/*
 * Please refer to the LICENSE file in the root directory of the project.
 * https://github.com/kubesphere/kubesphere/blob/master/LICENSE
 */

package namespace

import (
	"bytes"
	"context"
	"fmt"

	"github.com/go-logr/logr"
	"github.com/pkg/errors"
	corev1 "k8s.io/api/core/v1"
	rbacv1 "k8s.io/api/rbac/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/util/yaml"
	"k8s.io/client-go/tools/record"
	"k8s.io/klog/v2"
	iamv1beta1 "kubesphere.io/api/iam/v1beta1"
	tenantv1alpha1 "kubesphere.io/api/tenant/v1beta1"
	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/controller/controllerutil"
	"sigs.k8s.io/controller-runtime/pkg/reconcile"

	"kubesphere.io/kubesphere/pkg/constants"
	kscontroller "kubesphere.io/kubesphere/pkg/controller"
)

const (
	controllerName = "namespace"
)

var _ kscontroller.Controller = &Reconciler{}
var _ reconcile.Reconciler = &Reconciler{}

// Reconciler reconciles a Namespace object
type Reconciler struct {
	client.Client
	logger   logr.Logger
	recorder record.EventRecorder
}

func (r *Reconciler) Name() string {
	return controllerName
}

func (r *Reconciler) SetupWithManager(mgr *kscontroller.Manager) error {
	r.Client = mgr.GetClient()
	r.logger = ctrl.Log.WithName("controllers").WithName(controllerName)
	r.recorder = mgr.GetEventRecorderFor(controllerName)
	return ctrl.NewControllerManagedBy(mgr).
		Named(controllerName).
		WithOptions(controller.Options{MaxConcurrentReconciles: 2}).
		For(&corev1.Namespace{}).
		Complete(r)
}

// +kubebuilder:rbac:groups="",resources=namespaces,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=iam.kubesphere.io,resources=builtinroles,verbs=get;list;watch
// +kubebuilder:rbac:groups=iam.kubesphere.io,resources=roles,verbs=get;list;watch
// +kubebuilder:rbac:groups=iam.kubesphere.io,resources=rolebindings,verbs=get;list;watch

func (r *Reconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := r.logger.WithValues("namespace", req.NamespacedName)
	ctx = klog.NewContext(ctx, logger)
	namespace := &corev1.Namespace{}
	if err := r.Get(ctx, req.NamespacedName, namespace); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	if !namespace.ObjectMeta.DeletionTimestamp.IsZero() {
		// The object is being deleted
		if controllerutil.ContainsFinalizer(namespace, constants.CascadingDeletionFinalizer) {
			controllerutil.RemoveFinalizer(namespace, constants.CascadingDeletionFinalizer)
			if err := r.Update(ctx, namespace); err != nil {
				return ctrl.Result{}, errors.Wrapf(err, "failed to remove finalizer")
			}
		}
		// Our finalizer has finished, so the reconciler can do nothing.
		return ctrl.Result{}, nil
	}

	_, workspaceLabelExists := namespace.Labels[constants.WorkspaceLabelKey]

	// The object is not being deleted, so if it does not have our finalizer,
	// then lets add the finalizer and update the object.
	if workspaceLabelExists && !controllerutil.ContainsFinalizer(namespace, constants.CascadingDeletionFinalizer) {
		if err := r.initRoles(ctx, namespace); err != nil {
			return ctrl.Result{}, errors.Wrapf(err, "failed to init roles in namespace %s", namespace.Name)
		}
		if err := r.initCreatorRoleBinding(ctx, namespace); err != nil {
			return ctrl.Result{}, errors.Wrapf(err, "failed to init creator role binding")
		}
		updated := namespace.DeepCopy()
		// Remove legacy finalizer
		controllerutil.RemoveFinalizer(updated, "finalizers.kubesphere.io/namespaces")
		// Remove legacy ownerReferences
		updated.OwnerReferences = make([]metav1.OwnerReference, 0)
		controllerutil.AddFinalizer(updated, constants.CascadingDeletionFinalizer)
		if err := r.Patch(ctx, updated, client.MergeFrom(namespace)); err != nil {
			return ctrl.Result{}, errors.Wrapf(err, "failed to add finalizer")
		}
		return ctrl.Result{}, nil
	}

	if !workspaceLabelExists {
		if err := r.cleanUp(ctx, namespace); err != nil {
			return ctrl.Result{}, errors.Wrapf(err, "failed to clean up namespace %s", namespace.Name)
		}
	}

	r.recorder.Event(namespace, corev1.EventTypeNormal, kscontroller.Synced, kscontroller.MessageResourceSynced)
	return ctrl.Result{}, nil
}

