#!/bin/sh

# this script encodes flac files at level 8 to achieve the highest amount of
# lossless compression and reduce file sizes. it obviously requires flac!

# it should always be run first before any of the tagging scripts, as flac/metaflac
# may error when decoding files that haven't been re-encoded. this is especially
# common with flac 1.4 which has much stricter standards compared to earlier versions.

# the erroring seems to happen when ID3 tags are present (which flacs should not have!)
# or if track lengths are very short (<20s). see these issues for more info:
# https://github.com/xiph/flac/issues/487
# https://github.com/xiph/flac/issues/653

# the -e arg can be used to activate exhaustive / precision searching. theoretically
# this should result in the best possible compression but I've found that the difference
# between this and regular level 8 compression is often little to none, whilst taking far,
# far longer to run. I've left it here as an option, but it really isn't necessary to use.

while getopts "d:emh" o; do case "${o}" in
	d) master="$OPTARG";;
	e) ex=1;;
	m) mod=1;;
	h|*) printf "usage: ./%s [OPTION]...\n\noptions:
 -d specify directory to scan
 -e use exhaustive searching
 -m modify files\n" "$(basename "$0")" && exit 1
esac done

# check variables and programs.
[ ! "$(command -v flac)" ] && echo "flac must be installed to use this script." && exit
[ ! -d "$master" ] && echo "invalid directory!" && exit

[ -z "$mod" ] && printf "\033[1mperforming DRY RUN. use -m to modify files.\033[0m\n\n"

# find sub directories in master directory
dirs="$(find "$master" -type d -links 2)"

num=1
# loop through sub directories
echo "$dirs" | while read -r dir; do
	# check if sub directories contain flac files
	if ls "$dir"/*.flac >/dev/null 2>&1; then
		printf "\033[1m[%d/%d] %s\033[0m\n" "$num" "$(echo "$dirs" | wc -l)" "$(basename "$dir")"
		# encode files
		if [ -n "$mod" ]; then
			if [ -n "$ex" ]; then
				flac -8 -r 8 -f -e -p "$dir"/*.flac
			else
				flac -8 -r 8 -f "$dir"/*.flac
			fi
		fi
		num=$((num+1))
	fi
done

printf "\n\033[1mscript completed!\033[0m\n"