/*
Copyright The Helm 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 action

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"maps"
	"os"
	"path"
	"path/filepath"
	"slices"
	"strings"
	"sync"
	"text/template"
	"time"

	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/client-go/discovery"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
	"sigs.k8s.io/kustomize/kyaml/kio"
	kyaml "sigs.k8s.io/kustomize/kyaml/yaml"

	"helm.sh/helm/v4/internal/logging"
	"helm.sh/helm/v4/pkg/chart/common"
	chart "helm.sh/helm/v4/pkg/chart/v2"
	chartutil "helm.sh/helm/v4/pkg/chart/v2/util"
	"helm.sh/helm/v4/pkg/engine"
	"helm.sh/helm/v4/pkg/kube"
	"helm.sh/helm/v4/pkg/postrenderer"
	"helm.sh/helm/v4/pkg/registry"
	ri "helm.sh/helm/v4/pkg/release"
	release "helm.sh/helm/v4/pkg/release/v1"
	releaseutil "helm.sh/helm/v4/pkg/release/v1/util"
	"helm.sh/helm/v4/pkg/storage"
	"helm.sh/helm/v4/pkg/storage/driver"
)

// Timestamper is a function capable of producing a timestamp.Timestamper.
//
// By default, this is a time.Time function from the Helm time package. This can
// be overridden for testing though, so that timestamps are predictable.
var Timestamper = time.Now

var (
	// errMissingChart indicates that a chart was not provided.
	errMissingChart = errors.New("no chart provided")
	// errMissingRelease indicates that a release (name) was not provided.
	errMissingRelease = errors.New("no release provided")
	// errInvalidRevision indicates that an invalid release revision number was provided.
	errInvalidRevision = errors.New("invalid release revision")
	// errPending indicates that another instance of Helm is already applying an operation on a release.
	errPending = errors.New("another operation (install/upgrade/rollback) is in progress")
)

type DryRunStrategy string

const (
	// DryRunNone indicates the client will make all mutating calls
	DryRunNone DryRunStrategy = "none"

	// DryRunClient, or client-side dry-run, indicates the client will avoid
	// making calls to the server
	DryRunClient DryRunStrategy = "client"

	// DryRunServer, or server-side dry-run, indicates the client will send
	// calls to the APIServer with the dry-run parameter to prevent persisting changes
	DryRunServer DryRunStrategy = "server"
)

// Configuration injects the dependencies that all actions share.
type Configuration struct {
	// RESTClientGetter is an interface that loads Kubernetes clients.
	RESTClientGetter RESTClientGetter

	// Releases stores records of releases.
	Releases *storage.Storage

	// KubeClient is a Kubernetes API client.
	KubeClient kube.Interface

	// RegistryClient is a client for working with registries
	RegistryClient *registry.Client

	// Capabilities describes the capabilities of the Kubernetes cluster.
	Capabilities *common.Capabilities

	// CustomTemplateFuncs is defined by users to provide custom template funcs
	CustomTemplateFuncs template.FuncMap

	// HookOutputFunc called with container name and returns and expects writer that will receive the log output.
	HookOutputFunc func(namespace, pod, container string) io.Writer

	// Mutex is an exclusive lock for concurrent access to the action
	mutex sync.Mutex

	// Embed a LogHolder to provide logger functionality
	logging.LogHolder
}

type ConfigurationOption func(c *Configuration)

// Override the default logging handler
// If unspecified, the default logger will be used
func ConfigurationSetLogger(h slog.Handler) ConfigurationOption {
	return func(c *Configuration) {
		c.SetLogger(h)
	}
}

func NewConfiguration(options ...ConfigurationOption) *Configuration {
	c := &Configuration{}
	c.SetLogger(slog.Default().Handler())

	for _, o := range options {
		o(c)
	}

	return c
}

const (
	// filenameAnnotation is the annotation key used to store the original filename
	// information in manifest annotations for post-rendering reconstruction.
	filenameAnnotation = "postrenderer.helm.sh/postrender-filename"
)

