package main

import (
	"context"
	"errors"
	"flag"
	"os"
	"strings"
	"sync"
	"time"

	"github.com/kyverno/kyverno/cmd/internal"
	"github.com/kyverno/kyverno/pkg/client/clientset/versioned"
	kyvernoinformer "github.com/kyverno/kyverno/pkg/client/informers/externalversions"
	"github.com/kyverno/kyverno/pkg/clients/dclient"
	"github.com/kyverno/kyverno/pkg/config"
	admissionreportcontroller "github.com/kyverno/kyverno/pkg/controllers/report/admission"
	aggregatereportcontroller "github.com/kyverno/kyverno/pkg/controllers/report/aggregate/resource"
	backgroundscancontroller "github.com/kyverno/kyverno/pkg/controllers/report/background"
	resourcereportcontroller "github.com/kyverno/kyverno/pkg/controllers/report/resource"
	engineapi "github.com/kyverno/kyverno/pkg/engine/api"
	"github.com/kyverno/kyverno/pkg/engine/jmespath"
	"github.com/kyverno/kyverno/pkg/event"
	"github.com/kyverno/kyverno/pkg/leaderelection"
	"github.com/kyverno/kyverno/pkg/logging"
	"k8s.io/apimachinery/pkg/runtime/schema"
	kubeinformers "k8s.io/client-go/informers"
	admissionregistrationv1alpha1informers "k8s.io/client-go/informers/admissionregistration/v1alpha1"
	metadatainformers "k8s.io/client-go/metadata/metadatainformer"
	kyamlopenapi "sigs.k8s.io/kustomize/kyaml/openapi"
)

const (
	resyncPeriod = 15 * time.Minute
)

func createReportControllers(
	eng engineapi.Engine,
	backgroundScan bool,
	admissionReports bool,
	aggregateReports bool,
	policyReports bool,
	validatingAdmissionPolicyReports bool,
	reportsChunkSize int,
	backgroundScanWorkers int,
	client dclient.Interface,
	kyvernoClient versioned.Interface,
	metadataFactory metadatainformers.SharedInformerFactory,
	kubeInformer kubeinformers.SharedInformerFactory,
	kyvernoInformer kyvernoinformer.SharedInformerFactory,
	backgroundScanInterval time.Duration,
	configuration config.Configuration,
	jp jmespath.Interface,
	eventGenerator event.Interface,
) ([]internal.Controller, func(context.Context) error) {
	var ctrls []internal.Controller
	var warmups []func(context.Context) error
	var vapInformer admissionregistrationv1alpha1informers.ValidatingAdmissionPolicyInformer
	// check if validating admission policies are registered in the API server
	if validatingAdmissionPolicyReports {
		vapInformer = kubeInformer.Admissionregistration().V1alpha1().ValidatingAdmissionPolicies()
	}

	kyvernoV1 := kyvernoInformer.Kyverno().V1()
	if backgroundScan || admissionReports {
		resourceReportController := resourcereportcontroller.NewController(
			client,
			kyvernoV1.Policies(),
			kyvernoV1.ClusterPolicies(),
			vapInformer,
		)
		warmups = append(warmups, func(ctx context.Context) error {
			return resourceReportController.Warmup(ctx)
		})
		ctrls = append(ctrls, internal.NewController(
			resourcereportcontroller.ControllerName,
			resourceReportController,
			resourcereportcontroller.Workers,
		))
		if aggregateReports {
			ctrls = append(ctrls, internal.NewController(
				aggregatereportcontroller.ControllerName,
				aggregatereportcontroller.NewController(
					kyvernoClient,
					metadataFactory,
					kyvernoV1.Policies(),
					kyvernoV1.ClusterPolicies(),
					vapInformer,
					resourceReportController,
					reportsChunkSize,
				),
				aggregatereportcontroller.Workers,
			))
		}
		if admissionReports {
			ctrls = append(ctrls, internal.NewController(
				admissionreportcontroller.ControllerName,
				admissionreportcontroller.NewController(
					kyvernoClient,
					client,
					metadataFactory,
				),
				admissionreportcontroller.Workers,
			))
		}
		if backgroundScan {
			backgroundScanController := backgroundscancontroller.NewController(
				client,
				kyvernoClient,
				eng,
				metadataFactory,
				kyvernoV1.Policies(),
				kyvernoV1.ClusterPolicies(),
				vapInformer,
				kubeInformer.Core().V1().Namespaces(),
				resourceReportController,
				backgroundScanInterval,
				configuration,
				jp,
				eventGenerator,
				policyReports,
			)
			ctrls = append(ctrls, internal.NewController(
				backgroundscancontroller.ControllerName,
				backgroundScanController,
				backgroundScanWorkers),
			)
		}
	}
	return ctrls, func(ctx context.Context) error {
		for _, warmup := range warmups {
			if err := warmup(ctx); err != nil {
				return err
			}
		}
		return nil
	}
}

