#!/bin/bash

function g_compress_audio {
 # Datei OK und noch da?
 local g_aud=$@
 g_test_mediafile "$g_aud" || return 1
 # File already converted
 if egrep -q "HE-AAC.+32 kb" "$g_tmp"/audinfo
 then
  g_echo "Audio $g_aud bereits bearbeitet - Bearbeite nur Metadata/Tags"
  g_audiosettings="-c:a copy"
 else
  # Audio Mono/Stereo Codec?
  if cat "$g_tmp"/audinfo | egrep -q "Stream.+mono"
  then
   g_echo "Bearbeite Mono Audiodatei $g_aud"
   #g_audiosettings="-af loudnorm=I=-16:LRA=11 -ar 44100 -c:a libfdk_aac -profile:a aac_he -b:a 32k"
   g_audiosettings="-ar 44100 -c:a libfdk_aac -profile:a aac_he -b:a 64k"
  else
   g_echo "Bearbeite Audiodatei $g_aud"
   #g_audiosettings="-af loudnorm=I=-16:LRA=11 -ar 44100 -ac 2 -c:a libfdk_aac -profile:a aac_he_v2 -b:a 32k"
   g_audiosettings="-ar 44100 -ac 2 -c:a libfdk_aac -profile:a aac_he_v2 -b:a 64k"
  fi
 fi
 # Tags/Metadata
 # Convert to UTF if ISO
 file -b "$g_tmp"/audinfo | grep -q "ISO-8859 text" && iconv -f ISO-8859-15 -t UTF-8 "$g_tmp"/audinfo -o "$g_tmp"/audinfo
 # Tag substitutions
 cat <<EOF > ${g_tmp}/perlsubstitutions
## Prepare ffmpeg output
# Ignore Picture/Video/Cover metadata
\$ign='1' if (/Stream .+ Video/);
\$_='' if (\$ign);
# Substitute multiple spaces with one
s/ +/ /g;
# Remove space in line beginning
s/^ //;
# Substitute " : " with "='" for variable setting
s/ : /=/;
s/^(title|album|artist|track|date|genre)= +/\$1=/;
# Case insensitive Tags
s/^title/title/i;
s/^artist/artist/i;
s/^date/date/i;
s/^album/album/i;
s/^genre/genre/i;
s/^track/track/i;

# Ignore everything but the 6 tags
\$_='' unless (/^(title|album|artist|track|date|genre)=/);
unless (/^\$/) {
 ## Work on TAGs
 # Remove unwanted stings
 s/’/´/g; 
 s/'/\´/g;
 s/\`/\´/g;
 s/ +$//; 
 s/\'/\´/g;
 # cyrillic2latin
 if (/^(title|album|artist)=/) {
  chomp;
  \$before_equal=\$_;
  \$before_equal=~s/^(title|album|artist)=.+/\$1/;
  \$tag=\$_;
  \$tag=~s/ - \(.+$//g;
  \$tag=~s/^(title|album|artist)=//;
  \$_=\$tag;
  s/а/a/g; s/А/A/g; s/б/b/g; s/Б/B/g; s/в/w/g; s/В/W/g; s/г/g/g; s/Г/G/g; s/д/d/g; s/Д/D/g; s/ье/je/g; s/ъе/je/g; s/\sе/je/g; s/\sЕ/Je/g; s/е/e/g; s/Е/E/g; s/шё/scho/g; s/жё/sho/g; s/чё/tscho/g; s/щё/schtscho/g; s/ё/jo/g; s/Ё/Jo/g; s/ж/sh/g; s/Ж/Sh/g; s/з/s/g; s/З/S/g; s/ьи/ji/g; s/ьий/ji/g; s/ий/i/g; s/ый/y/g; s/Й/I/g; s/и/i/g; s/И/I/g; s/й/j/g; s/Й/J/g; s/кс/x/g; s/к/k/g; s/К/K/g; s/л/l/g; s/Л/L/g; s/м/m/g; s/М/M/g; s/н/n/g; s/Н/N/g; s/ьо/jo/g; s/ь/´/g; s/о/o/g; s/О/O/g; s/п/p/g; s/П/P/g; s/р/r/g; s/Р/R/g; s/с/s/g; s/С/S/g; s/т/t/g; s/Т/T/g; s/у/u/g; s/У/U/g; s/ф/f/g; s/Ф/F/g; s/х/ch/g; s/Х/Ch/g; s/ц/z/g; s/Ц/Z/g; s/ч/tsch/g; s/Ч/Tsch/g; s/ш/sch/g; s/Ш/Sch/g; s/щ/schtsch/g; s/Щ/Schtsch/g; s/ы/y/g; s/Ы/Y/g; s/э/e/; s/Э/e/; s/ю/ju/g; s/Ю/Ju/g; s/я/ja/g; s/Я/Ja/g; s/ў/w/g; s/Ў/W/g;
  \$newtag=\$_;
  if (\$tag eq \$newtag) {
   \$_="\$before_equal=\$tag\n";
  }
  else {
   \$_="\$before_equal=\$tag - (\$newtag)\n";
  }
 }
 # date/year
 s/^date.+([1-2][890][0-9][0-9]).+\$/date=\$1/ if (/^date=/);
 # track no 0 in the beginning
 s/=0+/=/ if (/^track=/);
 # Add ' in line end - variable string end and after =
 s/^(title|album|artist|track|date|genre)=/\$1='/;
 s/(.+)$/\$1\'/;
 
