func parseMetadataFromParams(p params.CloudImageMetadata) cloudimagemetadata.Metadata {

	parseSource := func(s string) cloudimagemetadata.SourceType {
		switch cloudimagemetadata.SourceType(strings.ToLower(s)) {
		case cloudimagemetadata.Public:
			return cloudimagemetadata.Public
		case cloudimagemetadata.Custom:
			return cloudimagemetadata.Custom
		default:
			panic(fmt.Sprintf("unknown cloud image metadata source %q", s))
		}
	}

	result := cloudimagemetadata.Metadata{
		cloudimagemetadata.MetadataAttributes{
			Stream:          p.Stream,
			Region:          p.Region,
			Series:          p.Series,
			Arch:            p.Arch,
			VirtualType:     p.VirtualType,
			RootStorageType: p.RootStorageType,
			RootStorageSize: p.RootStorageSize,
			Source:          parseSource(p.Source),
		},
		p.ImageId,
	}
	if p.Stream == "" {
		result.Stream = "released"
	}
	return result
}

// storeImageMetadataInState writes image metadata into state store.
func storeImageMetadataInState(st *state.State, source string, priority int, existingMetadata []*imagemetadata.ImageMetadata) error {
	if len(existingMetadata) == 0 {
		return nil
	}
	metadataState := make([]cloudimagemetadata.Metadata, len(existingMetadata))
	for i, one := range existingMetadata {
		m := cloudimagemetadata.Metadata{
			cloudimagemetadata.MetadataAttributes{
				Stream:          one.Stream,
				Region:          one.RegionName,
				Arch:            one.Arch,
				VirtType:        one.VirtType,
				RootStorageType: one.Storage,
				Source:          source,
			},
			priority,
			one.Id,
		}
		s, err := seriesFromVersion(one.Version)
		if err != nil {
			return errors.Annotatef(err, "cannot determine series for version %v", one.Version)
		}
		m.Series = s
		metadataState[i] = m
	}
	if err := st.CloudImageMetadataStorage.SaveMetadata(metadataState); err != nil {
		return errors.Annotatef(err, "cannot cache image metadata")
	}
	return nil
}

// saveCustomImageMetadata reads the custom image metadata from disk,
// and saves it in state server.
func (c *BootstrapCommand) saveCustomImageMetadata(st *state.State) error {
	logger.Debugf("saving custom image metadata from %q", c.ImageMetadataDir)

	baseURL := fmt.Sprintf("file://%s", filepath.ToSlash(c.ImageMetadataDir))
	datasource := simplestreams.NewURLDataSource("bootstrap metadata", baseURL, utils.NoVerifySSLHostnames)

	// Read the image metadata, as we'll want to upload it to the environment.
	imageConstraint := imagemetadata.NewImageConstraint(simplestreams.LookupParams{})
	existingMetadata, _, err := imagemetadata.Fetch(
		[]simplestreams.DataSource{datasource}, imageConstraint, false)
	if err != nil && !errors.IsNotFound(err) {
		return errors.Annotate(err, "cannot read image metadata")
	}

	if len(existingMetadata) == 0 {
		return nil
	}
	msg := ""
	for _, one := range existingMetadata {
		m := cloudimagemetadata.Metadata{
			cloudimagemetadata.MetadataAttributes{
				Stream:          one.Stream,
				Region:          one.RegionName,
				Arch:            one.Arch,
				VirtType:        one.VirtType,
				RootStorageType: one.Storage,
				Source:          "custom",
			},
			one.Id,
		}
		s, err := seriesFromVersion(one.Version)
		if err != nil {
			return errors.Annotatef(err, "cannot determine series for version %v", one.Version)
		}
		m.Series = s
		err = st.CloudImageMetadataStorage.SaveMetadata(m)
		if err != nil {
			return errors.Annotatef(err, "cannot cache image metadata %v", m)
		}
	}
	if len(msg) > 0 {
		return errors.New(msg)
	}
	return nil
}

func (s *cloudImageMetadataSuite) TestSaveDiffMetadataConcurrentlyAndOrderByDateCreated(c *gc.C) {
	attrs := cloudimagemetadata.MetadataAttributes{
		Stream: "stream",
		Series: "series",
		Arch:   "arch",
	}
	metadata0 := cloudimagemetadata.Metadata{attrs, "0"}
	metadata1 := cloudimagemetadata.Metadata{attrs, "1"}
	metadata1.Stream = "scream"

	s.assertConcurrentSave(c,
		metadata0, // add this one
		metadata1, // add this one
		// last added should be first as order is by date created
		metadata1, // verify it's in the list
		metadata0, // verify it's in the list
	)
}

