/*

 Copyright 2019 The KubeSphere 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 tenant

import (
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apiserver/pkg/authentication/user"
	"k8s.io/klog"
	"kubesphere.io/kubesphere/pkg/api"
	iamv1alpha2 "kubesphere.io/kubesphere/pkg/apis/iam/v1alpha2"
	tenantv1alpha1 "kubesphere.io/kubesphere/pkg/apis/tenant/v1alpha1"
	"kubesphere.io/kubesphere/pkg/apiserver/authorization/authorizer"
	"kubesphere.io/kubesphere/pkg/apiserver/authorization/authorizerfactory"
	"kubesphere.io/kubesphere/pkg/informers"
	"kubesphere.io/kubesphere/pkg/models/iam/am"
	"kubesphere.io/kubesphere/pkg/simple/client/k8s"
)

type Interface interface {
	ListWorkspaces(user user.Info) (*api.ListResult, error)
	ListNamespaces(user user.Info, workspace string) (*api.ListResult, error)
}

type tenantOperator struct {
	informers  informers.InformerFactory
	am         am.AccessManagementInterface
	authorizer authorizer.Authorizer
}

func New(k8sClient k8s.Client, informers informers.InformerFactory) Interface {
	amOperator := am.NewAMOperator(k8sClient.KubeSphere(), informers.KubeSphereSharedInformerFactory())
	opaAuthorizer := authorizerfactory.NewOPAAuthorizer(amOperator)
	return &tenantOperator{
		informers:  informers,
		am:         amOperator,
		authorizer: opaAuthorizer,
	}
}

func (t *tenantOperator) ListWorkspaces(user user.Info) (*api.ListResult, error) {

	workspaces := make([]*tenantv1alpha1.Workspace, 0)

	listWS := authorizer.AttributesRecord{
		User:       user,
		Verb:       "list",
		APIGroup:   "tenant.kubesphere.io",
		APIVersion: "v1alpha2",
		Resource:   "workspaces",
	}

	decision, _, err := t.authorizer.Authorize(listWS)

	if err != nil {
		klog.Error(err)
		return nil, err
	}

	if decision == authorizer.DecisionAllow {
		workspaces, err = t.informers.KubeSphereSharedInformerFactory().
			Tenant().V1alpha1().Workspaces().Lister().List(labels.Everything())

		if err != nil {
			klog.Error(err)
			return nil, err
		}
	} else {
		workspaceRoles, err := t.am.ListRolesOfUser(iamv1alpha2.WorkspaceScope, user.GetName())
		if err != nil {
			klog.Error(err)
			return nil, err
		}

		for _, role := range workspaceRoles {

			workspace, err := t.informers.KubeSphereSharedInformerFactory().
				Tenant().V1alpha1().Workspaces().Lister().Get(role.Target.Name)

			if errors.IsNotFound(err) {
				klog.Warningf("workspace role: %s found but workspace not exist", role.Target)
				continue
			}

			if err != nil {
				klog.Error(err)
				return nil, err
			}

			if !containsWorkspace(workspaces, workspace) {
				workspaces = append(workspaces, workspace)
			}
		}
	}

	return &api.ListResult{
		TotalItems: len(workspaces),
		Items:      workspacesToInterfaces(workspaces),
	}, nil
}

func (t *tenantOperator) ListNamespaces(user user.Info, workspace string) (*api.ListResult, error) {
	namespaces := make([]*corev1.Namespace, 0)

	listNSInWS := authorizer.AttributesRecord{
		User:       user,
		Verb:       "list",
		APIGroup:   "",
		APIVersion: "v1",
		Workspace:  workspace,
		Resource:   "namespaces",
	}

	decision, _, err := t.authorizer.Authorize(listNSInWS)

	if err != nil {
		klog.Error(err)
		return nil, err
	}

	if decision == authorizer.DecisionAllow {
		namespaces, err = t.informers.KubernetesSharedInformerFactory().
			Core().V1().Namespaces().Lister().List(labels.Everything())

		if err != nil {
			klog.Error(err)
			return nil, err
		}
	} else {
		namespaceRoles, err := t.am.ListRolesOfUser(iamv1alpha2.NamespaceScope, workspace)

		if err != nil {
			klog.Error(err)
			return nil, err
		}

		for _, role := range namespaceRoles {

			namespace, err := t.informers.KubernetesSharedInformerFactory().
				Core().V1().Namespaces().Lister().Get(role.Target.Name)

			if errors.IsNotFound(err) {
				klog.Warningf("workspace role: %s found but workspace not exist", role.Target)
				continue
			}

			if err != nil {
				klog.Error(err)
				return nil, err
			}

			if !containsNamespace(namespaces, namespace) {
				namespaces = append(namespaces, namespace)
			}
		}
	}

	return &api.ListResult{
		TotalItems: len(namespaces),
		Items:      namespacesToInterfaces(namespaces),
	}, nil
}

func containsWorkspace(workspaces []*tenantv1alpha1.Workspace, workspace *tenantv1alpha1.Workspace) bool {
	for _, item := range workspaces {
		if item.Name == workspace.Name {
			return true
		}
	}
	return false
}

func containsNamespace(namespaces []*corev1.Namespace, namespace *corev1.Namespace) bool {
	for _, item := range namespaces {
		if item.Name == namespace.Name {
			return true
		}
	}
	return false
}

func workspacesToInterfaces(workspaces []*tenantv1alpha1.Workspace) []interface{} {
	ret := make([]interface{}, len(workspaces))
	for index, v := range workspaces {
		ret[index] = v
	}
	return ret
}

func namespacesToInterfaces(namespaces []*corev1.Namespace) []interface{} {
	ret := make([]interface{}, len(namespaces))
	for index, v := range namespaces {
		ret[index] = v
	}
	return ret
}