/*
Copyright 2020 The Flux 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 main

import (
	"fmt"
	"os"
	"time"

	flag "github.com/spf13/pflag"
	"helm.sh/helm/v3/pkg/kube"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	"k8s.io/utils/ptr"
	ctrl "sigs.k8s.io/controller-runtime"
	ctrlcache "sigs.k8s.io/controller-runtime/pkg/cache"
	ctrlclient "sigs.k8s.io/controller-runtime/pkg/client"
	ctrlcfg "sigs.k8s.io/controller-runtime/pkg/config"
	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"

	"github.com/fluxcd/pkg/runtime/acl"
	"github.com/fluxcd/pkg/runtime/client"
	helper "github.com/fluxcd/pkg/runtime/controller"
	"github.com/fluxcd/pkg/runtime/events"
	feathelper "github.com/fluxcd/pkg/runtime/features"
	"github.com/fluxcd/pkg/runtime/jitter"
	"github.com/fluxcd/pkg/runtime/leaderelection"
	"github.com/fluxcd/pkg/runtime/logger"
	"github.com/fluxcd/pkg/runtime/metrics"
	"github.com/fluxcd/pkg/runtime/pprof"
	"github.com/fluxcd/pkg/runtime/probes"
	sourcev1 "github.com/fluxcd/source-controller/api/v1"
	sourcev1beta2 "github.com/fluxcd/source-controller/api/v1beta2"

	v2 "github.com/fluxcd/helm-controller/api/v2"
	intdigest "github.com/fluxcd/helm-controller/internal/digest"

	// +kubebuilder:scaffold:imports

	intacl "github.com/fluxcd/helm-controller/internal/acl"
	"github.com/fluxcd/helm-controller/internal/controller"
	"github.com/fluxcd/helm-controller/internal/features"
	intkube "github.com/fluxcd/helm-controller/internal/kube"
	"github.com/fluxcd/helm-controller/internal/oomwatch"
)

const controllerName = "helm-controller"

var (
	scheme   = runtime.NewScheme()
	setupLog = ctrl.Log.WithName("setup")
)

func init() {
	utilruntime.Must(clientgoscheme.AddToScheme(scheme))

	utilruntime.Must(sourcev1.AddToScheme(scheme))
	utilruntime.Must(sourcev1beta2.AddToScheme(scheme))
	utilruntime.Must(v2.AddToScheme(scheme))
	// +kubebuilder:scaffold:scheme
}

func main() {
	var (
		metricsAddr               string
		eventsAddr                string
		healthAddr                string
		concurrent                int
		requeueDependency         time.Duration
		gracefulShutdownTimeout   time.Duration
		httpRetry                 int
		clientOptions             client.Options
		kubeConfigOpts            client.KubeConfigOptions
		featureGates              feathelper.FeatureGates
		logOptions                logger.Options
		aclOptions                acl.Options
		leaderElectionOptions     leaderelection.Options
		rateLimiterOptions        helper.RateLimiterOptions
		watchOptions              helper.WatchOptions
		intervalJitterOptions     jitter.IntervalOptions
		oomWatchInterval          time.Duration
		oomWatchMemoryThreshold   uint8
		oomWatchMaxMemoryPath     string
		oomWatchCurrentMemoryPath string
		snapshotDigestAlgo        string
	)

