/*
Copyright 2016 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 app implements a server that runs a set of active
// components.  This includes replication controllers, service endpoints and
// nodes.
//
package app

import (
	"fmt"
	"os"

	"k8s.io/klog"

	"net/http"

	"k8s.io/apimachinery/pkg/runtime/schema"
	utilfeature "k8s.io/apiserver/pkg/util/feature"
	kubeoptions "k8s.io/kubernetes/cmd/kube-controller-manager/app/options"
	"k8s.io/kubernetes/pkg/controller/certificates/approver"
	"k8s.io/kubernetes/pkg/controller/certificates/cleaner"
	"k8s.io/kubernetes/pkg/controller/certificates/rootcacertpublisher"
	"k8s.io/kubernetes/pkg/controller/certificates/signer"
	"k8s.io/kubernetes/pkg/features"
)

func startCSRSigningController(ctx ControllerContext) (http.Handler, bool, error) {
	if !ctx.AvailableResources[schema.GroupVersionResource{Group: "certificates.k8s.io", Version: "v1beta1", Resource: "certificatesigningrequests"}] {
		return nil, false, nil
	}
	if ctx.ComponentConfig.CSRSigningController.ClusterSigningCertFile == "" || ctx.ComponentConfig.CSRSigningController.ClusterSigningKeyFile == "" {
		return nil, false, nil
	}

	// Deprecation warning for old defaults.
	//
	// * If the signing cert and key are the default paths but the files
	// exist, warn that the paths need to be specified explicitly in a
	// later release and the defaults will be removed. We don't expect this
	// to be the case.
	//
	// * If the signing cert and key are default paths but the files don't exist,
	// bail out of startController without logging.
	var keyFileExists, keyUsesDefault, certFileExists, certUsesDefault bool

	_, err := os.Stat(ctx.ComponentConfig.CSRSigningController.ClusterSigningCertFile)
	certFileExists = !os.IsNotExist(err)

	certUsesDefault = (ctx.ComponentConfig.CSRSigningController.ClusterSigningCertFile == kubeoptions.DefaultClusterSigningCertFile)

	_, err = os.Stat(ctx.ComponentConfig.CSRSigningController.ClusterSigningKeyFile)
	keyFileExists = !os.IsNotExist(err)

	keyUsesDefault = (ctx.ComponentConfig.CSRSigningController.ClusterSigningKeyFile == kubeoptions.DefaultClusterSigningKeyFile)

	switch {
	case (keyFileExists && keyUsesDefault) || (certFileExists && certUsesDefault):
		klog.Warningf("You might be using flag defaulting for --cluster-signing-cert-file and" +
			" --cluster-signing-key-file. These defaults are deprecated and will be removed" +
			" in a subsequent release. Please pass these options explicitly.")
	case (!keyFileExists && keyUsesDefault) && (!certFileExists && certUsesDefault):
		// This is what we expect right now if people aren't
		// setting up the signing controller. This isn't
		// actually a problem since the signer is not a
		// required controller.
		return nil, false, nil
	default:
		// Note that '!filesExist && !usesDefaults' is obviously
		// operator error. We don't handle this case here and instead
		// allow it to be handled by NewCSR... below.
	}

	c := ctx.ClientBuilder.ClientOrDie("certificate-controller")

	signer, err := signer.NewCSRSigningController(
		c,
		ctx.InformerFactory.Certificates().V1beta1().CertificateSigningRequests(),
		ctx.ComponentConfig.CSRSigningController.ClusterSigningCertFile,
		ctx.ComponentConfig.CSRSigningController.ClusterSigningKeyFile,
		ctx.ComponentConfig.CSRSigningController.ClusterSigningDuration.Duration,
	)
	if err != nil {
		return nil, false, fmt.Errorf("failed to start certificate controller: %v", err)
	}
	go signer.Run(1, ctx.Stop)

	return nil, true, nil
}

func startCSRApprovingController(ctx ControllerContext) (http.Handler, bool, error) {
	if !ctx.AvailableResources[schema.GroupVersionResource{Group: "certificates.k8s.io", Version: "v1beta1", Resource: "certificatesigningrequests"}] {
		return nil, false, nil
	}

	approver := approver.NewCSRApprovingController(
		ctx.ClientBuilder.ClientOrDie("certificate-controller"),
		ctx.InformerFactory.Certificates().V1beta1().CertificateSigningRequests(),
	)
	go approver.Run(1, ctx.Stop)

	return nil, true, nil
}

func startCSRCleanerController(ctx ControllerContext) (http.Handler, bool, error) {
	cleaner := cleaner.NewCSRCleanerController(
		ctx.ClientBuilder.ClientOrDie("certificate-controller").CertificatesV1beta1().CertificateSigningRequests(),
		ctx.InformerFactory.Certificates().V1beta1().CertificateSigningRequests(),
	)
	go cleaner.Run(1, ctx.Stop)
	return nil, true, nil
}

func startRootCACertPublisher(ctx ControllerContext) (http.Handler, bool, error) {
	if !utilfeature.DefaultFeatureGate.Enabled(features.BoundServiceAccountTokenVolume) {
		return nil, false, nil
	}

	var (
		rootCA []byte
		err    error
	)
	if ctx.ComponentConfig.SAController.RootCAFile != "" {
		if rootCA, err = readCA(ctx.ComponentConfig.SAController.RootCAFile); err != nil {
			return nil, true, fmt.Errorf("error parsing root-ca-file at %s: %v", ctx.ComponentConfig.SAController.RootCAFile, err)
		}
	} else {
		rootCA = ctx.ClientBuilder.ConfigOrDie("root-ca-cert-publisher").CAData
	}

	sac, err := rootcacertpublisher.NewPublisher(
		ctx.InformerFactory.Core().V1().ConfigMaps(),
		ctx.InformerFactory.Core().V1().Namespaces(),
		ctx.ClientBuilder.ClientOrDie("root-ca-cert-publisher"),
		rootCA,
	)
	if err != nil {
		return nil, true, fmt.Errorf("error creating root CA certificate publisher: %v", err)
	}
	go sac.Run(1, ctx.Stop)
	return nil, true, nil
}