// Copyright 2019-2020 Authors of Cilium
//
// 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 main

import (
	"context"

	"github.com/cilium/cilium/pkg/ipam/allocator"
	"github.com/cilium/cilium/pkg/k8s"
	"github.com/cilium/cilium/pkg/k8s/apis/cilium.io/v2"
	"github.com/cilium/cilium/pkg/k8s/informer"
	k8sversion "github.com/cilium/cilium/pkg/k8s/version"

	"k8s.io/api/core/v1"
	apiextensionsclientset "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/tools/cache"
)

var k8sCiliumNodesCacheSynced = make(chan struct{})

// startSynchronizingCiliumNodes waits for the CiliumNode CRD availability and
// then synchronizes CiliumNode resources.
func startSynchronizingCiliumNodes(apiextensionsK8sClient apiextensionsclientset.Interface, nodeManager allocator.NodeEventHandler) error {
	log.Info("Starting to synchronize CiliumNode custom resources...")

	// TODO: The operator is currently storing a full copy of the
	// CiliumNode resource, as the resource grows, we may want to consider
	// introducing a slim version of it.
	_, ciliumNodeInformer := informer.NewInformer(
		cache.NewListWatchFromClient(ciliumK8sClient.CiliumV2().RESTClient(),
			v2.CNPluralName, v1.NamespaceAll, fields.Everything()),
		&v2.CiliumNode{},
		0,
		cache.ResourceEventHandlerFuncs{
			AddFunc: func(obj interface{}) {
				if node := k8s.ObjToCiliumNode(obj); node != nil {
					// node is deep copied before it is stored in pkg/aws/eni
					nodeManager.Create(node)
				} else {
					log.Warningf("Unknown CiliumNode object type %T received: %+v", obj, obj)
				}
			},
			UpdateFunc: func(oldObj, newObj interface{}) {
				if oldNode := k8s.ObjToCiliumNode(oldObj); oldNode != nil {
					if node := k8s.ObjToCiliumNode(newObj); node != nil {
						if oldNode.DeepEqual(node) {
							return
						}
						// node is deep copied before it is stored in pkg/aws/eni
						nodeManager.Update(node)
					}
				}
			},
			DeleteFunc: func(obj interface{}) {
				if node := k8s.ObjToCiliumNode(obj); node != nil {
					nodeManager.Delete(node.Name)
				}
			},
		},
		k8s.ConvertToCiliumNode,
	)

	if err := WaitForCRD(apiextensionsK8sClient, v2.CNName); err != nil {
		return err
	}

	go func() {
		cache.WaitForCacheSync(wait.NeverStop, ciliumNodeInformer.HasSynced)
		close(k8sCiliumNodesCacheSynced)
	}()

	go ciliumNodeInformer.Run(wait.NeverStop)
	return nil
}

func deleteCiliumNode(nodeManager *allocator.NodeEventHandler, name string) {
	if err := ciliumK8sClient.CiliumV2().CiliumNodes().Delete(context.TODO(), name, metav1.DeleteOptions{}); err == nil {
		log.WithField("name", name).Info("Removed CiliumNode after receiving node deletion event")
	}
	if nodeManager != nil {
		(*nodeManager).Delete(name)
	}
}

type ciliumNodeUpdateImplementation struct{}

func (c *ciliumNodeUpdateImplementation) Create(node *v2.CiliumNode) (*v2.CiliumNode, error) {
	return ciliumK8sClient.CiliumV2().CiliumNodes().Create(context.TODO(), node, metav1.CreateOptions{})
}

func (c *ciliumNodeUpdateImplementation) Get(node string) (*v2.CiliumNode, error) {
	return ciliumK8sClient.CiliumV2().CiliumNodes().Get(context.TODO(), node, metav1.GetOptions{})
}

func (c *ciliumNodeUpdateImplementation) UpdateStatus(origNode, node *v2.CiliumNode) (*v2.CiliumNode, error) {
	// If k8s supports status as a sub-resource, then we need to update the status separately
	k8sCapabilities := k8sversion.Capabilities()
	switch {
	case k8sCapabilities.UpdateStatus:
		if origNode == nil || !origNode.Status.DeepEqual(&node.Status) {
			return ciliumK8sClient.CiliumV2().CiliumNodes().UpdateStatus(context.TODO(), node, metav1.UpdateOptions{})
		}
	default:
		if origNode == nil || !origNode.Status.DeepEqual(&node.Status) {
			return ciliumK8sClient.CiliumV2().CiliumNodes().Update(context.TODO(), node, metav1.UpdateOptions{})
		}
	}

	return nil, nil
}

func (c *ciliumNodeUpdateImplementation) Update(origNode, node *v2.CiliumNode) (*v2.CiliumNode, error) {
	// If k8s supports status as a sub-resource, then we need to update the status separately
	k8sCapabilities := k8sversion.Capabilities()
	switch {
	case k8sCapabilities.UpdateStatus:
		if origNode == nil || !origNode.Spec.DeepEqual(&node.Spec) {
			return ciliumK8sClient.CiliumV2().CiliumNodes().Update(context.TODO(), node, metav1.UpdateOptions{})
		}
	default:
		if origNode == nil || !origNode.DeepEqual(node) {
			return ciliumK8sClient.CiliumV2().CiliumNodes().Update(context.TODO(), node, metav1.UpdateOptions{})
		}
	}

	return nil, nil
}

func (c *ciliumNodeUpdateImplementation) Delete(nodeName string) error {
	return ciliumK8sClient.CiliumV2().CiliumNodes().Delete(context.TODO(), nodeName, metav1.DeleteOptions{})
}