message TopTracks {
    optional string country = 1;
    repeated Track track = 2;
}
message ActivityPeriod {
    optional sint32 start_year = 1;
    optional sint32 end_year = 2;
    optional sint32 decade = 3;
}
message Artist {
    optional bytes gid = 1;
    optional string name = 2;
    optional sint32 popularity = 3;
    repeated TopTracks top_track = 4;
    repeated AlbumGroup album_group = 5;
    repeated AlbumGroup single_group = 6;
    repeated AlbumGroup compilation_group = 7;
    repeated AlbumGroup appears_on_group = 8;
    repeated string genre = 9;
    repeated ExternalId external_id = 10;
    repeated Image portrait = 11;
    repeated Biography biography = 12;
    repeated ActivityPeriod activity_period = 13;
    repeated Restriction restriction = 14;
    repeated Artist related = 15;
    optional bool is_portrait_album_cover = 16;
    optional ImageGroup portrait_group = 17;
}
message AlbumGroup {
    repeated Album album = 1;
}
message Date {
    optional sint32 year = 1;
    optional sint32 month = 2;
    optional sint32 day = 3;
}
message Album {
    enum Type {
        ALBUM = 1;
        SINGLE = 2;
        COMPILATION = 3;
    }
    optional bytes gid = 1;
    optional string name = 2;
    repeated Artist artist = 3;
    optional Type typ = 4;
    optional string label = 5;
    optional Date date = 6;
    optional sint32 popularity = 7;
    repeated string genre = 8;
    repeated Image cover = 9;
    repeated ExternalId external_id = 10;
    repeated Disc disc = 11;
    repeated string review = 12;
    repeated Copyright copyright = 13;
    repeated Restriction restriction = 14;
    repeated Album related = 15;
    repeated SalePeriod sale_period  = 16;
    optional ImageGroup cover_group  = 17;
}

message Track {
    optional bytes gid = 1;
    optional string name = 2;
    optional Album album = 3;
    repeated Artist artist = 4;
    optional sint32 number = 5;
    optional sint32 disc_number = 6;
    optional sint32 duration = 7;
    optional sint32 popularity = 8;
    optional bool explicit = 9;
    repeated ExternalId external_id = 10;
    repeated Restriction restriction = 11;
    repeated AudioFile file = 12;
    repeated Track alternative = 13;
    repeated SalePeriod sale_period = 14;
    repeated AudioFile preview = 15;
}
message Image {
    enum Size {
        DEFAULT = 0;
        SMALL = 1;
        LARGE = 2;
        XLARGE = 3;
    }
    optional bytes file_id = 1;
    optional Size size = 2;
    optional sint32 width = 3;
    optional sint32 height = 4;
}
message ImageGroup {
    repeated Image image = 1;
}
message Biography {
    optional string text = 1;
    repeated Image portrait = 2;
    repeated ImageGroup portrait_group = 3;
}
message Disc {
    optional sint32 number = 1;
    optional string name = 2;
    repeated Track track = 3;
}
message Copyright {
    enum Type {
        P = 0;
        C = 1;
    }
    optional Type typ = 1;
    optional string text = 2;
}
message Restriction {
    enum Catalogue {
        FREE = 0;
        PREMIUM = 1;
        SHUFFLE = 3;
        COMMERCIAL = 4;
    }
    enum Type {
        STREAMING = 0;
    }
    repeated Catalogue catalogue = 1;
    optional string countries_allowed = 2;
    optional string countries_forbidden = 3;
    optional Type typ = 4;
    repeated string usage = 5;
}

message SalePeriod {
    repeated Restriction restriction = 1;
    optional Date start = 2;
    optional Date end = 3;
}

message ExternalId {
    optional string typ = 1;
    optional string id = 2;
}

message AudioFile {
    enum Format {
        OGG_VORBIS_96 = 0;
        OGG_VORBIS_160 = 1;
        OGG_VORBIS_320 = 2;
        MP3_256 = 3;
        MP3_320 = 4;
        MP3_160 = 5;
        MP3_96 = 6;
        OTHER1 = 7; // TODO
        OTHER2 = 8; // TODO
    }
    optional bytes gid = 1;
    optional Format format = 2;
}