/*
Copyright 2014 The Kubernetes 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 apply

import (
	"context"
	"fmt"
	"io"
	"net/http"

	"github.com/spf13/cobra"
	"sigs.k8s.io/structured-merge-diff/v4/fieldpath"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	utilerrors "k8s.io/apimachinery/pkg/util/errors"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/cli-runtime/pkg/genericiooptions"
	"k8s.io/cli-runtime/pkg/printers"
	"k8s.io/cli-runtime/pkg/resource"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/openapi3"
	"k8s.io/client-go/util/csaupgrade"
	"k8s.io/component-base/version"
	"k8s.io/klog/v2"
	cmddelete "k8s.io/kubectl/pkg/cmd/delete"
	cmdutil "k8s.io/kubectl/pkg/cmd/util"
	"k8s.io/kubectl/pkg/scheme"
	"k8s.io/kubectl/pkg/util"
	"k8s.io/kubectl/pkg/util/i18n"
	"k8s.io/kubectl/pkg/util/openapi"
	"k8s.io/kubectl/pkg/util/prune"
	"k8s.io/kubectl/pkg/util/templates"
	"k8s.io/kubectl/pkg/validation"
)

// ApplyFlags directly reflect the information that CLI is gathering via flags.  They will be converted to Options, which
// reflect the runtime requirements for the command.  This structure reduces the transformation to wiring and makes
// the logic itself easy to unit test
type ApplyFlags struct {
	RecordFlags *genericclioptions.RecordFlags
	PrintFlags  *genericclioptions.PrintFlags

	DeleteFlags *cmddelete.DeleteFlags

	FieldManager   string
	Selector       string
	Prune          bool
	PruneResources []prune.Resource
	ApplySetRef    string
	All            bool
	Overwrite      bool
	OpenAPIPatch   bool
	Subresource    string

	PruneAllowlist []string

	genericiooptions.IOStreams
}

// ApplyOptions defines flags and other configuration parameters for the `apply` command
type ApplyOptions struct {
	Recorder genericclioptions.Recorder

	PrintFlags *genericclioptions.PrintFlags
	ToPrinter  func(string) (printers.ResourcePrinter, error)

	DeleteOptions *cmddelete.DeleteOptions

	ServerSideApply bool
	ForceConflicts  bool
	FieldManager    string
	Selector        string
	DryRunStrategy  cmdutil.DryRunStrategy
	Prune           bool
	PruneResources  []prune.Resource
	cmdBaseName     string
	All             bool
	Overwrite       bool
	OpenAPIPatch    bool
	Subresource     string

	ValidationDirective string
	Validator           validation.Schema
	Builder             *resource.Builder
	Mapper              meta.RESTMapper
	DynamicClient       dynamic.Interface
	OpenAPIGetter       openapi.OpenAPIResourcesGetter
	OpenAPIV3Root       openapi3.Root

	Namespace        string
	EnforceNamespace bool

	genericiooptions.IOStreams

	// Objects (and some denormalized data) which are to be
	// applied. The standard way to fill in this structure
	// is by calling "GetObjects()", which will use the
	// resource builder if "objectsCached" is false. The other
	// way to set this field is to use "SetObjects()".
	// Subsequent calls to "GetObjects()" after setting would
	// not call the resource builder; only return the set objects.
	objects       []*resource.Info
	objectsCached bool

	// Stores visited objects/namespaces for later use
	// calculating the set of objects to prune.
	VisitedUids       sets.Set[types.UID]
	VisitedNamespaces sets.Set[string]

	// Function run after the objects are generated and
	// stored in the "objects" field, but before the
	// apply is run on these objects.
	PreProcessorFn func() error
	// Function run after all objects have been applied.
	// The standard PostProcessorFn is "PrintAndPrunePostProcessor()".
	PostProcessorFn func() error

	// ApplySet tracks the set of objects that have been applied, for the purposes of pruning.
	// See git.k8s.io/enhancements/keps/sig-cli/3659-kubectl-apply-prune
	ApplySet *ApplySet
}

var (
	applyLong = templates.LongDesc(i18n.T(`
		Apply a configuration to a resource by file name or stdin.
		The resource name must be specified. This resource will be created if it doesn't exist yet.
		To use 'apply', always create the resource initially with either 'apply' or 'create --save-config'.

		JSON and YAML formats are accepted.

