/*
Copyright 2020 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 (
	"context"

	"github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
	cephv1 "github.com/rook/rook/pkg/apis/ceph.rook.io/v1"
	"github.com/rook/rook/pkg/clusterd"
	discoverDaemon "github.com/rook/rook/pkg/daemon/discover"
	opcontroller "github.com/rook/rook/pkg/operator/ceph/controller"
	"github.com/rook/rook/pkg/operator/k8sutil"
	"github.com/rook/rook/pkg/util/log"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/event"
	"sigs.k8s.io/controller-runtime/pkg/predicate"
)

// Always trigger a reconcile when a secret is deleted. This will cause a
// reconciliation failure to happen immediately in hopes of alerting the end
// user to the configuration problem.
var changedOrDeleted = predicate.Or(
	predicate.TypedResourceVersionChangedPredicate[*corev1.Secret]{},
	predicate.TypedFuncs[*corev1.Secret]{
		DeleteFunc: func(e event.TypedDeleteEvent[*corev1.Secret]) bool {
			return true
		},
	},
)

func shouldReconcileChangedNode(objOld, objNew *corev1.Node) bool {
	// do not watch node if only resourceversion got changed
	resourceQtyComparer := cmpopts.IgnoreFields(v1.ObjectMeta{}, "ResourceVersion")
	diff := cmp.Diff(objOld.Spec, objNew.Spec, resourceQtyComparer)

	// do not watch node if only LastHeartbeatTime got changed
	resourceQtyComparer = cmpopts.IgnoreFields(corev1.NodeCondition{}, "LastHeartbeatTime")
	diff1 := cmp.Diff(objOld.Spec, objNew.Spec, resourceQtyComparer)

	if diff == "" && diff1 == "" {
		return false
	}
	return true
}

// predicateForNodeWatcher is the predicate function to trigger reconcile on Node events
func predicateForNodeWatcher[T *corev1.Node](ctx context.Context, client client.Client, context *clusterd.Context, opNamespace string) predicate.TypedFuncs[T] {
	return predicate.TypedFuncs[T]{
		CreateFunc: func(e event.TypedCreateEvent[T]) bool {
			obj := (*corev1.Node)(e.Object)

			clientCluster := newClientCluster(client, obj.GetNamespace(), context)
			return clientCluster.onK8sNode(ctx, obj, opNamespace)
		},

		UpdateFunc: func(e event.TypedUpdateEvent[T]) bool {
			objOld := (*corev1.Node)(e.ObjectOld)
			objNew := (*corev1.Node)(e.ObjectNew)

			if !shouldReconcileChangedNode(objOld, objNew) {
				return false
			}

			clientCluster := newClientCluster(client, objNew.GetNamespace(), context)
			return clientCluster.onK8sNode(ctx, objNew, opNamespace)
		},

		DeleteFunc: func(e event.TypedDeleteEvent[T]) bool {
			return false
		},

		GenericFunc: func(e event.TypedGenericEvent[T]) bool {
			return false
		},
	}
}

// predicateForHotPlugCMWatcher is the predicate function to trigger reconcile on ConfigMap events (hot-plug)
func predicateForHotPlugCMWatcher[T *corev1.ConfigMap](client client.Client) predicate.TypedFuncs[T] {
	return predicate.TypedFuncs[T]{
		UpdateFunc: func(e event.TypedUpdateEvent[T]) bool {
			objOld := (*corev1.ConfigMap)(e.ObjectOld)
			objNew := (*corev1.ConfigMap)(e.ObjectNew)

			if !isHotPlugCM(objNew) {
				return false
			}

			clientCluster := newClientCluster(client, objNew.GetNamespace(), &clusterd.Context{})
			return clientCluster.onDeviceCMUpdate(objOld, objNew)
		},

		DeleteFunc: func(e event.TypedDeleteEvent[T]) bool {
			// TODO: if the configmap goes away we could retrigger rook-discover DS
			// However at this point the returned bool can only trigger a reconcile of the CephCluster object
			// Definitely non-trivial but nice to have in the future
			return false
		},

		CreateFunc: func(e event.TypedCreateEvent[T]) bool {
			return false
		},

		GenericFunc: func(e event.TypedGenericEvent[T]) bool {
			return false
		},
	}
}

// isHotPlugCM informs whether the object is the cm for hot-plug disk
func isHotPlugCM(cm *corev1.ConfigMap) bool {
	// Get the labels
	labels := cm.GetLabels()

	labelVal, labelKeyExist := labels[k8sutil.AppAttr]
	if labelKeyExist && labelVal == discoverDaemon.AppName {
		return true
	}

	return false
}

// predicateForOperatorConfigCMWatcher is the predicate function to trigger reconcile on operator config ConfigMap events
func predicateForOperatorConfigCMWatcher[T *corev1.ConfigMap]() predicate.TypedFuncs[T] {
	return predicate.TypedFuncs[T]{
		UpdateFunc: func(e event.TypedUpdateEvent[T]) bool {
			objNew := (*corev1.ConfigMap)(e.ObjectNew)
			objOld := (*corev1.ConfigMap)(e.ObjectOld)

