package collectdplugin

import (
	"context"
	"fmt"
	"reflect"
	"strings"

	"github.com/go-logr/logr"
	"github.com/operator-framework/operator-sdk/pkg/predicate"

	onapv1alpha1 "collectd-operator/pkg/apis/onap/v1alpha1"
	collectdutils "collectd-operator/pkg/controller/utils"
	dspredicate "collectd-operator/pkg/controller/utils"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/util/retry"
	"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/manager"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"
	logf "sigs.k8s.io/controller-runtime/pkg/runtime/log"
	"sigs.k8s.io/controller-runtime/pkg/source"
)

var log = logf.Log.WithName("controller_collectdplugin")

// Add creates a new CollectdPlugin Controller and adds it to the Manager. The Manager will set fields on the Controller
// and Start it when the Manager is Started.
func Add(mgr manager.Manager) error {
	return add(mgr, newReconciler(mgr))
}

// newReconciler returns a new reconcile.Reconciler
func newReconciler(mgr manager.Manager) reconcile.Reconciler {
	return &ReconcileCollectdPlugin{client: mgr.GetClient(), scheme: mgr.GetScheme()}
}

// add adds a new Controller to mgr with r as the reconcile.Reconciler
func add(mgr manager.Manager, r reconcile.Reconciler) error {
	// Create a new controller
	log.V(1).Info("Creating a new controller for CollectdPlugin")
	c, err := controller.New("collectdplugin-controller", mgr, controller.Options{Reconciler: r})
	if err != nil {
		return err
	}

	// Watch for changes to primary resource CollectdPlugin
	log.V(1).Info("Add watcher for primary resource CollectdPlugin")
	err = c.Watch(&source.Kind{Type: &onapv1alpha1.CollectdPlugin{}}, &handler.EnqueueRequestForObject{}, predicate.GenerationChangedPredicate{})
	if err != nil {
		return err
	}

	log.V(1).Info("Add watcher for secondary resource Collectd Daemonset")
	err = c.Watch(
		&source.Kind{Type: &appsv1.DaemonSet{}},
		&handler.EnqueueRequestsFromMapFunc{
			ToRequests: handler.ToRequestsFunc(func(a handler.MapObject) []reconcile.Request {
				labelSelector, err := collectdutils.GetWatchLabels()
				labels := strings.Split(labelSelector, "=")
				if err != nil {
					log.Error(err, "Failed to get watch labels, continuing with default label")
				}
				rcp := r.(*ReconcileCollectdPlugin)
				// Select the Daemonset with labelSelector (Default  is app=collectd)
				if a.Meta.GetLabels()[labels[0]] == labels[1] {
					var requests []reconcile.Request
					cpList, err := collectdutils.GetCollectdPluginList(rcp.client, a.Meta.GetNamespace())
					if err != nil || cpList == nil || cpList.Items == nil || len(cpList.Items) == 0 {
						log.V(1).Info("No CollectdPlugin CR instance Exist")
						return nil
					}
					for _, cp := range cpList.Items {
						requests = append(requests, reconcile.Request{
							NamespacedName: client.ObjectKey{Namespace: cp.Namespace, Name: cp.Name}})
					}
					return requests
				}
				return nil
			}),
		}, dspredicate.DaemonSetStatusChangedPredicate{})

	return nil
}

// blank assignment to verify that ReconcileCollectdPlugin implements reconcile.Reconciler
var _ reconcile.Reconciler = &ReconcileCollectdPlugin{}

// ReconcileCollectdPlugin reconciles a CollectdPlugin object
type ReconcileCollectdPlugin struct {
	// This client, initialized using mgr.Client() above, is a split client
	// that reads objects from the cache and writes to the apiserver
	client client.Client
	scheme *runtime.Scheme
}

// Reconcile reads that state of the cluster for a CollectdPlugin object and makes changes based on the state read
// and what is in the CollectdPlugin.Spec
// TODO(user): Modify this Reconcile function to implement your Controller logic.  This example creates
// a Pod as an example
// Note:
// The Controller will requeue the Request to be processed again if the returned error is non-nil or
// Result.Requeue is true, otherwise upon completion it will remove the work from the queue.
func (r *ReconcileCollectdPlugin) Reconcile(request reconcile.Request) (reconcile.Result, error) {
	reqLogger := log.WithValues("Request.Namespace", request.Namespace, "Request.Name", request.Name)
	reqLogger.Info("Reconciling CollectdPlugin")