func createrLeaderControllers(
	eng engineapi.Engine,
	backgroundScan bool,
	admissionReports bool,
	aggregateReports bool,
	policyReports bool,
	validatingAdmissionPolicyReports bool,
	reportsChunkSize int,
	backgroundScanWorkers int,
	kubeInformer kubeinformers.SharedInformerFactory,
	kyvernoInformer kyvernoinformer.SharedInformerFactory,
	metadataInformer metadatainformers.SharedInformerFactory,
	kyvernoClient versioned.Interface,
	dynamicClient dclient.Interface,
	configuration config.Configuration,
	jp jmespath.Interface,
	eventGenerator event.Interface,
	backgroundScanInterval time.Duration,
) ([]internal.Controller, func(context.Context) error, error) {
	reportControllers, warmup := createReportControllers(
		eng,
		backgroundScan,
		admissionReports,
		aggregateReports,
		policyReports,
		validatingAdmissionPolicyReports,
		reportsChunkSize,
		backgroundScanWorkers,
		dynamicClient,
		kyvernoClient,
		metadataInformer,
		kubeInformer,
		kyvernoInformer,
		backgroundScanInterval,
		configuration,
		jp,
		eventGenerator,
	)
	return reportControllers, warmup, nil
}

func main() {
	var (
		backgroundScan                   bool
		admissionReports                 bool
		aggregateReports                 bool
		policyReports                    bool
		validatingAdmissionPolicyReports bool
		reportsChunkSize                 int
		backgroundScanWorkers            int
		backgroundScanInterval           time.Duration
		maxQueuedEvents                  int
		omitEvents                       string
		skipResourceFilters              bool
	)
	flagset := flag.NewFlagSet("reports-controller", flag.ExitOnError)
	flagset.BoolVar(&backgroundScan, "backgroundScan", true, "Enable or disable background scan.")
	flagset.BoolVar(&admissionReports, "admissionReports", true, "Enable or disable admission reports.")
	flagset.BoolVar(&aggregateReports, "aggregateReports", true, "Enable or disable aggregated policy reports.")
	flagset.BoolVar(&policyReports, "policyReports", true, "Enable or disable policy reports.")
	flagset.BoolVar(&validatingAdmissionPolicyReports, "validatingAdmissionPolicyReports", false, "Enable or disable validating admission policy reports.")
	flagset.IntVar(&reportsChunkSize, "reportsChunkSize", 1000, "Max number of results in generated reports, reports will be split accordingly if there are more results to be stored.")
	flagset.IntVar(&backgroundScanWorkers, "backgroundScanWorkers", backgroundscancontroller.Workers, "Configure the number of background scan workers.")
	flagset.DurationVar(&backgroundScanInterval, "backgroundScanInterval", time.Hour, "Configure background scan interval.")
	flagset.IntVar(&maxQueuedEvents, "maxQueuedEvents", 1000, "Maximum events to be queued.")
	flagset.StringVar(&omitEvents, "omit-events", "", "Set this flag to a comma separated list of PolicyViolation, PolicyApplied, PolicyError, PolicySkipped to disable events, e.g. --omit-events=PolicyApplied,PolicyViolation")
	flagset.BoolVar(&skipResourceFilters, "skipResourceFilters", true, "If true, resource filters wont be considered.")
	// config
	appConfig := internal.NewConfiguration(
		internal.WithProfiling(),
		internal.WithMetrics(),
		internal.WithTracing(),
		internal.WithKubeconfig(),
		internal.WithPolicyExceptions(),
		internal.WithConfigMapCaching(),
		internal.WithDeferredLoading(),
		internal.WithCosign(),
		internal.WithRegistryClient(),
		internal.WithImageVerifyCache(),
		internal.WithLeaderElection(),
		internal.WithKyvernoClient(),
		internal.WithDynamicClient(),
		internal.WithMetadataClient(),
		internal.WithKyvernoDynamicClient(),
		internal.WithFlagSets(flagset),
	)
	// parse flags
	internal.ParseFlags(
		appConfig,
		internal.WithDefaultQps(300),
		internal.WithDefaultBurst(300),
	)
	// setup
	ctx, setup, sdown := internal.Setup(appConfig, "kyverno-reports-controller", skipResourceFilters)
	defer sdown()
	// THIS IS AN UGLY FIX
	// ELSE KYAML IS NOT THREAD SAFE
	kyamlopenapi.Schema()
	setup.Logger.Info("background scan interval", "duration", backgroundScanInterval.String())
