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# -*- coding: binary -*-
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module Rex
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module Ui
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###
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#
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# This class implements the stubs that are needed to provide an interactive
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# user interface that is backed against something arbitrary.
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#
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###
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module Interactive
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  #
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  # Interactive sessions by default may interact with the local user input
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  # and output.
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  #
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  include Rex::Ui::Subscriber
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  #
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  # Starts interacting with the session at the most raw level, simply
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  # forwarding input from user_input to rstream and forwarding input from
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  # rstream to user_output.
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  #
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  def interact(user_input, user_output)
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    # Detach from any existing console
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    if self.interacting
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      detach()
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    end
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    init_ui(user_input, user_output)
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    self.interacting = true
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    self.completed = false
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    eof = false
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    # Start the readline stdin monitor
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    # XXX disabled
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    # user_input.readline_start() if user_input.supports_readline
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    # Handle suspend notifications
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    handle_suspend
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    handle_usr1
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    handle_winch
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    # As long as we're interacting...
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    while (self.interacting == true)
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      begin
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        _interact
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      rescue Interrupt
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        # If we get an interrupt exception, ask the user if they want to
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        # abort the interaction.  If they do, then we return out of
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        # the interact function and call it a day.
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        eof = true if (_interrupt)
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      rescue EOFError, Errno::ECONNRESET, IOError
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        # If we reach EOF or the connection is reset...
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        eof = true
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      end
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      break if eof
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    end
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    begin
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      # Restore the suspend handler
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      restore_suspend
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      restore_winch
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      # If we've hit eof, call the interact complete handler
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      _interact_complete if (eof == true)
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      # Shutdown the readline thread
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      # XXX disabled
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      # user_input.readline_stop() if user_input.supports_readline
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      # Detach from the input/output handles
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      reset_ui()
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    ensure
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      # Mark this as completed
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      self.completed = true
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    end
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    # if another session was requested, store it
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    next_session = self.next_session
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    # clear the value from the object
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    self.next_session = nil
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    # return this session id
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    return next_session
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  end
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  #
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  # Stops the current interaction
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  #
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  def detach
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    if (self.interacting)
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      self.interacting = false
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      while(not self.completed)
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        ::IO.select(nil, nil, nil, 0.25)
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      end
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    end
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  end
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  #
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  # Whether or not the session is currently being interacted with
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  #
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  attr_accessor   :interacting
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  #
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  # If another session needs interaction, this is where it goes
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  #
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  attr_accessor   :next_session
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  #
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  # Whether or not the session has completed interaction
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  #
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  attr_accessor	:completed
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  attr_accessor :on_print_proc
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  attr_accessor :on_command_proc
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  #
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  # A function to be run when running a session command hits an error
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  #
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  # @return [Proc,nil] A function to be run when running a session command hits an error
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  attr_accessor :on_run_command_error_proc
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protected
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  #
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  # The original suspend proc.
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  #
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  attr_accessor :orig_suspend
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  attr_accessor :orig_usr1
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  attr_accessor :orig_winch
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  #
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  # Stub method that is meant to handler interaction
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  #
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  def _interact
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  end
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  #
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  # Called when an interrupt is sent.
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  #
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  def _interrupt
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    true
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  end
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  #
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  # Called when a suspend is sent.
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  #
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  def _suspend
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    false
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  end
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  #
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  # Called when interaction has completed and one of the sides has closed.
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  #
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  def _interact_complete
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    true
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  end
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  #
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  # Read from remote and write to local.
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  #
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  def _stream_read_remote_write_local(stream)
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    data = stream.get
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    self.on_print_proc.call(data) if self.on_print_proc
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    user_output.print(data)
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  end
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  #
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  # Read from local and write to remote.
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  #
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  def _stream_read_local_write_remote(stream)
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    data = user_input.gets
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    self.on_command_proc.call(data) if self.on_command_proc
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    stream.put(data)
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  end
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  #
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  # The local file descriptor handle.
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  #
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  def _local_fd
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    user_input.fd
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  end
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  #
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  # The remote file descriptor handle.
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  #
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  def _remote_fd(stream)
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    stream.fd
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  end
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  #
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  # Interacts with two streaming connections, reading data from one and
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  # writing it to the other.  Both are expected to implement Rex::IO::Stream.
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  #
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  def interact_stream(stream)
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    while self.interacting && _remote_fd(stream)
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      # Select input and rstream
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      sd = Rex::ThreadSafe.select([ _local_fd, _remote_fd(stream) ], nil, nil, 0.25)
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      # Cycle through the items that have data
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      # From the stream?  Write to user_output.
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      sd[0].each { |s|
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        if (s == _remote_fd(stream))
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          _stream_read_remote_write_local(stream)
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        # From user_input?  Write to stream.
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        elsif (s == _local_fd)
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          _stream_read_local_write_remote(stream)
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        end
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      } if (sd)
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      Thread.pass
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    end
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  end
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  #
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  # Installs a signal handler to monitor suspend signal notifications.
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  #
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  def handle_suspend
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    if orig_suspend.nil?
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      begin
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        self.orig_suspend = Signal.trap("TSTP") do
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          Thread.new { _suspend }.join
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        end
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      rescue
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      end
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    end
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  end
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  #
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  # Restores the previously installed signal handler for suspend
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  # notifications.
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  #
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  def restore_suspend
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    begin
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      if orig_suspend
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        Signal.trap("TSTP", orig_suspend)
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      else
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        Signal.trap("TSTP", "DEFAULT")
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      end
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      self.orig_suspend = nil
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    rescue
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    end
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  end
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  def handle_usr1
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    if orig_usr1.nil?
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      begin
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        self.orig_usr1 = Signal.trap("USR1") do
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          Thread.new { _usr1 }.join
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        end
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      rescue
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      end
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    end
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  end
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  def handle_winch
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    if orig_winch.nil?
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      begin
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        self.orig_winch = Signal.trap("WINCH") do
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          Thread.new { _winch }.join
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        end
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      rescue
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      end
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    end
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  end
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  def restore_winch
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    begin
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      if orig_winch
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        Signal.trap("WINCH", orig_winch)
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      else
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        Signal.trap("WINCH", "DEFAULT")
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      end
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      self.orig_winch = nil
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    rescue
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    end
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  end
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  def _winch
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  end
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  def restore_usr1
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    begin
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      if orig_usr1
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        Signal.trap("USR1", orig_usr1)
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      else
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        Signal.trap("USR1", "DEFAULT")
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      end
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      self.orig_usr1 = nil
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    rescue
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    end
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  end
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  #
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  # Prompt the user for input if possible.
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  # XXX: This is not thread-safe on Windows
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  #
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  def prompt(query)
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    if (user_output and user_input)
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      user_output.print("\n" + query)
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      user_input.sysread(2)
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    end
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  end
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  #
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  # Check the return value of a yes/no prompt
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  #
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  def prompt_yesno(query)
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    (prompt(query + " [y/N]  ") =~ /^y/i) ? true : false
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  end
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end
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end
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end
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