id3v1.go

package tag

import (
	"bytes"
	"image"
	"io"
	"io/ioutil"
	"os"
	"strconv"
	"time"
)

// ID3v1 - struct for store id3v1 data format
// with fix size - 128 bytes.
type ID3v1 struct {
	Type     string // Always 'TAG'
	Title    string // length 30. 30 characters of the title
	Artist   string // length 30. 30 characters of the artist name
	Album    string // length 30. 30 characters of the album name
	Year     int    // length 4. A four-digit year.
	Comment  string // length 28 or 30. The comment.
	ZeroByte byte   // length 1. If a track number is stored, this byte contains a binary 0.
	Track    byte   // length 1. The number of the track on the album, or 0. Invalid, if previous byte is not a binary 0.
	Genre    Genre  // length 1. Index in a list of genres, or 255

	// another file data
	Data []byte
}

func (id3v1 *ID3v1) GetFileData() []byte {
	return id3v1.Data
}

func (id3v1 *ID3v1) String() string {
	var trackNumber string
	if id3v1.ZeroByte == 0 {
		trackNumber = "TrackNumber: " + strconv.Itoa(int(id3v1.Track)) + "\n"
	}

	return "Type: " + id3v1.Type + "\n" +
		"Title: " + id3v1.Title + "\n" +
		"Artist: " + id3v1.Artist + "\n" +
		"Album: " + id3v1.Album + "\n" +
		"Year: " + strconv.Itoa(id3v1.Year) + "\n" +
		"Comment: " + id3v1.Comment + "\n" +
		trackNumber
}

func checkID3v1(input io.ReadSeeker) bool {
	marker, err := seekAndReadString(input, -id3v1SizeHeader, io.SeekEnd, id3v1SizeType)
	if err != nil || marker != id3MarkerName {
		return false
	}

	return true
}

func ReadID3v1(input io.ReadSeeker) (*ID3v1, error) {
	header := ID3v1{}

	// 128 byte - Header size
	headerByte, err := seekAndRead(input, -id3v1SizeHeader, io.SeekEnd, id3v1SizeHeader)
	if err != nil {
		return nil, err
	}

	// Type
	marker := string(headerByte[0:3])
	if marker != id3MarkerName {
		return nil, ErrFileMarker
	}
	header.Type = marker

	// Title
	header.Title = stringBeforeZero(headerByte[3:33])

	// Artist
	header.Artist = stringBeforeZero(headerByte[33:63])

	// Album
	header.Album = stringBeforeZero(headerByte[63:93])

	// Year
	header.Year, err = strconv.Atoi(string(headerByte[93:97]))
	if err != nil {
		return nil, ErrReadFile
	}

	// Comment
	// The track number is stored in the last two bytes of the comment field.
	// If the comment is 29 or 30 characters long, no track number can be stored
	if headerByte[125] == 0 {
		header.Comment = stringBeforeZero(headerByte[97:125])
		header.ZeroByte = 0
		header.Track = headerByte[126]
	} else {
		header.Comment = stringBeforeZero(headerByte[97:127])
		header.ZeroByte = headerByte[125]
		header.Track = 0
	}

	// Genre
	// Index in a list of genres, or 255
	header.Genre = Genre(headerByte[127])

	// Read another file data
	_, err = input.Seek(0, io.SeekStart)
	if err != nil {
		return nil, err
	}

	data, err := ioutil.ReadAll(input)
	if err != nil {
		return nil, err
	}
	// without header
	header.Data = data[:len(data)-128]

	return &header, nil
}

// Return string without zero characters.
func stringBeforeZero(data []byte) string {
	n := bytes.IndexByte(data, 0)
	if n == -1 {
		return string(data)
	}
	return string(data[:n])
}

func (id3v1 *ID3v1) SaveFile(path string) error {
	file, err := os.Create(path)
	if err != nil {
		return err
	}
	defer file.Close()

	return id3v1.Save(file)
}

func (id3v1 *ID3v1) Save(input io.WriteSeeker) error {
	_, err := input.Write(id3v1.Data)
	if err != nil {
		return err
	}

	// id3v1 marker
	_, err = input.Write([]byte(id3MarkerName))
	if err != nil {
		return err
	}

	// Title
	err = writeString(input, id3v1.Title, 30)
	if err != nil {
		return err
	}

	// Artist
	err = writeString(input, id3v1.Artist, 30)
	if err != nil {
		return err
	}

	// Album
	err = writeString(input, id3v1.Album, 30)
	if err != nil {
		return err
	}

	// Year
	err = writeString(input, strconv.Itoa(id3v1.Year), 4)
	if err != nil {
		return err
	}

	// Track number
	// nolint:nestif
	if id3v1.ZeroByte != 0 {
		if len(id3v1.Comment) > 28 {
			err = writeString(input, id3v1.Comment, 30)
			if err != nil {
				return err
			}
		} else {
			// for fill track number
			err = writeString(input, id3v1.Comment, 28)
			if err != nil {
				return err
			}
			_, err = input.Write([]byte{1, 0})
			if err != nil {
				return err
			}
		}
	} else {
		err = writeString(input, id3v1.Comment, 28)
		if err != nil {
			return err
		}
		_, err = input.Write([]byte{0, id3v1.Track})
		if err != nil {
			return err
		}
	}

