#!/bin/sh
#
# metaflac-field2field.sh, Copyright © 2009 Matteo Cypriani
#
# This program is free software. It comes without any warranty, to
# the extent permitted by applicable law. You can redistribute it
# and/or modify it under the terms of the Do What The Fuck You Want
# To Public License, Version 2, as published by Sam Hocevar. See
# http://sam.zoy.org/wtfpl/COPYING for more details.
#
# This script uses metaflac to process field to field copy/rename on
# FLAC file metadatas.
# Launch this script without arguments to display usage.
# ----
# Ce script utilise metaflac pour effectuer des actions de copie ou
# renommage de champ à champ sur les fichiers FLAC.
# Lancer ce script sans argument pour afficher son utilisation.

#set -x

print_usage()
{
    echo "Usage:"
    echo "  $0 <ACTION> <SRC_FIELD> <DST_FIELD> <FILE.flac> [ <FILE2.flac> [...] ]"
    echo "<ACTION> : copy | move | rmcopy | mvcopy"
    echo "  copy: each occurrence of SRC_FIELD is duplicated to create an occurrence of"
    echo "        DST_FIELD; all the existing occurrences of SRC_FIELD and DST_FIELD are"
    echo "        kept."
    echo "  move: each occurrence of SRC_FIELD is renamed to create an occurrence of"
    echo "        DST_FIELD; the existing occurrences of DST_FIELD are kept."
    echo "  rmcopy: the existing occurrences of DST_FIELD are deleted, then each"
    echo "          occurrence of SRC_FIELD is duplicated to create an occurrence"
    echo "          of DST_FIELD; the occurrences of SRC_FIELD are kept."
    echo "  rmmove: the existing occurrences of DST_FIELD are deleted, then each"
    echo "          occurrence of SRC_FIELD is renamed to create an occurrence of"
    echo "          DST_FIELD."
    exit 1
}

# Right number of arguments?
if [ $# -lt 4 ] ; then
    echo "Wrong number of arguments!"
    print_usage
fi

ACTION=$1
shift

# Known action type?
case $ACTION in
    copy) ;;
    move) ;;
    rmcopy) ;;
    rmmove) ;;
    *) echo "Action unknown \"$ACTION\"!" ; print_usage ;;
esac

SRC_FIELD=$1
shift
DST_FIELD=$1
shift

echo "Source field: $SRC_FIELD"
echo "Destination field: $DST_FIELD"
echo "Action: $ACTION"

echo "Processing files..."

if echo $ACTION | egrep '^rm' >/dev/null ; then
    echo "Deleting field $DST_FIELD on each file..."
    metaflac --remove-tag=$DST_FIELD "$@"
fi

for file in "$@" ; do
    echo "Setting field \"$DST_FIELD\" on file: $file"
    metaflac --show-tag=$SRC_FIELD "$file" | sed 's/^[A-Z]\+=//' | while read c1 ; do
    echo "Adding $DST_FIELD=$c1..."
    metaflac --set-tag=$DST_FIELD="$c1" "$file"
done
done

if echo $ACTION | egrep 'move$' >/dev/null ; then
    echo "Deleting $SRC_FIELD on each file..."
    metaflac --remove-tag=$SRC_FIELD "$@"
fi

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