		Alpha Disclaimer: the --prune functionality is not yet complete. Do not use unless you are aware of what the current state is. See https://issues.k8s.io/34274.`))

	applyExample = templates.Examples(i18n.T(`
		# Apply the configuration in pod.json to a pod
		kubectl apply -f ./pod.json

		# Apply resources from a directory containing kustomization.yaml - e.g. dir/kustomization.yaml
		kubectl apply -k dir/

		# Apply the JSON passed into stdin to a pod
		cat pod.json | kubectl apply -f -

		# Apply the configuration from all files that end with '.json'
		kubectl apply -f '*.json'

		# Note: --prune is still in Alpha
		# Apply the configuration in manifest.yaml that matches label app=nginx and delete all other resources that are not in the file and match label app=nginx
		kubectl apply --prune -f manifest.yaml -l app=nginx

		# Apply the configuration in manifest.yaml and delete all the other config maps that are not in the file
		kubectl apply --prune -f manifest.yaml --all --prune-allowlist=core/v1/ConfigMap`))

	warningNoLastAppliedConfigAnnotation = "Warning: resource %[1]s is missing the %[2]s annotation which is required by %[3]s apply. %[3]s apply should only be used on resources created declaratively by either %[3]s create --save-config or %[3]s apply. The missing annotation will be patched automatically.\n"
	warningChangesOnDeletingResource     = "Warning: Detected changes to resource %[1]s which is currently being deleted.\n"
	warningMigrationLastAppliedFailed    = "Warning: failed to migrate kubectl.kubernetes.io/last-applied-configuration for Server-Side Apply. This is non-fatal and will be retried next time you apply. Error: %[1]s\n"
	warningMigrationPatchFailed          = "Warning: server rejected managed fields migration to Server-Side Apply. This is non-fatal and will be retried next time you apply. Error: %[1]s\n"
	warningMigrationReapplyFailed        = "Warning: failed to re-apply configuration after performing Server-Side Apply migration. This is non-fatal and will be retried next time you apply. Error: %[1]s\n"
)

var ApplySetToolVersion = version.Get().GitVersion

// NewApplyFlags returns a default ApplyFlags
func NewApplyFlags(streams genericiooptions.IOStreams) *ApplyFlags {
	return &ApplyFlags{
		RecordFlags: genericclioptions.NewRecordFlags(),
		DeleteFlags: cmddelete.NewDeleteFlags("The files that contain the configurations to apply."),
		PrintFlags:  genericclioptions.NewPrintFlags("created").WithTypeSetter(scheme.Scheme),

		Overwrite:    true,
		OpenAPIPatch: true,

		IOStreams: streams,
	}
}

// NewCmdApply creates the `apply` command
func NewCmdApply(baseName string, f cmdutil.Factory, ioStreams genericiooptions.IOStreams) *cobra.Command {
	flags := NewApplyFlags(ioStreams)

	cmd := &cobra.Command{
		Use:                   "apply (-f FILENAME | -k DIRECTORY)",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Apply a configuration to a resource by file name or stdin"),
		Long:                  applyLong,
		Example:               applyExample,
		Run: func(cmd *cobra.Command, args []string) {
			o, err := flags.ToOptions(f, cmd, baseName, args)
			cmdutil.CheckErr(err)
			cmdutil.CheckErr(o.Validate())
			cmdutil.CheckErr(o.Run())
		},
	}

	flags.AddFlags(cmd)

	// apply subcommands
	cmd.AddCommand(NewCmdApplyViewLastApplied(f, flags.IOStreams))
	cmd.AddCommand(NewCmdApplySetLastApplied(f, flags.IOStreams))
	cmd.AddCommand(NewCmdApplyEditLastApplied(f, flags.IOStreams))

	return cmd
}

// AddFlags registers flags for a cli
func (flags *ApplyFlags) AddFlags(cmd *cobra.Command) {
	// bind flag structs
	flags.DeleteFlags.AddFlags(cmd)
	flags.RecordFlags.AddFlags(cmd)
	flags.PrintFlags.AddFlags(cmd)

	cmdutil.AddValidateFlags(cmd)
	cmdutil.AddDryRunFlag(cmd)
	cmdutil.AddServerSideApplyFlags(cmd)
	cmdutil.AddFieldManagerFlagVar(cmd, &flags.FieldManager, FieldManagerClientSideApply)
	cmdutil.AddLabelSelectorFlagVar(cmd, &flags.Selector)
	cmdutil.AddPruningFlags(cmd, &flags.Prune, &flags.PruneAllowlist, &flags.All, &flags.ApplySetRef)
	cmd.Flags().BoolVar(&flags.Overwrite, "overwrite", flags.Overwrite, "Automatically resolve conflicts between the modified and live configuration by using values from the modified configuration")
	cmd.Flags().BoolVar(&flags.OpenAPIPatch, "openapi-patch", flags.OpenAPIPatch, "If true, use openapi to calculate diff when the openapi presents and the resource can be found in the openapi spec. Otherwise, fall back to use baked-in types.")
	cmdutil.AddSubresourceFlags(cmd, &flags.Subresource, "If specified, apply will operate on the subresource of the requested object.  Only allowed when using --server-side.")
}

