
	recorder record.EventRecorder
}

func NewController(k8sClient kubernetes.Interface, ksClient kubesphere.Interface, workspaceTemplateInformer tenantv1alpha2informers.WorkspaceTemplateInformer,
	workspaceInformer tenantv1alpha1informers.WorkspaceInformer, roleBaseInformer iamv1alpha2informers.RoleBaseInformer, workspaceRoleInformer iamv1alpha2informers.WorkspaceRoleInformer,
	fedWorkspaceCache cache.Store, fedWorkspaceCacheController cache.Controller, multiClusterEnabled bool) *Controller {
	// Create event broadcaster
	// Add sample-controller types to the default Kubernetes Scheme so Events can be
	// logged for sample-controller types.

	klog.V(4).Info("Creating event broadcaster")
	eventBroadcaster := record.NewBroadcaster()
	eventBroadcaster.StartLogging(klog.Infof)
	eventBroadcaster.StartRecordingToSink(&typedcorev1.EventSinkImpl{Interface: k8sClient.CoreV1().Events("")})
	recorder := eventBroadcaster.NewRecorder(scheme.Scheme, corev1.EventSource{Component: controllerName})
	ctl := &Controller{
		k8sClient:                   k8sClient,
		ksClient:                    ksClient,
		workspaceTemplateInformer:   workspaceTemplateInformer,
		workspaceTemplateLister:     workspaceTemplateInformer.Lister(),
		workspaceTemplateSynced:     workspaceTemplateInformer.Informer().HasSynced,
		workspaceInformer:           workspaceInformer,
		workspaceLister:             workspaceInformer.Lister(),
		workspaceSynced:             workspaceInformer.Informer().HasSynced,
		workspaceRoleInformer:       workspaceRoleInformer,
		workspaceRoleLister:         workspaceRoleInformer.Lister(),
		workspaceRoleSynced:         workspaceRoleInformer.Informer().HasSynced,
		roleBaseInformer:            roleBaseInformer,
		roleBaseLister:              roleBaseInformer.Lister(),
		roleBaseSynced:              roleBaseInformer.Informer().HasSynced,
		fedWorkspaceCache:           fedWorkspaceCache,
		fedWorkspaceCacheController: fedWorkspaceCacheController,
		multiClusterEnabled:         multiClusterEnabled,
		workqueue:                   workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "WorkspaceTemplate"),
		recorder:                    recorder,
	}
	klog.Info("Setting up event handlers")
	workspaceTemplateInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc: ctl.enqueueClusterRole,
		UpdateFunc: func(old, new interface{}) {
			ctl.enqueueClusterRole(new)
		},
		DeleteFunc: ctl.enqueueClusterRole,
	})
	return ctl
}

func (c *Controller) Run(threadiness int, stopCh <-chan struct{}) error {
	defer utilruntime.HandleCrash()
	defer c.workqueue.ShutDown()

	// Start the informer factories to begin populating the informer caches
	klog.Info("Starting WorkspaceTemplate controller")

	// Wait for the caches to be synced before starting workers
	klog.Info("Waiting for informer caches to sync")

	synced := make([]cache.InformerSynced, 0)
	synced = append(synced, c.workspaceTemplateSynced, c.workspaceSynced, c.workspaceRoleSynced, c.roleBaseSynced)
	if c.multiClusterEnabled {
		synced = append(synced, c.fedWorkspaceCacheController.HasSynced)
	}
	if ok := cache.WaitForCacheSync(stopCh, synced...); !ok {
		return fmt.Errorf("failed to wait for caches to sync")
	}

	klog.Info("Starting workers")
	// Launch two workers to process Foo resources
	for i := 0; i < threadiness; i++ {
		go wait.Until(c.runWorker, time.Second, stopCh)
	}

	klog.Info("Started workers")
	<-stopCh
	klog.Info("Shutting down workers")
	return nil
}

func (c *Controller) enqueueClusterRole(obj interface{}) {
	var key string
	var err error
	if key, err = cache.MetaNamespaceKeyFunc(obj); err != nil {
		utilruntime.HandleError(err)
		return
	}
	c.workqueue.Add(key)
}