	// Fetch the CollectdPlugin instance
	instance := &onapv1alpha1.CollectdPlugin{}
	err := r.client.Get(context.TODO(), request.NamespacedName, instance)
	if err != nil {
		if errors.IsNotFound(err) {
			// Request object not found, could have been deleted after reconcile request.
			// Owned objects are automatically garbage collected. For additional cleanup logic use finalizers.
			// Return and don't requeue
			reqLogger.V(1).Info("CollectdPlugin object Not found")
			return reconcile.Result{}, nil
		}
		// Error reading the object - requeue the request.
		reqLogger.V(1).Info("Error reading the CollectdPlugin object, Requeuing")
		return reconcile.Result{}, err
	}

	// Handle Delete CR for additional cleanup
	isDelete, err := r.handleDelete(reqLogger, instance)
	if isDelete {
		return reconcile.Result{}, err
	}

	// Add finalizer for this CR
	if !collectdutils.Contains(instance.GetFinalizers(), collectdutils.CollectdFinalizer) {
		if err := r.addFinalizer(reqLogger, instance); err != nil {
			return reconcile.Result{}, err
		}
		//return reconcile.Result{}, nil
	}
	// Handle the reconciliation for CollectdPlugin.
	// At this stage the Status of the CollectdPlugin should NOT be ""
	err = r.handleCollectdPlugin(reqLogger, instance, false)
	return reconcile.Result{}, err
}

// handleCollectdPlugin regenerates the collectd conf on CR Create, Update, Delete events
func (r *ReconcileCollectdPlugin) handleCollectdPlugin(reqLogger logr.Logger, cr *onapv1alpha1.CollectdPlugin, isDelete bool) error {
	collectdutils.ReconcileLock.Lock()
	defer collectdutils.ReconcileLock.Unlock()
	retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
		cm, err := collectdutils.GetConfigMap(r.client, reqLogger, cr.Namespace)
		if err != nil {
			reqLogger.Error(err, "Skip reconcile: ConfigMap not found")
			return err
		}
		reqLogger.V(1).Info(":::: ConfigMap Info ::::", "ConfigMap.Namespace", cm.Namespace, "ConfigMap.Name", cm.Name)

		collectdConf, err := collectdutils.RebuildCollectdConf(r.client, cr.Namespace, isDelete, cr.Spec.PluginName)
		if err != nil {
			reqLogger.Error(err, "Skip reconcile: Rebuild conf failed")
			return err
		}

		cm.SetAnnotations(map[string]string{
			"daaas-random": collectdutils.ComputeSHA256([]byte(collectdConf)),
		})
		cm.Data["collectd.conf"] = collectdConf

		// Update the ConfigMap with new Spec and reload DaemonSets
		reqLogger.Info("Updating the ConfigMap", "ConfigMap.Namespace", cm.Namespace, "ConfigMap.Name", cm.Name)
		updateErr := r.client.Update(context.TODO(), cm)
		if updateErr != nil {
			reqLogger.Error(updateErr, "Update ConfigMap failed")
			return updateErr
		}

		// Retrieve the latest version of Daemonset before attempting update
		// RetryOnConflict uses exponential backoff to avoid exhausting the apiserver
		// Select DaemonSets with label
		dsList := &appsv1.DaemonSetList{}
		opts := &client.ListOptions{}
		labelSelector, err := collectdutils.GetWatchLabels()
		if err != nil {
			reqLogger.Error(err, "Failed to get watch labels, continuing with default label")
		}
		opts.SetLabelSelector(labelSelector)
		opts.InNamespace(cr.Namespace)
		err = r.client.List(context.TODO(), opts, dsList)
		if err != nil {
			panic(fmt.Errorf("Failed to get latest version of DaemonSet: %v", err))
		}

		if dsList.Items == nil || len(dsList.Items) == 0 {
			return errors.NewNotFound(corev1.Resource("daemonset"), "DaemonSet")
		}
		ds := &dsList.Items[0]
		//Restart Collectd Pods
		reqLogger.Info("Reloading the Daemonset", "DaemonSet.Namespace", ds.Namespace, "DaemonSet.Name", ds.Name)
		//Restart only if hash of conf has changed.
		ds.Spec.Template.SetAnnotations(map[string]string{
			"daaas-random": collectdutils.ComputeSHA256([]byte(collectdConf)),
		})
		updateErr = r.client.Update(context.TODO(), ds)
		return updateErr
	})
	if retryErr != nil {
		panic(fmt.Errorf("Update failed: %v", retryErr))
	}

	retryErr = retry.RetryOnConflict(retry.DefaultRetry, func() error {
		err := r.updateStatus(cr)
		return err
	})

	if retryErr != nil {
		panic(fmt.Errorf("Update failed: %v", retryErr))
	}
	// Reconcile success
	reqLogger.Info("Reconcile success!!")
	return nil
}