func (r *Reconciler) initRoles(ctx context.Context, namespace *corev1.Namespace) error {
	logger := klog.FromContext(ctx)
	var templates iamv1beta1.BuiltinRoleList
	if err := r.List(ctx, &templates, client.MatchingLabels{iamv1beta1.ScopeLabel: iamv1beta1.ScopeNamespace}); err != nil {
		return errors.Wrapf(err, "failed to list builtin role templates")
	}
	for _, template := range templates.Items {
		selector, err := metav1.LabelSelectorAsSelector(&template.TargetSelector)
		if err != nil {
			logger.V(4).Error(err, "failed to pares target selector", "template", template.Name)
			continue
		}
		if !selector.Matches(labels.Set(namespace.Labels)) {
			continue
		}
		var builtinRoleTemplate iamv1beta1.Role
		if err := yaml.NewYAMLOrJSONDecoder(bytes.NewBuffer(template.Role.Raw), 1024).Decode(&builtinRoleTemplate); err == nil &&
			builtinRoleTemplate.Kind == iamv1beta1.ResourceKindRole {
			existingRole := &iamv1beta1.Role{ObjectMeta: metav1.ObjectMeta{Name: builtinRoleTemplate.Name, Namespace: namespace.Name}}
			op, err := controllerutil.CreateOrUpdate(ctx, r.Client, existingRole, func() error {
				existingRole.Labels = builtinRoleTemplate.Labels
				existingRole.Annotations = builtinRoleTemplate.Annotations
				existingRole.AggregationRoleTemplates = builtinRoleTemplate.AggregationRoleTemplates
				existingRole.Rules = builtinRoleTemplate.Rules
				return nil
			})
			if err != nil {
				return errors.Wrapf(err, "failed to create or update builtin role")
			}
			logger.V(4).Info("builtin role initialized", "operation", op)
		} else if err != nil {
			logger.Error(err, "invalid builtin role found", "name", template.Name)
		}
	}
	return nil
}

func (r *Reconciler) initCreatorRoleBinding(ctx context.Context, namespace *corev1.Namespace) error {
	creator := namespace.Annotations[constants.CreatorAnnotationKey]
	if creator == "" {
		return nil
	}
	roleBinding := &iamv1beta1.RoleBinding{
		ObjectMeta: metav1.ObjectMeta{
			Name:      fmt.Sprintf("%s-%s", creator, iamv1beta1.NamespaceAdmin),
			Namespace: namespace.Name,
		},
	}
	op, err := controllerutil.CreateOrUpdate(ctx, r.Client, roleBinding, func() error {
		roleBinding.Labels = map[string]string{
			iamv1beta1.UserReferenceLabel: creator,
			iamv1beta1.RoleReferenceLabel: iamv1beta1.NamespaceAdmin,
		}
		roleBinding.RoleRef = rbacv1.RoleRef{
			APIGroup: iamv1beta1.GroupName,
			Kind:     iamv1beta1.ResourceKindRole,
			Name:     iamv1beta1.NamespaceAdmin,
		}
		roleBinding.Subjects = []rbacv1.Subject{
			{
				Name:     creator,
				Kind:     iamv1beta1.ResourceKindUser,
				APIGroup: iamv1beta1.GroupName,
			},
		}
		return nil
	})
	if err != nil {
		return errors.Wrapf(err, "failed to create or update creator role binding")
	}
	klog.FromContext(ctx).V(4).Info("creator role binding initialized", "operation", op)
	return nil
}

func (r *Reconciler) cleanUp(ctx context.Context, namespace *corev1.Namespace) error {
	role := &iamv1beta1.Role{}
	if err := r.DeleteAllOf(ctx, role, client.InNamespace(namespace.Name)); err != nil {
		return errors.Wrapf(err, "failed to delete roles")
	}
	roleBinding := &iamv1beta1.RoleBinding{}
	if err := r.DeleteAllOf(ctx, roleBinding, client.InNamespace(namespace.Name)); err != nil {
		return errors.Wrapf(err, "failed to delete role bindings")
	}
	updated := namespace.DeepCopy()
	modified := false
	newOwnerReferences := make([]metav1.OwnerReference, 0, len(updated.OwnerReferences))
	for _, owner := range updated.OwnerReferences {
		if owner.Kind != tenantv1alpha1.ResourceKindWorkspace {
			newOwnerReferences = append(newOwnerReferences, owner)
		} else {
			modified = true
		}
	}

	if modified {
		updated.OwnerReferences = newOwnerReferences
		if err := r.Patch(ctx, updated, client.MergeFrom(namespace)); err != nil {
			return errors.Wrapf(err, "failed to cleanup ownerReferences for namespace %s", namespace.Name)
		}
	}
	return nil
}