func (c *Controller) runWorker() {
	for c.processNextWorkItem() {
	}
}

func (c *Controller) processNextWorkItem() bool {
	obj, shutdown := c.workqueue.Get()

	if shutdown {
		return false
	}

	// We wrap this block in a func so we can defer c.workqueue.Done.
	err := func(obj interface{}) error {
		// We call Done here so the workqueue knows we have finished
		// processing this item. We also must remember to call Forget if we
		// do not want this work item being re-queued. For example, we do
		// not call Forget if a transient error occurs, instead the item is
		// put back on the workqueue and attempted again after a back-off
		// period.
		defer c.workqueue.Done(obj)
		var key string
		var ok bool
		// We expect strings to come off the workqueue. These are of the
		// form namespace/name. We do this as the delayed nature of the
		// workqueue means the items in the informer cache may actually be
		// more up to date that when the item was initially put onto the
		// workqueue.
		if key, ok = obj.(string); !ok {
			// As the item in the workqueue is actually invalid, we call
			// Forget here else we'd go into a loop of attempting to
			// process a work item that is invalid.
			c.workqueue.Forget(obj)
			utilruntime.HandleError(fmt.Errorf("expected string in workqueue but got %#v", obj))
			return nil
		}
		// Run the reconcile, passing it the namespace/name string of the
		// Foo resource to be synced.
		if err := c.reconcile(key); err != nil {
			// Put the item back on the workqueue to handle any transient errors.
			c.workqueue.AddRateLimited(key)
			return fmt.Errorf("error syncing '%s': %s, requeuing", key, err.Error())
		}
		// Finally, if no error occurs we Forget this item so it does not
		// get queued again until another change happens.
		c.workqueue.Forget(obj)
		klog.Infof("Successfully synced %s:%s", "key", key)
		return nil
	}(obj)

	if err != nil {
		utilruntime.HandleError(err)
		return true
	}

	return true
}

// syncHandler compares the actual state with the desired, and attempts to
// converge the two. It then updates the Status block of the Foo resource
// with the current status of the resource.
func (c *Controller) reconcile(key string) error {

	workspaceTemplate, err := c.workspaceTemplateLister.Get(key)
	if err != nil {
		// The user may no longer exist, in which case we stop
		// processing.
		if errors.IsNotFound(err) {
			utilruntime.HandleError(fmt.Errorf("workspace template '%s' in work queue no longer exists", key))
			return nil
		}
		klog.Error(err)
		return err
	}

	if err = c.initRoles(workspaceTemplate); err != nil {
		klog.Error(err)
		return err
	}

	if err = c.initManagerRoleBinding(workspaceTemplate); err != nil {
		klog.Error(err)
		return err
	}

	if c.multiClusterEnabled {
		if err = c.multiClusterSync(workspaceTemplate); err != nil {
			klog.Error(err)
			return err
		}
	} else {
		if err = c.sync(workspaceTemplate); err != nil {
			klog.Error(err)
			return err
		}
	}

	c.recorder.Event(workspaceTemplate, corev1.EventTypeNormal, successSynced, messageResourceSynced)
	return nil
}

func (c *Controller) Start(stopCh <-chan struct{}) error {
	return c.Run(4, stopCh)
}

func (c *Controller) multiClusterSync(workspaceTemplate *tenantv1alpha2.WorkspaceTemplate) error {

	obj, exist, err := c.fedWorkspaceCache.GetByKey(workspaceTemplate.Name)
	if !exist {
		return c.createFederatedWorkspace(workspaceTemplate)
	}
	if err != nil {
		klog.Error(err)
		return err
	}

	var fedWorkspace tenantv1alpha2.FederatedWorkspace

	if err = runtime.DefaultUnstructuredConverter.FromUnstructured(obj.(*unstructured.Unstructured).Object, &fedWorkspace); err != nil {
		klog.Error(err)
		return err
	}