// Handle Delete CR event for additional cleanup
func (r *ReconcileCollectdPlugin) handleDelete(reqLogger logr.Logger, cr *onapv1alpha1.CollectdPlugin) (bool, error) {
	// Check if the CollectdPlugin instance is marked to be deleted, which is
	// indicated by the deletion timestamp being set.
	isMarkedToBeDeleted := cr.GetDeletionTimestamp() != nil
	if isMarkedToBeDeleted {
		// Update status to Deleting state
		cr.Status.Status = onapv1alpha1.Deleting
		cr.Status.CollectdAgents = nil
		_ = r.client.Status().Update(context.TODO(), cr)

		if collectdutils.Contains(cr.GetFinalizers(), collectdutils.CollectdFinalizer) {
			// Run finalization logic for collectdPluginFinalizer. If the
			// finalization logic fails, don't remove the finalizer so
			// that we can retry during the next reconciliation.
			if err := r.finalizeCollectdPlugin(reqLogger, cr); err != nil {
				return isMarkedToBeDeleted, err
			}

			// Remove collectdPluginFinalizer. Once all finalizers have been
			// removed, the object will be deleted.
			cr.SetFinalizers(collectdutils.Remove(cr.GetFinalizers(), collectdutils.CollectdFinalizer))
			err := r.client.Update(context.TODO(), cr)
			if err != nil {
				return isMarkedToBeDeleted, err
			}
		}
	}
	return isMarkedToBeDeleted, nil
}

func (r *ReconcileCollectdPlugin) updateStatus(cr *onapv1alpha1.CollectdPlugin) error {
	// Fetch the CollectdGlobal instance
	instance := &onapv1alpha1.CollectdPlugin{}
	key := types.NamespacedName{Namespace: cr.Namespace, Name: cr.Name}
	err := r.client.Get(context.TODO(), key, instance)
	if err != nil {
		return err
	}
	switch instance.Status.Status {
	case onapv1alpha1.Initial:
		instance.Status.Status = onapv1alpha1.Created
	case onapv1alpha1.Created, onapv1alpha1.Enabled:
		pods, err := collectdutils.GetPodList(r.client, instance.Namespace)
		if err != nil {
			return err
		}
		if !reflect.DeepEqual(pods, instance.Status.CollectdAgents) {
			instance.Status.CollectdAgents = pods
			instance.Status.Status = onapv1alpha1.Enabled
		}
	case onapv1alpha1.Deleting, onapv1alpha1.Deprecated:
		return nil
	}
	err = r.client.Status().Update(context.TODO(), instance)
	return err
}

func (r *ReconcileCollectdPlugin) finalizeCollectdPlugin(reqLogger logr.Logger, cr *onapv1alpha1.CollectdPlugin) error {
	// Cleanup by regenerating new collectd conf and rolling update of DaemonSet
	if err := r.handleCollectdPlugin(reqLogger, cr, true); err != nil {
		reqLogger.Error(err, "Finalize CollectdPlugin failed!!")
		return err
	}
	reqLogger.Info("Successfully finalized CollectdPlugin!!")
	return nil
}

func (r *ReconcileCollectdPlugin) addFinalizer(reqLogger logr.Logger, cr *onapv1alpha1.CollectdPlugin) error {
	reqLogger.Info("Adding Finalizer for the CollectdPlugin")
	cr.SetFinalizers(append(cr.GetFinalizers(), collectdutils.CollectdFinalizer))
	// Update status from Initial to Created
	// Since addFinalizer will be executed only once,
	// the status will be changed from Initial state to Created
	// updateErr := r.updateStatus(cr)
	// if updateErr != nil {
	// 	reqLogger.Error(updateErr, "Failed to update status from Initial state")
	// }
	// Update CR
	cr.Status.Status = onapv1alpha1.Created
	err := r.client.Update(context.TODO(), cr)
	if err != nil {
		reqLogger.Error(err, "Failed to update CollectdPlugin with finalizer")
		return err
	}
	return nil
}