/*
Copyright 2023 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 (
	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
	apiextensionsapiserver "k8s.io/apiextensions-apiserver/pkg/apiserver"
	apiextensionsoptions "k8s.io/apiextensions-apiserver/pkg/cmd/server/options"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apiserver/pkg/admission"
	"k8s.io/apiserver/pkg/server"
	"k8s.io/apiserver/pkg/util/webhook"
	"k8s.io/client-go/informers"

	controlplaneapiserver "k8s.io/kubernetes/pkg/controlplane/apiserver/options"
)

func CreateAPIExtensionsConfig(
	kubeAPIServerConfig server.Config,
	kubeInformers informers.SharedInformerFactory,
	pluginInitializers []admission.PluginInitializer,
	commandOptions controlplaneapiserver.CompletedOptions,
	masterCount int,
	serviceResolver webhook.ServiceResolver,
	authResolverWrapper webhook.AuthenticationInfoResolverWrapper,
) (*apiextensionsapiserver.Config, error) {
	// make a shallow copy to let us twiddle a few things
	// most of the config actually remains the same.  We only need to mess with a couple items related to the particulars of the apiextensions
	genericConfig := kubeAPIServerConfig
	genericConfig.PostStartHooks = map[string]server.PostStartHookConfigEntry{}
	genericConfig.RESTOptionsGetter = nil

	// copy the etcd options so we don't mutate originals.
	// we assume that the etcd options have been completed already.  avoid messing with anything outside
	// of changes to StorageConfig as that may lead to unexpected behavior when the options are applied.
	etcdOptions := *commandOptions.Etcd
	// this is where the true decodable levels come from.
	etcdOptions.StorageConfig.Codec = apiextensionsapiserver.Codecs.LegacyCodec(v1beta1.SchemeGroupVersion, v1.SchemeGroupVersion)
	// prefer the more compact serialization (v1beta1) for storage until https://issue.k8s.io/82292 is resolved for objects whose v1 serialization is too big but whose v1beta1 serialization can be stored
	etcdOptions.StorageConfig.EncodeVersioner = runtime.NewMultiGroupVersioner(v1beta1.SchemeGroupVersion, schema.GroupKind{Group: v1beta1.GroupName})
	etcdOptions.SkipHealthEndpoints = true // avoid double wiring of health checks
	if err := etcdOptions.ApplyTo(&genericConfig); err != nil {
		return nil, err
	}

	// override MergedResourceConfig with apiextensions defaults and registry
	if err := commandOptions.APIEnablement.ApplyTo(
		&genericConfig,
		apiextensionsapiserver.DefaultAPIResourceConfigSource(),
		apiextensionsapiserver.Scheme); err != nil {
		return nil, err
	}
	apiextensionsConfig := &apiextensionsapiserver.Config{
		GenericConfig: &server.RecommendedConfig{
			Config:                genericConfig,
			SharedInformerFactory: kubeInformers,
		},
		ExtraConfig: apiextensionsapiserver.ExtraConfig{
			CRDRESTOptionsGetter: apiextensionsoptions.NewCRDRESTOptionsGetter(etcdOptions, genericConfig.ResourceTransformers, genericConfig.StorageObjectCountTracker),
			MasterCount:          masterCount,
			AuthResolverWrapper:  authResolverWrapper,
			ServiceResolver:      serviceResolver,
		},
	}

	// we need to clear the poststarthooks so we don't add them multiple times to all the servers (that fails)
	apiextensionsConfig.GenericConfig.PostStartHooks = map[string]server.PostStartHookConfigEntry{}

	return apiextensionsConfig, nil
}