/*
Copyright 2020 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 devopsproject

import (
	"fmt"
	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/apimachinery/pkg/util/wait"
	corev1informer "k8s.io/client-go/informers/core/v1"
	clientset "k8s.io/client-go/kubernetes"
	v1core "k8s.io/client-go/kubernetes/typed/core/v1"
	corev1lister "k8s.io/client-go/listers/core/v1"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/record"
	"k8s.io/client-go/util/workqueue"
	"k8s.io/klog"
	devopsv1alpha3 "kubesphere.io/kubesphere/pkg/apis/devops/v1alpha3"
	"kubesphere.io/kubesphere/pkg/client/clientset/versioned/scheme"
	tenantv1alpha1informers "kubesphere.io/kubesphere/pkg/client/informers/externalversions/tenant/v1alpha1"
	tenantv1alpha1listers "kubesphere.io/kubesphere/pkg/client/listers/tenant/v1alpha1"
	"kubesphere.io/kubesphere/pkg/constants"
	devopsClient "kubesphere.io/kubesphere/pkg/simple/client/devops"
	"kubesphere.io/kubesphere/pkg/utils/k8sutil"
	"kubesphere.io/kubesphere/pkg/utils/sliceutil"
	"reflect"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"time"

	kubesphereclient "kubesphere.io/kubesphere/pkg/client/clientset/versioned"
	devopsinformers "kubesphere.io/kubesphere/pkg/client/informers/externalversions/devops/v1alpha3"
	devopslisters "kubesphere.io/kubesphere/pkg/client/listers/devops/v1alpha3"
)

/**
  DevOps project controller is used to maintain the state of the DevOps project.
*/

type Controller struct {
	client           clientset.Interface
	kubesphereClient kubesphereclient.Interface

	eventBroadcaster record.EventBroadcaster
	eventRecorder    record.EventRecorder

	devOpsProjectLister devopslisters.DevOpsProjectLister
	devOpsProjectSynced cache.InformerSynced

	namespaceLister corev1lister.NamespaceLister
	namespaceSynced cache.InformerSynced

	workspaceLister tenantv1alpha1listers.WorkspaceLister
	workspaceSynced cache.InformerSynced

	workqueue workqueue.RateLimitingInterface

	workerLoopPeriod time.Duration

	devopsClient devopsClient.Interface
}

func NewController(client clientset.Interface,
	kubesphereClient kubesphereclient.Interface,
	devopsClinet devopsClient.Interface,
	namespaceInformer corev1informer.NamespaceInformer,
	devopsInformer devopsinformers.DevOpsProjectInformer,
	workspaceInformer tenantv1alpha1informers.WorkspaceInformer) *Controller {

	broadcaster := record.NewBroadcaster()
	broadcaster.StartLogging(func(format string, args ...interface{}) {
		klog.Info(fmt.Sprintf(format, args))
	})
	broadcaster.StartRecordingToSink(&v1core.EventSinkImpl{Interface: client.CoreV1().Events("")})
	recorder := broadcaster.NewRecorder(scheme.Scheme, v1.EventSource{Component: "devopsproject-controller"})

	v := &Controller{
		client:              client,
		devopsClient:        devopsClinet,
		kubesphereClient:    kubesphereClient,
		workqueue:           workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "devopsproject"),
		devOpsProjectLister: devopsInformer.Lister(),
		devOpsProjectSynced: devopsInformer.Informer().HasSynced,
		namespaceLister:     namespaceInformer.Lister(),
		namespaceSynced:     namespaceInformer.Informer().HasSynced,
		workspaceLister:     workspaceInformer.Lister(),
		workspaceSynced:     workspaceInformer.Informer().HasSynced,
		workerLoopPeriod:    time.Second,
	}

	v.eventBroadcaster = broadcaster
	v.eventRecorder = recorder

	devopsInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc: v.enqueueDevOpsProject,
		UpdateFunc: func(oldObj, newObj interface{}) {
			old := oldObj.(*devopsv1alpha3.DevOpsProject)
			new := newObj.(*devopsv1alpha3.DevOpsProject)
			if old.ResourceVersion == new.ResourceVersion {
				return
			}
			v.enqueueDevOpsProject(newObj)
		},
		DeleteFunc: v.enqueueDevOpsProject,
	})
	return v
}