// fixDocSeparators ensures YAML document separators ("---") are always
// followed by a newline in rendered template content. Go template whitespace
// trimming ({{-) can remove the newline after "---", producing e.g.
// "---apiVersion: v1" which is not a valid YAML document separator.
// This function inserts a newline after any "---" at the start of a line
// that is immediately followed by non-whitespace content.
func fixDocSeparators(content string) string {
	var b strings.Builder
	remaining := content
	for {
		// Find "---" at the start of a line (or start of content).
		idx := strings.Index(remaining, "---")
		if idx == -1 {
			b.WriteString(remaining)
			break
		}
		// "---" must be at the start of a line: either idx==0 or preceded by '\n'.
		if idx > 0 && remaining[idx-1] != '\n' {
			b.WriteString(remaining[:idx+3])
			remaining = remaining[idx+3:]
			continue
		}
		b.WriteString(remaining[:idx+3])
		remaining = remaining[idx+3:]
		// If "---" is followed by non-whitespace (e.g. "---apiVersion"),
		// insert a newline to make it a proper document separator.
		if len(remaining) > 0 && remaining[0] != '\n' && remaining[0] != '\r' && remaining[0] != ' ' && remaining[0] != '\t' {
			b.WriteByte('\n')
		}
	}
	return b.String()
}

// annotateAndMerge combines multiple YAML files into a single stream of documents,
// adding filename annotations to each document for later reconstruction.
func annotateAndMerge(files map[string]string) (string, error) {
	var combinedManifests []*kyaml.RNode

	// Get sorted filenames to ensure result is deterministic
	fnames := slices.Sorted(maps.Keys(files))

	for _, fname := range fnames {
		content := files[fname]
		// Skip partials and empty files.
		if strings.HasPrefix(path.Base(fname), "_") || strings.TrimSpace(content) == "" {
			continue
		}

		// Fix document separators where Go template whitespace trimming
		// ({{-) has removed the newline after "---", producing e.g.
		// "---apiVersion: v1" which is not a valid YAML document
		// separator. Insert the missing newline so kio.ParseAll can
		// parse the content correctly.
		content = fixDocSeparators(content)

		manifests, err := kio.ParseAll(content)
		if err != nil {
			return "", fmt.Errorf("parsing %s: %w", fname, err)
		}
		for _, manifest := range manifests {
			if err := manifest.PipeE(kyaml.SetAnnotation(filenameAnnotation, fname)); err != nil {
				return "", fmt.Errorf("annotating %s: %w", fname, err)
			}
			combinedManifests = append(combinedManifests, manifest)
		}
	}

	merged, err := kio.StringAll(combinedManifests)
	if err != nil {
		return "", fmt.Errorf("writing merged docs: %w", err)
	}
	return merged, nil
}

// splitAndDeannotate reconstructs individual files from a merged YAML stream,
// removing filename annotations and grouping documents by their original filenames.
func splitAndDeannotate(postrendered string) (map[string]string, error) {
	manifests, err := kio.ParseAll(postrendered)
	if err != nil {
		return nil, fmt.Errorf("error parsing YAML: %w", err)
	}

	manifestsByFilename := make(map[string][]*kyaml.RNode)
	for i, manifest := range manifests {
		meta, err := manifest.GetMeta()
		if err != nil {
			return nil, fmt.Errorf("getting metadata: %w", err)
		}
		fname := meta.Annotations[filenameAnnotation]
		if fname == "" {
			fname = fmt.Sprintf("generated-by-postrender-%d.yaml", i)
		}
		if err := manifest.PipeE(kyaml.ClearAnnotation(filenameAnnotation)); err != nil {
			return nil, fmt.Errorf("clearing filename annotation: %w", err)
		}
		manifestsByFilename[fname] = append(manifestsByFilename[fname], manifest)
	}

	reconstructed := make(map[string]string, len(manifestsByFilename))
	for fname, docs := range manifestsByFilename {
		fileContents, err := kio.StringAll(docs)
		if err != nil {
			return nil, fmt.Errorf("re-writing %s: %w", fname, err)
		}
		reconstructed[fname] = fileContents
	}
	return reconstructed, nil
}

// renderResources renders the templates in a chart
//
// TODO: This function is badly in need of a refactor.
// TODO: As part of the refactor the duplicate code in cmd/helm/template.go should be removed
//
//	This code has to do with writing files to disk.
func (cfg *Configuration) renderResources(ch *chart.Chart, values common.Values, releaseName, outputDir string, subNotes, useReleaseName, includeCrds bool, pr postrenderer.PostRenderer, interactWithRemote, enableDNS, hideSecret bool) ([]*release.Hook, *bytes.Buffer, string, error) {
	var hs []*release.Hook
	b := bytes.NewBuffer(nil)

