/*
Copyright 2021 The actions-runner-controller 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 (
	"context"
	"errors"
	"flag"
	"net/http"
	"os"
	"sync"
	"time"

	actionsv1alpha1 "github.com/summerwind/actions-runner-controller/api/v1alpha1"
	"github.com/summerwind/actions-runner-controller/controllers"
	"k8s.io/apimachinery/pkg/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	_ "k8s.io/client-go/plugin/pkg/client/auth/exec"
	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
	// +kubebuilder:scaffold:imports
)

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

func init() {
	_ = clientgoscheme.AddToScheme(scheme)

	_ = actionsv1alpha1.AddToScheme(scheme)
	// +kubebuilder:scaffold:scheme
}

func main() {
	var (
		err error

		webhookAddr string
		metricsAddr string

		// The secret token of the GitHub Webhook. See https://docs.github.com/en/developers/webhooks-and-events/securing-your-webhooks
		webhookSecretToken string

		watchNamespace string

		enableLeaderElection bool
		syncPeriod           time.Duration
	)

	webhookSecretToken = os.Getenv("GITHUB_WEBHOOK_SECRET_TOKEN")

	flag.StringVar(&webhookAddr, "webhook-addr", ":8000", "The address the metric endpoint binds to.")
	flag.StringVar(&metricsAddr, "metrics-addr", ":8080", "The address the metric endpoint binds to.")
	flag.StringVar(&watchNamespace, "watch-namespace", "", "The namespace to watch for HorizontalRunnerAutoscaler's to scale on Webhook. Set to empty for letting it watch for all namespaces.")
	flag.BoolVar(&enableLeaderElection, "enable-leader-election", false,
		"Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.")
	flag.DurationVar(&syncPeriod, "sync-period", 10*time.Minute, "Determines the minimum frequency at which K8s resources managed by this controller are reconciled. When you use autoscaling, set to a lower value like 10 minute, because this corresponds to the minimum time to react on demand change")
	flag.Parse()

	if webhookSecretToken == "" {
		setupLog.Info("-webhook-secret-token is missing or empty. Create one following https://docs.github.com/en/developers/webhooks-and-events/securing-your-webhooks")
	}

	if watchNamespace == "" {
		setupLog.Info("-watch-namespace is empty. HorizontalRunnerAutoscalers in all the namespaces are watched, cached, and considered as scale targets.")
	} else {
		setupLog.Info("-watch-namespace is %q. Only HorizontalRunnerAutoscalers in %q are watched, cached, and considered as scale targets.")
	}

	logger := zap.New(func(o *zap.Options) {
		o.Development = true
	})

	ctrl.SetLogger(logger)

	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
		Scheme:             scheme,
		SyncPeriod:         &syncPeriod,
		LeaderElection:     enableLeaderElection,
		Namespace:          watchNamespace,
		MetricsBindAddress: metricsAddr,
		Port:               9443,
	})
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	hraGitHubWebhook := &controllers.HorizontalRunnerAutoscalerGitHubWebhook{
		Client:         mgr.GetClient(),
		Log:            ctrl.Log.WithName("controllers").WithName("Runner"),
		Recorder:       nil,
		Scheme:         mgr.GetScheme(),
		SecretKeyBytes: []byte(webhookSecretToken),
		WatchNamespace: watchNamespace,
	}

	if err = hraGitHubWebhook.SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "Runner")
		os.Exit(1)
	}

	var wg sync.WaitGroup

	ctx, cancel := context.WithCancel(context.Background())

	wg.Add(1)
	go func() {
		defer cancel()
		defer wg.Done()

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

	mux := http.NewServeMux()
	mux.HandleFunc("/", hraGitHubWebhook.Handle)

	srv := http.Server{
		Addr:    webhookAddr,
		Handler: mux,
	}

	wg.Add(1)
	go func() {
		defer cancel()
		defer wg.Done()

		go func() {
			<-ctx.Done()

			srv.Shutdown(context.Background())
		}()

		if err := srv.ListenAndServe(); err != nil {
			if !errors.Is(err, http.ErrServerClosed) {
				setupLog.Error(err, "problem running http server")
			}
		}
	}()

	go func() {
		<-ctrl.SetupSignalHandler()
		cancel()
	}()

	wg.Wait()
}