#
# Copyright (c) 2006-2024 Wade Alcorn - wade@bindshell.net
# Browser Exploitation Framework (BeEF) - https://beefproject.com
# See the file 'doc/COPYING' for copying permission
#
module BeEF
  module Extension
    module ETag
      require 'sinatra/base'
      require 'singleton'

      class ETagMessages
        include Singleton
        attr_accessor :messages

        def initialize
          @messages = {}
        end
      end

      class ETagWebServer < Sinatra::Base
        def create_ET_header
          inode = File.stat(__FILE__).ino
          size  = 3
          mtime = (Time.now.to_f * 1_000_000).to_i
          "#{inode.to_s(16)}L-#{size.to_s(16)}L-#{mtime.to_s(16)}L"
        end

        get '/:id/start' do
          data = ETagMessages.instance.messages[params[:id].to_i]

          $etag_server_state = {} unless defined?($etag_server_state)
          $etag_server_state[params[:id]]               = {}
          $etag_server_state[params[:id]][:cur_bit]     = -1
          $etag_server_state[params[:id]][:last_header] = create_ET_header
          $etag_server_state[params[:id]][:message] = data

          headers 'ETag' => $etag_server_state[params[:id]][:last_header]
          body 'Message start'
        end

        get '/:id' do
          return 'Not started yet' if !defined?($etag_server_state) || $etag_server_state[params[:id]].nil?

          if $etag_server_state[params[:id]][:cur_bit] < $etag_server_state[params[:id]][:message].length - 1
            $etag_server_state[params[:id]][:cur_bit] += 1
          else
            $etag_server_state.delete(params[:id])
            status 404
            return 'Bing'
          end

          $etag_server_state[params[:id]][:last_header] = create_ET_header if $etag_server_state[params[:id]][:message][$etag_server_state[params[:id]][:cur_bit]] == '1'

          headers 'ETag' => $etag_server_state[params[:id]][:last_header]
          body 'Bit'
        end
      end
    end
  end
end