class IRB::ExtendCommand::Debug

def binding_irb?
  caller.any? do |frame|
    BINDING_IRB_FRAME_REGEXPS.any? do |regexp|
      frame.match?(regexp)
    end
  end
end

def execute(pre_cmds: nil, do_cmds: nil)
  if irb_context.with_debugger
    # If IRB is already running with a debug session, throw the command and IRB.debug_readline will pass it to the debugger.
    if cmd = pre_cmds || do_cmds
      throw :IRB_EXIT, cmd
    else
      puts "IRB is already running with a debug session."
      return
    end
  else
    # If IRB is not running with a debug session yet, then:
    # 1. Check if the debugging command is run from a `binding.irb` call.
    # 2. If so, try setting up the debug gem.
    # 3. Insert a debug breakpoint at `Irb#debug_break` with the intended command.
    # 4. Exit the current Irb#run call via `throw :IRB_EXIT`.
    # 5. `Irb#debug_break` will be called and trigger the breakpoint, which will run the intended command.
    unless binding_irb?
      puts "`debug` command is only available when IRB is started with binding.irb"
      return
    end
    if IRB.respond_to?(:JobManager)
      warn "Can't start the debugger when IRB is running in a multi-IRB session."
      return
    end
    unless IRB::Debug.setup(irb_context.irb)
      puts <<~MSG
        You need to install the debug gem before using this command.
        If you use `bundle exec`, please add `gem "debug"` into your Gemfile.
      MSG
      return
    end
    IRB::Debug.insert_debug_break(pre_cmds: pre_cmds, do_cmds: do_cmds)
    # exit current Irb#run call
    throw :IRB_EXIT
  end
end