/*
Copyright 2016 The Rook Authors. All rights reserved.

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 cluster to manage a Ceph cluster.
package cluster

import (
	"fmt"
	"os"
	"reflect"
	"time"

	"github.com/coreos/pkg/capnslog"
	opkit "github.com/rook/operator-kit"
	cephv1beta1 "github.com/rook/rook/pkg/apis/ceph.rook.io/v1beta1"
	rookv1alpha1 "github.com/rook/rook/pkg/apis/rook.io/v1alpha1"
	"github.com/rook/rook/pkg/clusterd"
	"github.com/rook/rook/pkg/daemon/ceph/agent/flexvolume/attachment"

	"github.com/rook/rook/pkg/operator/ceph/cluster/mon"
	"github.com/rook/rook/pkg/operator/ceph/cluster/osd"
	"github.com/rook/rook/pkg/operator/ceph/file"
	"github.com/rook/rook/pkg/operator/ceph/object"
	"github.com/rook/rook/pkg/operator/ceph/pool"
	"github.com/rook/rook/pkg/operator/discover"
	"github.com/rook/rook/pkg/operator/k8sutil"
	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/tools/cache"
)

const (
	CustomResourceName       = "cluster"
	CustomResourceNamePlural = "clusters"
	crushConfigMapName       = "rook-crush-config"
	crushmapCreatedKey       = "initialCrushMapCreated"
	clusterCreateInterval    = 6 * time.Second
	clusterCreateTimeout     = 60 * time.Minute
	updateClusterInterval    = 30 * time.Second
	updateClusterTimeout     = 1 * time.Hour
)

const (
	// DefaultClusterName states the default name of the rook-cluster if not provided.
	DefaultClusterName         = "rook-ceph"
	clusterDeleteRetryInterval = 2 //seconds
	clusterDeleteMaxRetries    = 15
)

var (
	logger                  = capnslog.NewPackageLogger("github.com/rook/rook", "op-cluster")
	finalizerName           = fmt.Sprintf("%s.%s", ClusterResource.Name, ClusterResource.Group)
	finalizerNameRookLegacy = fmt.Sprintf("%s.%s", ClusterResourceRookLegacy.Name, ClusterResourceRookLegacy.Group)
)

var ClusterResource = opkit.CustomResource{
	Name:    CustomResourceName,
	Plural:  CustomResourceNamePlural,
	Group:   cephv1beta1.CustomResourceGroup,
	Version: cephv1beta1.Version,
	Scope:   apiextensionsv1beta1.NamespaceScoped,
	Kind:    reflect.TypeOf(cephv1beta1.Cluster{}).Name(),
}

var ClusterResourceRookLegacy = opkit.CustomResource{
	Name:    CustomResourceName,
	Plural:  CustomResourceNamePlural,
	Group:   rookv1alpha1.CustomResourceGroup,
	Version: rookv1alpha1.Version,
	Scope:   apiextensionsv1beta1.NamespaceScoped,
	Kind:    reflect.TypeOf(rookv1alpha1.Cluster{}).Name(),
}

// ClusterController controls an instance of a Rook cluster
type ClusterController struct {
	context          *clusterd.Context
	volumeAttachment attachment.Attachment
	devicesInUse     bool
	rookImage        string
	clusterMap       map[string]*cluster
}

// NewClusterController create controller for watching cluster custom resources created
func NewClusterController(context *clusterd.Context, rookImage string, volumeAttachment attachment.Attachment) *ClusterController {
	return &ClusterController{
		context:          context,
		volumeAttachment: volumeAttachment,
		rookImage:        rookImage,
		clusterMap:       make(map[string]*cluster),
	}
}

// Watch watches instances of cluster resources
func (c *ClusterController) StartWatch(namespace string, stopCh chan struct{}) error {
	resourceHandlerFuncs := cache.ResourceEventHandlerFuncs{
		AddFunc:    c.onAdd,
		UpdateFunc: c.onUpdate,
		DeleteFunc: c.onDelete,
	}

	logger.Infof("start watching clusters in all namespaces")
	watcher := opkit.NewWatcher(ClusterResource, namespace, resourceHandlerFuncs, c.context.RookClientset.CephV1beta1().RESTClient())
	go watcher.Watch(&cephv1beta1.Cluster{}, stopCh)

