/*
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.
*/

package apiserver

import (
	"fmt"
	"net/http"
	"time"

	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/apimachinery/pkg/version"
	"k8s.io/apiserver/pkg/endpoints/discovery"
	genericregistry "k8s.io/apiserver/pkg/registry/generic"
	"k8s.io/apiserver/pkg/registry/rest"
	genericapiserver "k8s.io/apiserver/pkg/server"
	serverstorage "k8s.io/apiserver/pkg/server/storage"

	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/install"
	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
	"k8s.io/apiextensions-apiserver/pkg/client/clientset/internalclientset"
	internalinformers "k8s.io/apiextensions-apiserver/pkg/client/informers/internalversion"
	"k8s.io/apiextensions-apiserver/pkg/controller/establish"
	"k8s.io/apiextensions-apiserver/pkg/controller/finalizer"
	"k8s.io/apiextensions-apiserver/pkg/controller/status"
	"k8s.io/apiextensions-apiserver/pkg/registry/customresourcedefinition"

	_ "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
	_ "k8s.io/apiextensions-apiserver/pkg/client/informers/externalversions"
	_ "k8s.io/apiextensions-apiserver/pkg/client/informers/internalversion"
)

var (
	Scheme = runtime.NewScheme()
	Codecs = serializer.NewCodecFactory(Scheme)

	// if you modify this, make sure you update the crEncoder
	unversionedVersion = schema.GroupVersion{Group: "", Version: "v1"}
	unversionedTypes   = []runtime.Object{
		&metav1.Status{},
		&metav1.WatchEvent{},
		&metav1.APIVersions{},
		&metav1.APIGroupList{},
		&metav1.APIGroup{},
		&metav1.APIResourceList{},
	}
)

func init() {
	install.Install(Scheme)

	// we need to add the options to empty v1
	metav1.AddToGroupVersion(Scheme, schema.GroupVersion{Group: "", Version: "v1"})

	Scheme.AddUnversionedTypes(unversionedVersion, unversionedTypes...)
}

type ExtraConfig struct {
	CRDRESTOptionsGetter genericregistry.RESTOptionsGetter

	// MasterCount is used to detect whether cluster is HA, and if it is
	// the CRD Establishing will be hold by 5 seconds.
	MasterCount int
}

type Config struct {
	GenericConfig *genericapiserver.RecommendedConfig
	ExtraConfig   ExtraConfig
}

type completedConfig struct {
	GenericConfig genericapiserver.CompletedConfig
	ExtraConfig   *ExtraConfig
}

type CompletedConfig struct {
	// Embed a private pointer that cannot be instantiated outside of this package.
	*completedConfig
}

type CustomResourceDefinitions struct {
	GenericAPIServer *genericapiserver.GenericAPIServer

	// provided for easier embedding
	Informers internalinformers.SharedInformerFactory
}

// Complete fills in any fields not set that are required to have valid data. It's mutating the receiver.
func (cfg *Config) Complete() CompletedConfig {
	c := completedConfig{
		cfg.GenericConfig.Complete(),
		&cfg.ExtraConfig,
	}

	c.GenericConfig.EnableDiscovery = false
	c.GenericConfig.Version = &version.Info{
		Major: "0",
		Minor: "1",
	}

	return CompletedConfig{&c}
}

// New returns a new instance of CustomResourceDefinitions from the given config.
func (c completedConfig) New(delegationTarget genericapiserver.DelegationTarget) (*CustomResourceDefinitions, error) {
	genericServer, err := c.GenericConfig.New("apiextensions-apiserver", delegationTarget)
	if err != nil {
		return nil, err
	}