// storeImageMetadataInState writes image metadata into state store.
func storeImageMetadataInState(st *state.State, env environs.Environ, source string, priority int, existingMetadata []*imagemetadata.ImageMetadata) error {
	if len(existingMetadata) == 0 {
		return nil
	}
	cfg := env.Config()
	metadataState := make([]cloudimagemetadata.Metadata, len(existingMetadata))
	for i, one := range existingMetadata {
		m := cloudimagemetadata.Metadata{
			MetadataAttributes: cloudimagemetadata.MetadataAttributes{
				Stream:          one.Stream,
				Region:          one.RegionName,
				Arch:            one.Arch,
				VirtType:        one.VirtType,
				RootStorageType: one.Storage,
				Source:          source,
				Version:         one.Version,
			},
			Priority: priority,
			ImageId:  one.Id,
		}
		s, err := seriesFromVersion(one.Version)
		if err != nil {
			return errors.Annotatef(err, "cannot determine series for version %v", one.Version)
		}
		m.Series = s
		if m.Stream == "" {
			m.Stream = cfg.ImageStream()
		}
		if m.Source == "" {
			m.Source = "custom"
		}
		metadataState[i] = m
	}
	if err := st.CloudImageMetadataStorage.SaveMetadata(metadataState); err != nil {
		return errors.Annotatef(err, "cannot cache image metadata")
	}
	return nil
}

func (api *API) parseMetadataFromParams(p params.CloudImageMetadata, env environs.Environ) (cloudimagemetadata.Metadata, error) {
	result := cloudimagemetadata.Metadata{
		cloudimagemetadata.MetadataAttributes{
			Stream:          p.Stream,
			Region:          p.Region,
			Version:         p.Version,
			Series:          p.Series,
			Arch:            p.Arch,
			VirtType:        p.VirtType,
			RootStorageType: p.RootStorageType,
			RootStorageSize: p.RootStorageSize,
			Source:          p.Source,
		},
		p.Priority,
		p.ImageId,
	}

	// Fill in any required default values.
	if p.Stream == "" {
		result.Stream = env.Config().ImageStream()
	}
	if p.Source == "" {
		result.Source = "custom"
	}
	if result.Arch == "" {
		result.Arch = "amd64"
	}
	if result.Series == "" {
		result.Series = config.PreferredSeries(env.Config())
	}
	if result.Region == "" {
		// If the env supports regions, use the env default.
		if r, ok := env.(simplestreams.HasRegion); ok {
			spec, err := r.Region()
			if err != nil {
				return cloudimagemetadata.Metadata{}, errors.Annotatef(err, "getting cloud region")
			}
			result.Region = spec.Region
		}
	}
	return result, nil
}

// imageMetadataFromDataSources finds image metadata that match specified criteria in existing data sources.
func (p *ProvisionerAPI) imageMetadataFromDataSources(env environs.Environ, constraint *imagemetadata.ImageConstraint) ([]params.CloudImageMetadata, error) {
	sources, err := environs.ImageMetadataSources(env)
	if err != nil {
		return nil, errors.Trace(err)
	}

	cfg := env.Config()
	toModel := func(m *imagemetadata.ImageMetadata, mSeries string, source string, priority int) cloudimagemetadata.Metadata {
		result := cloudimagemetadata.Metadata{
			MetadataAttributes: cloudimagemetadata.MetadataAttributes{
				Region:          m.RegionName,
				Arch:            m.Arch,
				VirtType:        m.VirtType,
				RootStorageType: m.Storage,
				Source:          source,
				Series:          mSeries,
				Stream:          m.Stream,
				Version:         m.Version,
			},
			Priority: priority,
			ImageId:  m.Id,
		}
		// TODO (anastasiamac 2016-08-24) This is a band-aid solution.
		// Once correct value is read from simplestreams, this needs to go.
		// Bug# 1616295
		if result.Stream == "" {
			result.Stream = constraint.Stream
		}
		if result.Stream == "" {
			result.Stream = cfg.ImageStream()
		}
		return result
	}

	var metadataState []cloudimagemetadata.Metadata
	for _, source := range sources {
		logger.Debugf("looking in data source %v", source.Description())
		found, info, err := imagemetadata.Fetch([]simplestreams.DataSource{source}, constraint)
		if err != nil {
			// Do not stop looking in other data sources if there is an issue here.
			logger.Warningf("encountered %v while getting published images metadata from %v", err, source.Description())
			continue
		}
		for _, m := range found {
			mSeries, err := series.VersionSeries(m.Version)
			if err != nil {
				logger.Warningf("could not determine series for image id %s: %v", m.Id, err)
				continue
			}
			metadataState = append(metadataState, toModel(m, mSeries, info.Source, source.Priority()))
		}
	}
	if len(metadataState) > 0 {
		if err := p.st.CloudImageMetadataStorage.SaveMetadata(metadataState); err != nil {
			// No need to react here, just take note
			logger.Warningf("failed to save published image metadata: %v", err)
		}
	}

	// Since we've fallen through to data sources search and have saved all needed images into controller,
	// let's try to get them from controller to avoid duplication of conversion logic here.
	all, err := p.imageMetadataFromState(constraint)
	if err != nil {
		return nil, errors.Annotate(err, "could not read metadata from controller after saving it there from data sources")
	}

	if len(all) == 0 {
		return nil, errors.NotFoundf("image metadata for series %v, arch %v", constraint.Series, constraint.Arches)
	}

	return all, nil
}