// ToOptions converts from CLI inputs to runtime inputs
func (flags *ApplyFlags) ToOptions(f cmdutil.Factory, cmd *cobra.Command, baseName string, args []string) (*ApplyOptions, error) {
	if len(args) != 0 {
		return nil, cmdutil.UsageErrorf(cmd, "Unexpected args: %v", args)
	}

	serverSideApply := cmdutil.GetServerSideApplyFlag(cmd)
	forceConflicts := cmdutil.GetForceConflictsFlag(cmd)
	dryRunStrategy, err := cmdutil.GetDryRunStrategy(cmd)
	if err != nil {
		return nil, err
	}

	dynamicClient, err := f.DynamicClient()
	if err != nil {
		return nil, err
	}

	fieldManager := GetApplyFieldManagerFlag(cmd, serverSideApply)

	// allow for a success message operation to be specified at print time
	toPrinter := func(operation string) (printers.ResourcePrinter, error) {
		flags.PrintFlags.NamePrintFlags.Operation = operation
		cmdutil.PrintFlagsWithDryRunStrategy(flags.PrintFlags, dryRunStrategy)
		return flags.PrintFlags.ToPrinter()
	}

	flags.RecordFlags.Complete(cmd)
	recorder, err := flags.RecordFlags.ToRecorder()
	if err != nil {
		return nil, err
	}

	deleteOptions, err := flags.DeleteFlags.ToOptions(dynamicClient, flags.IOStreams)
	if err != nil {
		return nil, err
	}

	err = deleteOptions.FilenameOptions.RequireFilenameOrKustomize()
	if err != nil {
		return nil, err
	}

	var openAPIV3Root openapi3.Root
	if !cmdutil.OpenAPIV3Patch.IsDisabled() {
		openAPIV3Client, err := f.OpenAPIV3Client()
		if err == nil {
			openAPIV3Root = openapi3.NewRoot(openAPIV3Client)
		} else {
			klog.V(4).Infof("warning: OpenAPI V3 Patch is enabled but is unable to be loaded. Will fall back to OpenAPI V2")
		}
	}

	validationDirective, err := cmdutil.GetValidationDirective(cmd)
	if err != nil {
		return nil, err
	}
	validator, err := f.Validator(validationDirective)
	if err != nil {
		return nil, err
	}
	builder := f.NewBuilder()
	mapper, err := f.ToRESTMapper()
	if err != nil {
		return nil, err
	}

	namespace, enforceNamespace, err := f.ToRawKubeConfigLoader().Namespace()
	if err != nil {
		return nil, err
	}

	var applySet *ApplySet
	if flags.ApplySetRef != "" {
		parent, err := ParseApplySetParentRef(flags.ApplySetRef, mapper)
		if err != nil {
			return nil, fmt.Errorf("invalid parent reference %q: %w", flags.ApplySetRef, err)
		}
		// ApplySet uses the namespace value from the flag, but not from the kubeconfig or defaults
		// This means the namespace flag is required when using a namespaced parent.
		if enforceNamespace && parent.IsNamespaced() {
			parent.Namespace = namespace
		}
		tooling := ApplySetTooling{Name: baseName, Version: ApplySetToolVersion}
		restClient, err := f.UnstructuredClientForMapping(parent.RESTMapping)
		if err != nil {
			return nil, fmt.Errorf("failed to initialize RESTClient for ApplySet: %w", err)
		}
		if restClient == nil {
			return nil, fmt.Errorf("could not build RESTClient for ApplySet")
		}
		applySet = NewApplySet(parent, tooling, mapper, restClient)
	}
	if flags.Prune {
		flags.PruneResources, err = prune.ParseResources(mapper, flags.PruneAllowlist)
		if err != nil {
			return nil, err
		}
	}

	o := &ApplyOptions{
		// 	Store baseName for use in printing warnings / messages involving the base command name.
		// 	This is useful for downstream command that wrap this one.
		cmdBaseName: baseName,

		PrintFlags: flags.PrintFlags,

		DeleteOptions:   deleteOptions,
		ToPrinter:       toPrinter,
		ServerSideApply: serverSideApply,
		ForceConflicts:  forceConflicts,
		FieldManager:    fieldManager,
		Selector:        flags.Selector,
		DryRunStrategy:  dryRunStrategy,
		Prune:           flags.Prune,
		PruneResources:  flags.PruneResources,
		All:             flags.All,
		Overwrite:       flags.Overwrite,
		OpenAPIPatch:    flags.OpenAPIPatch,
		Subresource:     flags.Subresource,

		Recorder:            recorder,
		Namespace:           namespace,
		EnforceNamespace:    enforceNamespace,
		Validator:           validator,
		ValidationDirective: validationDirective,
		Builder:             builder,
		Mapper:              mapper,
		DynamicClient:       dynamicClient,
		OpenAPIGetter:       f,
		OpenAPIV3Root:       openAPIV3Root,

