shellfu-bash-saturnin/src/libexec/saturnin-au

#!/bin/bash

. $(ffoom path)

ffoo import pretty


usage() {
    usage_is "up"     \
             "down"   \
             "flip"   \
             "mute"   \
             "unmute"
}


sound_is_muted() {
    #
    # At least one playback channel is muted
    #
    local master_status="$(amixer get Master)"
    echo "$master_status" \
      | grep "Playback channels" \
      | sed -e 's/.*: //; s/ - /\n/' \
      | while read chname
        do
            grep -e "^ *$chname" <<<"$master_status"
        done \
      | grep -qse '\[off\]$'
}

do_down() {
    #
    # turn volume down
    #
    amixer -q sset Master 5%-
}

do_flip() {
    #
    # mute or unmute
    #
    if sound_is_muted;
    then
        amixer -q sset Master unmute;
    else
        amixer -q sset Master mute;
    fi
}

do_mute() {
    #
    # mute
    #
    amixer -q sset Master mute
}

do_up() {
    #
    # turn volume up
    #
    amixer -q sset Master 5%+
}

do_unmute() {
    #
    # mute
    #
    amixer -q sset Master unmute
}


action=
while true; do case "$1" in
    up)     action=up;     shift ;;
    down)   action=down;   shift ;;
    flip)   action=flip;   shift ;;
    mute)   action=mute;   shift ;;
    unmute) action=unmute; shift ;;
    "")     break                ;;
    *)      usage                ;;
esac done

debug "\$@='$@'"
debug -v action

case $action in
    up|down|flip|mute|unmute) do_$action ;;
    *)                        usage      ;;
esac