#!/bin/sh
# ---------------------------------------------------------------------
# DESCRIPTION:
# Maintains an OGG Vorbis mirror of a file tree of FLAC audio files
#
# AUTHOR:
# Simon Kinsella, November 2009
# Chris Quirk, January 2010
#
# LICENSE: BSD license
# WARRANTY: NONE. Not rigorously tested, but it works for me!
# Use at your own risk.
#
# ---------------------------------------------------------------------
#
# IMPORTANT - paths to master and slave trees MUST be absolute!
#
# Syntax:
# ------
# ogg-sync.sh <master-tree> <slave-tree>
# where <master-tree> is an absolute path to the base of the FLAC audio
# tree.
# The OGG mirrors will be created under a directory 'q<n>' under
# absolute path <slave-tree> where n is defined by the QUALITY variable
# e.g.:
# ogg-sync.sh /music/flac-audio /music/ogg-mirrors
# will create an OGG mirror of '/music/flac-audio' under
# '/music/ogg-mirrors/q2/'
#
# FINAL WARNING: Please back-up your files and test the operation
# of this script before using day-to-day.
#
# TODO:
# 1) Make the syntax more forgiving, possibly
# 2) Better error handling / recovery, the usual stuff.
# 3) Find a way to dispatch encoding jobs concurrently for SMP systems.
#    Tried xjobs but was unsuccessful.
# 4) Make stat commands portable between linux and fbsd or clean up the conditionals
# 5) tag dump, reinsert all non-null tags into the new ogg as part of encoding (inserts new dependancy on metaflac)
# 6) test for absolute paths

OGGENC="$(which oggenc)"
SCRIPT="$(basename $0)"
ARCH="$(uname)"
#set quality to a value between or equal to -1 and 10.
#See: http://en.wikipedia.org/wiki/Vorbis
QUALITY=5 #override the quality argument

if [ -z "$QUALITY" ]; then
while getopts ":q:" Option
do
	case $Option in
	q ) QUALITY="${OPTARG}"
		if [ ${QUALITY} -lt -1 -o ${QUALITY} -gt 10 ]
		then
			echo "${SCRIPT}: Invalid Quality value '${QUALITY}'"
			exit 1
		fi
	esac
done
shift $(($OPTIND - 1))
fi

if [ "$1" ]
then
	if [ ! -d "$1" ]
	then
		echo "${SCRIPT}: Invalid master directory '$1'"
		exit 1
	fi
	MASTER_DIR="$1"
else
	echo "${SCRIPT}: Master directory not specified"
	exit 1
fi

if [ "$2" ]
then
	SLAVE_DIR="$2"
else
	echo "${SCRIPT}: Slave directory not specified"
	exit 1
fi

#=============================================================================
#1) For each ogg file in the slave tree:
#  1.1) Look for flac file of the same path and name in the master tree:
#    1.1.1) If not found, delete the ogg

echo "Removing stale ogg files..."
mkdir -p "${SLAVE_DIR}/q${QUALITY}"
cd "${SLAVE_DIR}/q${QUALITY}"
SLAVE_DIR="$(pwd)"

find . -type f -name '*.ogg' | while read FILE
do
	if [ ! -f "${MASTER_DIR}/${FILE%.*}.flac" ]
	then
		echo "Master file ${MASTER_DIR}/${FILE%.*}.flac not found - deleting ${SLAVE_DIR}/${FILE}"
		rm -vf "${SLAVE_DIR}/${FILE}"
	fi
done


# 2) Look for existing manifest file in MASTER_DIR/ogg-sync-q${QUALITY}.manifest

cd "${MASTER_DIR}"
echo "Preparing manifests..."
MANIFEST="${MASTER_DIR}/ogg-sync-q${QUALITY}.manifest"
touch "${MANIFEST}"
rm -f "${MANIFEST}.new" #in case the script didnt complete successfully on last invocation
touch "${MANIFEST}.new"


#3) For each entry in the manifest:
#  3.1) If no matching flac file exists, remove the manifest entry
#  3.2) If it does, reinsert into new manifest to be parsed in step 4
# Manifest lines consist of size date and filename, delimited by tabs
echo "Cleaning manifest..."
cat ${MANIFEST}|while IFS=$(echo '\t') read OLD_SIZE OLD_DATE FILE
do
	if [ -f "${FILE}" ]; then
		if [ "$ARCH" = "FreeBSD" ]; then
			NEW_SIZE="$(stat -f "%z" "${FILE}")"
			NEW_DATE="$(stat -f "%Sm" "${FILE}")"
		elif [ "$ARCH" = "Linux" ]; then
			NEW_SIZE="$(stat -c %s "${FILE}")"
			NEW_DATE="$(stat -c %y "${FILE}")" #gnu coreutils date output is ugly, check others for consistency
		else echo "Unknown arch: $ARCH" && exit 1
		fi
		#if the size and date are the same, add it back to the manifest
		if [ "${OLD_SIZE}" = "${NEW_SIZE}" -a "${OLD_DATE}" = "${NEW_DATE}" ]; then
			echo "${NEW_SIZE}"'\t'"${NEW_DATE}"'\t'"${FILE}" >> "${MANIFEST}.new"			
		fi
	fi
done

rm "${MANIFEST}"
mv "${MANIFEST}.new" "${MANIFEST}"

#4) For each flac file in the master tree:
#  4.1) If file entry doesnt exists in the manifest (same size, date, and filename; tab delimited):
#    4.1.1) Dump tags
#    4.1.2) Create a new ogg w/ tags
#    4.1.3) Add a manifest entry
echo "Generating OGG files..."
cd ${MASTER_DIR}
find . -type f -name '*.flac' \
| while read FILE
	do
		if [ "$ARCH" = "FreeBSD" ]; then
			SIZE="$(stat -f "%z" "${FILE}")"
			DATE="$(stat -f "%Sm" "${FILE}")"
		elif [ "$ARCH" = "Linux" ]; then
			SIZE="$(stat -c %s "${FILE}")"
			DATE="$(stat -c %y "${FILE}")"
		else echo "Unknown arch: $ARCH" && exit 1
		fi
		#if grep exits with 1, process file, add file to manifest
		ENTRY="$(echo "${SIZE}"'\t'"${DATE}"'\t'"${FILE}")"
		grep -qF "${ENTRY}" "${MANIFEST}"
		if [ $? -ne 0 ]; then
			mkdir -p "${FILE%/*}" \
				&& "${OGGENC}" -Qq"${QUALITY}" -o "${SLAVE_DIR}/${FILE%.*}.ogg" "${FILE}" \
				&& echo "${SIZE}"'\t'"${DATE}"'\t'"${FILE}" >> "${MANIFEST}"
		fi
	done
exit 0