		IOStreams: flags.IOStreams,

		objects:       []*resource.Info{},
		objectsCached: false,

		VisitedUids:       sets.New[types.UID](),
		VisitedNamespaces: sets.New[string](),

		ApplySet: applySet,
	}

	o.PostProcessorFn = o.PrintAndPrunePostProcessor()

	return o, nil
}

// Validate verifies if ApplyOptions are valid and without conflicts.
func (o *ApplyOptions) Validate() error {
	if o.ForceConflicts && !o.ServerSideApply {
		return fmt.Errorf("--force-conflicts only works with --server-side")
	}

	if o.DryRunStrategy == cmdutil.DryRunClient && o.ServerSideApply {
		return fmt.Errorf("--dry-run=client doesn't work with --server-side (did you mean --dry-run=server instead?)")
	}

	if o.ServerSideApply && o.DeleteOptions.ForceDeletion {
		return fmt.Errorf("--force cannot be used with --server-side")
	}

	if o.DryRunStrategy == cmdutil.DryRunServer && o.DeleteOptions.ForceDeletion {
		return fmt.Errorf("--dry-run=server cannot be used with --force")
	}

	if o.All && len(o.Selector) > 0 {
		return fmt.Errorf("cannot set --all and --selector at the same time")
	}

	if o.ApplySet != nil {
		if !o.Prune {
			return fmt.Errorf("--applyset requires --prune")
		}
		if err := o.ApplySet.Validate(context.TODO(), o.DynamicClient); err != nil {
			return err
		}
	}
	if o.Prune {
		// Do not force the recreation of an object(s) if we're pruning; this can cause
		// undefined behavior since object UID's change.
		if o.DeleteOptions.ForceDeletion {
			return fmt.Errorf("--force cannot be used with --prune")
		}

		if o.ApplySet != nil {
			if o.All {
				return fmt.Errorf("--all is incompatible with --applyset")
			} else if o.Selector != "" {
				return fmt.Errorf("--selector is incompatible with --applyset")
			} else if len(o.PruneResources) > 0 {
				return fmt.Errorf("--prune-allowlist is incompatible with --applyset")
			}
		} else {
			if !o.All && o.Selector == "" {
				return fmt.Errorf("all resources selected for prune without explicitly passing --all. To prune all resources, pass the --all flag. If you did not mean to prune all resources, specify a label selector")
			}
			if o.ServerSideApply {
				return fmt.Errorf("--prune is in alpha and doesn't currently work on objects created by server-side apply")
			}
		}
	}
	if len(o.Subresource) > 0 && !o.ServerSideApply {
		return fmt.Errorf("--subresource can only be specified for --server-side")
	}

	return nil
}

func isIncompatibleServerError(err error) bool {
	// 415: Unsupported media type means we're talking to a server which doesn't
	// support server-side apply.
	if _, ok := err.(*errors.StatusError); !ok {
		// Non-StatusError means the error isn't because the server is incompatible.
		return false
	}
	return err.(*errors.StatusError).Status().Code == http.StatusUnsupportedMediaType
}

// GetObjects returns a (possibly cached) version of all the valid objects to apply
// as a slice of pointer to resource.Info and an error if one or more occurred.
// IMPORTANT: This function can return both valid objects AND an error, since
// "ContinueOnError" is set on the builder. This function should not be called
// until AFTER the "complete" and "validate" methods have been called to ensure that
// the ApplyOptions is filled in and valid.
func (o *ApplyOptions) GetObjects() ([]*resource.Info, error) {
	var err error = nil
	if !o.objectsCached {
		r := o.Builder.
			Unstructured().
			Schema(o.Validator).
			ContinueOnError().
			NamespaceParam(o.Namespace).DefaultNamespace().
			FilenameParam(o.EnforceNamespace, &o.DeleteOptions.FilenameOptions).
			LabelSelectorParam(o.Selector).
			Flatten().
			Do()

		o.objects, err = r.Infos()

		if o.ApplySet != nil {
			if err := o.ApplySet.AddLabels(o.objects...); err != nil {
				return nil, err
			}
		}

		o.objectsCached = true
	}
	return o.objects, err
}

// SetObjects stores the set of objects (as resource.Info) to be
// subsequently applied.
func (o *ApplyOptions) SetObjects(infos []*resource.Info) {
	o.objects = infos
	o.objectsCached = true
}

// Run executes the `apply` command.
func (o *ApplyOptions) Run() error {
	if o.PreProcessorFn != nil {
		klog.V(4).Infof("Running apply pre-processor function")
		if err := o.PreProcessorFn(); err != nil {
			return err
		}
	}

	// Enforce CLI specified namespace on server request.
	if o.EnforceNamespace {
		o.VisitedNamespaces.Insert(o.Namespace)
	}

