/*
MIT License

Copyright (c) 2020-2024 1Password

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

package main

import (
	"context"
	"crypto/tls"
	"errors"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"time"

	// Import all Kubernetes client auth plugins (e.g. Azure, GCP, OIDC, etc.)
	// to ensure that exec-entrypoint and run can make use of them.
	_ "k8s.io/client-go/plugin/pkg/client/auth"

	k8sruntime "k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	"k8s.io/client-go/rest"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/cache"
	"sigs.k8s.io/controller-runtime/pkg/certwatcher"
	"sigs.k8s.io/controller-runtime/pkg/healthz"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
	"sigs.k8s.io/controller-runtime/pkg/metrics/filters"
	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
	"sigs.k8s.io/controller-runtime/pkg/webhook"

	onepasswordcomv1 "github.com/1Password/onepassword-operator/api/v1"
	"github.com/1Password/onepassword-operator/internal/controller"
	op "github.com/1Password/onepassword-operator/pkg/onepassword"
	opclient "github.com/1Password/onepassword-operator/pkg/onepassword/client"
	"github.com/1Password/onepassword-operator/pkg/utils"
	"github.com/1Password/onepassword-operator/version"
	// +kubebuilder:scaffold:imports
)

var (
	scheme   = k8sruntime.NewScheme()
	setupLog = ctrl.Log.WithName("setup")
)

const (
	envPollingIntervalVariable    = "POLLING_INTERVAL"
	manageConnect                 = "MANAGE_CONNECT"
	restartDeploymentsEnvVariable = "AUTO_RESTART"
	defaultPollingInterval        = 600

	annotationRegExpString = "^operator.1password.io\\/[a-zA-Z\\.]+"
)

func printVersion() {
	setupLog.Info(fmt.Sprintf("Operator Version: %s", version.OperatorVersion))
	setupLog.Info(fmt.Sprintf("Go Version: %s", runtime.Version()))
	setupLog.Info(fmt.Sprintf("Go OS/Arch: %s/%s", runtime.GOOS, runtime.GOARCH))
	setupLog.Info(fmt.Sprintf("Version of operator-sdk: %v", version.OperatorSDKVersion))
}

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

	utilruntime.Must(onepasswordcomv1.AddToScheme(scheme))
	// +kubebuilder:scaffold:scheme
}

func main() {
	var metricsAddr string
	var metricsCertPath, metricsCertName, metricsCertKey string
	var webhookCertPath, webhookCertName, webhookCertKey string
	var enableLeaderElection bool
	var probeAddr string
	var secureMetrics bool
	var enableHTTP2 bool
	var tlsOpts []func(*tls.Config)
	flag.StringVar(&metricsAddr, "metrics-bind-address", "8080",
		"The address the metrics endpoint binds to. "+
			"Use :8443 for HTTPS or :8080 for HTTP, or leave as 0 to disable the metrics service.")
	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081",
		"The address the probe endpoint binds to.")
	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
		"Enable leader election for controller manager. "+
			"Enabling this will ensure there is only one active controller manager.")
	flag.BoolVar(&secureMetrics, "metrics-secure", true,
		"If set, the metrics endpoint is served securely via HTTPS. Use --metrics-secure=false to use HTTP instead.")
	flag.StringVar(&metricsCertPath, "metrics-cert-path", "",
		"The directory that contains the metrics server certificate.")
	flag.StringVar(&metricsCertName, "metrics-cert-name", "tls.crt",
		"The name of the metrics server certificate file.")
	flag.StringVar(&metricsCertKey, "metrics-cert-key", "tls.key",
		"The name of the metrics server key file.")
	flag.BoolVar(&enableHTTP2, "enable-http2", false,
		"If set, HTTP/2 will be enabled for the metrics")
	opts := zap.Options{
		Development: true,
	}
	opts.BindFlags(flag.CommandLine)
	flag.Parse()

	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))

	// if the enable-http2 flag is false (the default), http/2 should be disabled
	// due to its vulnerabilities. More specifically, disabling http/2 will
	// prevent from being vulnerable to the HTTP/2 Stream Cancelation and
	// Rapid Reset CVEs. For more information see:
	// - https://github.com/advisories/GHSA-qppj-fm5r-hxr3
	// - https://github.com/advisories/GHSA-4374-p667-p6c8
	disableHTTP2 := func(c *tls.Config) {
		setupLog.Info("disabling http/2")
		c.NextProtos = []string{"http/1.1"}
	}

	if !enableHTTP2 {
		tlsOpts = append(tlsOpts, disableHTTP2)
	}

	printVersion()

	// Create a root context that will be cancelled on termination signals
	ctx := ctrl.SetupSignalHandler()

	watchNamespace, err := getWatchNamespace()
	if err != nil {
		setupLog.Error(err, "unable to get WatchNamespace, "+
			"the manager will watch and manage resources in all namespaces")
	}

	deploymentNamespace, err := utils.GetOperatorNamespace()
	if err != nil {
		setupLog.Error(err, "Failed to get namespace")
		os.Exit(1)
	}