	// watch for events on all legacy types too
	c.watchLegacyClusters(namespace, stopCh, resourceHandlerFuncs)

	return nil
}

func (c *ClusterController) StopWatch() {
	for _, cluster := range c.clusterMap {
		close(cluster.stopCh)
	}
	c.clusterMap = make(map[string]*cluster)
}

// ************************************************************************************************
// Add event functions
// ************************************************************************************************
func (c *ClusterController) onAdd(obj interface{}) {
	clusterObj, migrationNeeded, err := getClusterObject(obj)
	if err != nil {
		logger.Errorf("failed to get cluster object: %+v", err)
		return
	}

	if migrationNeeded {
		err = c.migrateClusterObject(clusterObj, obj)
		if err != nil {
			logger.Errorf("failed to migrate legacy cluster %s in namespace %s: %+v", clusterObj.Name, clusterObj.Namespace, err)
		}

		// no matter the outcome of the migration, bail out now. if it was successful, then we'll be getting
		// another event for the migrated object and we'll just handle it there.
		return
	}

	cluster := newCluster(clusterObj, c.context)
	c.clusterMap[cluster.Namespace] = cluster

	logger.Infof("starting cluster in namespace %s", cluster.Namespace)

	if c.devicesInUse && cluster.Spec.Storage.AnyUseAllDevices() {
		message := "using all devices in more than one namespace not supported"
		logger.Error(message)
		if err := c.updateClusterStatus(clusterObj.Namespace, clusterObj.Name, cephv1beta1.ClusterStateError, message); err != nil {
			logger.Errorf("failed to update cluster status in namespace %s: %+v", cluster.Namespace, err)
		}
		return
	}

	if cluster.Spec.Storage.AnyUseAllDevices() {
		c.devicesInUse = true
	}

	if cluster.Spec.Mon.Count <= 0 {
		logger.Warningf("mon count is 0 or less, should be at least 1, will use default value of %d", mon.DefaultMonCount)
		cluster.Spec.Mon.Count = mon.DefaultMonCount
		cluster.Spec.Mon.AllowMultiplePerNode = true
	}
	if cluster.Spec.Mon.Count > mon.MaxMonCount {
		logger.Warningf("mon count is bigger than %d (given: %d), not supported, changing to %d", mon.MaxMonCount, cluster.Spec.Mon.Count, mon.MaxMonCount)
		cluster.Spec.Mon.Count = mon.MaxMonCount
	}
	if cluster.Spec.Mon.Count%2 == 0 {
		logger.Warningf("mon count is even (given: %d), should be uneven, continuing", cluster.Spec.Mon.Count)
	}

	err = cluster.setCephMajorVersion(15 * time.Minute)
	if err != nil {
		logger.Errorf("unknown ceph major version. %+v", err)
		return
	}

	if !cluster.Spec.CephVersion.AllowUnsupported {
		if !versionSupported(cluster.Spec.CephVersion.Name) {
			logger.Errorf("unsupported ceph version detected: %s. allowUnupported must be set to true to run with this version.", cluster.Spec.CephVersion.Name)
			return
		}
	}

	// Start the Rook cluster components. Retry several times in case of failure.
	err = wait.Poll(clusterCreateInterval, clusterCreateTimeout, func() (bool, error) {
		if err := c.updateClusterStatus(clusterObj.Namespace, clusterObj.Name, cephv1beta1.ClusterStateCreating, ""); err != nil {
			logger.Errorf("failed to update cluster status in namespace %s: %+v", cluster.Namespace, err)
			return false, nil
		}

		err := cluster.createInstance(c.rookImage)
		if err != nil {
			logger.Errorf("failed to create cluster in namespace %s. %+v", cluster.Namespace, err)
			return false, nil
		}

		// cluster is created, update the cluster CRD status now
		if err := c.updateClusterStatus(clusterObj.Namespace, clusterObj.Name, cephv1beta1.ClusterStateCreated, ""); err != nil {
			logger.Errorf("failed to update cluster status in namespace %s: %+v", cluster.Namespace, err)
			return false, nil
		}

		return true, nil
	})
	if err != nil {
		message := fmt.Sprintf("giving up creating cluster in namespace %s after %s", cluster.Namespace, clusterCreateTimeout)
		logger.Error(message)
		if err := c.updateClusterStatus(clusterObj.Namespace, clusterObj.Name, cephv1beta1.ClusterStateError, message); err != nil {
			logger.Errorf("failed to update cluster status in namespace %s: %+v", cluster.Namespace, err)
		}
		return
	}