	flag.StringVar(&metricsAddr, "metrics-addr", ":8080",
		"The address the metric endpoint binds to.")
	flag.StringVar(&eventsAddr, "events-addr", "",
		"The address of the events receiver.")
	flag.StringVar(&healthAddr, "health-addr", ":9440",
		"The address the health endpoint binds to.")
	flag.IntVar(&concurrent, "concurrent", 4,
		"The number of concurrent HelmRelease reconciles.")
	flag.DurationVar(&requeueDependency, "requeue-dependency", 30*time.Second,
		"The interval at which failing dependencies are reevaluated.")
	flag.DurationVar(&gracefulShutdownTimeout, "graceful-shutdown-timeout", 600*time.Second,
		"The duration given to the reconciler to finish before forcibly stopping.")
	flag.IntVar(&httpRetry, "http-retry", 9,
		"The maximum number of retries when failing to fetch artifacts over HTTP.")
	flag.StringVar(&intkube.DefaultServiceAccountName, "default-service-account", "",
		"Default service account used for impersonation.")
	flag.Uint8Var(&oomWatchMemoryThreshold, "oom-watch-memory-threshold", 95,
		"The memory threshold in percentage at which the OOM watcher will trigger a graceful shutdown. Requires feature gate 'OOMWatch' to be enabled.")
	flag.DurationVar(&oomWatchInterval, "oom-watch-interval", 500*time.Millisecond,
		"The interval at which the OOM watcher will check for memory usage. Requires feature gate 'OOMWatch' to be enabled.")
	flag.StringVar(&oomWatchMaxMemoryPath, "oom-watch-max-memory-path", "",
		"The path to the cgroup memory limit file. Requires feature gate 'OOMWatch' to be enabled. If not set, the path will be automatically detected.")
	flag.StringVar(&oomWatchCurrentMemoryPath, "oom-watch-current-memory-path", "",
		"The path to the cgroup current memory usage file. Requires feature gate 'OOMWatch' to be enabled. If not set, the path will be automatically detected.")
	flag.StringVar(&snapshotDigestAlgo, "snapshot-digest-algo", intdigest.Canonical.String(),
		"The algorithm to use to calculate the digest of Helm release storage snapshots.")

	clientOptions.BindFlags(flag.CommandLine)
	logOptions.BindFlags(flag.CommandLine)
	aclOptions.BindFlags(flag.CommandLine)
	leaderElectionOptions.BindFlags(flag.CommandLine)
	rateLimiterOptions.BindFlags(flag.CommandLine)
	kubeConfigOpts.BindFlags(flag.CommandLine)
	featureGates.BindFlags(flag.CommandLine)
	watchOptions.BindFlags(flag.CommandLine)
	intervalJitterOptions.BindFlags(flag.CommandLine)

	flag.Parse()

	logger.SetLogger(logger.NewLogger(logOptions))

	err := featureGates.WithLogger(setupLog).
		SupportedFeatures(features.FeatureGates())
	if err != nil {
		setupLog.Error(err, "unable to load feature gates")
		os.Exit(1)
	}

	if err := intervalJitterOptions.SetGlobalJitter(nil); err != nil {
		setupLog.Error(err, "unable to set global jitter")
		os.Exit(1)
	}

	watchNamespace := ""
	if !watchOptions.AllNamespaces {
		watchNamespace = os.Getenv("RUNTIME_NAMESPACE")
	}

	watchSelector, err := helper.GetWatchSelector(watchOptions)
	if err != nil {
		setupLog.Error(err, "unable to configure watch label selector for manager")
		os.Exit(1)
	}

	var disableCacheFor []ctrlclient.Object
	shouldCache, err := features.Enabled(features.CacheSecretsAndConfigMaps)
	if err != nil {
		setupLog.Error(err, "unable to check feature gate CacheSecretsAndConfigMaps")
		os.Exit(1)
	}
	if !shouldCache {
		disableCacheFor = append(disableCacheFor, &corev1.Secret{}, &corev1.ConfigMap{})
	}

	leaderElectionId := fmt.Sprintf("%s-%s", controllerName, "leader-election")
	if watchOptions.LabelSelector != "" {
		leaderElectionId = leaderelection.GenerateID(leaderElectionId, watchOptions.LabelSelector)
	}

	// Set the managedFields owner for resources reconciled from Helm charts.
	kube.ManagedFieldsManager = controllerName

	// Configure the ACL policy.
	intacl.AllowCrossNamespaceRef = !aclOptions.NoCrossNamespaceRefs

