// CreateStateFile creates an empty state file on the given storage, and
// returns its URL.
func CreateStateFile(stor storage.Storage) (string, error) {
	err := putState(stor, []byte{})
	if err != nil {
		return "", fmt.Errorf("cannot create initial state file: %v", err)
	}
	return stor.URL(StateFile)
}

func restoreBootstrapVerificationFile(c *gc.C, stor storage.Storage) {
	content := "juju-core storage writing verified: ok\n"
	contentReader := strings.NewReader(content)
	err := stor.Put("bootstrap-verify", contentReader,
		int64(len(content)))
	c.Assert(err, gc.IsNil)
}

// RemoveFakeToolsMetadata deletes the fake simplestreams tools metadata from the supplied storage.
func RemoveFakeToolsMetadata(c *gc.C, stor storage.Storage) {
	files := []string{simplestreams.UnsignedIndex, envtools.ProductMetadataPath}
	for _, file := range files {
		toolspath := path.Join("tools", file)
		err := stor.Remove(toolspath)
		c.Check(err, gc.IsNil)
	}
}

// RemoveTools deletes all tools from the supplied storage.
func RemoveTools(c *gc.C, stor storage.Storage) {
	names, err := storage.List(stor, "tools/releases/juju-")
	c.Assert(err, gc.IsNil)
	c.Logf("removing files: %v", names)
	for _, name := range names {
		err = stor.Remove(name)
		c.Check(err, gc.IsNil)
	}
	RemoveFakeToolsMetadata(c, stor)
}

// VerifyStorage writes the bootstrap init file to the storage to indicate
// that the storage is writable.
func VerifyStorage(stor storage.Storage) error {
	reader := strings.NewReader(verificationContent)
	err := stor.Put(VerificationFilename, reader,
		int64(len(verificationContent)))
	if err != nil {
		logger.Warningf("failed to write bootstrap-verify file: %v", err)
		return VerifyStorageError
	}
	return nil
}

func uploadMetadataFile(stor storage.Storage, metadataDir, fileName string, size int64) error {
	fullSourceFilename := filepath.Join(metadataDir, fileName)
	logger.Debugf("uploading metadata file %s", fileName)
	f, err := os.Open(fullSourceFilename)
	if err != nil {
		return err
	}
	defer f.Close()
	destMetadataDir := path.Join(storage.BaseImagesPath, simplestreams.StreamsDir)
	return stor.Put(path.Join(destMetadataDir, fileName), f, size)
}

func UseTestImageData(stor storage.Storage, cred *identity.Credentials) {
	// Put some image metadata files into the public storage.
	t := template.Must(template.New("").Parse(indexData))
	var metadata bytes.Buffer
	if err := t.Execute(&metadata, cred); err != nil {
		panic(fmt.Errorf("cannot generate index metdata: %v", err))
	}
	data := metadata.Bytes()
	stor.Put(simplestreams.DefaultIndexPath+".json", bytes.NewReader(data), int64(len(data)))
	stor.Put(
		productMetadatafile, strings.NewReader(imagesData), int64(len(imagesData)))
}

func storageCopy(source storage.Storage, sourcePath string, target storage.Storage, targetPath string) error {
	rc, err := storage.Get(source, sourcePath)
	if err != nil {
		return err
	}
	var buf bytes.Buffer
	_, err = io.Copy(&buf, rc)
	rc.Close()
	if err != nil {
		return err
	}
	return target.Put(targetPath, &buf, int64(buf.Len()))
}

