// PullImage initiates a pull operation. image is the repository name to pull, and
// tag may be either empty, or indicate a specific tag to pull.
func (daemon *Daemon) PullImage(ref reference.Named, metaHeaders map[string][]string, authConfig *types.AuthConfig, outStream io.Writer) error {
	// Include a buffer so that slow client connections don't affect
	// transfer performance.
	progressChan := make(chan progress.Progress, 100)

	writesDone := make(chan struct{})

	ctx, cancelFunc := context.WithCancel(context.Background())

	go func() {
		writeDistributionProgress(cancelFunc, outStream, progressChan)
		close(writesDone)
	}()

	imagePullConfig := &distribution.ImagePullConfig{
		MetaHeaders:     metaHeaders,
		AuthConfig:      authConfig,
		ProgressOutput:  progress.ChanOutput(progressChan),
		RegistryService: daemon.RegistryService,
		EventsService:   daemon.EventsService,
		MetadataStore:   daemon.distributionMetadataStore,
		ImageStore:      daemon.imageStore,
		TagStore:        daemon.tagStore,
		DownloadManager: daemon.downloadManager,
	}

	err := distribution.Pull(ctx, ref, imagePullConfig)
	close(progressChan)
	<-writesDone
	return err
}

func (pm *Manager) pull(ctx context.Context, ref reference.Named, config *distribution.ImagePullConfig, outStream io.Writer) error {
	if outStream != nil {
		// Include a buffer so that slow client connections don't affect
		// transfer performance.
		progressChan := make(chan progress.Progress, 100)

		writesDone := make(chan struct{})

		defer func() {
			close(progressChan)
			<-writesDone
		}()

		var cancelFunc context.CancelFunc
		ctx, cancelFunc = context.WithCancel(ctx)

		go func() {
			progressutils.WriteDistributionProgress(cancelFunc, outStream, progressChan)
			close(writesDone)
		}()

		config.ProgressOutput = progress.ChanOutput(progressChan)
	} else {
		config.ProgressOutput = progress.DiscardOutput()
	}
	return distribution.Pull(ctx, ref, config)
}

func (daemon *Daemon) pullImageWithReference(ctx context.Context, ref reference.Named, metaHeaders map[string][]string, authConfig *types.AuthConfig, outStream io.Writer) error {
	// Include a buffer so that slow client connections don't affect
	// transfer performance.
	progressChan := make(chan progress.Progress, 100)

	writesDone := make(chan struct{})

	ctx, cancelFunc := context.WithCancel(ctx)

	go func() {
		progressutils.WriteDistributionProgress(cancelFunc, outStream, progressChan)
		close(writesDone)
	}()

	imagePullConfig := &distribution.ImagePullConfig{
		Config: distribution.Config{
			MetaHeaders:      metaHeaders,
			AuthConfig:       authConfig,
			ProgressOutput:   progress.ChanOutput(progressChan),
			RegistryService:  daemon.RegistryService,
			ImageEventLogger: daemon.LogImageEvent,
			MetadataStore:    daemon.distributionMetadataStore,
			ImageStore:       distribution.NewImageConfigStoreFromStore(daemon.imageStore),
			ReferenceStore:   daemon.referenceStore,
		},
		DownloadManager: daemon.downloadManager,
		Schema2Types:    distribution.ImageTypes,
	}

	err := distribution.Pull(ctx, ref, imagePullConfig)
	close(progressChan)
	<-writesDone
	return err
}

// PullImage initiates a pull operation. image is the repository name to pull, and
// tag may be either empty, or indicate a specific tag to pull.
func (daemon *Daemon) PullImage(ref reference.Named, metaHeaders map[string][]string, authConfig *cliconfig.AuthConfig, outStream io.Writer) error {
	imagePullConfig := &distribution.ImagePullConfig{
		MetaHeaders:     metaHeaders,
		AuthConfig:      authConfig,
		OutStream:       outStream,
		RegistryService: daemon.RegistryService,
		EventsService:   daemon.EventsService,
		MetadataStore:   daemon.distributionMetadataStore,
		LayerStore:      daemon.layerStore,
		ImageStore:      daemon.imageStore,
		TagStore:        daemon.tagStore,
		Pool:            daemon.distributionPool,
	}

	return distribution.Pull(ref, imagePullConfig)
}