/*
Copyright 2019 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.
*/

// scale-out, multi-cloud Edge-X S3 services controller
package s3x

import (
	"fmt"
	"reflect"

	"github.com/coreos/pkg/capnslog"
	"github.com/google/go-cmp/cmp"
	opkit "github.com/rook/operator-kit"
	edgefsv1 "github.com/rook/rook/pkg/apis/edgefs.rook.io/v1"
	rookalpha "github.com/rook/rook/pkg/apis/rook.io/v1alpha2"
	"github.com/rook/rook/pkg/clusterd"
	v1 "k8s.io/api/core/v1"
	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/tools/cache"
)

const (
	customResourceName       = "s3x"
	customResourceNamePlural = "s3xs"
)

var logger = capnslog.NewPackageLogger("github.com/rook/rook", "edgefs-op-s3x")

// S3XResource represents the s3x custom resource
var S3XResource = opkit.CustomResource{
	Name:    customResourceName,
	Plural:  customResourceNamePlural,
	Group:   edgefsv1.CustomResourceGroup,
	Version: edgefsv1.Version,
	Scope:   apiextensionsv1beta1.NamespaceScoped,
	Kind:    reflect.TypeOf(edgefsv1.S3X{}).Name(),
}

// S3XController represents a controller object for s3x custom resources
type S3XController struct {
	context          *clusterd.Context
	namespace        string
	rookImage        string
	NetworkSpec      rookalpha.NetworkSpec
	dataDirHostPath  string
	dataVolumeSize   resource.Quantity
	annotations      rookalpha.Annotations
	placement        rookalpha.Placement
	resources        v1.ResourceRequirements
	resourceProfile  string
	ownerRef         metav1.OwnerReference
	useHostLocalTime bool
}

// NewS3XController create controller for watching S3X custom resources created
func NewS3XController(
	context *clusterd.Context,
	namespace string,
	rookImage string,
	NetworkSpec rookalpha.NetworkSpec,
	dataDirHostPath string,
	dataVolumeSize resource.Quantity,
	placement rookalpha.Placement,
	resources v1.ResourceRequirements,
	resourceProfile string,
	ownerRef metav1.OwnerReference,
	useHostLocalTime bool,
) *S3XController {
	return &S3XController{
		context:          context,
		namespace:        namespace,
		rookImage:        rookImage,
		NetworkSpec:      NetworkSpec,
		dataDirHostPath:  dataDirHostPath,
		dataVolumeSize:   dataVolumeSize,
		placement:        placement,
		resources:        resources,
		resourceProfile:  resourceProfile,
		ownerRef:         ownerRef,
		useHostLocalTime: useHostLocalTime,
	}
}

// StartWatch watches for instances of S3X custom resources and acts on them
func (c *S3XController) StartWatch(stopCh chan struct{}) error {

	resourceHandlerFuncs := cache.ResourceEventHandlerFuncs{
		AddFunc:    c.onAdd,
		UpdateFunc: c.onUpdate,
		DeleteFunc: c.onDelete,
	}

	logger.Infof("start watching s3x resources in namespace %s", c.namespace)
	watcher := opkit.NewWatcher(S3XResource, c.namespace, resourceHandlerFuncs, c.context.RookClientset.EdgefsV1().RESTClient())
	go watcher.Watch(&edgefsv1.S3X{}, stopCh)

	return nil
}

func (c *S3XController) onAdd(obj interface{}) {
	s3x, err := getS3XObject(obj)
	if err != nil {
		logger.Errorf("failed to get s3x object: %+v", err)
		return
	}

	if err = c.CreateService(*s3x, c.serviceOwners(s3x)); err != nil {
		logger.Errorf("failed to create s3x %s. %+v", s3x.Name, err)
	}
}

func (c *S3XController) onUpdate(oldObj, newObj interface{}) {
	oldService, err := getS3XObject(oldObj)
	if err != nil {
		logger.Errorf("failed to get old s3x object: %+v", err)
		return
	}
	newService, err := getS3XObject(newObj)
	if err != nil {
		logger.Errorf("failed to get new s3x object: %+v", err)
		return
	}

	if !serviceChanged(oldService.Spec, newService.Spec) {
		logger.Debugf("s3x %s did not change", newService.Name)
		return
	}

	logger.Infof("applying s3x %s changes", newService.Name)
	if err = c.UpdateService(*newService, c.serviceOwners(newService)); err != nil {
		logger.Errorf("failed to create (modify) s3x %s. %+v", newService.Name, err)
	}
}

func (c *S3XController) onDelete(obj interface{}) {
	s3x, err := getS3XObject(obj)
	if err != nil {
		logger.Errorf("failed to get s3x object: %+v", err)
		return
	}

	if err = c.DeleteService(*s3x); err != nil {
		logger.Errorf("failed to delete s3x %s. %+v", s3x.Name, err)
	}
}

func (c *S3XController) serviceOwners(service *edgefsv1.S3X) []metav1.OwnerReference {
	// Only set the cluster crd as the owner of the S3X resources.
	// If the S3X crd is deleted, the operator will explicitly remove the S3X resources.
	// If the S3X crd still exists when the cluster crd is deleted, this will make sure the S3X
	// resources are cleaned up.
	return []metav1.OwnerReference{c.ownerRef}
}

func (c *S3XController) ParentClusterChanged(cluster edgefsv1.ClusterSpec) {
	if c.rookImage == cluster.EdgefsImageName {
		logger.Infof("No need to update the s3x service, the same images present")
		return
	}

	// update controller options by updated cluster spec
	c.rookImage = cluster.EdgefsImageName

	s3xs, err := c.context.RookClientset.EdgefsV1().S3Xs(c.namespace).List(metav1.ListOptions{})
	if err != nil {
		logger.Errorf("failed to retrieve S3Xs to update the Edgefs version. %+v", err)
		return
	}
	for _, s3x := range s3xs.Items {
		logger.Infof("updating the Edgefs version for s3x service %s to %s", s3x.Name, cluster.EdgefsImageName)
		err := c.UpdateService(s3x, nil)
		if err != nil {
			logger.Errorf("failed to update s3x service %s. %+v", s3x.Name, err)
		} else {
			logger.Infof("updated s3x service %s to Edgefs version %s", s3x.Name, cluster.EdgefsImageName)
		}
	}
}

func serviceChanged(oldService, newService edgefsv1.S3XSpec) bool {
	var diff string
	if !reflect.DeepEqual(oldService, newService) {
		func() {
			defer func() {
				if err := recover(); err != nil {
					logger.Warningf("Encountered an issue getting S3X service change differences: %v", err)
				}
			}()

			// resource.Quantity has non-exportable fields, so we use its comparator method
			resourceQtyComparer := cmp.Comparer(func(x, y resource.Quantity) bool { return x.Cmp(y) == 0 })
			diff = cmp.Diff(oldService, newService, resourceQtyComparer)
			logger.Infof("The S3X Service has changed. diff=%s", diff)
		}()
	}

	if len(diff) > 0 {
		return true
	}

	return false
}

func getS3XObject(obj interface{}) (s3x *edgefsv1.S3X, err error) {
	var ok bool
	s3x, ok = obj.(*edgefsv1.S3X)
	if ok {
		// the s3x object is of the latest type, simply return it
		return s3x.DeepCopy(), nil
	}

	return nil, fmt.Errorf("not a known s3x object: %+v", obj)
}