#!/usr/bin/env bash

: "${1?How to use: $0 minutes}"

var_sec=$((${1} * 60 ))
var_vol=$(mpc status %volume% | tr -d ' ,%')
time_step=$(( "$var_sec" / 12 ))
vol_step=$(( "$var_vol" /12 ))

while (( "$var_sec" > 0 )); do
	sleep "$time_step"
	mpc volume -"$vol_step" > /dev/null
	var_sec=$(( "$var_sec" - "$time_step" ))
	if [[ $var_sec == 0 ]]
	then
		mpc stop > /dev/null
		mpc volume "$var_vol" > /dev/null
	fi
done
exit 0