// RemoveFakeTools deletes the fake tools from the supplied storage.
func RemoveFakeTools(c *gc.C, stor storage.Storage) {
	c.Logf("removing fake tools")
	toolsVersion := version.Current
	name := envtools.StorageName(toolsVersion)
	err := stor.Remove(name)
	c.Check(err, gc.IsNil)
	defaultSeries := coretesting.FakeDefaultSeries
	if version.Current.Series != defaultSeries {
		toolsVersion.Series = defaultSeries
		name := envtools.StorageName(toolsVersion)
		err := stor.Remove(name)
		c.Check(err, gc.IsNil)
	}
	RemoveFakeToolsMetadata(c, stor)
}

func uploadFakeToolsVersion(stor storage.Storage, vers version.Binary) (*coretools.Tools, error) {
	logger.Infof("uploading FAKE tools %s", vers)
	tgz, checksum := coretesting.TarGz(
		coretesting.NewTarFile("jujud", 0777, "jujud contents "+vers.String()))
	size := int64(len(tgz))
	name := envtools.StorageName(vers)
	if err := stor.Put(name, bytes.NewReader(tgz), size); err != nil {
		return nil, err
	}
	url, err := stor.URL(name)
	if err != nil {
		return nil, err
	}
	return &coretools.Tools{URL: url, Version: vers, Size: size, SHA256: checksum}, nil
}

// writeMetadata generates some basic simplestreams metadata using the specified cloud and image details and writes
// it to the supplied store.
func writeMetadata(metadata []*ImageMetadata, cloudSpec []simplestreams.CloudSpec,
	metadataStore storage.Storage) error {

	index, products, err := MarshalImageMetadataJSON(metadata, cloudSpec, time.Now())
	if err != nil {
		return err
	}
	metadataInfo := []MetadataFile{
		{simplestreams.UnsignedIndex, index},
		{ProductMetadataPath, products},
	}
	for _, md := range metadataInfo {
		err = metadataStore.Put(
			filepath.Join(storage.BaseImagesPath, md.Path), bytes.NewReader(md.Data), int64(len(md.Data)))
		if err != nil {
			return err
		}
	}
	return nil
}

func checkRemoveAll(c *gc.C, stor storage.Storage) {
	contents := []byte("File contents.")
	aFile := "a-file.txt"
	err := stor.Put(aFile, bytes.NewBuffer(contents), int64(len(contents)))
	c.Assert(err, gc.IsNil)
	err = stor.Put("empty-file", bytes.NewBuffer(nil), 0)
	c.Assert(err, gc.IsNil)

	err = stor.RemoveAll()
	c.Assert(err, gc.IsNil)

	files, err := storage.List(stor, "")
	c.Assert(err, gc.IsNil)
	c.Check(files, gc.HasLen, 0)

	_, err = storage.Get(stor, aFile)
	c.Assert(err, gc.NotNil)
	c.Check(err, gc.ErrorMatches, fmt.Sprintf("file %q not found", aFile))
}

// UploadToStorage uploads tools and metadata for the specified versions to storage.
func UploadToStorage(c *gc.C, stor storage.Storage, versions ...version.Binary) map[version.Binary]string {
	uploaded := map[version.Binary]string{}
	if len(versions) == 0 {
		return uploaded
	}
	var err error
	for _, vers := range versions {
		filename := fmt.Sprintf("tools/releases/tools-%s.tar.gz", vers.String())
		// Put a file in images since the dummy storage provider requires a
		// file to exist before the URL can be found. This is to ensure it behaves
		// the same way as MAAS.
		err = stor.Put(filename, strings.NewReader("dummy"), 5)
		c.Assert(err, gc.IsNil)
		uploaded[vers], err = stor.URL(filename)
		c.Assert(err, gc.IsNil)
	}
	objects := generateMetadata(c, versions...)
	for _, object := range objects {
		toolspath := path.Join("tools", object.path)
		err = stor.Put(toolspath, bytes.NewReader(object.data), int64(len(object.data)))
		c.Assert(err, gc.IsNil)
	}
	return uploaded
}

func RemoveTestImageData(stor storage.Storage) {
	stor.Remove(simplestreams.DefaultIndexPath + ".json")
	stor.Remove(productMetadatafile)
}

// DeleteStateFile deletes the state file on the given storage.
func DeleteStateFile(stor storage.Storage) error {
	return stor.Remove(StateFile)
}