#!/usr/bin/env ruby
args = ARGV.reverse
paranoia = true
f_tags = "./lst"

def usage()
    puts "
usage:
    #{__FILE__} [-x] [filename]
        -x: don't use cdparanoia
        filename: the file where to find the tags
        
        the tag file must be formated in order to contain a soundfile group of tags per line as this:
            <tag>: <data>
        the accepted tags are: artist, album, year, comment and style,
        plus the track number for the title infos.
            e.g.:
                artist: roger
                album: the musette big back
                1: acordeon hardcore
                2: psychimamie

                etc."
    exit
end

class F_tags

    attr_reader :infos

    def initialize(filename)
        begin
            f_tags = File.open(filename)
        rescue
            puts "error while opening the tag file:"
            puts $!
            exit
        end

        tracks = []
        artist = album = year = comment = style = "unknown"
        track_count = 0
        while (line = f_tags.gets)
            if not line[/^ *$/]
                case line[/^\w+: /]
                    when "artist: ", "artiste: " then artist = $'
                    when "album: " then album = $'
                    when "year: ", "année: " then year = $'
                    when "comment: ", "commentaire: " then comment = $'
                    when "style: " then style = $'
                else
                    tag, data = $&, $'
                    if data[/^\d{2}/]
                        tracks << $&
                        track_count += 1
                    else
                        puts "invalid tag: #{tag}"
                        exit
                    end
                end
            end
        end
        f_tags.close
        @infos = {  "artist"    => artist,
                    "album"     => album,
                    "year"      => year,
                    "comment"   => comment,
                    "style"     => style,
                    "count"     => track_count,
                    "tracks"    => tracks
        }
    end
end

while args != []
    argument = args[args.length - 1]
    case argument
        when "-x" then paranoia = false
        else File.exist?(argument) ? f_tags = argument : usage
    end
    args.pop
end

tags = F_tags.new(f_tags)

%x(cdparanoia -B) if paranoia
fichiers = Dir.new('.').entries.delete_if { |f| ! f[/\.wav/] }

if fichiers.length != tags.infos['count']
    puts "error: the number of extracted tracks and the one get from the tagsfile do not match"
    exit
end

fichiers.each { |fichier|
    numero = fichier[/\d{2}/]
    %x(oggenc -q8 \
    -N #{numero} \
    -a #{tags.infos['artist']} \
    -g #{tags.infos['style']} \
    -d #{tags.infos['year']} \
    -t #{tags.infos['tracks'][numero-1]} \
    -l #{tags.infos['album']} \
    -c #{tags.infos['comment']} \
    #{fichier})
}