 ## Prepare commandline for ffmpeg
 s/^/-metadata /; 
 s/\n/ /;
}
EOF
# Script for getting ID3-Tags in the right codepage - ffmpeg doesn't convert some codepages
#echo '#!/usr/bin/perl
#use MP3::Tag;
#$filename = $ARGV[0];
#$mp3 = MP3::Tag->new($filename);
#$mp3->get_tags();
#if (exists $mp3->{ID3v2}) {
# $frames = $mp3->{ID3v2}->get_frame_ids();
# foreach $frame (keys %$frames) {
#  ($value, $desc) = $mp3->{ID3v2}->get_frame($frame);
#  $frame="date" if ( $frame eq "TDRL" );
#  $frame="date" if ( $frame eq "TYER" );
#  $frame="title" if ( $frame eq "TIT2" );
#  $frame="genre" if ( $frame eq "TCON" );
#  $frame="album" if ( $frame eq "TALB" );
#  $frame="track" if ( $frame eq "TRCK" );
#  $frame="artist" if ( $frame eq "TPE1" );
#  print "$frame : $value\n";
# }
#}
#$mp3->close();
#' >"$g_tmp"/id3tags.pl
# perl "$g_tmp"/id3tags.pl "$g_aud" >"$g_tmp"/id3tags 2>/dev/null
# if [ -s "$g_tmp"/id3tags ] 
# then
#  file -b "$g_tmp"/id3tags | grep -q "ISO-8859 text" && iconv -f ISO-8859-15 -t UTF-8 "$g_tmp"/id3tags -o "$g_tmp"/id3tags
#  g_metadata=$(cat "$g_tmp"/id3tags | perl -pe "do \"${g_tmp}/perlsubstitutions\";")
# else
 g_metadata=$(cat "$g_tmp"/audinfo | perl -pe "do \"${g_tmp}/perlsubstitutions\";")
# fi
 # Convert!
 echo "ffmpeg -loglevel warning -threads 1 -i \"$g_aud\" -map_metadata -1 $g_audiosettings $g_metadata -map a:0 -y \"$g_tmp/m4a.m4a\" < /dev/null 2>&1" >"$g_tmp"/cmd
 sh "$g_tmp"/cmd
 if ffmpeg -i "$g_tmp/m4a.m4a" 2>&1 | egrep -q "Invalid data found when processing input|No such file or directory|Invalid argument|moov atom not found"
 then
  g_echo "Bearbeitung von $g_aud fehlgeschlagen"
  rm -f "$g_tmp/m4a.m4a"
  ffmpeg -i "$g_tmp/m4a.m4a"
  return 1
 fi
 local g_timestamp=$(ls --time-style='+%Y%m%d%H%M' -l "$g_aud" | cut -d" " -f6)
 # For update-copy or rsync one second newer file
 #g_timestamp=$((g_timestamp+1))
 cat "$g_tmp/m4a.m4a" >"$g_aud"
 rm -f "$g_tmp/m4a.m4a"
 touch -t $g_timestamp "$g_aud"
 g_naud=$(echo "$g_aud" | perl -pe 's/\.....$/.m4a/; s/\....$/.m4a/;')
 [ "$g_aud" != "$g_naud" ] && mv -v "$g_aud" "$g_naud"
}