Simple PipeWire AutoSwitcher

usb-audio.sh

#!/bin/bash -x
# Simple PipeWire AutoSwitcher
# LICENSE: BSD-0
# Copyright (C) 2024 by JohnnyonFlame
# Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
#                                                                                                                                                                                                                                                                                       # THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
# OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

function use_device()
{
        [[ "$1" =~ .*/usb[0-9]+/.* ]] && return 0
        return 1
}

udevadm monitor --udev --subsystem-match=sound | while read -r line; do
    if echo "$line" | grep -q "change"; then
        # Ignore non-usb devices
        use_device "$line" || continue

        # Query for the device's alsa id
        devpath=$(echo "$line" | awk '{ print $4; }')
        card=$(basename "$devpath")
        id=$(echo "$card" | sed 's/card//')
        [ "$card" == "" ] && continue

        # Query for the PipeWire ID for the device's node
        pwid=$(pw-dump | jq --argjson card "$id" 'first(.[] | select(.type == "PipeWire:Interface:Node" and .info.props["alsa.card"] == $card)).id')
        [ "$pwid" == "" ] && continue

        # Set the node as default
        wpctl set-default "$pwid"
    fi
done