package controllers

import (
	"context"
	"fmt"
	mapset "github.com/deckarep/golang-set"
	"github.com/go-logr/logr"
	_ "k8s.io/api/apps/v1beta1"
	rayiov1alpha1 "ray-operator/api/v1alpha1"
	"ray-operator/controllers/common"
	_ "ray-operator/controllers/common"
	"ray-operator/controllers/utils"
	"strings"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	apierrs "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"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("RayCluster-Controller")

// newReconciler returns a new reconcile.Reconciler
func newReconciler(mgr manager.Manager) reconcile.Reconciler {
	return &RayClusterReconciler{Client: mgr.GetClient(), Scheme: mgr.GetScheme()}
}

var _ reconcile.Reconciler = &RayClusterReconciler{}

// RayClusterReconciler reconciles a RayCluster object
type RayClusterReconciler struct {
	client.Client
	Log    logr.Logger
	Scheme *runtime.Scheme
}

// Reconcile reads that state of the cluster for a RayCluster object and makes changes based on it
// and what is in the RayCluster.Spec
// Automatically generate RBAC rules to allow the Controller to read and write workloads
// +kubebuilder:rbac:groups=ray.io,resources=rayclusters,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=ray.io,resources=rayclusters/status,verbs=get;update;patch
// +kubebuilder:rbac:groups=core,resources=events,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=core,resources=pods/status,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=core,resources=services,verbs=get;list;watch;create;update;patch;delete

func (r *RayClusterReconciler) Reconcile(request reconcile.Request) (reconcile.Result, error) {
	_ = r.Log.WithValues("raycluster", request.NamespacedName)
	log.Info("Reconciling RayCluster", "cluster name", request.Name)

	// Fetch the RayCluster instance
	instance := &rayiov1alpha1.RayCluster{}
	err := r.Get(context.TODO(), request.NamespacedName, instance)

	if err != nil {
		if errors.IsNotFound(err) {
			// Object not found, return.  Created objects are automatically garbage collected.
			// For additional cleanup logic use finalizers.
			return reconcile.Result{}, nil
		}
		log.Error(err, "Read request instance error!")
		// Error reading the object - requeue the request.
		if !apierrs.IsNotFound(err) {
			return reconcile.Result{}, err
		}
		return reconcile.Result{}, nil
	}

	log.Info("Print instance - ", "Instance.ToString", instance)

	// Build pods for instance
	expectedPods := r.buildPods(instance)

	expectedPodNameList := mapset.NewSet()
	expectedPodMap := make(map[string]corev1.Pod)
	needServicePodMap := mapset.NewSet()
	for _, pod := range expectedPods {
		expectedPodNameList.Add(pod.Name)
		expectedPodMap[pod.Name] = pod
		if strings.EqualFold(pod.Labels[common.ClusterPodType], common.Head) {
			needServicePodMap.Add(pod.Name)
		}
	}

	log.Info("Build pods according to the ray cluster instance", "size", len(expectedPods), "podNames", expectedPodNameList)

	runtimePods := corev1.PodList{}
	if err = r.List(context.TODO(), &runtimePods, client.InNamespace(instance.Namespace), client.MatchingLabels{common.RayClusterOwnerKey: request.Name}); err != nil {
		return reconcile.Result{}, err
	}

	runtimePodNameList := mapset.NewSet()
	runtimePodMap := make(map[string]corev1.Pod)
	for _, runtimePod := range runtimePods.Items {
		runtimePodNameList.Add(runtimePod.Name)
		runtimePodMap[runtimePod.Name] = runtimePod
	}

	log.Info("Runtime Pods", "size", len(runtimePods.Items), "runtime pods namelist", runtimePodNameList)

	// Record that the pod needs to be deleted.
	difference := runtimePodNameList.Difference(expectedPodNameList)

	// fill replicas with runtime if exists or expectedPod if not exists
	var replicas []corev1.Pod
	for _, pod := range expectedPods {
		if runtimePodNameList.Contains(pod.Name) {
			replicas = append(replicas, runtimePodMap[pod.Name])
		} else {
			replicas = append(replicas, pod)
		}
	}