	// Start pool CRD watcher
	poolController := pool.NewPoolController(c.context)
	poolController.StartWatch(cluster.Namespace, cluster.stopCh)

	// Start object store CRD watcher
	objectStoreController := object.NewObjectStoreController(c.context, c.rookImage, cluster.Spec.CephVersion, cluster.Spec.Network.HostNetwork, cluster.ownerRef)
	objectStoreController.StartWatch(cluster.Namespace, cluster.stopCh)

	// Start file system CRD watcher
	fileController := file.NewFilesystemController(c.context, c.rookImage, cluster.Spec.CephVersion, cluster.Spec.Network.HostNetwork, cluster.ownerRef)
	fileController.StartWatch(cluster.Namespace, cluster.stopCh)

	// Start mon health checker
	healthChecker := mon.NewHealthChecker(cluster.mons)
	go healthChecker.Check(cluster.stopCh)

	// Start the osd health checker
	osdChecker := osd.NewMonitor(c.context, cluster.Namespace)
	go osdChecker.Start(cluster.stopCh)

	// add the finalizer to the crd
	err = c.addFinalizer(clusterObj)
	if err != nil {
		logger.Errorf("failed to add finalizer to cluster crd. %+v", err)
	}
}

// ************************************************************************************************
// Update event functions
// ************************************************************************************************
func (c *ClusterController) onUpdate(oldObj, newObj interface{}) {
	oldClust, _, err := getClusterObject(oldObj)
	if err != nil {
		logger.Errorf("failed to get old cluster object: %+v", err)
		return
	}
	newClust, migrationNeeded, err := getClusterObject(newObj)
	if err != nil {
		logger.Errorf("failed to get new cluster object: %+v", err)
		return
	}

	if migrationNeeded {
		logger.Infof("update event for legacy cluster %s", newClust.Namespace)

		if isLegacyClusterObjectDeleted(newObj) {
			// the legacy cluster object has been requested to be deleted but the finalizer is preventing
			// that.  Let's remove the finalizer and allow the deletion of the legacy object to proceed.
			c.removeFinalizer(newObj)
			return
		}

		if err = c.migrateClusterObject(newClust, newObj); err != nil {
			logger.Errorf("failed to migrate legacy cluster %s in namespace %s: %+v", newClust.Name, newClust.Namespace, err)
		}

		// no matter the outcome of the migration, bail out now. if it was successful, then we'll be getting
		// another event for the migrated object and we'll just handle it there.
		return
	}

	logger.Infof("update event for cluster %s", newClust.Namespace)

	// Check if the cluster is being deleted. This code path is called when a finalizer is specified in the crd.
	// When a cluster is requested for deletion, K8s will only set the deletion timestamp if there are any finalizers in the list.
	// K8s will only delete the crd and child resources when the finalizers have been removed from the crd.
	if newClust.DeletionTimestamp != nil {
		logger.Infof("cluster %s has a deletion timestamp", newClust.Namespace)
		err := c.handleDelete(newClust, time.Duration(clusterDeleteRetryInterval)*time.Second)
		if err != nil {
			logger.Errorf("failed finalizer for cluster. %+v", err)
			return
		}
		// remove the finalizer from the crd, which indicates to k8s that the resource can safely be deleted
		c.removeFinalizer(newClust)
		return
	}
	cluster, ok := c.clusterMap[newClust.Namespace]
	if !ok {
		logger.Errorf("Cannot update cluster %s that does not exist", newClust.Namespace)
		return
	}

	if !clusterChanged(oldClust.Spec, newClust.Spec, cluster) {
		logger.Infof("update event for cluster %s is not supported", newClust.Namespace)
		return
	}

	logger.Infof("update event for cluster %s is supported, orchestrating update now", newClust.Namespace)
	logger.Debugf("old cluster: %+v", oldClust.Spec)
	logger.Debugf("new cluster: %+v", newClust.Spec)

	cluster.Spec = &newClust.Spec

	// attempt to update the cluster.  note this is done outside of wait.Poll because that function
	// will wait for the retry interval before trying for the first time.
	done, _ := c.handleUpdate(newClust, cluster)
	if done {
		return
	}

