/*
Copyright 2020 The Flux CD contributors.

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 controllers

import (
	"context"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"
	"time"

	sourcev1 "github.com/fluxcd/source-controller/api/v1alpha1"
	"github.com/go-logr/logr"
	"helm.sh/helm/v3/pkg/action"
	"helm.sh/helm/v3/pkg/chart"
	"helm.sh/helm/v3/pkg/chart/loader"
	"helm.sh/helm/v3/pkg/release"
	"helm.sh/helm/v3/pkg/storage/driver"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/client-go/rest"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"

	"github.com/fluxcd/pkg/lockedfile"

	v2 "github.com/fluxcd/helm-controller/api/v2alpha1"
)

// HelmReleaseReconciler reconciles a HelmRelease object
type HelmReleaseReconciler struct {
	client.Client
	Config *rest.Config
	Log    logr.Logger
	Scheme *runtime.Scheme
}

// +kubebuilder:rbac:groups=helm.fluxcd.io,resources=helmreleases,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=helm.fluxcd.io,resources=helmreleases/status,verbs=get;update;patch

func (r *HelmReleaseReconciler) Reconcile(req ctrl.Request) (ctrl.Result, error) {
	ctx := context.Background()
	start := time.Now()

	var hr v2.HelmRelease
	if err := r.Get(ctx, req.NamespacedName, &hr); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	log := r.Log.WithValues(strings.ToLower(hr.Kind), req.NamespacedName)

	hr = v2.HelmReleaseProgressing(hr)
	if err := r.Status().Update(ctx, &hr); err != nil {
		log.Error(err, "unable to update HelmRelease status")
		return ctrl.Result{Requeue: true}, err
	}

	// Get the artifact
	var source sourcev1.Source
	switch hr.Spec.SourceRef.Kind {
	case "HelmChart":
		var helmChart sourcev1.HelmChart
		chartName := types.NamespacedName{
			Namespace: hr.GetNamespace(),
			Name:      hr.Spec.SourceRef.Name,
		}
		err := r.Client.Get(ctx, chartName, &helmChart)
		if err != nil {
			log.Error(err, "HelmChart not found", "helmchart", chartName)
			return ctrl.Result{Requeue: true}, err
		}
		source = &helmChart
	default:
		err := fmt.Errorf("source '%s' kind '%s' not supported", hr.Spec.SourceRef.Name, hr.Spec.SourceRef.Kind)
		return ctrl.Result{}, err
	}

	// Check source readiness
	if source.GetArtifact() == nil {
		msg := "Source is not ready"
		hr = v2.HelmReleaseNotReady(hr, v2.ArtifactFailedReason, msg)
		if err := r.Status().Update(ctx, &hr); err != nil {
			log.Error(err, "unable to update HelmRelease status")
			return ctrl.Result{Requeue: true}, err
		}
		log.Info(msg)
		return ctrl.Result{}, nil
	}

	reconciledHr, err := r.release(log, hr, source)
	if err != nil {
		log.Error(err, "HelmRelease reconciliation failed", "revision", source.GetArtifact().Revision)
	}

	if err := r.Status().Update(ctx, &reconciledHr); err != nil {
		log.Error(err, "unable to update HelmRelease status after reconciliation")
		return ctrl.Result{Requeue: true}, err
	}

	// Log reconciliation duration
	log.Info(fmt.Sprintf("HelmRelease reconcilation finished in %s, next run in %s",
		time.Now().Sub(start).String(),
		hr.Spec.Interval.Duration.String(),
	))

	return ctrl.Result{RequeueAfter: hr.Spec.Interval.Duration}, nil
}

type HelmReleaseReconcilerOptions struct {
	MaxConcurrentReconciles int
}

func (r *HelmReleaseReconciler) SetupWithManager(mgr ctrl.Manager, opts HelmReleaseReconcilerOptions) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&v2.HelmRelease{}).
		WithEventFilter(HelmReleaseReconcileAtPredicate{}).
		WithOptions(controller.Options{MaxConcurrentReconciles: opts.MaxConcurrentReconciles}).
		Complete(r)
}

func (r *HelmReleaseReconciler) release(log logr.Logger, hr v2.HelmRelease, source sourcev1.Source) (v2.HelmRelease, error) {
	// Acquire lock
	unlock, err := r.lock(fmt.Sprintf("%s-%s", hr.GetName(), hr.GetNamespace()))
	if err != nil {
		err = fmt.Errorf("tmp dir error: %w", err)
		return v2.HelmReleaseNotReady(hr, sourcev1.StorageOperationFailedReason, err.Error()), err
	}
	defer unlock()