	if !reflect.DeepEqual(fedWorkspace.Spec, workspaceTemplate.Spec) {

		fedWorkspace.Spec = workspaceTemplate.Spec

		return c.updateFederatedWorkspace(&fedWorkspace)
	}

	return nil
}

func (c *Controller) createFederatedWorkspace(workspaceTemplate *tenantv1alpha2.WorkspaceTemplate) error {
	federatedWorkspace := &tenantv1alpha2.FederatedWorkspace{
		TypeMeta: metav1.TypeMeta{
			Kind:       tenantv1alpha2.FedWorkspaceKind,
			APIVersion: tenantv1alpha2.FedWorkspaceResource.Group + "/" + tenantv1alpha2.FedWorkspaceResource.Version,
		},
		ObjectMeta: metav1.ObjectMeta{
			Name: workspaceTemplate.Name,
		},
		Spec: workspaceTemplate.Spec,
	}

	err := controllerutil.SetControllerReference(workspaceTemplate, federatedWorkspace, scheme.Scheme)
	if err != nil {
		return err
	}

	data, err := json.Marshal(federatedWorkspace)
	if err != nil {
		return err
	}

	cli := c.k8sClient.(*kubernetes.Clientset)
	err = cli.RESTClient().Post().
		AbsPath(fmt.Sprintf("/apis/%s/%s/%s", tenantv1alpha2.FedWorkspaceResource.Group,
			tenantv1alpha2.FedWorkspaceResource.Version, tenantv1alpha2.FedWorkspaceResource.Name)).
		Body(data).
		Do().Error()

	if err != nil {
		if errors.IsAlreadyExists(err) {
			return nil
		}
		return err
	}

	return nil
}

func (c *Controller) updateFederatedWorkspace(fedWorkspace *tenantv1alpha2.FederatedWorkspace) error {

	data, err := json.Marshal(fedWorkspace)
	if err != nil {
		return err
	}

	cli := c.k8sClient.(*kubernetes.Clientset)
	err = cli.RESTClient().Put().
		AbsPath(fmt.Sprintf("/apis/%s/%s/%s/%s", tenantv1alpha2.FedWorkspaceResource.Group,
			tenantv1alpha2.FedWorkspaceResource.Version, tenantv1alpha2.FedWorkspaceResource.Name,
			fedWorkspace.Name)).
		Body(data).
		Do().Error()

	if err != nil {
		if errors.IsNotFound(err) {
			return nil
		}
		return err
	}

	return nil
}

func (c *Controller) sync(workspaceTemplate *tenantv1alpha2.WorkspaceTemplate) error {
	workspace, err := c.workspaceLister.Get(workspaceTemplate.Name)
	if err != nil {
		if errors.IsNotFound(err) {
			return c.createWorkspace(workspaceTemplate)
		}
		klog.Error(err)
		return err
	}

	if !reflect.DeepEqual(workspace.Spec, workspaceTemplate.Spec.Template.Spec) ||
		!reflect.DeepEqual(workspace.Labels, workspaceTemplate.Spec.Template.Labels) ||
		!reflect.DeepEqual(workspace.Annotations, workspaceTemplate.Spec.Template.Annotations) {

		workspace = workspace.DeepCopy()
		workspace.Spec = workspaceTemplate.Spec.Template.Spec
		workspace.Labels = workspaceTemplate.Spec.Template.Labels
		workspace.Annotations = workspaceTemplate.Spec.Template.Annotations

		return c.updateWorkspace(workspace)
	}

	return nil
}

func (c *Controller) createWorkspace(workspaceTemplate *tenantv1alpha2.WorkspaceTemplate) error {
	workspace := &tenantv1alpha1.Workspace{
		ObjectMeta: metav1.ObjectMeta{
			Name:        workspaceTemplate.Name,
			Labels:      workspaceTemplate.Spec.Template.Labels,
			Annotations: workspaceTemplate.Spec.Template.Annotations,
		},
		Spec: workspaceTemplate.Spec.Template.Spec,
	}

	err := controllerutil.SetControllerReference(workspaceTemplate, workspace, scheme.Scheme)
	if err != nil {
		return err
	}