	err = wait.Poll(updateClusterInterval, updateClusterTimeout, func() (bool, error) {
		return c.handleUpdate(newClust, cluster)
	})
	if err != nil {
		message := fmt.Sprintf("giving up trying to update cluster in namespace %s after %s", cluster.Namespace, updateClusterTimeout)
		logger.Error(message)
		if err := c.updateClusterStatus(newClust.Namespace, newClust.Name, cephv1beta1.ClusterStateError, message); err != nil {
			logger.Errorf("failed to update cluster status in namespace %s: %+v", newClust.Namespace, err)
		}
		return
	}
}

func (c *ClusterController) handleUpdate(newClust *cephv1beta1.Cluster, cluster *cluster) (bool, error) {
	if err := c.updateClusterStatus(newClust.Namespace, newClust.Name, cephv1beta1.ClusterStateUpdating, ""); err != nil {
		logger.Errorf("failed to update cluster status in namespace %s: %+v", newClust.Namespace, err)
		return false, nil
	}

	if err := cluster.createInstance(c.rookImage); err != nil {
		logger.Errorf("failed to update cluster in namespace %s. %+v", newClust.Namespace, err)
		return false, nil
	}

	if err := c.updateClusterStatus(newClust.Namespace, newClust.Name, cephv1beta1.ClusterStateCreated, ""); err != nil {
		logger.Errorf("failed to update cluster status in namespace %s: %+v", newClust.Namespace, err)
		return false, nil
	}

	logger.Infof("succeeded updating cluster in namespace %s", newClust.Namespace)
	return true, nil
}

// ************************************************************************************************
// Delete event functions
// ************************************************************************************************
func (c *ClusterController) onDelete(obj interface{}) {
	clust, migrationNeeded, err := getClusterObject(obj)
	if err != nil {
		logger.Errorf("failed to get cluster object: %+v", err)
		return
	}

	if migrationNeeded {
		// ignore deletion of a legacy cluster as it should have been migrated to an object of the current type
		// and tracked now with that object.
		logger.Infof("ignoring deletion of legacy cluster %s in namespace %s", clust.Name, clust.Namespace)
		return
	}

	logger.Infof("delete event for cluster %s in namespace %s", clust.Name, clust.Namespace)

	err = c.handleDelete(clust, time.Duration(clusterDeleteRetryInterval)*time.Second)
	if err != nil {
		logger.Errorf("failed to delete cluster. %+v", err)
	}
	if cluster, ok := c.clusterMap[clust.Namespace]; ok {
		close(cluster.stopCh)
		delete(c.clusterMap, clust.Namespace)
	}
	if clust.Spec.Storage.AnyUseAllDevices() {
		c.devicesInUse = false
	}
	discover.FreeDevicesByCluster(c.context, clust.Namespace)
}

func (c *ClusterController) handleDelete(cluster *cephv1beta1.Cluster, retryInterval time.Duration) error {

	operatorNamespace := os.Getenv(k8sutil.PodNamespaceEnvVar)
	retryCount := 0
	for {
		// TODO: filter this List operation by cluster namespace on the server side
		vols, err := c.volumeAttachment.List(operatorNamespace)
		if err != nil {
			return fmt.Errorf("failed to get volume attachments for operator namespace %s: %+v", operatorNamespace, err)
		}

		// find volume attachments in the deleted cluster
		attachmentsExist := false
	AttachmentLoop:
		for _, vol := range vols.Items {
			for _, a := range vol.Attachments {
				if a.ClusterName == cluster.Namespace {
					// there is still an outstanding volume attachment in the cluster that is being deleted.
					attachmentsExist = true
					break AttachmentLoop
				}
			}
		}

		if !attachmentsExist {
			logger.Infof("no volume attachments for cluster %s to clean up.", cluster.Namespace)
			break
		}

		retryCount++
		if retryCount == clusterDeleteMaxRetries {
			logger.Warningf(
				"exceeded retry count while waiting for volume attachments for cluster %s to be cleaned up. vols: %+v",
				cluster.Namespace,
				vols.Items)
			break
		}

		logger.Infof("waiting for volume attachments in cluster %s to be cleaned up. Retrying in %s.",
			cluster.Namespace, retryInterval)
		<-time.After(retryInterval)
	}

	return nil
}

func isLegacyClusterObjectDeleted(obj interface{}) bool {
	// if the object is a legacy cluster type and the deletion timestamp on the legacy cluster object is set,
	// it has been requested to be deleted
	if clusterLegacy, ok := obj.(*rookv1alpha1.Cluster); ok {
		return clusterLegacy.DeletionTimestamp != nil
	}