	// Generates the objects using the resource builder if they have not
	// already been stored by calling "SetObjects()" in the pre-processor.
	errs := []error{}
	infos, err := o.GetObjects()
	if err != nil {
		errs = append(errs, err)
	}
	if len(infos) == 0 && len(errs) == 0 {
		return fmt.Errorf("no objects passed to apply")
	}

	if o.ApplySet != nil {
		if err := o.ApplySet.BeforeApply(infos, o.DryRunStrategy, o.ValidationDirective); err != nil {
			return err
		}
	}

	// Iterate through all objects, applying each one.
	for _, info := range infos {
		if err := o.applyOneObject(info); err != nil {
			errs = append(errs, err)
		}
	}
	// If any errors occurred during apply, then return error (or
	// aggregate of errors).
	if len(errs) == 1 {
		return errs[0]
	}
	if len(errs) > 1 {
		return utilerrors.NewAggregate(errs)
	}

	if o.PostProcessorFn != nil {
		klog.V(4).Infof("Running apply post-processor function")
		if err := o.PostProcessorFn(); err != nil {
			return err
		}
	}

	return nil
}

func (o *ApplyOptions) applyOneObject(info *resource.Info) error {
	o.MarkNamespaceVisited(info)

	if err := o.Recorder.Record(info.Object); err != nil {
		klog.V(4).Infof("error recording current command: %v", err)
	}

	if len(info.Name) == 0 {
		metadata, _ := meta.Accessor(info.Object)
		generatedName := metadata.GetGenerateName()
		if len(generatedName) > 0 {
			return fmt.Errorf("from %s: cannot use generate name with apply", generatedName)
		}
	}

	helper := resource.NewHelper(info.Client, info.Mapping).
		DryRun(o.DryRunStrategy == cmdutil.DryRunServer).
		WithFieldManager(o.FieldManager).
		WithFieldValidation(o.ValidationDirective)

	if o.ServerSideApply {
		// Send the full object to be applied on the server side.
		data, err := runtime.Encode(unstructured.UnstructuredJSONScheme, info.Object)
		if err != nil {
			return cmdutil.AddSourceToErr("serverside-apply", info.Source, err)
		}

		options := metav1.PatchOptions{
			Force: &o.ForceConflicts,
		}
		obj, err := helper.
			WithSubresource(o.Subresource).
			Patch(
				info.Namespace,
				info.Name,
				types.ApplyPatchType,
				data,
				&options,
			)
		if err != nil {
			if isIncompatibleServerError(err) {
				err = fmt.Errorf("Server-side apply not available on the server: (%v)", err)
			}
			if errors.IsConflict(err) {
				err = fmt.Errorf(`%v
Please review the fields above--they currently have other managers. Here
are the ways you can resolve this warning:
* If you intend to manage all of these fields, please re-run the apply
  command with the `+"`--force-conflicts`"+` flag.
* If you do not intend to manage all of the fields, please edit your
  manifest to remove references to the fields that should keep their
  current managers.
* You may co-own fields by updating your manifest to match the existing
  value; in this case, you'll become the manager if the other manager(s)
  stop managing the field (remove it from their configuration).
See https://kubernetes.io/docs/reference/using-api/server-side-apply/#conflicts`, err)
			}
			return err
		}

		info.Refresh(obj, true)

		// Migrate managed fields if necessary.
		//
		// By checking afterward instead of fetching the object beforehand and
		// unconditionally fetching we can make 3 network requests in the rare
		// case of migration and 1 request if migration is unnecessary.
		//
		// To check beforehand means 2 requests for most operations, and 3
		// requests in worst case.
		if err = o.saveLastApplyAnnotationIfNecessary(helper, info); err != nil {
			fmt.Fprintf(o.ErrOut, warningMigrationLastAppliedFailed, err.Error())
		} else if performedMigration, err := o.migrateToSSAIfNecessary(helper, info); err != nil {
			// Print-error as a warning.
			// This is a non-fatal error because object was successfully applied
			// above, but it might have issues since migration failed.
			//
			// This migration will be re-attempted if necessary upon next
			// apply.
			fmt.Fprintf(o.ErrOut, warningMigrationPatchFailed, err.Error())
		} else if performedMigration {
			if obj, err = helper.Patch(
				info.Namespace,
				info.Name,
				types.ApplyPatchType,
				data,
				&options,
			); err != nil {
				// Re-send original SSA patch (this will allow dropped fields to
				// finally be removed)
				fmt.Fprintf(o.ErrOut, warningMigrationReapplyFailed, err.Error())
			} else {
				info.Refresh(obj, false)
			}
		}