	// Create watchers for metrics and webhooks certificates
	var metricsCertWatcher, webhookCertWatcher *certwatcher.CertWatcher

	// Initial webhook TLS options
	webhookTLSOpts := tlsOpts

	if len(webhookCertPath) > 0 {
		setupLog.Info("Initializing webhook certificate watcher using provided certificates",
			"webhook-cert-path", webhookCertPath, "webhook-cert-name", webhookCertName, "webhook-cert-key", webhookCertKey)

		var err error
		webhookCertWatcher, err = certwatcher.New(
			filepath.Join(webhookCertPath, webhookCertName),
			filepath.Join(webhookCertPath, webhookCertKey),
		)
		if err != nil {
			setupLog.Error(err, "Failed to initialize webhook certificate watcher")
			os.Exit(1)
		}

		webhookTLSOpts = append(webhookTLSOpts, func(config *tls.Config) {
			config.GetCertificate = webhookCertWatcher.GetCertificate
		})
	}

	webhookServer := webhook.NewServer(webhook.Options{
		TLSOpts: webhookTLSOpts,
	})

	// Metrics endpoint is enabled in 'config/default/kustomization.yaml'. The Metrics options configure the server.
	// More info:
	// - https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.21.0/pkg/metrics/server
	// - https://book.kubebuilder.io/reference/metrics.html
	metricsServerOptions := metricsserver.Options{
		BindAddress:   metricsAddr,
		SecureServing: secureMetrics,
		// TODO(user): TLSOpts is used to allow configuring the TLS config used for the server. If certificates are
		// not provided, self-signed certificates will be generated by default. This option is not recommended for
		// production environments as self-signed certificates do not offer the same level of trust and security
		// as certificates issued by a trusted Certificate Authority (CA). The primary risk is potentially allowing
		// unauthorized access to sensitive metrics data. Consider replacing with CertDir, CertName, and KeyName
		// to provide certificates, ensuring the server communicates using trusted and secure certificates.
		TLSOpts: tlsOpts,
	}

	if secureMetrics {
		// FilterProvider is used to protect the metrics endpoint with authn/authz.
		// These configurations ensure that only authorized users and service accounts
		// can access the metrics endpoint. The RBAC are configured in 'config/rbac/kustomization.yaml'. More info:
		// https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.19.0/pkg/metrics/filters#WithAuthenticationAndAuthorization
		metricsServerOptions.FilterProvider = filters.WithAuthenticationAndAuthorization
	}

	// If the certificate is not specified, controller-runtime will automatically
	// generate self-signed certificates for the metrics server. While convenient for development and testing,
	// this setup is not recommended for production.
	//
	// TODO(user): If you enable certManager, uncomment the following lines:
	// - [METRICS-WITH-CERTS] at config/default/kustomization.yaml to generate and use certificates
	// managed by cert-manager for the metrics server.
	// - [PROMETHEUS-WITH-CERTS] at config/prometheus/kustomization.yaml for TLS certification.
	if len(metricsCertPath) > 0 {
		setupLog.Info("Initializing metrics certificate watcher using provided certificates",
			"metrics-cert-path", metricsCertPath, "metrics-cert-name", metricsCertName, "metrics-cert-key", metricsCertKey)

		var err error
		metricsCertWatcher, err = certwatcher.New(
			filepath.Join(metricsCertPath, metricsCertName),
			filepath.Join(metricsCertPath, metricsCertKey),
		)
		if err != nil {
			setupLog.Error(err, "Failed to initialize metrics certificate watcher")
			os.Exit(1)
		}

		metricsServerOptions.TLSOpts = append(metricsServerOptions.TLSOpts, func(config *tls.Config) {
			config.GetCertificate = metricsCertWatcher.GetCertificate
		})
	}

	options := ctrl.Options{
		Scheme:                 scheme,
		Metrics:                metricsServerOptions,
		WebhookServer:          webhookServer,
		HealthProbeBindAddress: probeAddr,
		LeaderElection:         enableLeaderElection,
		LeaderElectionID:       "c26807fd.onepassword.com",
		// LeaderElectionReleaseOnCancel defines if the leader should step down voluntarily
		// when the Manager ends. This requires the binary to immediately end when the
		// Manager is stopped, otherwise, this setting is unsafe. Setting this significantly
		// speeds up voluntary leader transitions as the new leader don't have to wait
		// LeaseDuration time first.
		//
		// In the default scaffold provided, the program ends immediately after
		// the manager stops, so would be fine to enable this option. However,
		// if you are doing or is intended to do any operation such as perform cleanups
		// after the manager stops then its usage might be unsafe.
		// LeaderElectionReleaseOnCancel: true,
	}