	// check if validating admission policies are registered in the API server
	if validatingAdmissionPolicyReports {
		groupVersion := schema.GroupVersion{Group: "admissionregistration.k8s.io", Version: "v1alpha1"}
		if _, err := setup.KyvernoDynamicClient.GetKubeClient().Discovery().ServerResourcesForGroupVersion(groupVersion.String()); err != nil {
			setup.Logger.Error(err, "validating admission policies aren't supported.")
			os.Exit(1)
		}
	}
	// informer factories
	kyvernoInformer := kyvernoinformer.NewSharedInformerFactory(setup.KyvernoClient, resyncPeriod)
	omitEventsValues := strings.Split(omitEvents, ",")
	if omitEvents == "" {
		omitEventsValues = []string{}
	}
	eventGenerator := event.NewEventGenerator(
		setup.KyvernoDynamicClient,
		kyvernoInformer.Kyverno().V1().ClusterPolicies(),
		kyvernoInformer.Kyverno().V1().Policies(),
		maxQueuedEvents,
		omitEventsValues,
		logging.WithName("EventGenerator"),
	)
	// engine
	engine := internal.NewEngine(
		ctx,
		setup.Logger,
		setup.Configuration,
		setup.MetricsConfiguration,
		setup.Jp,
		setup.KyvernoDynamicClient,
		setup.RegistryClient,
		setup.ImageVerifyCacheClient,
		setup.KubeClient,
		setup.KyvernoClient,
		setup.RegistrySecretLister,
	)
	// start informers and wait for cache sync
	if !internal.StartInformersAndWaitForCacheSync(ctx, setup.Logger, kyvernoInformer) {
		setup.Logger.Error(errors.New("failed to wait for cache sync"), "failed to wait for cache sync")
		os.Exit(1)
	}
	// start event generator
	var wg sync.WaitGroup
	go eventGenerator.Run(ctx, 3, &wg)
	// setup leader election
	le, err := leaderelection.New(
		setup.Logger.WithName("leader-election"),
		"kyverno-reports-controller",
		config.KyvernoNamespace(),
		setup.LeaderElectionClient,
		config.KyvernoPodName(),
		internal.LeaderElectionRetryPeriod(),
		func(ctx context.Context) {
			logger := setup.Logger.WithName("leader")
			// create leader factories
			kubeInformer := kubeinformers.NewSharedInformerFactory(setup.KubeClient, resyncPeriod)
			kubeKyvernoInformer := kubeinformers.NewSharedInformerFactoryWithOptions(setup.KubeClient, resyncPeriod, kubeinformers.WithNamespace(config.KyvernoNamespace()))
			kyvernoInformer := kyvernoinformer.NewSharedInformerFactory(setup.KyvernoClient, resyncPeriod)
			metadataInformer := metadatainformers.NewSharedInformerFactory(setup.MetadataClient, 15*time.Minute)
			// create leader controllers
			leaderControllers, warmup, err := createrLeaderControllers(
				engine,
				backgroundScan,
				admissionReports,
				aggregateReports,
				policyReports,
				validatingAdmissionPolicyReports,
				reportsChunkSize,
				backgroundScanWorkers,
				kubeInformer,
				kyvernoInformer,
				metadataInformer,
				setup.KyvernoClient,
				setup.KyvernoDynamicClient,
				setup.Configuration,
				setup.Jp,
				eventGenerator,
				backgroundScanInterval,
			)
			if err != nil {
				logger.Error(err, "failed to create leader controllers")
				os.Exit(1)
			}
			// start informers and wait for cache sync
			if !internal.StartInformersAndWaitForCacheSync(ctx, logger, kyvernoInformer, kubeInformer, kubeKyvernoInformer) {
				logger.Error(errors.New("failed to wait for cache sync"), "failed to wait for cache sync")
				os.Exit(1)
			}
			internal.StartInformers(ctx, metadataInformer)
			if !internal.CheckCacheSync(logger, metadataInformer.WaitForCacheSync(ctx.Done())) {
				logger.Error(errors.New("failed to wait for cache sync"), "failed to wait for cache sync")
				os.Exit(1)
			}
			if err := warmup(ctx); err != nil {
				logger.Error(err, "failed to run warmup")
				os.Exit(1)
			}
			// start leader controllers
			var wg sync.WaitGroup
			for _, controller := range leaderControllers {
				controller.Run(ctx, logger.WithName("controllers"), &wg)
			}
			// wait all controllers shut down
			wg.Wait()
		},
		nil,
	)
	if err != nil {
		setup.Logger.Error(err, "failed to initialize leader election")
		os.Exit(1)
	}
	le.Run(ctx)
	sdown()
	wg.Wait()
}