class Gem::Commands::HelpCommand

def arguments # :nodoc:
  args = <<-EOF
    commands      List all 'gem' commands
    examples      Show examples of 'gem' usage
    <command>     Show specific help for <command>
  EOF
  return args.gsub(/^\s+/, '')
end

def execute
  command_manager = Gem::CommandManager.instance
  arg = options[:args][0]
  if begins? "commands", arg then
    out = []
    out << "GEM commands are:"
    out << nil
    margin_width = 4
    desc_width = command_manager.command_names.map { |n| n.size }.max + 4
    summary_width = 80 - margin_width - desc_width
    wrap_indent = ' ' * (margin_width + desc_width)
    format = "#{' ' * margin_width}%-#{desc_width}s%s"
    command_manager.command_names.each do |cmd_name|
      summary = command_manager[cmd_name].summary
      summary = wrap(summary, summary_width).split "\n"
      out << sprintf(format, cmd_name, summary.shift)
      until summary.empty? do
        out << "#{wrap_indent}#{summary.shift}"
      end
    end
    out << nil
    out << "For help on a particular command, use 'gem help COMMAND'."
    out << nil
    out << "Commands may be abbreviated, so long as they are unambiguous."
    out << "e.g. 'gem i rake' is short for 'gem install rake'."
    say out.join("\n")
  elsif begins? "options", arg then
    say Gem::Command::HELP
  elsif begins? "examples", arg then
    say EXAMPLES
  elsif begins? "platforms", arg then
    say PLATFORMS
  elsif options[:help] then
    command = command_manager[options[:help]]
    if command
      # help with provided command
      command.invoke("--help")
    else
      alert_error "Unknown command #{options[:help]}.  Try 'gem help commands'"
    end
  elsif arg then
    possibilities = command_manager.find_command_possibilities(arg.downcase)
    if possibilities.size == 1
      command = command_manager[possibilities.first]
      command.invoke("--help")
    elsif possibilities.size > 1
      alert_warning "Ambiguous command #{arg} (#{possibilities.join(', ')})"
    else
      alert_warning "Unknown command #{arg}. Try gem help commands"
    end
  else
    say Gem::Command::HELP
  end
end

def initialize
  super 'help', "Provide help on the 'gem' command"
end

def usage # :nodoc:
  "#{program_name} ARGUMENT"
end