	caps, err := cfg.getCapabilities()
	if err != nil {
		return hs, b, "", err
	}

	if ch.Metadata.KubeVersion != "" {
		if !chartutil.IsCompatibleRange(ch.Metadata.KubeVersion, caps.KubeVersion.String()) {
			return hs, b, "", fmt.Errorf("chart requires kubeVersion: %s which is incompatible with Kubernetes %s", ch.Metadata.KubeVersion, caps.KubeVersion.Version)
		}
	}

	var files map[string]string
	var err2 error

	// A `helm template` should not talk to the remote cluster. However, commands with the flag
	// `--dry-run` with the value of `false`, `none`, or `server` should try to interact with the cluster.
	// It may break in interesting and exotic ways because other data (e.g. discovery) is mocked.
	if interactWithRemote && cfg.RESTClientGetter != nil {
		restConfig, err := cfg.RESTClientGetter.ToRESTConfig()
		if err != nil {
			return hs, b, "", err
		}
		e := engine.New(restConfig)
		e.EnableDNS = enableDNS
		e.CustomTemplateFuncs = cfg.CustomTemplateFuncs

		files, err2 = e.Render(ch, values)
	} else {
		var e engine.Engine
		e.EnableDNS = enableDNS
		e.CustomTemplateFuncs = cfg.CustomTemplateFuncs

		files, err2 = e.Render(ch, values)
	}

	if err2 != nil {
		return hs, b, "", err2
	}

	// NOTES.txt gets rendered like all the other files, but because it's not a hook nor a resource,
	// pull it out of here into a separate file so that we can actually use the output of the rendered
	// text file. We have to spin through this map because the file contains path information, so we
	// look for terminating NOTES.txt. We also remove it from the files so that we don't have to skip
	// it in the sortHooks.
	var notesBuffer bytes.Buffer
	for k, v := range files {
		if strings.HasSuffix(k, notesFileSuffix) {
			if subNotes || (k == path.Join(ch.Name(), "templates", notesFileSuffix)) {
				// If buffer contains data, add newline before adding more
				if notesBuffer.Len() > 0 {
					notesBuffer.WriteString("\n")
				}
				notesBuffer.WriteString(v)
			}
			delete(files, k)
		}
	}
	notes := notesBuffer.String()

	if pr != nil {
		// We need to send files to the post-renderer before sorting and splitting
		// hooks from manifests. The post-renderer interface expects a stream of
		// manifests (similar to what tools like Kustomize and kubectl expect), whereas
		// the sorter uses filenames.
		// Here, we merge the documents into a stream, post-render them, and then split
		// them back into a map of filename -> content.

		// Merge files as stream of documents for sending to post renderer
		merged, err := annotateAndMerge(files)
		if err != nil {
			return hs, b, notes, fmt.Errorf("error merging manifests: %w", err)
		}

		// Run the post renderer
		postRendered, err := pr.Run(bytes.NewBufferString(merged))
		if err != nil {
			return hs, b, notes, fmt.Errorf("error while running post render on files: %w", err)
		}

		// Use the file list and contents received from the post renderer
		files, err = splitAndDeannotate(postRendered.String())
		if err != nil {
			return hs, b, notes, fmt.Errorf("error while parsing post rendered output: %w", err)
		}
	}

	// Sort hooks, manifests, and partials. Only hooks and manifests are returned,
	// as partials are not used after renderer.Render. Empty manifests are also
	// removed here.
	hs, manifests, err := releaseutil.SortManifests(files, nil, releaseutil.InstallOrder)
	if err != nil {
		// By catching parse errors here, we can prevent bogus releases from going
		// to Kubernetes.
		//
		// We return the files as a big blob of data to help the user debug parser
		// errors.
		for name, content := range files {
			if strings.TrimSpace(content) == "" {
				continue
			}
			fmt.Fprintf(b, "---\n# Source: %s\n%s\n", name, content)
		}
		return hs, b, "", err
	}