	// Configure the digest algorithm.
	if snapshotDigestAlgo != intdigest.Canonical.String() {
		algo, err := intdigest.AlgorithmForName(snapshotDigestAlgo)
		if err != nil {
			setupLog.Error(err, "unable to configure canonical digest algorithm")
			os.Exit(1)
		}
		intdigest.Canonical = algo
	}

	restConfig := client.GetConfigOrDie(clientOptions)

	mgrConfig := ctrl.Options{
		Scheme:                        scheme,
		HealthProbeBindAddress:        healthAddr,
		LeaderElection:                leaderElectionOptions.Enable,
		LeaderElectionReleaseOnCancel: leaderElectionOptions.ReleaseOnCancel,
		LeaseDuration:                 &leaderElectionOptions.LeaseDuration,
		RenewDeadline:                 &leaderElectionOptions.RenewDeadline,
		RetryPeriod:                   &leaderElectionOptions.RetryPeriod,
		GracefulShutdownTimeout:       &gracefulShutdownTimeout,
		LeaderElectionID:              leaderElectionId,
		Logger:                        ctrl.Log,
		Client: ctrlclient.Options{
			Cache: &ctrlclient.CacheOptions{
				DisableFor: disableCacheFor,
			},
		},
		Cache: ctrlcache.Options{
			ByObject: map[ctrlclient.Object]ctrlcache.ByObject{
				&v2.HelmRelease{}: {Label: watchSelector},
			},
		},
		Controller: ctrlcfg.Controller{
			RecoverPanic:            ptr.To(true),
			MaxConcurrentReconciles: concurrent,
		},
		Metrics: metricsserver.Options{
			BindAddress:   metricsAddr,
			ExtraHandlers: pprof.GetHandlers(),
		},
	}

	if watchNamespace != "" {
		mgrConfig.Cache.DefaultNamespaces = map[string]ctrlcache.Config{
			watchNamespace: ctrlcache.Config{},
		}
	}

	mgr, err := ctrl.NewManager(restConfig, mgrConfig)
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	probes.SetupChecks(mgr, setupLog)

	metricsH := helper.NewMetrics(mgr, metrics.MustMakeRecorder(), v2.HelmReleaseFinalizer)
	var eventRecorder *events.Recorder
	if eventRecorder, err = events.NewRecorder(mgr, ctrl.Log, eventsAddr, controllerName); err != nil {
		setupLog.Error(err, "unable to create event recorder")
		os.Exit(1)
	}

	ctx := ctrl.SetupSignalHandler()
	if ok, _ := features.Enabled(features.OOMWatch); ok {
		setupLog.Info("setting up OOM watcher")
		ow, err := oomwatch.New(
			oomWatchMaxMemoryPath,
			oomWatchCurrentMemoryPath,
			oomWatchMemoryThreshold,
			oomWatchInterval,
			ctrl.Log.WithName("OOMwatch"),
		)
		if err != nil {
			setupLog.Error(err, "unable to setup OOM watcher")
			os.Exit(1)
		}
		ctx = ow.Watch(ctx)
	}

	if err = (&controller.HelmReleaseReconciler{
		Client:           mgr.GetClient(),
		APIReader:        mgr.GetAPIReader(),
		EventRecorder:    eventRecorder,
		Metrics:          metricsH,
		GetClusterConfig: ctrl.GetConfig,
		ClientOpts:       clientOptions,
		KubeConfigOpts:   kubeConfigOpts,
		FieldManager:     controllerName,
	}).SetupWithManager(ctx, mgr, controller.HelmReleaseReconcilerOptions{
		DependencyRequeueInterval: requeueDependency,
		HTTPRetry:                 httpRetry,
		RateLimiter:               helper.GetRateLimiter(rateLimiterOptions),
	}); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", v2.HelmReleaseKind)
		os.Exit(1)
	}
	// +kubebuilder:scaffold:builder

	setupLog.Info("starting manager")
	if err := mgr.Start(ctx); err != nil {
		setupLog.Error(err, "problem running manager")
		os.Exit(1)
	}
}