# frozen_string_literal: true

require_relative 'sxmrb/version'

require 'shell'
require 'shellwords'

require 'singleton'
require 'forwardable'

# SXMO user scripts in ruby.
class Sxmrb
  include Singleton

  # Normally when using Singleton there is no way to pass arguments
  # when instantiating.  The renew hack below allows the singleton
  # instance to be re-instantiated and can pass arguments at that time;
  # this was added as an experiment to assist with testing.
  def initialize(shell: ::Shell.new) # :nodoc:
    @_sh = shell
  end

  # Run a system shell command.
  #
  # @example
  #   sh('ls -tr').to_s.lines.last
  def sh(...)
    @_sh.system(...)
  rescue ::StandardError => e
    raise Error, e
  end

  # Display a menu using dmenu [X11] or vis-menu [ssh].
  # A newline-separated list of items is read from standard input.
  # The selected item is printed to standard output.
  #
  # @example
  #   file = (sh('ls') | menu(prompt: 'File?')).to_s.chomp
  def menu(prompt: nil)
    sh String.new.tap { |cmd|
      if ENV['SSH_CLIENT'] || ENV['SSH_TTY']
        cmd << 'vis-menu -i -l 18'
      else
        cmd << 'dmenu -c -i -l 18'
        sh 'sxmo_keyboard.sh open'
      end

      cmd << " -p #{prompt.inspect}" if prompt
    }
  end

  # Run the awk command.
  #
  # @example
  #   print(sh('ls -l') | awk('{print $1}').to_s)
  def awk(arg = '')
    sh("awk -e #{Shellwords.escape arg.chomp}")
  end

  # Run the cat command.
  #
  # @example
  #   print cat('/etc/passwd').to_s
  def cat(arg = '')
    sh("cat #{arg.chomp}")
  end

  # Run the column command.
  #
  # @example
  #   print(sh('ls -l') | column('-t').to_s)
  def column(arg = '')
    sh("column #{arg.chomp}")
  end

  # Run the shell echo command.
  #
  # @example
  #   print echo('Hello World').to_s
  def echo(arg = '')
    sh("echo #{Shellwords.escape arg.chomp}")
  end

  # Run the tac command.
  #
  # @example
  #   print tac('/etc/passwd').to_s
  def tac(arg = '')
    sh("tac #{arg.chomp}")
  end

  # Use a blank #menu to prompt for a value.
  #
  # @example
  #   value = input(prompt: 'Amount?').to_i
  def input(prompt:)
    (echo | menu(prompt: prompt)).to_s.chomp
  end

  class <<self
    # This evil hack experiment is intended to allow swapping out the
    # Shell instance when testing.
    def renew_instance(...) # :nodoc:
      @singleton__mutex__.synchronize {
        @singleton__instance__ = new(...)
      }
    end

    # Forward instance methods to the Singleton instance; false here
    # excludes ancestor methods.
    extend Forwardable
    def_delegators :instance, *Sxmrb.instance_methods(false)
  end

  class Error < ::StandardError; end
end