		WarnIfDeleting(info.Object, o.ErrOut)

		if err := o.MarkObjectVisited(info); err != nil {
			return err
		}

		if o.shouldPrintObject() {
			return nil
		}

		printer, err := o.ToPrinter("serverside-applied")
		if err != nil {
			return err
		}

		if err = printer.PrintObj(info.Object, o.Out); err != nil {
			return err
		}
		return nil
	}

	// Get the modified configuration of the object. Embed the result
	// as an annotation in the modified configuration, so that it will appear
	// in the patch sent to the server.
	modified, err := util.GetModifiedConfiguration(info.Object, true, unstructured.UnstructuredJSONScheme)
	if err != nil {
		return cmdutil.AddSourceToErr(fmt.Sprintf("retrieving modified configuration from:\n%s\nfor:", info.String()), info.Source, err)
	}

	if err := info.Get(); err != nil {
		if !errors.IsNotFound(err) {
			return cmdutil.AddSourceToErr(fmt.Sprintf("retrieving current configuration of:\n%s\nfrom server for:", info.String()), info.Source, err)
		}

		// Create the resource if it doesn't exist
		// First, update the annotation used by kubectl apply
		if err := util.CreateApplyAnnotation(info.Object, unstructured.UnstructuredJSONScheme); err != nil {
			return cmdutil.AddSourceToErr("creating", info.Source, err)
		}

		// prune nulls when client-side apply does a create to match what will happen when client-side applying an update.
		// do this after CreateApplyAnnotation so the annotation matches what will be persisted on an update apply of the same manifest.
		if u, ok := info.Object.(runtime.Unstructured); ok {
			pruneNullsFromMap(u.UnstructuredContent())
		}

		if o.DryRunStrategy != cmdutil.DryRunClient {
			// Then create the resource and skip the three-way merge
			obj, err := helper.Create(info.Namespace, true, info.Object)
			if err != nil {
				return cmdutil.AddSourceToErr("creating", info.Source, err)
			}
			info.Refresh(obj, true)
		}

		if err := o.MarkObjectVisited(info); err != nil {
			return err
		}

		if o.shouldPrintObject() {
			return nil
		}

		printer, err := o.ToPrinter("created")
		if err != nil {
			return err
		}
		if err = printer.PrintObj(info.Object, o.Out); err != nil {
			return err
		}
		return nil
	}

	if err := o.MarkObjectVisited(info); err != nil {
		return err
	}

	if o.DryRunStrategy != cmdutil.DryRunClient {
		metadata, _ := meta.Accessor(info.Object)
		annotationMap := metadata.GetAnnotations()
		if _, ok := annotationMap[corev1.LastAppliedConfigAnnotation]; !ok {
			fmt.Fprintf(o.ErrOut, warningNoLastAppliedConfigAnnotation, info.ObjectName(), corev1.LastAppliedConfigAnnotation, o.cmdBaseName)
		}

		patcher, err := newPatcher(o, info, helper)
		if err != nil {
			return err
		}
		patchBytes, patchedObject, err := patcher.Patch(info.Object, modified, info.Source, info.Namespace, info.Name, o.ErrOut)
		if err != nil {
			return cmdutil.AddSourceToErr(fmt.Sprintf("applying patch:\n%s\nto:\n%v\nfor:", patchBytes, info), info.Source, err)
		}

		info.Refresh(patchedObject, true)

		WarnIfDeleting(info.Object, o.ErrOut)

		if string(patchBytes) == "{}" && !o.shouldPrintObject() {
			printer, err := o.ToPrinter("unchanged")
			if err != nil {
				return err
			}
			if err = printer.PrintObj(info.Object, o.Out); err != nil {
				return err
			}
			return nil
		}
	}

	if o.shouldPrintObject() {
		return nil
	}

	printer, err := o.ToPrinter("configured")
	if err != nil {
		return err
	}
	if err = printer.PrintObj(info.Object, o.Out); err != nil {
		return err
	}

	return nil
}

func pruneNullsFromMap(data map[string]interface{}) {
	for k, v := range data {
		if v == nil {
			delete(data, k)
		} else {
			pruneNulls(v)
		}
	}
}
func pruneNullsFromSlice(data []interface{}) {
	for _, v := range data {
		pruneNulls(v)
	}
}
func pruneNulls(v interface{}) {
	switch v := v.(type) {
	case map[string]interface{}:
		pruneNullsFromMap(v)
	case []interface{}:
		pruneNullsFromSlice(v)
	}
}