	s := &CustomResourceDefinitions{
		GenericAPIServer: genericServer,
	}

	apiResourceConfig := c.GenericConfig.MergedResourceConfig
	apiGroupInfo := genericapiserver.NewDefaultAPIGroupInfo(apiextensions.GroupName, Scheme, metav1.ParameterCodec, Codecs)
	if apiResourceConfig.VersionEnabled(v1beta1.SchemeGroupVersion) {
		storage := map[string]rest.Storage{}
		// customresourcedefinitions
		customResourceDefintionStorage := customresourcedefinition.NewREST(Scheme, c.GenericConfig.RESTOptionsGetter)
		storage["customresourcedefinitions"] = customResourceDefintionStorage
		storage["customresourcedefinitions/status"] = customresourcedefinition.NewStatusREST(Scheme, customResourceDefintionStorage)

		apiGroupInfo.VersionedResourcesStorageMap["v1beta1"] = storage
	}

	if err := s.GenericAPIServer.InstallAPIGroup(&apiGroupInfo); err != nil {
		return nil, err
	}

	crdClient, err := internalclientset.NewForConfig(s.GenericAPIServer.LoopbackClientConfig)
	if err != nil {
		// it's really bad that this is leaking here, but until we can fix the test (which I'm pretty sure isn't even testing what it wants to test),
		// we need to be able to move forward
		return nil, fmt.Errorf("failed to create clientset: %v", err)
	}
	s.Informers = internalinformers.NewSharedInformerFactory(crdClient, 5*time.Minute)

	delegateHandler := delegationTarget.UnprotectedHandler()
	if delegateHandler == nil {
		delegateHandler = http.NotFoundHandler()
	}

	versionDiscoveryHandler := &versionDiscoveryHandler{
		discovery: map[schema.GroupVersion]*discovery.APIVersionHandler{},
		delegate:  delegateHandler,
	}
	groupDiscoveryHandler := &groupDiscoveryHandler{
		discovery: map[string]*discovery.APIGroupHandler{},
		delegate:  delegateHandler,
	}
	establishingController := establish.NewEstablishingController(s.Informers.Apiextensions().InternalVersion().CustomResourceDefinitions(), crdClient.Apiextensions())
	crdHandler := NewCustomResourceDefinitionHandler(
		versionDiscoveryHandler,
		groupDiscoveryHandler,
		s.Informers.Apiextensions().InternalVersion().CustomResourceDefinitions(),
		delegateHandler,
		c.ExtraConfig.CRDRESTOptionsGetter,
		c.GenericConfig.AdmissionControl,
		establishingController,
		c.ExtraConfig.MasterCount,
	)
	s.GenericAPIServer.Handler.NonGoRestfulMux.Handle("/apis", crdHandler)
	s.GenericAPIServer.Handler.NonGoRestfulMux.HandlePrefix("/apis/", crdHandler)

	crdController := NewDiscoveryController(s.Informers.Apiextensions().InternalVersion().CustomResourceDefinitions(), versionDiscoveryHandler, groupDiscoveryHandler)
	namingController := status.NewNamingConditionController(s.Informers.Apiextensions().InternalVersion().CustomResourceDefinitions(), crdClient.Apiextensions())
	finalizingController := finalizer.NewCRDFinalizer(
		s.Informers.Apiextensions().InternalVersion().CustomResourceDefinitions(),
		crdClient.Apiextensions(),
		crdHandler,
	)

	s.GenericAPIServer.AddPostStartHook("start-apiextensions-informers", func(context genericapiserver.PostStartHookContext) error {
		s.Informers.Start(context.StopCh)
		return nil
	})
	s.GenericAPIServer.AddPostStartHook("start-apiextensions-controllers", func(context genericapiserver.PostStartHookContext) error {
		go crdController.Run(context.StopCh)
		go namingController.Run(context.StopCh)
		go establishingController.Run(context.StopCh)
		go finalizingController.Run(5, context.StopCh)
		return nil
	})

	return s, nil
}

func DefaultAPIResourceConfigSource() *serverstorage.ResourceConfig {
	ret := serverstorage.NewResourceConfig()
	// NOTE: GroupVersions listed here will be enabled by default. Don't put alpha versions in the list.
	ret.EnableVersions(
		v1beta1.SchemeGroupVersion,
	)

	return ret
}
