Simple Volume Control based on ``pactl``

volume-control

#!/usr/bin/env ruby

require 'shellwords'

# Simple Volume Control based on ``pactl``
#
# Sample of (CLI) use:
#
# ```
# volume-control up
# volume-control down
# volume-control toggle-mute
# volume-control to 50
# volume-control set 50
# ```
class VolumeControl
  attr_reader :sink

  attr_reader :increment

  def initialize(sink = 0, increment = 5)
    @sink = sink
    @increment = increment
  end

  # Increase volume
  def sink_up
    execute(:up)
  end

  # Decrease volume
  def sink_down
    execute(:down)
  end

  # Set volume to given ``volume``
  #
  # @param [Fixnum] volume
  def sink_to(volume)
    execute(:to, volume: volume.gsub(/%$/, '').to_i)
  end

  alias sink_set sink_to

  # Toggle mute
  def sink_toggle_mute
    execute(:toggle_mute)
  end

  # Get arguments
  #
  # @return [Hash]
  def arguments
    {
      toggle_mute: ['set-sink-mute', sink, :toggle],
      up: ['set-sink-volume', sink, "+#{increment}%"],
      down: ['set-sink-volume', sink, "-#{increment}%"],
      to: ['set-sink-volume', sink, "%<volume>s%"],
    }
  end

  # Get command for given ``keyword``
  #
  # @param [Symbol] keyword
  # @param [Hash] options
  # @return [Array<String>]
  def command(keyword, options = {})
    [:pactl].concat(arguments.fetch(keyword.to_sym))
      .map(&:to_s)
      .map { |s| s % options }
  end

  protected

  # Execute ``system`` command for given ``keyword``
  #
  # @param [Symbol] keyword
  # @param [Hash] options
  # @return [Boolean]
  def execute(keyword, options = {})
    command = self.command(keyword, options)

    puts '# %<command>s' % { command: Shellwords.shelljoin(command) }

    system(*command)
  end
end

if __FILE__ == $0
  action = 'sink_%<action>s' % { action: ARGV.fetch(0).tr('-', '_') }

  VolumeControl.new.public_send(action, *ARGV.drop(1)) || exit(1)
end