change sinks

#!/bin/bash

set -e

is_next=false
is_prev=false
if test "$1" = "next"; then
    is_next=true
fi
if test "$1" = "prev"; then
    is_prev=true
fi

if ! $is_next && ! $is_prev; then
    is_next=true
fi

pacmd list-sinks | fgrep ' index: ' | {
    index=0
    cur_pos=0
    declare sinks[0]
    while read -r line; do
        index=$((index+1))
        echo "$line" | fgrep -q '*' && cur_pos=$index
        sinks[$index]=$(echo "$line"|awk '{print $NF}')
    done

    # we are forced to continue here, or we lose the vars

    len="${#sinks[@]}"
    if test $len -le 0; then
        echo "no sinks!"
        exit 1
    fi

    if $is_next; then
        if test $cur_pos -ge $len; then
            new_pos=1
        else
            new_pos=$((cur_pos+1))
        fi
    fi
    if $is_prev; then
        if test $cur_pos -le 1; then
            new_pos=$len
        else
            new_pos=$((cur_pos-1))
        fi
    fi

    if test $new_pos -eq $cur_pos; then
        echo "nothing to do (only 1 sink?)"
        exit 0
    fi

    new_idx="${sinks[$new_pos]}"
    echo "Switching to $new_pos, pulse index $new_idx"
    pacmd set-default-sink $new_idx

}