/*
Copyright 2016 The Kubernetes Authors.
Copyright 2020 Authors of Arktos - file modified.

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.
*/

// this file contains factories with no other dependencies

package util

import (
	"sync"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/cli-runtime/pkg/resource"
	"k8s.io/client-go/discovery"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/kubernetes"
	restclient "k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/kubernetes/pkg/kubectl/cmd/util/openapi"
	openapivalidation "k8s.io/kubernetes/pkg/kubectl/cmd/util/openapi/validation"
	"k8s.io/kubernetes/pkg/kubectl/validation"
)

type factoryImpl struct {
	clientGetter genericclioptions.RESTClientGetter

	// openAPIGetter loads and caches openapi specs
	openAPIGetter openAPIGetter
}

type openAPIGetter struct {
	once   sync.Once
	getter openapi.Getter
}

func NewFactory(clientGetter genericclioptions.RESTClientGetter) Factory {
	if clientGetter == nil {
		panic("attempt to instantiate client_access_factory with nil clientGetter")
	}

	f := &factoryImpl{
		clientGetter: clientGetter,
	}

	return f
}

func (f *factoryImpl) ToRESTConfig() (*restclient.Config, error) {
	return f.clientGetter.ToRESTConfig()
}

func (f *factoryImpl) ToRESTMapper() (meta.RESTMapper, error) {
	return f.clientGetter.ToRESTMapper()
}

func (f *factoryImpl) ToDiscoveryClient() (discovery.CachedDiscoveryInterface, error) {
	return f.clientGetter.ToDiscoveryClient()
}

func (f *factoryImpl) ToRawKubeConfigLoader() clientcmd.ClientConfig {
	return f.clientGetter.ToRawKubeConfigLoader()
}

func (f *factoryImpl) KubernetesClientSet() (*kubernetes.Clientset, error) {
	clientConfig, err := f.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	return kubernetes.NewForConfig(clientConfig)
}

func (f *factoryImpl) DynamicClient() (dynamic.Interface, error) {
	clientConfig, err := f.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	return dynamic.NewForConfig(clientConfig)
}

// NewBuilder returns a new resource builder for structured api objects.
func (f *factoryImpl) NewBuilder() *resource.Builder {
	return resource.NewBuilder(f.clientGetter)
}

// Use for non watch command
func (f *factoryImpl) RESTClient() (*restclient.RESTClient, error) {
	clientConfigs, err := f.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	setKubernetesDefaults(clientConfigs)
	return restclient.RESTClientFor(clientConfigs.GetConfig())
}

// Used only for watch
func (f *factoryImpl) RESTClients() ([]*restclient.RESTClient, error) {
	clientConfigs, err := f.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	setKubernetesDefaults(clientConfigs)

	restClients := make([]*restclient.RESTClient, len(clientConfigs.GetAllConfigs()))
	for i, clientConfig := range clientConfigs.GetAllConfigs() {
		restClient, err := restclient.RESTClientFor(clientConfig)
		if err != nil {
			return restClients, err
		}
		restClients[i] = restClient
	}
	return restClients, nil
}

// TODO - assume single client for now
func (f *factoryImpl) ClientForMapping(mapping *meta.RESTMapping) (resource.RESTClient, error) {
	cfgs, err := f.clientGetter.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	if err := setKubernetesDefaults(cfgs); err != nil {
		return nil, err
	}
	gvk := mapping.GroupVersionKind

	cfg := cfgs.GetConfig()
	switch gvk.Group {
	case corev1.GroupName:
		cfg.APIPath = "/api"
	default:
		cfg.APIPath = "/apis"
	}
	gv := gvk.GroupVersion()
	cfg.GroupVersion = &gv
	return restclient.RESTClientFor(cfg)
}

// TODO - assume single client for now
func (f *factoryImpl) UnstructuredClientForMapping(mapping *meta.RESTMapping) (resource.RESTClient, error) {
	cfgs, err := f.clientGetter.ToRESTConfig()
	if err != nil {
		return nil, err
	}
	cfg := cfgs.GetConfig()
	if err := restclient.SetKubernetesDefaults(cfg); err != nil {
		return nil, err
	}
	cfg.APIPath = "/apis"
	if mapping.GroupVersionKind.Group == corev1.GroupName {
		cfg.APIPath = "/api"
	}
	gv := mapping.GroupVersionKind.GroupVersion()
	cfg.ContentConfig = resource.UnstructuredPlusDefaultContentConfig()
	cfg.GroupVersion = &gv
	return restclient.RESTClientFor(cfg)
}

func (f *factoryImpl) Validator(validate bool) (validation.Schema, error) {
	if !validate {
		return validation.NullSchema{}, nil
	}

	resources, err := f.OpenAPISchema()
	if err != nil {
		return nil, err
	}

	return validation.ConjunctiveSchema{
		openapivalidation.NewSchemaValidation(resources),
		validation.NoDoubleKeySchema{},
	}, nil
}

// OpenAPISchema returns metadata and structural information about Kubernetes object definitions.
func (f *factoryImpl) OpenAPISchema() (openapi.Resources, error) {
	discovery, err := f.clientGetter.ToDiscoveryClient()
	if err != nil {
		return nil, err
	}

	// Lazily initialize the OpenAPIGetter once
	f.openAPIGetter.once.Do(func() {
		// Create the caching OpenAPIGetter
		f.openAPIGetter.getter = openapi.NewOpenAPIGetter(discovery)
	})

	// Delegate to the OpenAPIGetter
	return f.openAPIGetter.getter.Get()
}