// Saves the last-applied-configuration annotation in a separate SSA field manager
// to prevent it from being dropped by users who have transitioned to SSA.
//
// If this operation is not performed, then the last-applied-configuration annotation
// would be removed from the object upon the first SSA usage. We want to keep it
// around for a few releases since it is required to downgrade to
// SSA per [1] and [2]. This code should be removed once the annotation is
// deprecated.
//
// - [1] https://kubernetes.io/docs/reference/using-api/server-side-apply/#downgrading-from-server-side-apply-to-client-side-apply
// - [2] https://github.com/kubernetes/kubernetes/pull/90187
//
// If the annotation is not already present, or if it is already managed by the
// separate SSA fieldmanager, this is a no-op.
func (o *ApplyOptions) saveLastApplyAnnotationIfNecessary(
	helper *resource.Helper,
	info *resource.Info,
) error {
	if o.FieldManager != fieldManagerServerSideApply {
		// There is no point in preserving the annotation if the field manager
		// will not remain default. This is because the server will not keep
		// the annotation up to date.
		return nil
	}

	// Send an apply patch with the last-applied-annotation
	// so that it is not orphaned by SSA in the following patch:
	accessor, err := meta.Accessor(info.Object)
	if err != nil {
		return err
	}

	// Get the current annotations from the object.
	annots := accessor.GetAnnotations()
	if annots == nil {
		annots = map[string]string{}
	}

	fieldManager := fieldManagerLastAppliedAnnotation
	originalAnnotation, hasAnnotation := annots[corev1.LastAppliedConfigAnnotation]

	// If the annotation does not already exist, we do not do anything
	if !hasAnnotation {
		return nil
	}

	// If there is already an SSA field manager which owns the field, then there
	// is nothing to do here.
	if owners := csaupgrade.FindFieldsOwners(
		accessor.GetManagedFields(),
		metav1.ManagedFieldsOperationApply,
		lastAppliedAnnotationFieldPath,
	); len(owners) > 0 {
		return nil
	}

	justAnnotation := &unstructured.Unstructured{}
	justAnnotation.SetGroupVersionKind(info.Mapping.GroupVersionKind)
	justAnnotation.SetName(accessor.GetName())
	justAnnotation.SetNamespace(accessor.GetNamespace())
	justAnnotation.SetAnnotations(map[string]string{
		corev1.LastAppliedConfigAnnotation: originalAnnotation,
	})

	modified, err := runtime.Encode(unstructured.UnstructuredJSONScheme, justAnnotation)
	if err != nil {
		return nil
	}

	helperCopy := *helper
	newObj, err := helperCopy.WithFieldManager(fieldManager).Patch(
		info.Namespace,
		info.Name,
		types.ApplyPatchType,
		modified,
		nil,
	)

	if err != nil {
		return err
	}

	return info.Refresh(newObj, false)
}

// Check if the returned object needs to have its kubectl-client-side-apply
// managed fields migrated server-side-apply.
//
// field ownership metadata is stored in three places:
//   - server-side managed fields
//   - client-side managed fields
//   - and the last_applied_configuration annotation.
//
// The migration merges the client-side-managed fields into the
// server-side-managed fields, leaving the last_applied_configuration
// annotation in place. Server will keep the annotation up to date
// after every server-side-apply where the following conditions are ment:
//
//  1. field manager is 'kubectl'
//  2. annotation already exists
func (o *ApplyOptions) migrateToSSAIfNecessary(
	helper *resource.Helper,
	info *resource.Info,
) (migrated bool, err error) {
	accessor, err := meta.Accessor(info.Object)
	if err != nil {
		return false, err
	}

	// To determine which field managers were used by kubectl for client-side-apply
	// we search for a manager used in `Update` operations which owns the
	// last-applied-annotation.
	//
	// This is the last client-side-apply manager which changed the field.
	//
	// There may be multiple owners if multiple managers wrote the same exact
	// configuration. In this case there are multiple owners, we want to migrate
	// them all.
	csaManagers := csaupgrade.FindFieldsOwners(
		accessor.GetManagedFields(),
		metav1.ManagedFieldsOperationUpdate,
		lastAppliedAnnotationFieldPath)

	managerNames := sets.New[string]()
	for _, entry := range csaManagers {
		managerNames.Insert(entry.Manager)
	}

	// Re-attempt patch as many times as it is conflicting due to ResourceVersion
	// test failing
	for i := 0; i < maxPatchRetry; i++ {
		var patchData []byte
		var obj runtime.Object

		patchData, err = csaupgrade.UpgradeManagedFieldsPatch(
			info.Object, managerNames, o.FieldManager)

		if err != nil {
			// If patch generation failed there was likely a bug.
			return false, err
		} else if patchData == nil {
			// nil patch data means nothing to do - object is already migrated
			return false, nil
		}

		// Send the patch to upgrade the managed fields if it is non-nil
		obj, err = helper.Patch(
			info.Namespace,
			info.Name,
			types.JSONPatchType,
			patchData,
			nil,
		)

		if err == nil {
			// Stop retrying upon success.
			info.Refresh(obj, false)
			return true, nil
		} else if !errors.IsConflict(err) {
			// Only retry if there was a conflict
			return false, err
		}