	// Aggregate all valid manifests into one big doc.
	fileWritten := make(map[string]bool)

	if includeCrds {
		for _, crd := range ch.CRDObjects() {
			if outputDir == "" {
				fmt.Fprintf(b, "---\n# Source: %s\n%s\n", crd.Filename, string(crd.File.Data[:]))
			} else {
				err = writeToFile(outputDir, crd.Filename, string(crd.File.Data[:]), fileWritten[crd.Filename])
				if err != nil {
					return hs, b, "", err
				}
				fileWritten[crd.Filename] = true
			}
		}
	}

	for _, m := range manifests {
		if outputDir == "" {
			if hideSecret && m.Head.Kind == "Secret" && m.Head.Version == "v1" {
				fmt.Fprintf(b, "---\n# Source: %s\n# HIDDEN: The Secret output has been suppressed\n", m.Name)
			} else {
				fmt.Fprintf(b, "---\n# Source: %s\n%s\n", m.Name, m.Content)
			}
		} else {
			newDir := outputDir
			if useReleaseName {
				newDir = filepath.Join(outputDir, releaseName)
			}
			// NOTE: We do not have to worry about the post-renderer because
			// output dir is only used by `helm template`. In the next major
			// release, we should move this logic to template only as it is not
			// used by install or upgrade
			err = writeToFile(newDir, m.Name, m.Content, fileWritten[m.Name])
			if err != nil {
				return hs, b, "", err
			}
			fileWritten[m.Name] = true
		}
	}

	return hs, b, notes, nil
}

// RESTClientGetter gets the rest client
type RESTClientGetter interface {
	ToRESTConfig() (*rest.Config, error)
	ToDiscoveryClient() (discovery.CachedDiscoveryInterface, error)
	ToRESTMapper() (meta.RESTMapper, error)
}

// capabilities builds a Capabilities from discovery information.
func (cfg *Configuration) getCapabilities() (*common.Capabilities, error) {
	if cfg.Capabilities != nil {
		return cfg.Capabilities, nil
	}
	dc, err := cfg.RESTClientGetter.ToDiscoveryClient()
	if err != nil {
		return nil, fmt.Errorf("could not get Kubernetes discovery client: %w", err)
	}
	// force a discovery cache invalidation to always fetch the latest server version/capabilities.
	dc.Invalidate()
	kubeVersion, err := dc.ServerVersion()
	if err != nil {
		return nil, fmt.Errorf("could not get server version from Kubernetes: %w", err)
	}
	// Issue #6361:
	// Client-Go emits an error when an API service is registered but unimplemented.
	// We trap that error here and print a warning. But since the discovery client continues
	// building the API object, it is correctly populated with all valid APIs.
	// See https://github.com/kubernetes/kubernetes/issues/72051#issuecomment-521157642
	apiVersions, err := GetVersionSet(dc)
	if err != nil {
		if discovery.IsGroupDiscoveryFailedError(err) {
			cfg.Logger().Warn("the kubernetes server has an orphaned API service", slog.Any("error", err))
			cfg.Logger().Warn("to fix this, kubectl delete apiservice <service-name>")
		} else {
			return nil, fmt.Errorf("could not get apiVersions from Kubernetes: %w", err)
		}
	}

	cfg.Capabilities = &common.Capabilities{
		APIVersions: apiVersions,
		KubeVersion: common.KubeVersion{
			Version: kubeVersion.GitVersion,
			Major:   kubeVersion.Major,
			Minor:   kubeVersion.Minor,
		},
		HelmVersion: common.DefaultCapabilities.HelmVersion,
	}
	return cfg.Capabilities, nil
}

// KubernetesClientSet creates a new kubernetes ClientSet based on the configuration
func (cfg *Configuration) KubernetesClientSet() (kubernetes.Interface, error) {
	conf, err := cfg.RESTClientGetter.ToRESTConfig()
	if err != nil {
		return nil, fmt.Errorf("unable to generate config for kubernetes client: %w", err)
	}

	return kubernetes.NewForConfig(conf)
}

// Now generates a timestamp
//
// If the configuration has a Timestamper on it, that will be used.
// Otherwise, this will use time.Now().
func (cfg *Configuration) Now() time.Time {
	return Timestamper()
}

func (cfg *Configuration) releaseContent(name string, version int) (ri.Releaser, error) {
	if err := chartutil.ValidateReleaseName(name); err != nil {
		return nil, fmt.Errorf("releaseContent: Release name is invalid: %s", name)
	}

	if version <= 0 {
		return cfg.Releases.Last(name)
	}

	return cfg.Releases.Get(name, version)
}

// GetVersionSet retrieves a set of available k8s API versions
func GetVersionSet(client discovery.ServerResourcesInterface) (common.VersionSet, error) {
	groups, resources, err := client.ServerGroupsAndResources()
	if err != nil && !discovery.IsGroupDiscoveryFailedError(err) {
		return common.DefaultVersionSet, fmt.Errorf("could not get apiVersions from Kubernetes: %w", err)
	}