			if objNew.Name != opcontroller.OperatorSettingConfigMapName {
				return false
			}

			if objOld.Data["ROOK_USE_CSI_OPERATOR"] != objNew.Data["ROOK_USE_CSI_OPERATOR"] {
				log.NamespacedInfo(objNew.Namespace, logger, "ROOK_USE_CSI_OPERATOR changed from %q to %q", objOld.Data["ROOK_USE_CSI_OPERATOR"], objNew.Data["ROOK_USE_CSI_OPERATOR"])
				return true
			}

			return false
		},

		CreateFunc: func(e event.TypedCreateEvent[T]) bool {
			objNew := (*corev1.ConfigMap)(e.Object)
			if objNew.Name != opcontroller.OperatorSettingConfigMapName {
				return false
			}

			if objNew.Data["ROOK_USE_CSI_OPERATOR"] == "true" {
				return true
			}

			return false
		},

		DeleteFunc: func(e event.TypedDeleteEvent[T]) bool {
			return false
		},

		GenericFunc: func(e event.TypedGenericEvent[T]) bool {
			return false
		},
	}
}

func watchControllerPredicate[T *cephv1.CephCluster](ctx context.Context, c client.Client) predicate.TypedFuncs[T] {
	return predicate.TypedFuncs[T]{
		CreateFunc: func(e event.TypedCreateEvent[T]) bool {
			if opcontroller.DuplicateCephClusters(ctx, c, e.Object, true) {
				return false
			}
			logger.Debug("create event from a CR")
			return true
		},
		DeleteFunc: func(e event.TypedDeleteEvent[T]) bool {
			logger.Debug("delete event from a CR")
			return true
		},
		UpdateFunc: func(e event.TypedUpdateEvent[T]) bool {
			// We still need to check on update event since the user must delete the additional CR
			// Until this is done, the user can still update the CR and the operator will reconcile
			// This should not happen
			if opcontroller.DuplicateCephClusters(ctx, c, e.ObjectOld, true) {
				return false
			}

			// 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 })

			objOld := (*cephv1.CephCluster)(e.ObjectOld)
			objNew := (*cephv1.CephCluster)(e.ObjectNew)

			log.NamespacedDebug(objNew.Namespace, logger, "update event on CephCluster CR")
			// If the user sets the skip-reconcile label, avoid doing anything (including manager reloads)
			// for this CephCluster.
			//
			// However, we still want to trigger a reconcile when the label is added/removed so the
			// controller can early-exit and record a "ReconcileSkipped" event (when label is added),
			// and also resume reconciliation immediately when the label is removed.
			_, oldHasSkipLabel := objOld.GetLabels()[cephv1.SkipReconcileLabelKey]
			_, newHasSkipLabel := objNew.GetLabels()[cephv1.SkipReconcileLabelKey]
			if oldHasSkipLabel != newHasSkipLabel {
				log.NamespacedDebug(objNew.Namespace, logger, "CephCluster %q skip-reconcile label changed (%v -> %v); triggering reconcile", objNew.Name, oldHasSkipLabel, newHasSkipLabel)
				return true
			}
			if newHasSkipLabel {
				log.NamespacedInfo(objNew.Namespace, logger, "object %q matched on update but %q label is set, doing nothing", objNew.Name, cephv1.SkipReconcileLabelKey)
				return false
			}

			// Backwards/alternative label used by some controllers to avoid reconciling an object.
			// If this label is set on the object, let's not reconcile that request.
			if opcontroller.IsDoNotReconcile(objNew.GetLabels()) {
				log.NamespacedDebug(objNew.Namespace, logger, "object %q matched on update but %q label is set, doing nothing", opcontroller.DoNotReconcileLabelName, objNew.Name)
				return false
			}
			diff := cmp.Diff(objOld.Spec, objNew.Spec, resourceQtyComparer)
			if diff != "" {
				log.NamespacedInfo(objNew.Namespace, logger, "CR has changed for %q. diff=%s", objNew.Name, diff)

				if objNew.Spec.CleanupPolicy.HasDataDirCleanPolicy() {
					log.NamespacedInfo(objNew.Namespace, logger, "skipping orchestration for cluster object %q in namespace %q because its cleanup policy is set. not reloading the manager", objNew.GetName(), objNew.GetNamespace())
					return false
				}

				// Stop any ongoing orchestration
				opcontroller.ReloadManager()

				return false

			} else if !objOld.GetDeletionTimestamp().Equal(objNew.GetDeletionTimestamp()) {
				log.NamespacedInfo(objNew.Namespace, logger, "CR %q is going be deleted, cancelling any ongoing orchestration", objNew.Name)

				// Stop any ongoing orchestration
				opcontroller.ReloadManager()

				return false

			} else if objOld.GetGeneration() != objNew.GetGeneration() {
				log.NamespacedDebug(objNew.Namespace, logger, "reconciling CephCluster %q with changed generation", objNew.Name)
				return true
			}

			return false
		},
		GenericFunc: func(e event.TypedGenericEvent[T]) bool {
			return false
		},
	}
}