/*
Copyright 2016 The Kubernetes Authors.

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 create

import (
	"context"
	"fmt"
	"strings"

	"github.com/spf13/cobra"

	rbacv1 "k8s.io/api/rbac/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/cli-runtime/pkg/resource"
	rbacclientv1 "k8s.io/client-go/kubernetes/typed/rbac/v1"
	cmdutil "k8s.io/kubectl/pkg/cmd/util"
	"k8s.io/kubectl/pkg/scheme"
	"k8s.io/kubectl/pkg/util"
	"k8s.io/kubectl/pkg/util/i18n"
	"k8s.io/kubectl/pkg/util/templates"
)

var (
	roleBindingLong = templates.LongDesc(i18n.T(`
		Create a RoleBinding for a particular Role or ClusterRole.`))

	roleBindingExample = templates.Examples(i18n.T(`
		  # Create a RoleBinding for user1, user2, and group1 using the admin ClusterRole
		  kubectl create rolebinding admin --clusterrole=admin --user=user1 --user=user2 --group=group1`))
)

// RoleBindingOpts holds the options for 'create rolebinding' sub command
type RoleBindingOptions struct {
	PrintFlags *genericclioptions.PrintFlags
	PrintObj   func(obj runtime.Object) error

	Name             string
	Namespace        string
	EnforceNamespace bool
	ClusterRole      string
	Role             string
	Users            []string
	Groups           []string
	ServiceAccounts  []string
	FieldManager     string
	CreateAnnotation bool

	Client         rbacclientv1.RbacV1Interface
	DryRunStrategy cmdutil.DryRunStrategy
	DryRunVerifier *resource.DryRunVerifier

	genericclioptions.IOStreams
}

// NewRoleBindingOptions creates a new *RoleBindingOptions with sane defaults
func NewRoleBindingOptions(ioStreams genericclioptions.IOStreams) *RoleBindingOptions {
	return &RoleBindingOptions{
		Users:           []string{},
		Groups:          []string{},
		ServiceAccounts: []string{},
		PrintFlags:      genericclioptions.NewPrintFlags("created").WithTypeSetter(scheme.Scheme),
		IOStreams:       ioStreams,
	}
}

// NewCmdCreateRoleBinding returns an initialized Command instance for 'create rolebinding' sub command
func NewCmdCreateRoleBinding(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
	o := NewRoleBindingOptions(ioStreams)

	cmd := &cobra.Command{
		Use:                   "rolebinding NAME --clusterrole=NAME|--role=NAME [--user=username] [--group=groupname] [--serviceaccount=namespace:serviceaccountname] [--dry-run=server|client|none]",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Create a RoleBinding for a particular Role or ClusterRole"),
		Long:                  roleBindingLong,
		Example:               roleBindingExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(o.Complete(f, cmd, args))
			cmdutil.CheckErr(o.Validate())
			cmdutil.CheckErr(o.Run())
		},
	}

	o.PrintFlags.AddFlags(cmd)

	cmdutil.AddApplyAnnotationFlags(cmd)
	cmdutil.AddValidateFlags(cmd)
	cmdutil.AddDryRunFlag(cmd)
	cmd.Flags().StringVar(&o.ClusterRole, "clusterrole", "", i18n.T("ClusterRole this RoleBinding should reference"))
	cmd.Flags().StringVar(&o.Role, "role", "", i18n.T("Role this RoleBinding should reference"))
	cmd.Flags().StringArrayVar(&o.Users, "user", o.Users, "Usernames to bind to the role")
	cmd.Flags().StringArrayVar(&o.Groups, "group", o.Groups, "Groups to bind to the role")
	cmd.Flags().StringArrayVar(&o.ServiceAccounts, "serviceaccount", o.ServiceAccounts, "Service accounts to bind to the role, in the format <namespace>:<name>")
	cmdutil.AddFieldManagerFlagVar(cmd, &o.FieldManager, "kubectl-create")
	return cmd
}