// enqueueDevOpsProject takes a Foo resource and converts it into a namespace/name
// string which is then put onto the work workqueue. This method should *not* be
// passed resources of any type other than DevOpsProject.
func (c *Controller) enqueueDevOpsProject(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) processNextWorkItem() bool {
	obj, shutdown := c.workqueue.Get()

	if shutdown {
		return false
	}

	err := func(obj interface{}) error {
		defer c.workqueue.Done(obj)
		var key string
		var ok bool

		if key, ok = obj.(string); !ok {
			c.workqueue.Forget(obj)
			utilruntime.HandleError(fmt.Errorf("expected string in workqueue but got %#v", obj))
			return nil
		}
		if err := c.syncHandler(key); err != nil {
			c.workqueue.AddRateLimited(key)
			return fmt.Errorf("error syncing '%s': %s, requeuing", key, err.Error())
		}
		c.workqueue.Forget(obj)
		klog.V(5).Infof("Successfully synced '%s'", key)
		return nil
	}(obj)

	if err != nil {
		klog.Error(err, "could not reconcile devopsProject")
		utilruntime.HandleError(err)
		return true
	}

	return true
}

func (c *Controller) worker() {

	for c.processNextWorkItem() {
	}
}

func (c *Controller) Start(stopCh <-chan struct{}) error {
	return c.Run(1, stopCh)
}

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

	klog.Info("starting devops project controller")
	defer klog.Info("shutting down devops project controller")

	if !cache.WaitForCacheSync(stopCh, c.devOpsProjectSynced, c.devOpsProjectSynced, c.workspaceSynced) {
		return fmt.Errorf("failed to wait for caches to sync")
	}

	for i := 0; i < workers; i++ {
		go wait.Until(c.worker, c.workerLoopPeriod, stopCh)
	}

	<-stopCh
	return nil
}

// syncHandler compares the actual state with the desired, and attempts to
// converge the two. It then updates the Status block of the devopsproject resource
// with the current status of the resource.
func (c *Controller) syncHandler(key string) error {
	project, err := c.devOpsProjectLister.Get(key)
	if err != nil {
		if errors.IsNotFound(err) {
			klog.Info(fmt.Sprintf("devopsproject '%s' in work queue no longer exists ", key))
			return nil
		}
		klog.V(8).Info(err, fmt.Sprintf("could not get devopsproject %s ", key))
		return err
	}
	copyProject := project.DeepCopy()
	// DeletionTimestamp.IsZero() means DevOps project has not been deleted.
	if project.ObjectMeta.DeletionTimestamp.IsZero() {
		// Use Finalizers to sync DevOps status when DevOps project was deleted
		// https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/#finalizers
		if !sliceutil.HasString(project.ObjectMeta.Finalizers, devopsv1alpha3.DevOpsProjectFinalizerName) {
			copyProject.ObjectMeta.Finalizers = append(copyProject.ObjectMeta.Finalizers, devopsv1alpha3.DevOpsProjectFinalizerName)
		}

		if project.Status.AdminNamespace != "" {
			ns, err := c.namespaceLister.Get(project.Status.AdminNamespace)
			if err != nil && !errors.IsNotFound(err) {
				klog.V(8).Info(err, fmt.Sprintf("faild to get namespace"))
				return err
			} else if errors.IsNotFound(err) {
				// if admin ns is not found, clean project status, rerun reconcile
				copyProject.Status.AdminNamespace = ""
				_, err := c.kubesphereClient.DevopsV1alpha3().DevOpsProjects().Update(copyProject)
				if err != nil {
					klog.V(8).Info(err, fmt.Sprintf("failed to update project %s ", key))
					return err
				}
				c.enqueueDevOpsProject(key)
				return nil
			}
			// If ns exists, but the associated attributes with the project are not set correctly,
			// then reset the associated attributes
			if k8sutil.IsControlledBy(ns.OwnerReferences,
				devopsv1alpha3.ResourceKindDevOpsProject, project.Name) &&
				ns.Labels[constants.DevOpsProjectLabelKey] == project.Name {
			} else {
				copyNs := ns.DeepCopy()
				err := controllerutil.SetControllerReference(copyProject, copyNs, scheme.Scheme)
				if err != nil {
					klog.V(8).Info(err, fmt.Sprintf("failed to set ownerreference %s ", key))
					return err
				}
				copyNs.Labels[constants.DevOpsProjectLabelKey] = project.Name
				_, err = c.client.CoreV1().Namespaces().Update(copyNs)
				if err != nil {
					klog.V(8).Info(err, fmt.Sprintf("failed to update ns %s ", key))
					return err
				}
			}

