#!/bin/bash

#
# Movesoundoutput moves all sound outputs to a device, according to the given parameters.
#
# If the first parameter is '--list' , it only lists all known or filtered sound outputs.
# Otherwise, the first parameter tells which sound output to switch to.
# Only a partial name of the device or it's description is needed to select it.
#

function RequiredPrograms () {
  # Each program listed must exist, otherwise throw an error and exit.
  for List in "$@"
  do
    if ! command -v "$List" > /dev/null ;then
      echo "Error: Required command $List not found" >&2
      exit 1
    fi
  done
}

function ParsePacmd() {
  # $1 = search term
  list=$(pacmd list-sinks)
  while true; do
    nr=$(echo "$list" | grep -ni -m1 'index:' | cut -f1 -d':')
    [ "$nr" == "" ] && break
    PrintValidSink "$(head -n$nr <<< $list)" "$1"
    nrinc=$((nr+1))
    list=$(echo "$list" | tail -n+$nrinc)
  done
  PrintValidSink "$list" "$1"
}

function PrintValidSink() {
  # $1 = Sink data
  # $2 = Search item
  if grep 'device.master_device' <<< "$1" >/dev/null; then
    return 0
  fi
  if [ -n "$2" ] && ! grep -i "$2" <<< "$1" >/dev/null; then
    return 0
  fi
  GetSinkName "$1"
}

function GetSinkName() {
  # $1 = Sink Data
  echo "$1" | grep '^\s*name:' | cut -f2 -d'<' | cut -f1 -d'>'
}

function ErrorExit() {
  echo Error: $* >&2
  exit 1
}

# These programs must exist.
RequiredPrograms pacmd

# When --list parameter is applied, only list current sinks or filtered sinks.
if [ "$1" == "--list" ]; then
  shift
  ParsePacmd "$1"
  exit 0
fi

if [ "$1" == "" ]; then
  ErrorExit "No device string given"
fi

# Find the correct sink.
sink=$(ParsePacmd "$1")
if [ $(wc -w <<< "$sink") -ne 1 ]; then
  ErrorExit "Not exactly one sink filtered"
fi

# Change the default audio sink.
pacmd set-default-sink "$sink"

# Move all inputs to the new sink
for app in $(pacmd list-sink-inputs | sed -n -e 's/index:[[:space:]]\([[:digit:]]\)/\1/p');
do
    pacmd move-sink-input $app "$sink"
done

exit 0