	// FIXME: The Kubernetes test fixture for cli appears to always return nil
	// for calls to Discovery().ServerGroupsAndResources(). So in this case, we
	// return the default API list. This is also a safe value to return in any
	// other odd-ball case.
	if len(groups) == 0 && len(resources) == 0 {
		return common.DefaultVersionSet, nil
	}

	versionMap := make(map[string]interface{})
	var versions []string

	// Extract the groups
	for _, g := range groups {
		for _, gv := range g.Versions {
			versionMap[gv.GroupVersion] = struct{}{}
		}
	}

	// Extract the resources
	var id string
	var ok bool
	for _, r := range resources {
		for _, rl := range r.APIResources {

			// A Kind at a GroupVersion can show up more than once. We only want
			// it displayed once in the final output.
			id = path.Join(r.GroupVersion, rl.Kind)
			if _, ok = versionMap[id]; !ok {
				versionMap[id] = struct{}{}
			}
		}
	}

	// Convert to a form that NewVersionSet can use
	for k := range versionMap {
		versions = append(versions, k)
	}

	return common.VersionSet(versions), nil
}

// recordRelease with an update operation in case reuse has been set.
func (cfg *Configuration) recordRelease(r *release.Release) {
	if err := cfg.Releases.Update(r); err != nil {
		cfg.Logger().Warn(
			"failed to update release",
			slog.String("name", r.Name),
			slog.Int("revision", r.Version),
			slog.Any("error", err),
		)
	}
}

// Init initializes the action configuration
func (cfg *Configuration) Init(getter genericclioptions.RESTClientGetter, namespace, helmDriver string) error {
	kc := kube.New(getter)
	kc.SetLogger(cfg.Logger().Handler())

	lazyClient := &lazyClient{
		namespace: namespace,
		clientFn:  kc.Factory.KubernetesClientSet,
	}

	var store *storage.Storage
	switch helmDriver {
	case "secret", "secrets", "":
		d := driver.NewSecrets(newSecretClient(lazyClient))
		d.SetLogger(cfg.Logger().Handler())
		store = storage.Init(d)
	case "configmap", "configmaps":
		d := driver.NewConfigMaps(newConfigMapClient(lazyClient))
		d.SetLogger(cfg.Logger().Handler())
		store = storage.Init(d)
	case "memory":
		var d *driver.Memory
		if cfg.Releases != nil {
			if mem, ok := cfg.Releases.Driver.(*driver.Memory); ok {
				// This function can be called more than once (e.g., helm list --all-namespaces).
				// If a memory driver was already initialized, reuse it but set the possibly new namespace.
				// We reuse it in case some releases where already created in the existing memory driver.
				d = mem
			}
		}
		if d == nil {
			d = driver.NewMemory()
		}
		d.SetLogger(cfg.Logger().Handler())
		d.SetNamespace(namespace)
		store = storage.Init(d)
	case "sql":
		d, err := driver.NewSQL(
			os.Getenv("HELM_DRIVER_SQL_CONNECTION_STRING"),
			namespace,
		)
		if err != nil {
			return fmt.Errorf("unable to instantiate SQL driver: %w", err)
		}
		d.SetLogger(cfg.Logger().Handler())
		store = storage.Init(d)
	default:
		return fmt.Errorf("unknown driver %q", helmDriver)
	}

	cfg.RESTClientGetter = getter
	cfg.KubeClient = kc
	cfg.Releases = store
	cfg.HookOutputFunc = func(_, _, _ string) io.Writer { return io.Discard }

	return nil
}

// SetHookOutputFunc sets the HookOutputFunc on the Configuration.
func (cfg *Configuration) SetHookOutputFunc(hookOutputFunc func(_, _, _ string) io.Writer) {
	cfg.HookOutputFunc = hookOutputFunc
}

func determineReleaseSSApplyMethod(serverSideApply bool) release.ApplyMethod {
	if serverSideApply {
		return release.ApplyMethodServerSideApply
	}
	return release.ApplyMethodClientSideApply
}

// isDryRun returns true if the strategy is set to run as a DryRun
func isDryRun(strategy DryRunStrategy) bool {
	return strategy == DryRunClient || strategy == DryRunServer
}

// interactWithServer determine whether or not to interact with a remote Kubernetes server
func interactWithServer(strategy DryRunStrategy) bool {
	return strategy == DryRunNone || strategy == DryRunServer
}
