#!/bin/bash

# This script will walk a folder recursively and:
# - if it encounters a .mp3 file with metadata, the file will be copied to the target folder
# - if it encounters a .ogg file with metadata, a .mp3 file will be created with metadata in the target folder
# - files (.mp3 or .ogg) that are missing metadata are reported
#
# required packages: sox, mp3info, ogginfo
# this script was based on info found at:
# - http://www.linuxweblog.com/convert-ogg-to-mp3
# - http://ubuntuforums.org/showpost.php?p=9859875&postcount=8
# - http://www.fell.it/2009/11/28/convert-ogg-files-to-mp3/
#
# author: dirk@onesparrow.com

# source and target folders
export OGG2MP3_SOURCE_FOLDER="/home/dirk/music"
export OGG2MP3_TARGET_FOLDER="/home/dirk/music1"

function handleFile (){
  NEW_FILE=`echo $1 | sed "s|$OGG2MP3_SOURCE_FOLDER|$OGG2MP3_TARGET_FOLDER|g" | sed 's/.ogg/.mp3/g'` 
  PARENT_FOLDER=`dirname "$NEW_FILE"`
  echo $1 "=>" $NEW_FILE
  mkdir -p "$PARENT_FOLDER"
  case $1 in
    *.mp3)
        # just copy to target if it is an mp3
        # skip when metadata is missing (mp3info will output "does not have ..." to stderr)
        if [[ `mp3info "$1" 2>&1 |grep "does not have an ID3 1.x tag"|wc -l` -eq 1 ]]
        then
          echo "  => NO METADATA, SKIPPING ..."
        else
          cp "$1" "$NEW_FILE"
        fi
        ;;
    *.ogg)
        # convert and add metadata 
        # extract metadata from .ogg and add it to .mp3
        OGGINFO=`ogginfo "$1"`
        OLD_IFS=$IFS
        IFS="
"
        TITLE="Unknown"
        ALBUM="Unknown"
        ARTIST="Unknown"
        TRACKNUMBER="Unknown"
        DATE="Unknown"
        for line in $OGGINFO
        do
           if [[ $line == *TITLE=* ]]
           then
             TITLE=${line#*=}
           elif [[ $line == *ALBUM=* ]]
           then
             ALBUM=${line#*=}
           elif [[ $line == *ARTIST=* ]]
           then
             ARTIST=${line#*=}
           elif [[ $line == *TRACKNUMBER=* ]]
           then
             TRACKNUMBER=${line#*=}
           elif [[ $line == *DATE=* ]]
           then
             DATE=${line#*=}   
           fi 
        done 
        IFS=$OLD_IFS
        if [[ $TITLE  == "Unknown" ]]
        then
          echo "  => NO METADATA, SKIPPING ..."
        else
          sox "$1" "$NEW_FILE"
          mp3info -a "$ARTIST" -l "$ALBUM" -n "$TRACKNUMBER" -t "$TITLE" -y "$DATE" "$NEW_FILE"
        fi
        ;;
    *) echo "  => UNEXPECTED FILE TYPE, SKIPPING";;
  esac 
}

export -f handleFile 

# walk the tree
find $OGG2MP3_SOURCE_FOLDER -type f -exec bash -c 'handleFile "{}"' \;