	// not a legacy type
	return false
}

// ************************************************************************************************
// Finalizer functions
// ************************************************************************************************
func (c *ClusterController) addFinalizer(clust *cephv1beta1.Cluster) error {

	// get the latest cluster object since we probably updated it before we got to this point (e.g. by updating its status)
	clust, err := c.context.RookClientset.CephV1beta1().Clusters(clust.Namespace).Get(clust.Name, metav1.GetOptions{})
	if err != nil {
		return err
	}

	// add the finalizer (cluster.ceph.rook.io) if it is not yet defined on the cluster CRD
	for _, finalizer := range clust.Finalizers {
		if finalizer == finalizerName {
			logger.Infof("finalizer already set on cluster %s", clust.Namespace)
			return nil
		}
	}

	// adding finalizer to the cluster crd
	clust.Finalizers = append(clust.Finalizers, finalizerName)

	// update the crd
	_, err = c.context.RookClientset.CephV1beta1().Clusters(clust.Namespace).Update(clust)
	if err != nil {
		return fmt.Errorf("failed to add finalizer to cluster. %+v", err)
	}

	logger.Infof("added finalizer to cluster %s", clust.Name)
	return nil
}

func (c *ClusterController) removeFinalizer(obj interface{}) {
	var fname string
	var objectMeta *metav1.ObjectMeta

	// first determine what type/version of cluster we are dealing with
	if cl, ok := obj.(*cephv1beta1.Cluster); ok {
		fname = finalizerName
		objectMeta = &cl.ObjectMeta
	} else if cl, ok := obj.(*rookv1alpha1.Cluster); ok {
		fname = finalizerNameRookLegacy
		objectMeta = &cl.ObjectMeta
	} else {
		logger.Warningf("cannot remove finalizer from object that is not a cluster: %+v", obj)
		return
	}

	// remove the finalizer from the slice if it exists
	found := false
	for i, finalizer := range objectMeta.Finalizers {
		if finalizer == fname {
			objectMeta.Finalizers = append(objectMeta.Finalizers[:i], objectMeta.Finalizers[i+1:]...)
			found = true
			break
		}
	}
	if !found {
		logger.Infof("finalizer %s not found in the cluster crd '%s'", fname, objectMeta.Name)
		return
	}

	// update the crd to remove the finalizer for good. retry several times in case of intermittent failures.
	maxRetries := 5
	retrySeconds := 5 * time.Second
	for i := 0; i < maxRetries; i++ {
		var err error
		if cluster, ok := obj.(*cephv1beta1.Cluster); ok {
			_, err = c.context.RookClientset.CephV1beta1().Clusters(cluster.Namespace).Update(cluster)
		} else {
			clusterLegacy := obj.(*rookv1alpha1.Cluster)
			_, err = c.context.RookClientset.RookV1alpha1().Clusters(clusterLegacy.Namespace).Update(clusterLegacy)
		}

		if err != nil {
			logger.Errorf("failed to remove finalizer %s from cluster %s. %+v", fname, objectMeta.Name, err)
			time.Sleep(retrySeconds)
			continue
		}
		logger.Infof("removed finalizer %s from cluster %s", fname, objectMeta.Name)
		return
	}

	logger.Warningf("giving up from removing the %s cluster finalizer", fname)
}

func (c *ClusterController) updateClusterStatus(namespace, name string, state cephv1beta1.ClusterState, message string) error {
	// get the most recent cluster CRD object
	cluster, err := c.context.RookClientset.CephV1beta1().Clusters(namespace).Get(name, metav1.GetOptions{})
	if err != nil {
		return fmt.Errorf("failed to get cluster from namespace %s prior to updating its status: %+v", namespace, err)
	}

	// update the status on the retrieved cluster object
	cluster.Status = cephv1beta1.ClusterStatus{State: state, Message: message}
	if _, err := c.context.RookClientset.CephV1beta1().Clusters(cluster.Namespace).Update(cluster); err != nil {
		return fmt.Errorf("failed to update cluster %s status: %+v", cluster.Namespace, err)
	}

	return nil
}

func ClusterOwnerRef(namespace, clusterID string) metav1.OwnerReference {
	blockOwner := true
	return metav1.OwnerReference{
		APIVersion:         ClusterResource.Version,
		Kind:               ClusterResource.Kind,
		Name:               namespace,
		UID:                types.UID(clusterID),
		BlockOwnerDeletion: &blockOwner,
	}
}