	_, err = c.ksClient.TenantV1alpha1().Workspaces().Create(workspace)
	if err != nil {
		if errors.IsAlreadyExists(err) {
			return nil
		}
		klog.Error(err)
		return err
	}

	return nil
}

func (c *Controller) updateWorkspace(workspace *tenantv1alpha1.Workspace) error {
	_, err := c.ksClient.TenantV1alpha1().Workspaces().Update(workspace)
	if err != nil {
		klog.Error(err)
		return err
	}
	return nil
}

func (r *Controller) initRoles(workspace *tenantv1alpha2.WorkspaceTemplate) error {
	roleBases, err := r.roleBaseLister.List(labels.Everything())
	if err != nil {
		klog.Error(err)
		return err
	}
	for _, roleBase := range roleBases {
		var role iamv1alpha2.WorkspaceRole
		if err = yaml.NewYAMLOrJSONDecoder(bytes.NewBuffer(roleBase.Role.Raw), 1024).Decode(&role); err == nil && role.Kind == iamv1alpha2.ResourceKindWorkspaceRole {
			roleName := fmt.Sprintf("%s-%s", workspace.Name, role.Name)
			if role.Labels == nil {
				role.Labels = make(map[string]string, 0)
			}
			// make sure workspace label always exist
			role.Labels[tenantv1alpha1.WorkspaceLabel] = workspace.Name
			role.Name = roleName
			old, err := r.workspaceRoleLister.Get(roleName)
			if err != nil {
				if errors.IsNotFound(err) {
					_, err = r.ksClient.IamV1alpha2().WorkspaceRoles().Create(&role)
					if err != nil {
						klog.Error(err)
						return err
					}
					continue
				}
			}
			if !reflect.DeepEqual(role.Labels, old.Labels) ||
				!reflect.DeepEqual(role.Annotations, old.Annotations) ||
				!reflect.DeepEqual(role.Rules, old.Rules) {
				updated := old.DeepCopy()
				updated.Labels = role.Labels
				updated.Annotations = role.Annotations
				updated.Rules = role.Rules
				_, err = r.ksClient.IamV1alpha2().WorkspaceRoles().Update(updated)
				if err != nil {
					klog.Error(err)
					return err
				}
			}
		}
	}
	return nil
}

func (r *Controller) resetWorkspaceOwner(workspace *tenantv1alpha2.WorkspaceTemplate) error {
	workspace = workspace.DeepCopy()
	workspace.Spec.Template.Spec.Manager = ""
	_, err := r.ksClient.TenantV1alpha2().WorkspaceTemplates().Update(workspace)
	klog.V(4).Infof("update workspace after manager has been deleted")
	return err
}

func (r *Controller) initManagerRoleBinding(workspace *tenantv1alpha2.WorkspaceTemplate) error {
	manager := workspace.Spec.Template.Spec.Manager
	if manager == "" {
		return nil
	}

	user, err := r.ksClient.IamV1alpha2().Users().Get(manager, metav1.GetOptions{})
	if err != nil {
		// skip if user has been deleted
		if errors.IsNotFound(err) {
			return r.resetWorkspaceOwner(workspace)
		}
		klog.Error(err)
		return err
	}

	// skip if user has been deleted
	if !user.DeletionTimestamp.IsZero() {
		return r.resetWorkspaceOwner(workspace)
	}

	workspaceAdminRoleName := fmt.Sprintf(iamv1alpha2.WorkspaceAdminFormat, workspace.Name)
	managerRoleBinding := &iamv1alpha2.WorkspaceRoleBinding{
		ObjectMeta: metav1.ObjectMeta{
			Name: fmt.Sprintf("%s-%s", manager, workspaceAdminRoleName),
			Labels: map[string]string{
				tenantv1alpha1.WorkspaceLabel:  workspace.Name,
				iamv1alpha2.UserReferenceLabel: manager,
			},
		},
		RoleRef: rbacv1.RoleRef{
			APIGroup: iamv1alpha2.SchemeGroupVersion.Group,
			Kind:     iamv1alpha2.ResourceKindWorkspaceRole,
			Name:     workspaceAdminRoleName,
		},
		Subjects: []rbacv1.Subject{
			{
				Name:     manager,
				Kind:     iamv1alpha2.ResourceKindUser,
				APIGroup: rbacv1.GroupName,
			},
		},
	}
	_, err = r.ksClient.IamV1alpha2().WorkspaceRoleBindings().Create(managerRoleBinding)
	if err != nil {
		if errors.IsAlreadyExists(err) {
			return nil
		}
		klog.Error(err)
		return err
	}

	return nil
}