concat-mp3

#!/usr/bin/env bash

set -xeuo pipefail

if termux-battery-low; then
	echo "Battery is too low to concat files"
	exit 1
fi

deleteList=()
name=''

tmpSilenceDir=$(mktemp concat-mp3.XXXXXX --directory --tmpdir)
tmpWavSilenceFile="$tmpSilenceDir/silence.wav"
tmpMp3SilenceFile="$tmpSilenceDir/silence.mp3"

function cleanup()
{
	rm -f "$tmpWavSilenceFile" "$tmpMp3SilenceFile"
	if [ -d "$tmpSilenceDir" ]; then
		rmdir "$tmpSilenceDir"
	fi
}
trap cleanup EXIT

files=("$@")
[[ $# -eq 0 ]] && files=( *.mp3 )

for x in "${files[@]}"; do
	if [ -z "$name" ]; then
		name=$(basename "$x" .mp3)
		if contains "$name" "MP3WRAP"; then
			exit 2
		fi

		# make a silent file
		sox -n -r 44100 -c 2 "$tmpWavSilenceFile" trim 0.0 0.0
		lame "$tmpWavSilenceFile" "$tmpMp3SilenceFile"

		nice -n 15 mp3wrap "$name" "$x" "$tmpMp3SilenceFile"
	else
		nice -n 15 mp3wrap -a "${name}_MP3WRAP.mp3" "$x"
		mv -v "temp_MP3WRAP.mp3" "${name}_MP3WRAP.mp3"
	fi

	deleteList+=("$x")
done

cleanup

for mp3 in "${deleteList[@]}"; do
	s3-trash "$mp3"
done

exit 0