parsepa.nim

import osproc, strutils, pegs, os, parseopt2, sequtils

type Application = object
  id: int
  name: string
  volume: float

var verbose = false

proc tryExec(cmd): auto =
  if verbose: echo("executing $1" % [cmd])
  let output = execCmdEx(cmd)
  if output.exitCode != 0:
    raise newException(EBase, "Failed to execute `$1` with error code $2\nOutput:\n===\n$3\n===" %
                              [cmd, $output.exitCode, output.output])
  return output.output

iterator getPlayingApps(): auto =
  let paOutput = tryExec("pactl list sink-inputs")

  let sinkStrings = paOutput.split("\l\l")

  for str in sinkStrings:
    var num: int
    var volume: float
    var applicationName: string

    var matches = ["", ""]

    if str.find(peg"'Sink Input #'{\d+}", matches) != -1:
      num = parseInt(matches[0])
    else:
      raise newException(EBase, "Could not find sink input number in \n===\n$1" % [str])

    if str.find(peg"'Volume'@'/'\s*{\d+}'%'", matches) != -1:
      volume = parseFloat(matches[0])
    else:
      raise newException(EBase, "Could not find application volume in \n===\n$1" % [str])

    if str.find(peg"'application.name = ""'{[^""]+}'""'", matches) != -1:
      applicationName = matches[0]
    else:
      raise newException(EBase, "Could not find application name in \n===\n$1" % [str])

    yield Application(id: num, name: applicationName, volume: volume)

proc adjustAppVolume(app: Application, percent: float) =
  let nextVol = min((app.volume + (app.volume * (percent - 100) / 100.0)).int, 100)
  discard tryExec("pactl set-sink-input-volume $1 $2%" % [$app.id, $nextVol])

proc adjustName(name: string, percent: float) =
  for app in getPlayingApps():
    if app.name.contains(peg(name)):
      adjustAppVolume(app, percent)

proc printInfo() =
  for app in getPlayingApps():
    echo("$1\t$2\t$3" % [$app.id, app.name, $app.volume])

var params: seq[string] = @[]
for kind, key, val in getopt():
  case kind
  of cmdArgument:
    params.add(key)
  of cmdLongOption, cmdShortOption:
    case key
    of "help", "h":
      echo "usage: parsepa [-h|--help] [-v|--verbose] [<name expression> percent (-a|--adjust)] [-p|--print]"
      quit(QuitSuccess)
    of "verbose", "v":
      verbose = true
    of "adjust", "a":
      adjustName(params[0], parseFloat(params[1]))
      quit(QuitSuccess)
    of "print", "p":
      printInfo()
      quit(QuitSuccess)
    else:
      echo "Invalid Argument"
      quit(QuitFailure)
  else:
    echo "Invalid Argument"
    quit(QuitFailure)

parsepa.x64