	_, err = input.Write([]byte{byte(id3v1.Genre)})
	if err != nil {
		return err
	}

	return nil
}

func writeString(input io.Writer, data string, size int) error {
	if len(data) > size {
		return ErrWriteFile
	}

	bytesStr := make([]byte, size)
	for i, val := range data {
		bytesStr[i] = byte(val)
	}
	n, err := input.Write(bytesStr)
	if err != nil {
		return err
	}
	if n != size {
		return ErrWriteFile
	}

	return nil
}

func (id3v1 *ID3v1) GetAllTagNames() []string {
	result := []string{"Title", "Artist", "Album", "Year", "Comment"}
	if id3v1.ZeroByte == 0 {
		result = append(result, "TrackNumber")
	}
	return result
}

func (id3v1 *ID3v1) GetVersion() Version {
	return VersionID3v1
}

func (id3v1 *ID3v1) GetTitle() (string, error) {
	return id3v1.Title, nil
}

func (id3v1 *ID3v1) GetArtist() (string, error) {
	return id3v1.Artist, nil
}

func (id3v1 *ID3v1) GetAlbum() (string, error) {
	return id3v1.Album, nil
}

func (id3v1 *ID3v1) GetYear() (int, error) {
	return id3v1.Year, nil
}

func (id3v1 *ID3v1) GetComment() (string, error) {
	return id3v1.Comment, nil
}

func (id3v1 *ID3v1) GetGenre() (string, error) {
	return id3v1.Genre.String(), nil
}

func (id3v1 *ID3v1) GetAlbumArtist() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetDate() (time.Time, error) {
	return time.Now(), ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetArranger() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetAuthor() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetBPM() (int, error) {
	return 0, ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetCatalogNumber() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetCompilation() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetComposer() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetConductor() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetCopyright() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetDescription() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetDiscNumber() (int, int, error) {
	return 0, 0, ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetEncodedBy() (string, error) {
	return "", ErrUnsupportedTag
}

func (id3v1 *ID3v1) GetTrackNumber() (int, int, error) {
	if id3v1.ZeroByte == 0 {
		return int(id3v1.Track), int(id3v1.Track), nil
	}
	return 0, 0, ErrTagNotFound
}

func (id3v1 *ID3v1) GetPicture() (image.Image, error) {
	return nil, ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetTitle(title string) error {
	if len(title) > 30 {
		return ErrIncorrectLength
	}
	id3v1.Title = title
	return nil
}

func (id3v1 *ID3v1) SetArtist(artist string) error {
	if len(artist) > 30 {
		return ErrIncorrectLength
	}
	id3v1.Artist = artist
	return nil
}

func (id3v1 *ID3v1) SetAlbum(album string) error {
	if len(album) > 30 {
		return ErrIncorrectLength
	}
	id3v1.Album = album
	return nil
}

func (id3v1 *ID3v1) SetYear(year int) error {
	id3v1.Year = year
	return nil
}

func (id3v1 *ID3v1) SetComment(comment string) error {
	if len(comment) > 30 {
		return ErrIncorrectLength
	}
	if id3v1.ZeroByte == 0 && len(comment) > 28 {
		return ErrIncorrectLength
	}
	id3v1.Comment = comment
	return nil
}

func (id3v1 *ID3v1) SetGenre(genre string) error {
	gen, err := GetGenreByName(genre)
	if err != nil {
		return err
	}
	id3v1.Genre = gen
	return nil
}

func (id3v1 *ID3v1) SetAlbumArtist(albumArtist string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetDate(date time.Time) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetArranger(arranger string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetAuthor(author string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetBPM(bmp int) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetCatalogNumber(catalogNumber string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetCompilation(compilation string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetComposer(composer string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetConductor(conductor string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetCopyright(copyright string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetDescription(description string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetDiscNumber(number int, total int) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetEncodedBy(encodedBy string) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) SetTrackNumber(number int, total int) error {
	if len(id3v1.Comment) > 28 {
		return ErrIncorrectLength
	}
	id3v1.ZeroByte = 0
	id3v1.Track = byte(number)
	return nil
}

func (id3v1 *ID3v1) SetPicture(picture image.Image) error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteAll() error {
	id3v1.Title = ""
	id3v1.Artist = ""
	id3v1.Album = ""
	id3v1.Year = 0
	id3v1.Comment = ""
	id3v1.ZeroByte = id3v1NoTrackNumber // without track number
	id3v1.Track = 0
	id3v1.Genre = 255
	return nil
}

func (id3v1 *ID3v1) DeleteTitle() error {
	id3v1.Title = ""
	return nil
}

func (id3v1 *ID3v1) DeleteArtist() error {
	id3v1.Artist = ""
	return nil
}

func (id3v1 *ID3v1) DeleteAlbum() error {
	id3v1.Album = ""
	return nil
}

func (id3v1 *ID3v1) DeleteYear() error {
	id3v1.Year = 0
	return nil
}

func (id3v1 *ID3v1) DeleteComment() error {
	id3v1.Comment = ""
	return nil
}

func (id3v1 *ID3v1) DeleteGenre() error {
	id3v1.Genre = id3v1NoGenre
	return nil
}

func (id3v1 *ID3v1) DeleteAlbumArtist() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteDate() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteArranger() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteAuthor() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteBPM() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteCatalogNumber() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteCompilation() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteComposer() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteConductor() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteCopyright() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteDescription() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteDiscNumber() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteEncodedBy() error {
	return ErrUnsupportedTag
}

func (id3v1 *ID3v1) DeleteTrackNumber() error {
	id3v1.ZeroByte = id3v1NoTrackNumber
	id3v1.Track = 0
	return nil
}

func (id3v1 *ID3v1) DeletePicture() error {
	return ErrUnsupportedTag
}