package helm

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"strings"

	"github.com/pkg/errors"
	"github.com/portainer/libhelm/options"
	"github.com/portainer/libhelm/release"
	httperror "github.com/portainer/libhttp/error"
	"github.com/portainer/libhttp/request"
	"github.com/portainer/libhttp/response"
	"github.com/portainer/portainer/api/http/middlewares"
	"github.com/portainer/portainer/api/http/security"
	"github.com/portainer/portainer/api/kubernetes"
	"github.com/portainer/portainer/api/kubernetes/validation"
	"golang.org/x/sync/errgroup"
)

type installChartPayload struct {
	Namespace string `json:"namespace"`
	Name      string `json:"name"`
	Chart     string `json:"chart"`
	Repo      string `json:"repo"`
	Values    string `json:"values"`
}

var errChartNameInvalid = errors.New("invalid chart name. " +
	"Chart name must consist of lower case alphanumeric characters, '-' or '.'," +
	" and must start and end with an alphanumeric character",
)

// @id HelmInstall
// @summary Install Helm Chart
// @description
// @description **Access policy**: authenticated
// @tags helm
// @security ApiKeyAuth
// @security jwt
// @accept json
// @produce json
// @param id path int true "Environment(Endpoint) identifier"
// @param payload body installChartPayload true "Chart details"
// @success 201 {object} release.Release "Created"
// @failure 401 "Unauthorized"
// @failure 404 "Environment(Endpoint) or ServiceAccount not found"
// @failure 500 "Server error"
// @router /endpoints/{id}/kubernetes/helm [post]
func (handler *Handler) helmInstall(w http.ResponseWriter, r *http.Request) *httperror.HandlerError {
	var payload installChartPayload
	err := request.DecodeAndValidateJSONPayload(r, &payload)
	if err != nil {
		return &httperror.HandlerError{
			StatusCode: http.StatusBadRequest,
			Message:    "Invalid Helm install payload",
			Err:        err,
		}
	}

	release, err := handler.installChart(r, payload)
	if err != nil {
		return &httperror.HandlerError{
			StatusCode: http.StatusInternalServerError,
			Message:    "Unable to install a chart",
			Err:        err,
		}
	}

	w.WriteHeader(http.StatusCreated)
	return response.JSON(w, release)
}

func (p *installChartPayload) Validate(_ *http.Request) error {
	var required []string
	if p.Repo == "" {
		required = append(required, "repo")
	}
	if p.Name == "" {
		required = append(required, "name")
	}
	if p.Namespace == "" {
		required = append(required, "namespace")
	}
	if p.Chart == "" {
		required = append(required, "chart")
	}
	if len(required) > 0 {
		return fmt.Errorf("required field(s) missing: %s", strings.Join(required, ", "))
	}

	if errs := validation.IsDNS1123Subdomain(p.Name); len(errs) > 0 {
		return errChartNameInvalid
	}

	return nil
}

func (handler *Handler) installChart(r *http.Request, p installChartPayload) (*release.Release, error) {
	clusterAccess, httperr := handler.getHelmClusterAccess(r)
	if httperr != nil {
		return nil, httperr.Err
	}
	installOpts := options.InstallOptions{
		Name:      p.Name,
		Chart:     p.Chart,
		Namespace: p.Namespace,
		Repo:      p.Repo,
		KubernetesClusterAccess: &options.KubernetesClusterAccess{
			ClusterServerURL:         clusterAccess.ClusterServerURL,
			CertificateAuthorityFile: clusterAccess.CertificateAuthorityFile,
			AuthToken:                clusterAccess.AuthToken,
		},
	}

	if p.Values != "" {
		file, err := os.CreateTemp("", "helm-values")
		if err != nil {
			return nil, err
		}
		defer os.Remove(file.Name())
		_, err = file.WriteString(p.Values)
		if err != nil {
			file.Close()
			return nil, err
		}
		err = file.Close()
		if err != nil {
			return nil, err
		}
		installOpts.ValuesFile = file.Name()
	}

	release, err := handler.helmPackageManager.Install(installOpts)
	if err != nil {
		return nil, err
	}

	manifest, err := handler.applyPortainerLabelsToHelmAppManifest(r, installOpts, release.Manifest)
	if err != nil {
		return nil, err
	}

	err = handler.updateHelmAppManifest(r, manifest, installOpts.Namespace)
	if err != nil {
		return nil, err
	}

	return release, nil
}

// applyPortainerLabelsToHelmAppManifest will patch all the resources deployed in the helm release manifest
// with portainer specific labels. This is to mark the resources as managed by portainer - hence the helm apps
// wont appear external in the portainer UI.
func (handler *Handler) applyPortainerLabelsToHelmAppManifest(r *http.Request, installOpts options.InstallOptions, manifest string) ([]byte, error) {
	// Patch helm release by adding with portainer labels to all deployed resources
	tokenData, err := security.RetrieveTokenData(r)
	if err != nil {
		return nil, errors.Wrap(err, "unable to retrieve user details from authentication token")
	}
	user, err := handler.dataStore.User().User(tokenData.ID)
	if err != nil {
		return nil, errors.Wrap(err, "unable to load user information from the database")
	}

	appLabels := kubernetes.GetHelmAppLabels(installOpts.Name, user.Username)
	labeledManifest, err := kubernetes.AddAppLabels([]byte(manifest), appLabels)
	if err != nil {
		return nil, errors.Wrap(err, "failed to label helm release manifest")
	}

	return labeledManifest, nil
}

// updateHelmAppManifest will update the resources of helm release manifest with portainer labels using kubectl.
// The resources of the manifest will be updated in parallel and individuallly since resources of a chart
// can be deployed to different namespaces.
// NOTE: These updates will need to be re-applied when upgrading the helm release
func (handler *Handler) updateHelmAppManifest(r *http.Request, manifest []byte, namespace string) error {
	endpoint, err := middlewares.FetchEndpoint(r)
	if err != nil {
		return errors.Wrap(err, "unable to find an endpoint on request context")
	}

	tokenData, err := security.RetrieveTokenData(r)
	if err != nil {
		return errors.Wrap(err, "unable to retrieve user details from authentication token")
	}

	// extract list of yaml resources from helm manifest
	yamlResources, err := kubernetes.ExtractDocuments(manifest, nil)
	if err != nil {
		return errors.Wrap(err, "unable to extract documents from helm release manifest")
	}

	// deploy individual resources in parallel
	g := new(errgroup.Group)
	for _, resource := range yamlResources {
		resource := resource // https://golang.org/doc/faq#closures_and_goroutines
		g.Go(func() error {
			tmpfile, err := ioutil.TempFile("", "helm-manifest-*")
			if err != nil {
				return errors.Wrap(err, "failed to create a tmp helm manifest file")
			}
			defer func() {
				tmpfile.Close()
				os.Remove(tmpfile.Name())
			}()

			if _, err := tmpfile.Write(resource); err != nil {
				return errors.Wrap(err, "failed to write a tmp helm manifest file")
			}

			// get resource namespace, fallback to provided namespace if not explicit on resource
			resourceNamespace, err := kubernetes.GetNamespace(resource)
			if err != nil {
				return err
			}
			if resourceNamespace == "" {
				resourceNamespace = namespace
			}

			_, err = handler.kubernetesDeployer.Deploy(tokenData.ID, endpoint, []string{tmpfile.Name()}, resourceNamespace)
			return err
		})
	}
	if err := g.Wait(); err != nil {
		return errors.Wrap(err, "unable to patch helm release using kubectl")
	}

	return nil
}