	// Create temp working dir
	tmpDir, err := ioutil.TempDir("", hr.Name)
	if err != nil {
		err = fmt.Errorf("tmp dir error: %w", err)
	}
	defer os.RemoveAll(tmpDir)

	// Download artifact
	artifactPath, err := r.download(source.GetArtifact().URL, tmpDir)
	if err != nil {
		return v2.HelmReleaseNotReady(hr, v2.ArtifactFailedReason, "artifact acquisition failed"), err
	}

	// Load chart
	loadedChart, err := loader.Load(artifactPath)
	if err != nil {
		return v2.HelmReleaseNotReady(hr, v2.ArtifactFailedReason, "failed to load chart"), err
	}

	// Initialize config
	cfg, err := r.newActionCfg(log, hr)
	if err != nil {
		return v2.HelmReleaseNotReady(hr, v2.InitFailedReason, "failed to initialize Helm action configuration"), err
	}

	// Get the current release
	rel, err := cfg.Releases.Deployed(hr.Name)
	if err != nil && !errors.Is(err, driver.ErrNoDeployedReleases) {
		return v2.HelmReleaseNotReady(hr, v2.InitFailedReason, "failed to determine if release exists"), err
	}

	// Install or upgrade the release
	success := true
	if errors.Is(err, driver.ErrNoDeployedReleases) {
		if rel, err = r.install(cfg, loadedChart, hr); err != nil {
			success = false
			v2.SetHelmReleaseCondition(&hr, v2.InstallCondition, corev1.ConditionFalse, v2.InstallFailedReason, err.Error())
		} else {
			v2.SetHelmReleaseCondition(&hr, v2.InstallCondition, corev1.ConditionTrue, v2.InstallSucceededReason, "Helm installation succeeded")
		}
	} else if r.shouldUpgrade(&hr, source, rel) {
		if rel, err = r.upgrade(cfg, loadedChart, hr); err != nil {
			success = false
			v2.SetHelmReleaseCondition(&hr, v2.UpgradeCondition, corev1.ConditionFalse, v2.UpgradeFailedReason, err.Error())
		} else {
			v2.SetHelmReleaseCondition(&hr, v2.UpgradeCondition, corev1.ConditionTrue, v2.UpgradeSucceededReason, "Helm upgrade succeeded")
		}
	}

	// Run tests
	if r.shouldTest(&hr) {
		if rel, err = r.test(cfg, hr); err != nil {
			v2.SetHelmReleaseCondition(&hr, v2.TestCondition, corev1.ConditionFalse, v2.TestFailedReason, err.Error())
		} else {
			v2.SetHelmReleaseCondition(&hr, v2.TestCondition, corev1.ConditionTrue, v2.TestSucceededReason, "Helm test succeeded")
		}
	}

	// Run rollback
	if r.shouldRollback(&hr) {
		success = false
		if err = r.rollback(cfg, hr); err != nil {
			v2.SetHelmReleaseCondition(&hr, v2.RollbackCondition, corev1.ConditionFalse, v2.RollbackFailedReason, err.Error())
		} else {
			v2.SetHelmReleaseCondition(&hr, v2.RollbackCondition, corev1.ConditionTrue, v2.RollbackSucceededReason, "Helm rollback succeeded")
		}
	}

	// Run uninstall
	if r.shouldUninstall(&hr) {
		if err = r.uninstall(cfg, hr); err != nil {
			v2.SetHelmReleaseCondition(&hr, v2.UninstallCondition, corev1.ConditionFalse, v2.UninstallFailedReason, err.Error())
		} else {
			v2.SetHelmReleaseCondition(&hr, v2.UninstallCondition, corev1.ConditionTrue, v2.UninstallSucceededReason, "Helm uninstall succeeded")
		}
	}

	if !success {
		return v2.HelmReleaseNotReady(hr, v2.ReconciliationFailedReason, "release reconciliation failed"), err
	}
	return v2.HelmReleaseReady(hr, source.GetArtifact().Revision, rel.Version, v2.ReconciliationSucceededReason, "release reconciliation succeeded"), nil
}

func (r *HelmReleaseReconciler) install(cfg *action.Configuration, chart *chart.Chart, hr v2.HelmRelease) (*release.Release, error) {
	install := action.NewInstall(cfg)
	install.ReleaseName = hr.Name
	install.Namespace = hr.Namespace

