/*
Copyright 2020 VMware, Inc.
SPDX-License-Identifier: Apache-2.0
*/

package apiserver

import (
	"fmt"

	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"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/apiserver/pkg/authentication/authenticator"
	"k8s.io/apiserver/pkg/registry/rest"
	genericapiserver "k8s.io/apiserver/pkg/server"
	"k8s.io/client-go/pkg/version"
	"k8s.io/klog/v2"

	placeholderapi "github.com/suzerain-io/placeholder-name-api/pkg/apis/placeholder"
	placeholderv1alpha1 "github.com/suzerain-io/placeholder-name-api/pkg/apis/placeholder/v1alpha1"
	"github.com/suzerain-io/placeholder-name/pkg/registry/loginrequest"
)

var (
	//nolint: gochecknoglobals
	scheme = runtime.NewScheme()
	//nolint: gochecknoglobals
	//nolint: golint
	Codecs = serializer.NewCodecFactory(scheme)
)

//nolint: gochecknoinits
func init() {
	utilruntime.Must(placeholderv1alpha1.AddToScheme(scheme))
	utilruntime.Must(placeholderapi.AddToScheme(scheme))

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

	unversioned := schema.GroupVersion{Group: "", Version: "v1"}
	scheme.AddUnversionedTypes(unversioned,
		&metav1.Status{},
		&metav1.APIVersions{},
		&metav1.APIGroupList{},
		&metav1.APIGroup{},
		&metav1.APIResourceList{},
	)
}

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

type ExtraConfig struct {
	Webhook authenticator.Token
	Issuer  loginrequest.CertIssuer
}

type PlaceHolderServer struct {
	GenericAPIServer *genericapiserver.GenericAPIServer
}

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

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

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

	versionInfo := version.Get()
	completedCfg.GenericConfig.Version = &versionInfo

	return CompletedConfig{completedConfig: &completedCfg}
}

// New returns a new instance of AdmissionServer from the given config.
func (c completedConfig) New() (*PlaceHolderServer, error) {
	genericServer, err := c.GenericConfig.New("place-holder-server", genericapiserver.NewEmptyDelegate()) // completion is done in Complete, no need for a second time
	if err != nil {
		return nil, fmt.Errorf("completion error: %w", err)
	}

	s := &PlaceHolderServer{
		GenericAPIServer: genericServer,
	}

	gvr := placeholderv1alpha1.SchemeGroupVersion.WithResource("loginrequests")

	apiGroupInfo := genericapiserver.APIGroupInfo{
		PrioritizedVersions:          []schema.GroupVersion{gvr.GroupVersion()},
		VersionedResourcesStorageMap: map[string]map[string]rest.Storage{},
		OptionsExternalVersion:       &schema.GroupVersion{Version: "v1"},
		Scheme:                       scheme,
		ParameterCodec:               metav1.ParameterCodec,
		NegotiatedSerializer:         Codecs,
	}

	loginRequestStorage := loginrequest.NewREST(c.ExtraConfig.Webhook, c.ExtraConfig.Issuer)

	v1alpha1Storage, ok := apiGroupInfo.VersionedResourcesStorageMap[gvr.Version]
	if !ok {
		v1alpha1Storage = map[string]rest.Storage{}
	}
	v1alpha1Storage[gvr.Resource] = loginRequestStorage
	apiGroupInfo.VersionedResourcesStorageMap[gvr.Version] = v1alpha1Storage

	if err := s.GenericAPIServer.InstallAPIGroup(&apiGroupInfo); err != nil {
		return nil, fmt.Errorf("install API group error: %w", err)
	}

	s.GenericAPIServer.AddPostStartHookOrDie("place-holder-post-start-hook",
		func(context genericapiserver.PostStartHookContext) error {
			klog.InfoS("post start hook", "foo", "bar")
			return nil
		},
	)

	return s, nil
}