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

package user

import (
	"context"
	"fmt"
	"net/mail"

	"k8s.io/apimachinery/pkg/runtime"
	iamv1beta1 "kubesphere.io/api/iam/v1beta1"
	"sigs.k8s.io/controller-runtime/pkg/builder"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"

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

const webhookName = "user-webhook"

func (v *Webhook) Name() string {
	return webhookName
}

var _ kscontroller.Controller = &Webhook{}
var _ admission.CustomValidator = &Webhook{}

type Webhook struct {
	client.Client
}

func (v *Webhook) SetupWithManager(mgr *kscontroller.Manager) error {
	v.Client = mgr.GetClient()
	return builder.WebhookManagedBy(mgr).
		For(&iamv1beta1.User{}).
		WithValidator(v).
		WithDefaulter(v).
		Complete()
}

func (v *Webhook) Default(ctx context.Context, obj runtime.Object) error {
	return nil
}

// validate admits a pod if a specific annotation exists.
func (v *Webhook) validate(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
	user, ok := obj.(*iamv1beta1.User)
	if !ok {
		return nil, fmt.Errorf("expected a User but got a %T", obj)
	}

	allUsers := iamv1beta1.UserList{}
	if err := v.List(ctx, &allUsers, &client.ListOptions{}); err != nil {
		return nil, err
	}

	if _, err := mail.ParseAddress(user.Spec.Email); user.Spec.Email != "" && err != nil {
		return nil, fmt.Errorf("invalid email address:%s", user.Spec.Email)
	}

	alreadyExist := emailAlreadyExist(allUsers, user)
	if alreadyExist {
		return nil, fmt.Errorf("user email: %s already exists", user.Spec.Email)
	}
	return nil, nil
}

func (v *Webhook) ValidateCreate(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
	return v.validate(ctx, obj)
}

func (v *Webhook) ValidateUpdate(ctx context.Context, _, newObj runtime.Object) (admission.Warnings, error) {
	return v.validate(ctx, newObj)
}

func (v *Webhook) ValidateDelete(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
	return v.validate(ctx, obj)
}

func emailAlreadyExist(users iamv1beta1.UserList, user *iamv1beta1.User) bool {
	// empty email is allowed
	if user.Spec.Email == "" {
		return false
	}
	for _, exist := range users.Items {
		if exist.Spec.Email == user.Spec.Email && exist.Name != user.Name {
			return true
		}
	}
	return false
}