#!/usr/bin/env bash

set -e

SOURCE='@DEFAULT_AUDIO_SOURCE@'
SINK='@DEFAULT_AUDIO_SINK@'

case $1 in
  source)
    device=$SOURCE
    ;;
  sink)
    device=$SINK
    ;;
  *)
    echo "Invalid device: $1"
    echo "Valid options are 'source' and 'sink'"
    exit 1
    ;;
esac

print_device_info() {
  # The node description seems to be the most useful value here, though different values are available.
  # However, we'll strip the "Analog Stereo" part.
  description=$(wpctl inspect "$device" | sed -n -e 's/.*node.description = "\(.*\) Analog Stereo"/\1/p')

  # The output of a muted device is something like "Volume: 0.55", so we just nab the second field.
  volume=$(wpctl get-volume "$device" | awk '/Volume/ { print $2 }')

  # The output of a muted device is something like "Volume: 0.55 [MUTED]", so "true" if the third field is present, "false" otherwise.
  muted=$(wpctl get-volume "$device" | awk '/Volume/ { print ($3 ? "true" : "false") }')

  echo "{ \"description\": \"$description\", \"volume\": $volume, \"muted\": $muted }"
}

print_device_info

pactl --format=json subscribe | grep --line-buffered $1 | while read -r event; do print_device_info; done