class IRB::Command::Copy

def clipboard_available?
  !!clipboard_program
end

def clipboard_program
  @clipboard_program ||= if IRB.conf[:COPY_COMMAND]
                           IRB.conf[:COPY_COMMAND]
                         elsif executable?("pbcopy")
                           "pbcopy"
                         elsif executable?("xclip")
                           "xclip -selection clipboard"
                         end
end

def copy_to_clipboard(text)
  IO.popen(clipboard_program, 'w') do |io|
    io.write(text)
  end
  raise IOError.new("Copying to clipboard failed") unless $? == 0
  puts "Copied to system clipboard"
rescue Errno::ENOENT => e
  warn e.message
  warn "Is IRB.conf[:COPY_COMMAND] set to a bad value?"
end

def executable?(command)
  system("which #{command} > /dev/null 2>&1")
end

def execute(arg)
  # Copy last value if no expression was supplied
  arg = '_' if arg.to_s.strip.empty?
  value = irb_context.workspace.binding.eval(arg)
  output = irb_context.inspect_method.inspect_value(value, +'', colorize: false).chomp
  if clipboard_available?
    copy_to_clipboard(output)
  else
    warn "System clipboard not found"
  end
rescue StandardError => e
  warn "Error: #{e}"
end