	// Create the head node service.
	if needServicePodMap.Cardinality() > 0 {
		for elem := range needServicePodMap.Iterator().C {
			podName := elem.(string)
			svcConf := common.DefaultServiceConfig(*instance, podName)
			rayPodSvc := common.ServiceForPod(svcConf)
			blockOwnerDeletion := true
			ownerReference :=  metav1.OwnerReference{
				APIVersion: instance.APIVersion,
				Kind: instance.Kind,
				Name: instance.Name,
				UID: instance.UID,
				BlockOwnerDeletion: &blockOwnerDeletion,
			}
			rayPodSvc.OwnerReferences = append(rayPodSvc.OwnerReferences, ownerReference)
			if errSvc := r.Create(context.TODO(), rayPodSvc); errSvc != nil {
				if errors.IsAlreadyExists(errSvc) {
					log.Info("Pod service already exist,no need to create")
				} else {
					log.Error(errSvc, "Pod Service create error!", "Pod.Service.Error", errSvc)
					return reconcile.Result{}, errSvc
				}
			} else {
				log.Info("Pod Service create anew successfully", "podName", rayPodSvc.Name)
			}
		}
	}

	// Check if each pod exists and if not, create it.
	for i, replica := range replicas {
		if !utils.IsCreated(&replica) {
			log.Info("Creating pod", "index", i, "create pod", replica.Name)
			if err := r.Create(context.TODO(), &replica); err != nil {
				return reconcile.Result{}, err
			}
		}
	}

	// Delete pods if needed.
	if difference.Cardinality() > 0 {
		log.Info("difference", "pods", difference)
		for _, runtimePod := range runtimePods.Items {
			if difference.Contains(runtimePod.Name) {
				log.Info("Deleting pod", "namespace", runtimePod.Namespace, "name", runtimePod.Name)
				if err := r.Delete(context.TODO(), &runtimePod); err != nil {
					return reconcile.Result{}, err
				}
				if strings.EqualFold(runtimePod.Labels[common.ClusterPodType], common.Head) {
					svcConf := common.DefaultServiceConfig(*instance, runtimePod.Name)
					raySvcHead := common.ServiceForPod(svcConf)
					log.Info("delete head service", "headName", runtimePod.Name)
					if err := r.Delete(context.TODO(), raySvcHead); err != nil {
						return reconcile.Result{}, err
					}
				}
			}
		}
	}

	return reconcile.Result{}, nil
}

// Build cluster instance pods.
func (r *RayClusterReconciler) buildPods(instance *rayiov1alpha1.RayCluster) []corev1.Pod {
	var pods []corev1.Pod
	if instance.Spec.Extensions != nil && len(instance.Spec.Extensions) > 0 {
		for _, extension := range instance.Spec.Extensions {
			var i int32 = 0
			for i = 0; i < *extension.Replicas; i++ {
				podType := fmt.Sprintf("%v", extension.Type)
				podName := instance.Name + common.DashSymbol + extension.GroupName + common.DashSymbol + podType + common.DashSymbol + utils.FormatInt32(i)
				podConf := common.DefaultPodConfig(instance, podType, podName)
				podConf.Extension = extension
				pod := common.BuildPod(podConf)
				// Set raycluster instance as the owner and controller
				if err := controllerutil.SetControllerReference(instance, pod, r.Scheme); err != nil {
					log.Error(err, "Failed to set controller reference for raycluster pod")
				}
				pods = append(pods, *pod)
			}
		}
	} else {
		log.Info("RayCluster extensions are nil or empty")
	}

	return pods
}

// SetupWithManager builds the reconciler.
func (r *RayClusterReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&rayiov1alpha1.RayCluster{}).
		Watches(&source.Kind{Type: &corev1.Pod{}}, &handler.EnqueueRequestForOwner{
			IsController: true,
			OwnerType:    &rayiov1alpha1.RayCluster{},
		}).
		Complete(r)
}