/*
Copyright 2017 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.
*/

// Note: the example only works with the code within the same release/branch.
package main

import (
	"flag"
	"fmt"

	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/runtime/serializer"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/pkg/api"
	"k8s.io/client-go/pkg/apis/extensions/v1beta1"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/clientcmd"

	// Only required to authenticate against GKE clusters
	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
)

func main() {
	kubeconfig := flag.String("kubeconfig", "", "Path to a kube config. Only required if out-of-cluster.")
	flag.Parse()

	// Create the client config. Use kubeconfig if given, otherwise assume in-cluster.
	config, err := buildConfig(*kubeconfig)
	if err != nil {
		panic(err)
	}

	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err)
	}

	// initialize third party resource if it does not exist
	tpr, err := clientset.ExtensionsV1beta1().ThirdPartyResources().Get("example.k8s.io", metav1.GetOptions{})
	if err != nil {
		if errors.IsNotFound(err) {
			tpr := &v1beta1.ThirdPartyResource{
				ObjectMeta: metav1.ObjectMeta{
					Name: "example.k8s.io",
				},
				Versions: []v1beta1.APIVersion{
					{Name: "v1"},
				},
				Description: "An Example ThirdPartyResource",
			}

			result, err := clientset.ExtensionsV1beta1().ThirdPartyResources().Create(tpr)
			if err != nil {
				panic(err)
			}
			fmt.Printf("CREATED: %#v\nFROM: %#v\n", result, tpr)
		} else {
			panic(err)
		}
	} else {
		fmt.Printf("SKIPPING: already exists %#v\n", tpr)
	}

	// make a new config for our extension's API group, using the first config as a baseline
	var tprconfig *rest.Config
	tprconfig = config
	configureClient(tprconfig)

	tprclient, err := rest.RESTClientFor(tprconfig)
	if err != nil {
		panic(err)
	}

	var example Example

	err = tprclient.Get().
		Resource("examples").
		Namespace(api.NamespaceDefault).
		Name("example1").
		Do().Into(&example)

	if err != nil {
		if errors.IsNotFound(err) {
			// Create an instance of our TPR
			example := &Example{
				Metadata: metav1.ObjectMeta{
					Name: "example1",
				},
				Spec: ExampleSpec{
					Foo: "hello",
					Bar: true,
				},
			}

			var result Example
			err = tprclient.Post().
				Resource("examples").
				Namespace(api.NamespaceDefault).
				Body(example).
				Do().Into(&result)

			if err != nil {
				panic(err)
			}
			fmt.Printf("CREATED: %#v\n", result)
		} else {
			panic(err)
		}
	} else {
		fmt.Printf("GET: %#v\n", example)
	}

	// Fetch a list of our TPRs
	exampleList := ExampleList{}
	err = tprclient.Get().Resource("examples").Do().Into(&exampleList)
	if err != nil {
		panic(err)
	}
	fmt.Printf("LIST: %#v\n", exampleList)
}

func buildConfig(kubeconfig string) (*rest.Config, error) {
	if kubeconfig != "" {
		return clientcmd.BuildConfigFromFlags("", kubeconfig)
	}
	return rest.InClusterConfig()
}

func configureClient(config *rest.Config) {
	groupversion := schema.GroupVersion{
		Group:   "k8s.io",
		Version: "v1",
	}

	config.GroupVersion = &groupversion
	config.APIPath = "/apis"
	config.ContentType = runtime.ContentTypeJSON
	config.NegotiatedSerializer = serializer.DirectCodecFactory{CodecFactory: api.Codecs}

	schemeBuilder := runtime.NewSchemeBuilder(
		func(scheme *runtime.Scheme) error {
			scheme.AddKnownTypes(
				groupversion,
				&Example{},
				&ExampleList{},
			)
			return nil
		})
	metav1.AddToGroupVersion(api.Scheme, groupversion)
	schemeBuilder.AddToScheme(api.Scheme)
}