#!/bin/bash

switch() { /usr/local/bin/SwitchAudioSource "$@"; }

OLDIFS="$IFS"
IFS=$'\n'
####
ao_hw_in=( $(switch -a | awk -F'[()]' '/input/{print substr($1,1,length($1)-1)}') )
ao_hw_out=( $(switch -a | awk -F'[()]' '/output/{print substr($1,1,length($1)-1)}') )
ao_active_out="$(switch -c)"
####
IFS="$OLDIFS"

if [ "$ao_active_out" == "${ao_hw_out[0]}" ]; then
switch -t input -s "${ao_hw_in[1]}" &>/dev/null
switch -t output -s "${ao_hw_out[1]}" &>/dev/null
elif [ "$ao_active_out" == "${ao_hw_out[1]}" ]; then
switch -t input -s "${ao_hw_in[0]}" &>/dev/null;
switch -t output -s "${ao_hw_out[0]}" &>/dev/null
fi