#!/bin/bash
# 
# 	reflac.sh
#
# 	Script to reencode flac files while preserving metadata
#
# Copyright 2011 Torben Deumert. All rights reserved.
#
# File		: reflac.sh
# Author	: Torben Deumert (tordeu at googlemail dot com)
# Date		: 2011-07-07
# Version	: 2011-11-23
# License	: FreeBSD License (see "License" section below)
#
#==============================[ Description ]========================================
#
# 	Reflac reencodes a flac file while preserving metadata. It was created
# 	to "repair" flac files that can not be used with oggenc because of the way
# 	the metadata is stored. In those cases oggenc produces the following 
# 	error message:
# 	  ERROR: Input file <file> is not a supported format
# 
#	 Because reflac REPLACES the flac files, backing up the original flac files
# 	is encouraged in case something goes wrong.
#
#==============================[ Usage ]========================================
#
# Usage:
#
#   reflac.sh <flac file>...
#
# Examples:
#
#   to reflac a single flac file named foo.flac, run:
#   
#		reflac.sh foo.flac
#
#	to reflac multi flac files (named foo.flac, bar.flac and what.flac):
#
#		reflac.sh foo.flac bar.flac what.flac
#
#	to reflac all flac files in the current directory
#
#		reflac.sh *.flac
#
#==============================[ License ]========================================
#
# Copyright 2001 Torben Deumert. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are
# permitted provided that the following conditions are met:
#
#    1. Redistributions of source code must retain the above copyright notice, this list of
#       conditions and the following disclaimer.
# 
#    2. Redistributions in binary form must reproduce the above copyright notice, this list
#       of conditions and the following disclaimer in the documentation and/or other materials
#       provided with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
# FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# 
# The views and conclusions contained in the software and documentation are those of the
# authors and should not be interpreted as representing official policies, either expressed
# or implied, of <copyright holder>.
#=================================================================================

# let's make the script a little more robust
set -u			# exit if the script tries to use an unbound variable
set -e			# exit we a command fails 
set -o pipefail # exit if a command in a pipe fails

# loop through all the arguments
while [ $# -ne 0 ]; do

FLAC=$1

# create two temporary files (one for the metadata, one for the wav)
META_TMP=`mktemp reflac.XXX`
WAV_TMP=`mktemp reflac.XXX.wav`

# export the metadata
metaflac --export-tags-to="$META_TMP" "$FLAC"

# reencode the flac
flac -d "$FLAC" -f -o "$WAV_TMP"

# reencode the wav
flac "$WAV_TMP" -f -o "$FLAC"

# add the metadata to the new flac
metaflac --import-tags-from="$META_TMP" "$FLAC"

# delete both temporary files
rm "$META_TMP"
rm "$WAV_TMP"

shift

done