	// Add support for MultiNamespace set in WATCH_NAMESPACE (e.g ns1,ns2)
	if watchNamespace != "" {
		namespaces := strings.Split(watchNamespace, ",")
		namespaceMap := make(map[string]cache.Config)
		for _, namespace := range namespaces {
			namespaceMap[namespace] = cache.Config{}
		}
		options.NewCache = func(config *rest.Config, opts cache.Options) (cache.Cache, error) {
			opts.DefaultNamespaces = namespaceMap
			return cache.New(config, opts)
		}
	}

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

	// Setup One Password Client
	opClient, err := opclient.NewFromEnvironment(ctx, opclient.Config{
		Logger:  setupLog,
		Version: version.OperatorVersion,
	})
	if err != nil {
		setupLog.Error(err, "unable to create 1Password client")
		os.Exit(1)
	}

	if err = (&controller.OnePasswordItemReconciler{
		Client:   mgr.GetClient(),
		Scheme:   mgr.GetScheme(),
		OpClient: opClient,
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "OnePasswordItem")
		os.Exit(1)
	}

	r, _ := regexp.Compile(annotationRegExpString)
	if err = (&controller.DeploymentReconciler{
		Client:             mgr.GetClient(),
		Scheme:             mgr.GetScheme(),
		OpClient:           opClient,
		OpAnnotationRegExp: r,
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "Deployment")
		os.Exit(1)
	}
	// +kubebuilder:scaffold:builder

	// Setup 1PasswordConnect
	if shouldManageConnect() {
		setupLog.Info("Automated Connect Management Enabled")
		go func(ctx context.Context) {
			connectStarted := false
			for !connectStarted {
				err := op.SetupConnect(ctx, mgr.GetClient(), deploymentNamespace)
				// Cache Not Started is an acceptable error. Retry until cache is started.
				if err != nil && !errors.Is(err, &cache.ErrCacheNotStarted{}) {
					setupLog.Error(err, "")
					os.Exit(1)
				}
				if err == nil {
					connectStarted = true
				}
			}
		}(ctx)
	} else {
		setupLog.Info("Automated Connect Management Disabled")
	}

	// Setup update secrets task
	updatedSecretsPoller := op.NewManager(mgr.GetClient(), opClient, shouldAutoRestartDeployments())
	done := make(chan bool)
	ticker := time.NewTicker(getPollingIntervalForUpdatingSecrets())
	go func(ctx context.Context) {
		for {
			select {
			case <-done:
				ticker.Stop()
				return
			case <-ticker.C:
				err := updatedSecretsPoller.UpdateKubernetesSecretsTask(ctx)
				if err != nil {
					setupLog.Error(err, "error running update kubernetes secret task")
				}
			}
		}
	}(ctx)

	if metricsCertWatcher != nil {
		setupLog.Info("Adding metrics certificate watcher to manager")
		if err := mgr.Add(metricsCertWatcher); err != nil {
			setupLog.Error(err, "Unable to add metrics certificate watcher to manager")
			os.Exit(1)
		}
	}

	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {
		setupLog.Error(err, "unable to set up health check")
		os.Exit(1)
	}
	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
		setupLog.Error(err, "unable to set up ready check")
		os.Exit(1)
	}

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

// getWatchNamespace returns the Namespace the operator should be watching for changes
func getWatchNamespace() (string, error) {
	// WatchNamespaceEnvVar is the constant for env variable WATCH_NAMESPACE
	// which specifies the Namespace to watch.
	// An empty value means the operator is running with cluster scope.
	var watchNamespaceEnvVar = "WATCH_NAMESPACE"

	ns, found := os.LookupEnv(watchNamespaceEnvVar)
	if !found {
		return "", fmt.Errorf("%s must be set", watchNamespaceEnvVar)
	}
	return ns, nil
}

func shouldManageConnect() bool {
	shouldManageConnect, found := os.LookupEnv(manageConnect)
	if found {
		shouldManageConnectBool, err := strconv.ParseBool(strings.ToLower(shouldManageConnect))
		if err != nil {
			setupLog.Error(err, "")
			os.Exit(1)
		}
		return shouldManageConnectBool
	}
	return false
}

func shouldAutoRestartDeployments() bool {
	shouldAutoRestartDeployments, found := os.LookupEnv(restartDeploymentsEnvVariable)
	if found {
		shouldAutoRestartDeploymentsBool, err := strconv.ParseBool(strings.ToLower(shouldAutoRestartDeployments))
		if err != nil {
			setupLog.Error(err, "")
			os.Exit(1)
		}
		return shouldAutoRestartDeploymentsBool
	}
	return false
}

func getPollingIntervalForUpdatingSecrets() time.Duration {
	timeInSecondsString, found := os.LookupEnv(envPollingIntervalVariable)
	if found {
		timeInSeconds, err := strconv.Atoi(timeInSecondsString)
		if err == nil {
			return time.Duration(timeInSeconds) * time.Second
		}
		setupLog.Info("Invalid value set for polling interval. Must be a valid integer.")
	}

	setupLog.Info(fmt.Sprintf("Using default polling interval of %v seconds", defaultPollingInterval))
	return time.Duration(defaultPollingInterval) * time.Second
}