		} else {
			// list ns by devops project
			namespaces, err := c.namespaceLister.List(
				labels.SelectorFromSet(labels.Set{constants.DevOpsProjectLabelKey: project.Name}))
			if err != nil {
				klog.V(8).Info(err, fmt.Sprintf("failed to list ns %s ", key))
				return err
			}
			// if there is no ns, generate new one
			if len(namespaces) == 0 {
				ns := c.generateNewNamespace(project)
				ns, err := c.client.CoreV1().Namespaces().Create(ns)
				if err != nil {
					// devops project name is conflict, cannot create admin namespace
					if errors.IsAlreadyExists(err) {
						klog.Errorf("Failed to create admin namespace for devopsproject %s, error %v", project.Name, err)
						c.eventRecorder.Event(project, v1.EventTypeWarning, "CreateAdminNamespaceFailed", err.Error())
						return err
					}
					klog.V(8).Info(err, fmt.Sprintf("failed to create ns %s ", key))
					return err
				}
				copyProject.Status.AdminNamespace = ns.Name
			} else if len(namespaces) != 0 {
				ns := namespaces[0]
				// reset ownerReferences
				if !k8sutil.IsControlledBy(ns.OwnerReferences,
					devopsv1alpha3.ResourceKindDevOpsProject, project.Name) {
					copyNs := ns.DeepCopy()
					err := controllerutil.SetControllerReference(copyProject, copyNs, scheme.Scheme)
					if err != nil {
						klog.V(8).Info(err, fmt.Sprintf("failed to set ownerreference %s ", key))
						return err
					}
					copyNs.Labels[constants.DevOpsProjectLabelKey] = project.Name
					_, err = c.client.CoreV1().Namespaces().Update(copyNs)
					if err != nil {
						klog.V(8).Info(err, fmt.Sprintf("failed to update ns %s ", key))
						return err
					}
				}
				copyProject.Status.AdminNamespace = ns.Name
			}
		}

		if !reflect.DeepEqual(copyProject, project) {
			copyProject, err = c.kubesphereClient.DevopsV1alpha3().DevOpsProjects().Update(copyProject)
			if err != nil {
				klog.V(8).Info(err, fmt.Sprintf("failed to update ns %s ", key))
				return err
			}
		}

		if copyProject, err = c.bindWorkspace(copyProject); err != nil {
			klog.Error(err)
			return err
		}

		// Check project exists, otherwise we will create it.
		_, err := c.devopsClient.GetDevOpsProject(copyProject.Status.AdminNamespace)
		if err != nil {
			klog.Error(err, fmt.Sprintf("failed to get project %s ", key))
			_, err := c.devopsClient.CreateDevOpsProject(copyProject.Status.AdminNamespace)
			if err != nil {
				klog.V(8).Info(err, fmt.Sprintf("failed to get project %s ", key))
				return err
			}
		}

	} else {
		// Finalizers processing logic
		if sliceutil.HasString(project.ObjectMeta.Finalizers, devopsv1alpha3.DevOpsProjectFinalizerName) {
			if err := c.deleteDevOpsProjectInDevOps(project); err != nil {
				klog.V(8).Info(err, fmt.Sprintf("failed to delete resource %s in devops", key))
				return err
			}
			project.ObjectMeta.Finalizers = sliceutil.RemoveString(project.ObjectMeta.Finalizers, func(item string) bool {
				return item == devopsv1alpha3.DevOpsProjectFinalizerName
			})

			_, err = c.kubesphereClient.DevopsV1alpha3().DevOpsProjects().Update(project)
			if err != nil {
				klog.V(8).Info(err, fmt.Sprintf("failed to update project %s ", key))
				return err
			}
		}
	}

	return nil
}

func (c *Controller) bindWorkspace(project *devopsv1alpha3.DevOpsProject) (*devopsv1alpha3.DevOpsProject, error) {

	workspaceName := project.Labels[constants.WorkspaceLabelKey]

	if workspaceName == "" {
		return project, nil
	}

	workspace, err := c.workspaceLister.Get(workspaceName)

	if err != nil {
		// skip if workspace not found
		if errors.IsNotFound(err) {
			return project, nil
		}
		klog.Error(err)
		return nil, err
	}

	if !metav1.IsControlledBy(project, workspace) {
		project.OwnerReferences = nil
		if err := controllerutil.SetControllerReference(workspace, project, scheme.Scheme); err != nil {
			klog.Error(err)
			return nil, err
		}

		return c.kubesphereClient.DevopsV1alpha3().DevOpsProjects().Update(project)
	}

	return project, nil
}

func (c *Controller) deleteDevOpsProjectInDevOps(project *devopsv1alpha3.DevOpsProject) error {

	err := c.devopsClient.DeleteDevOpsProject(project.Status.AdminNamespace)
	if err != nil {
		klog.Errorf("error happened while deleting %s, %v", project.Name, err)
	}

	return nil
}

func (c *Controller) generateNewNamespace(project *devopsv1alpha3.DevOpsProject) *v1.Namespace {
	// devops project name and admin namespace name should be the same
	// solve the access control problem of devops API v1alpha2 and v1alpha3
	ns := &v1.Namespace{
		TypeMeta: metav1.TypeMeta{
			Kind:       "Namespace",
			APIVersion: v1.SchemeGroupVersion.String(),
		},
		ObjectMeta: metav1.ObjectMeta{
			Name: project.Name,
			Labels: map[string]string{
				constants.DevOpsProjectLabelKey: project.Name,
			},
		},
	}

	if creator := project.Annotations[constants.CreatorAnnotationKey]; creator != "" {
		ns.Annotations = map[string]string{constants.CreatorAnnotationKey: creator}
	}

	controllerutil.SetControllerReference(project, ns, scheme.Scheme)
	return ns
}