	return install.Run(chart, hr.GetValues())
}

func (r *HelmReleaseReconciler) upgrade(cfg *action.Configuration, chart *chart.Chart, hr v2.HelmRelease) (*release.Release, error) {
	upgrade := action.NewUpgrade(cfg)
	upgrade.Namespace = hr.Namespace
	// TODO(hidde): make this configurable
	upgrade.ResetValues = true

	return upgrade.Run(hr.Name, chart, hr.GetValues())
}

func (r *HelmReleaseReconciler) test(cfg *action.Configuration, hr v2.HelmRelease) (*release.Release, error) {
	test := action.NewReleaseTesting(cfg)
	test.Namespace = hr.Namespace
	test.Timeout = hr.Spec.Test.GetTimeout(hr.GetTimeout()).Duration

	return test.Run(hr.Name)
}

func (r *HelmReleaseReconciler) rollback(cfg *action.Configuration, hr v2.HelmRelease) error {
	rollback := action.NewRollback(cfg)
	rollback.Timeout = hr.Spec.Rollback.GetTimeout(hr.GetTimeout()).Duration

	return rollback.Run(hr.Name)
}

func (r *HelmReleaseReconciler) uninstall(cfg *action.Configuration, hr v2.HelmRelease) error {
	uninstall := action.NewUninstall(cfg)
	_, err := uninstall.Run(hr.Name)
	return err
}

func (r *HelmReleaseReconciler) shouldUpgrade(hr *v2.HelmRelease, source sourcev1.Source, rel *release.Release) bool {
	switch {
	case hr.Status.LatestAppliedRevision != source.GetArtifact().Revision:
		return true
	case hr.Status.LatestReleaseRevision != rel.Version:
		return true
	case hr.Generation != hr.Status.ObservedGeneration:
		return true
	default:
		return false
	}
}

func (r *HelmReleaseReconciler) shouldTest(hr *v2.HelmRelease) bool {
	if !hr.Spec.Test.Enable {
		return false
	}
	for _, c := range hr.Spec.Test.GetOnConditions() {
		for i := len(hr.Status.Conditions) - 1; i >= 0; i-- {
			if hr.Status.Conditions[i].Type == c.Type && hr.Status.Conditions[i].Status == c.Status {
				return true
			}
		}
	}
	return false
}

func (r *HelmReleaseReconciler) shouldRollback(hr *v2.HelmRelease) bool {
	if !hr.Spec.Rollback.Enable {
		return false
	}
	for _, c := range hr.Spec.Rollback.GetOnConditions() {
		for i := len(hr.Status.Conditions) - 1; i >= 0; i-- {
			if hr.Status.Conditions[i].Type == c.Type && hr.Status.Conditions[i].Status == c.Status {
				return true
			}
		}
	}
	return false
}

func (r *HelmReleaseReconciler) shouldUninstall(hr *v2.HelmRelease) bool {
	for _, c := range hr.Spec.Uninstall.GetOnConditions() {
		for i := len(hr.Status.Conditions) - 1; i >= 0; i-- {
			if hr.Status.Conditions[i].Type == c.Type && hr.Status.Conditions[i].Status == c.Status {
				return true
			}
		}
	}
	return false
}

func (r *HelmReleaseReconciler) lock(name string) (unlock func(), err error) {
	lockFile := path.Join(os.TempDir(), name+".lock")
	mutex := lockedfile.MutexAt(lockFile)
	return mutex.Lock()
}

func (r *HelmReleaseReconciler) download(url, tmpDir string) (string, error) {
	fp := filepath.Join(tmpDir, "artifact.tar.gz")
	out, err := os.Create(fp)
	if err != nil {
		return "", err
	}
	defer out.Close()

	resp, err := http.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fp, fmt.Errorf("artifact '%s' download failed (status code: %s)", url, resp.Status)
	}

	if _, err = io.Copy(out, resp.Body); err != nil {
		return "", err
	}

	return fp, nil
}

func (r *HelmReleaseReconciler) newActionCfg(log logr.Logger, hr v2.HelmRelease) (*action.Configuration, error) {
	cfg := new(action.Configuration)
	// TODO(hidde): write our own init
	err := cfg.Init(&genericclioptions.ConfigFlags{
		Namespace:   &hr.Namespace,
		APIServer:   &r.Config.Host,
		CAFile:      &r.Config.CAFile,
		BearerToken: &r.Config.BearerToken,
	}, hr.Namespace, "secret", actionLogger(log))
	return cfg, err
}

func actionLogger(logger logr.Logger) func(format string, v ...interface{}) {
	return func(format string, v ...interface{}) {
		logger.Info(fmt.Sprintf(format, v...))
	}
}