/*
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 controllers

import (
	"context"

	"github.com/aws/aws-app-mesh-controller-for-k8s/pkg/k8s"
	"github.com/aws/aws-app-mesh-controller-for-k8s/pkg/runtime"
	"github.com/aws/aws-app-mesh-controller-for-k8s/pkg/virtualnode"
	"github.com/go-logr/logr"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/client-go/tools/record"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/handler"
	"sigs.k8s.io/controller-runtime/pkg/source"

	appmesh "github.com/aws/aws-app-mesh-controller-for-k8s/apis/appmesh/v1beta2"
)

// NewVirtualNodeReconciler constructs new virtualNodeReconciler
func NewVirtualNodeReconciler(
	k8sClient client.Client,
	finalizerManager k8s.FinalizerManager,
	vnResManager virtualnode.ResourceManager,
	log logr.Logger,
	recorder record.EventRecorder,
	enableBackendGroups bool) *virtualNodeReconciler {
	return &virtualNodeReconciler{
		k8sClient:                              k8sClient,
		finalizerManager:                       finalizerManager,
		vnResManager:                           vnResManager,
		enqueueRequestsForMeshEvents:           virtualnode.NewEnqueueRequestsForMeshEvents(k8sClient, log),
		enqueueRequestsForBackendGroupEvents:   virtualnode.NewEnqueueRequestsForBackendGroupEvents(k8sClient, log),
		enqueueRequestsForVirtualServiceEvents: virtualnode.NewEnqueueRequestsForVirtualServiceEvents(k8sClient, log),
		log:                                    log,
		recorder:                               recorder,
		enableBackendGroups:                    enableBackendGroups,
	}
}

// virtualNodeReconciler reconciles a VirtualNode object
type virtualNodeReconciler struct {
	k8sClient        client.Client
	finalizerManager k8s.FinalizerManager
	vnResManager     virtualnode.ResourceManager

	enqueueRequestsForMeshEvents           handler.EventHandler
	enqueueRequestsForBackendGroupEvents   handler.EventHandler
	enqueueRequestsForVirtualServiceEvents handler.EventHandler
	log                                    logr.Logger
	recorder                               record.EventRecorder

	enableBackendGroups bool
}

// +kubebuilder:rbac:groups=appmesh.k8s.aws,resources=virtualnodes,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=appmesh.k8s.aws,resources=virtualnodes/status,verbs=get;update;patch
// +kubebuilder:rbac:groups="",resources=events,verbs=create;patch
// +kubebuilder:rbac:groups=appmesh.k8s.aws,resources=backendgroups,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=appmesh.k8s.aws,resources=backendgroups/status,verbs=get;update;patch

func (r *virtualNodeReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	return runtime.HandleReconcileError(r.reconcile(ctx, req), r.log)
}

func (r *virtualNodeReconciler) SetupWithManager(mgr ctrl.Manager) error {
	if r.enableBackendGroups {
		return ctrl.NewControllerManagedBy(mgr).
			For(&appmesh.VirtualNode{}).
			Watches(&source.Kind{Type: &appmesh.Mesh{}}, r.enqueueRequestsForMeshEvents).
			Watches(&source.Kind{Type: &appmesh.BackendGroup{}}, r.enqueueRequestsForBackendGroupEvents).
			Watches(&source.Kind{Type: &appmesh.VirtualService{}}, r.enqueueRequestsForVirtualServiceEvents).
			WithOptions(controller.Options{MaxConcurrentReconciles: 3}).
			Complete(r)
	} else {
		return ctrl.NewControllerManagedBy(mgr).
			For(&appmesh.VirtualNode{}).
			Watches(&source.Kind{Type: &appmesh.Mesh{}}, r.enqueueRequestsForMeshEvents).
			WithOptions(controller.Options{MaxConcurrentReconciles: 3}).
			Complete(r)
	}
}

func (r *virtualNodeReconciler) reconcile(ctx context.Context, req ctrl.Request) error {
	vn := &appmesh.VirtualNode{}
	if err := r.k8sClient.Get(ctx, req.NamespacedName, vn); err != nil {
		return client.IgnoreNotFound(err)
	}
	if !vn.DeletionTimestamp.IsZero() {
		return r.cleanupVirtualNode(ctx, vn)
	}
	if err := r.reconcileVirtualNode(ctx, vn); err != nil {
		r.recorder.Event(vn, corev1.EventTypeWarning, "ReconcileError", err.Error())
		return err
	}
	return nil
}

func (r *virtualNodeReconciler) reconcileVirtualNode(ctx context.Context, vn *appmesh.VirtualNode) error {
	if err := r.finalizerManager.AddFinalizers(ctx, vn, k8s.FinalizerAWSAppMeshResources); err != nil {
		return err
	}
	if err := r.vnResManager.Reconcile(ctx, vn); err != nil {
		return err
	}
	return nil
}

func (r *virtualNodeReconciler) cleanupVirtualNode(ctx context.Context, vn *appmesh.VirtualNode) error {
	if k8s.HasFinalizer(vn, k8s.FinalizerAWSAppMeshResources) {
		if err := r.vnResManager.Cleanup(ctx, vn); err != nil {
			return err
		}
		if err := r.finalizerManager.RemoveFinalizers(ctx, vn, k8s.FinalizerAWSAppMeshResources); err != nil {
			return err
		}
	}
	return nil
}