// Complete completes all the required options
func (o *RoleBindingOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	var err error
	o.Name, err = NameFromCommandArgs(cmd, args)
	if err != nil {
		return err
	}
	clientConfig, err := f.ToRESTConfig()
	if err != nil {
		return err
	}
	o.Client, err = rbacclientv1.NewForConfig(clientConfig)
	if err != nil {
		return err
	}

	o.Namespace, o.EnforceNamespace, err = f.ToRawKubeConfigLoader().Namespace()
	if err != nil {
		return err
	}

	o.CreateAnnotation = cmdutil.GetFlagBool(cmd, cmdutil.ApplyAnnotationsFlag)
	o.DryRunStrategy, err = cmdutil.GetDryRunStrategy(cmd)
	if err != nil {
		return err
	}
	dynamicCient, err := f.DynamicClient()
	if err != nil {
		return err
	}
	discoveryClient, err := f.ToDiscoveryClient()
	if err != nil {
		return err
	}
	o.DryRunVerifier = resource.NewDryRunVerifier(dynamicCient, discoveryClient)
	cmdutil.PrintFlagsWithDryRunStrategy(o.PrintFlags, o.DryRunStrategy)
	printer, err := o.PrintFlags.ToPrinter()
	if err != nil {
		return err
	}
	o.PrintObj = func(obj runtime.Object) error {
		return printer.PrintObj(obj, o.Out)
	}
	return nil
}

// Validate validates required fields are set
func (o *RoleBindingOptions) Validate() error {
	if len(o.Name) == 0 {
		return fmt.Errorf("name must be specified")
	}
	if (len(o.ClusterRole) == 0) == (len(o.Role) == 0) {
		return fmt.Errorf("exactly one of clusterrole or role must be specified")
	}
	return nil
}

// Run performs the execution of 'create rolebinding' sub command
func (o *RoleBindingOptions) Run() error {
	roleBinding, err := o.createRoleBinding()
	if err != nil {
		return err
	}
	if err := util.CreateOrUpdateAnnotation(o.CreateAnnotation, roleBinding, scheme.DefaultJSONEncoder()); err != nil {
		return err
	}

	if o.DryRunStrategy != cmdutil.DryRunClient {
		createOptions := metav1.CreateOptions{}
		if o.FieldManager != "" {
			createOptions.FieldManager = o.FieldManager
		}
		if o.DryRunStrategy == cmdutil.DryRunServer {
			if err := o.DryRunVerifier.HasSupport(roleBinding.GroupVersionKind()); err != nil {
				return err
			}
			createOptions.DryRun = []string{metav1.DryRunAll}
		}
		roleBinding, err = o.Client.RoleBindings(o.Namespace).Create(context.TODO(), roleBinding, createOptions)
		if err != nil {
			return fmt.Errorf("failed to create rolebinding: %v", err)
		}
	}
	return o.PrintObj(roleBinding)
}

func (o *RoleBindingOptions) createRoleBinding() (*rbacv1.RoleBinding, error) {
	namespace := ""
	if o.EnforceNamespace {
		namespace = o.Namespace
	}

	roleBinding := &rbacv1.RoleBinding{
		TypeMeta: metav1.TypeMeta{APIVersion: rbacv1.SchemeGroupVersion.String(), Kind: "RoleBinding"},
		ObjectMeta: metav1.ObjectMeta{
			Name:      o.Name,
			Namespace: namespace,
		},
	}

	switch {
	case len(o.Role) > 0:
		roleBinding.RoleRef = rbacv1.RoleRef{
			APIGroup: rbacv1.GroupName,
			Kind:     "Role",
			Name:     o.Role,
		}
	case len(o.ClusterRole) > 0:
		roleBinding.RoleRef = rbacv1.RoleRef{
			APIGroup: rbacv1.GroupName,
			Kind:     "ClusterRole",
			Name:     o.ClusterRole,
		}
	}

	for _, user := range o.Users {
		roleBinding.Subjects = append(roleBinding.Subjects, rbacv1.Subject{
			Kind:     rbacv1.UserKind,
			APIGroup: rbacv1.GroupName,
			Name:     user,
		})
	}

	for _, group := range o.Groups {
		roleBinding.Subjects = append(roleBinding.Subjects, rbacv1.Subject{
			Kind:     rbacv1.GroupKind,
			APIGroup: rbacv1.GroupName,
			Name:     group,
		})
	}

	for _, sa := range o.ServiceAccounts {
		tokens := strings.Split(sa, ":")
		if len(tokens) != 2 || tokens[0] == "" || tokens[1] == "" {
			return nil, fmt.Errorf("serviceaccount must be <namespace>:<name>")
		}
		roleBinding.Subjects = append(roleBinding.Subjects, rbacv1.Subject{
			Kind:      rbacv1.ServiceAccountKind,
			APIGroup:  "",
			Namespace: tokens[0],
			Name:      tokens[1],
		})
	}
	return roleBinding, nil
}