		// Refresh the object for next iteration
		err = info.Get()
		if err != nil {
			// If there was an error fetching, return error
			return false, err
		}
	}

	// Reaching this point with non-nil error means there was a conflict and
	// max retries was hit
	// Return the last error witnessed (which will be a conflict)
	return false, err
}

func (o *ApplyOptions) shouldPrintObject() bool {
	// Print object only if output format other than "name" is specified
	shouldPrint := false
	output := *o.PrintFlags.OutputFormat
	shortOutput := output == "name"
	if len(output) > 0 && !shortOutput {
		shouldPrint = true
	}
	return shouldPrint
}

func (o *ApplyOptions) printObjects() error {

	if !o.shouldPrintObject() {
		return nil
	}

	infos, err := o.GetObjects()
	if err != nil {
		return err
	}

	if len(infos) > 0 {
		printer, err := o.ToPrinter("")
		if err != nil {
			return err
		}

		objToPrint := infos[0].Object
		if len(infos) > 1 {
			objs := []runtime.Object{}
			for _, info := range infos {
				objs = append(objs, info.Object)
			}
			list := &corev1.List{
				TypeMeta: metav1.TypeMeta{
					Kind:       "List",
					APIVersion: "v1",
				},
				ListMeta: metav1.ListMeta{},
			}
			if err := meta.SetList(list, objs); err != nil {
				return err
			}

			objToPrint = list
		}
		if err := printer.PrintObj(objToPrint, o.Out); err != nil {
			return err
		}
	}

	return nil
}

// MarkNamespaceVisited keeps track of which namespaces the applied
// objects belong to. Used for pruning.
func (o *ApplyOptions) MarkNamespaceVisited(info *resource.Info) {
	if info.Namespaced() {
		o.VisitedNamespaces.Insert(info.Namespace)
	}
}

// MarkObjectVisited keeps track of UIDs of the applied
// objects. Used for pruning.
func (o *ApplyOptions) MarkObjectVisited(info *resource.Info) error {
	metadata, err := meta.Accessor(info.Object)
	if err != nil {
		return err
	}
	o.VisitedUids.Insert(metadata.GetUID())

	return nil
}

// PrintAndPrunePostProcessor returns a function which meets the PostProcessorFn
// function signature. This returned function prints all the
// objects as a list (if configured for that), and prunes the
// objects not applied. The returned function is the standard
// apply post processor.
func (o *ApplyOptions) PrintAndPrunePostProcessor() func() error {

	return func() error {
		ctx := context.TODO()
		if err := o.printObjects(); err != nil {
			return err
		}

		if o.Prune {
			if cmdutil.ApplySet.IsEnabled() && o.ApplySet != nil {
				if err := o.ApplySet.Prune(ctx, o); err != nil {
					// Do not update the ApplySet. If pruning failed, we want to keep the superset
					// of the previous and current resources in the ApplySet, so that the pruning
					// step of the next apply will be able to clean up the set correctly.
					return err
				}
			} else {
				p := newPruner(o)
				return p.pruneAll(o)
			}
		}

		return nil
	}
}

const (
	// FieldManagerClientSideApply is the default client-side apply field manager.
	//
	// The default field manager is not `kubectl-apply` to distinguish from
	// server-side apply.
	FieldManagerClientSideApply = "kubectl-client-side-apply"
	// The default server-side apply field manager is `kubectl`
	// instead of a field manager like `kubectl-server-side-apply`
	// for backward compatibility to not conflict with old versions
	// of kubectl server-side apply where `kubectl` has already been the field manager.
	fieldManagerServerSideApply = "kubectl"

	fieldManagerLastAppliedAnnotation = "kubectl-last-applied"
)

var (
	lastAppliedAnnotationFieldPath = fieldpath.NewSet(
		fieldpath.MakePathOrDie(
			"metadata", "annotations",
			corev1.LastAppliedConfigAnnotation),
	)
)

// GetApplyFieldManagerFlag gets the field manager for kubectl apply
// if it is not set.
//
// The default field manager is not `kubectl-apply` to distinguish between
// client-side and server-side apply.
func GetApplyFieldManagerFlag(cmd *cobra.Command, serverSide bool) string {
	// The field manager flag was set
	if cmd.Flag("field-manager").Changed {
		return cmdutil.GetFlagString(cmd, "field-manager")
	}

	if serverSide {
		return fieldManagerServerSideApply
	}

	return FieldManagerClientSideApply
}

// WarnIfDeleting prints a warning if a resource is being deleted
func WarnIfDeleting(obj runtime.Object, stderr io.Writer) {
	metadata, _ := meta.Accessor(obj)
	if metadata != nil && metadata.GetDeletionTimestamp() != nil {
		// just warn the user about the conflict
		fmt.Fprintf(stderr, warningChangesOnDeletingResource, metadata.GetName())
	}
}
