#!/usr/bin/env ruby

# rmt --
# This script implements a simple remote-control mechanism for
# Tk applications.  It allows you to select an application and
# then type commands to that application.

require 'tk'

class Rmt
  def initialize(parent=nil)
    win = self

    unless parent
      parent = TkRoot.new
    end
    root = TkWinfo.toplevel(parent)
    root.minsize(1,1)

    # The instance variable below keeps track of the remote application
    # that we're sending to.  If it's an empty string then we execute
    # the commands locally.
    @app = 'local'
    @mode = 'Ruby'

    # The instance variable below keeps track of whether we're in the
    # middle of executing a command entered via the text.
    @executing = 0

    # The instance variable below keeps track of the last command executed,
    # so it can be re-executed in response to !! commands.
    @lastCommand = ""

    # Create menu bar.  Arrange to recreate all the information in the
    # applications sub-menu whenever it is cascaded to.

    TkFrame.new(root, 'relief'=>'raised', 'bd'=>2) {|f|
      pack('side'=>'top', 'fill'=>'x')
      TkMenubutton.new(f, 'text'=>'File', 'underline'=>0) {|mb|
	TkMenu.new(mb) {|mf|
	  mb.menu(mf)
	  TkMenu.new(mf) {|ma|
	    postcommand proc{win.fillAppsMenu ma}
	    mf.add('cascade', 'label'=>'Select Application',
		   'menu'=>ma, 'underline'=>0)
	  }
	  add('command', 'label'=>'Quit',
	      'command'=>proc{root.destroy}, 'underline'=>0)
	}
	pack('side'=>'left')
      }
    }

    # Create text window and scrollbar.

    @txt = TkText.new(root, 'relief'=>'sunken', 'bd'=>2, 'setgrid'=>true) {
      yscrollbar(TkScrollbar.new(root){pack('side'=>'right', 'fill'=>'y')})
      pack('side'=>'left')
    }

    @promptEnd = TkTextMark.new(@txt, 'insert')

    # Create a binding to forward commands to the target application,
    # plus modify many of the built-in bindings so that only information
    # in the current command can be deleted (can still set the cursor
    # earlier in the text and select and insert;  just can't delete).

    @txt.bindtags([@txt, TkText, root, 'all'])
    @txt.bind('Return', proc{
		@txt.set_insert('end - 1c')
		@txt.insert('insert', "\n")
		win.invoke
		Tk.callback_break
	      })
    @txt.bind('Delete', proc{
		begin
		  @txt.tag_remove('sel', 'sel.first', @promptEnd)
		rescue
		end
		if @txt.tag_nextrange('sel', '1.0', 'end') == []
		  if @txt.compare('insert', '<', @promptEnd)
		    Tk.callback_break
		  end
		end
	      })
    @txt.bind('BackSpace', proc{
		begin
		  @txt.tag_remove('sel', 'sel.first', @promptEnd)
		rescue
		end
		if @txt.tag_nextrange('sel', '1.0', 'end') == []
		  if @txt.compare('insert', '<', @promptEnd)
		    Tk.callback_break
		  end
		end
	      })
    @txt.bind('Control-d', proc{
		if @txt.compare('insert', '<', @promptEnd)
		  Tk.callback_break
		end
	      })
    @txt.bind('Control-k', proc{
		if @txt.compare('insert', '<', @promptEnd)
		  @txt.set_insert(@promptEnd)
		end
	      })
    @txt.bind('Control-t', proc{
		if @txt.compare('insert', '<', @promptEnd)
		  Tk.callback_break
		end
	      })
    @txt.bind('Meta-d', proc{
		if @txt.compare('insert', '<', @promptEnd)
		  Tk.callback_break
		end
	      })
    @txt.bind('Meta-BackSpace', proc{
		if @txt.compare('insert', '<=', @promptEnd)
		  Tk.callback_break
		end
	      })
    @txt.bind('Control-h', proc{
		if @txt.compare('insert', '<=', @promptEnd)
		  Tk.callback_break
		end
	      })

    @txt.tag_configure('bold', 'font'=>['Courier', 12, 'bold'])

    @app = Tk.appname('rmt')
    if (@app =~ /^rmt(.*)$/)
      root.title("Tk Remote Controller#{$1}")
      root.iconname("Tk Remote#{$1}")
    end
    prompt
    @txt.focus
    #@app = TkWinfo.appname(TkRoot.new)
  end

  def tkTextInsert(w,s)
    return if s == ""
    begin
      if w.compare('sel.first','<=','insert') \
	&& w.compare('sel.last','>=','insert')
	w.tag_remove('sel', 'sel.first', @promptEnd)
	w.delete('sel.first', 'sel.last')
      end
    rescue
    end
    w.insert('insert', s)
    w.see('insert')
  end

  # The method below is used to print out a prompt at the
  # insertion point (which should be at the beginning of a line
  # right now).

  def prompt
    @txt.insert('insert', "#{@app}: ")
    @promptEnd.set('insert')
    @promptEnd.gravity = 'left'
    @txt.tag_add('bold', "#{@promptEnd.path} linestart", @promptEnd)
  end

  # The method below executes a command (it takes everything on the
  # current line after the prompt and either sends it to the remote
  # application or executes it locally, depending on "app".

  def invoke
    cmd = @txt.get(@promptEnd, 'insert')
    @executing += 1
    case (@mode)
    when 'Tcl'
      if Tk.info('complete', cmd)
	if (cmd == "!!\n")
	  cmd = @lastCommand
	else
	  @lastCommand = cmd
	end
	begin
	  msg = Tk.appsend(@app, false, cmd)
	rescue
	  msg = "Error: #{$!}"
	end
	@txt.insert('insert', msg + "\n") if msg != ""
	prompt
	@promptEnd.set('insert')
      end

    when 'Ruby'
      if (cmd == "!!\n")
	cmd = @lastCommand
      end
      complete = true
      begin
	eval("proc{#{cmd}}")
      rescue
	complete = false
      end
      if complete
	@lastCommand = cmd
	begin
#	  msg = Tk.appsend(@app, false,
#			   'ruby',
#			   '"(' + cmd.gsub(/[][$"]/, '\\\\\&') + ').to_s"')
	  msg = Tk.rb_appsend(@app, false, cmd)
	rescue
	  msg = "Error: #{$!}"
	end
	@txt.insert('insert', msg + "\n") if msg != ""
	prompt
	@promptEnd.set('insert')
      end
    end

    @executing -= 1
    @txt.yview_pickplace('insert')
  end

  # The following method is invoked to change the application that
  # we're talking to.  It also updates the prompt for the current
  # command, unless we're in the middle of executing a command from
  # the text item (in which case a new prompt is about to be output
  # so there's no need to change the old one).

  def newApp(appName, mode)
    @app = appName
    @mode = mode
    if @executing == 0
      @promptEnd.gravity = 'right'
      @txt.delete("#{@promptEnd.path} linestart", @promptEnd)
      @txt.insert(@promptEnd, "#{appName}: ")
      @txt.tag_add('bold', "#{@promptEnd.path} linestart", @promptEnd)
      @promptEnd.gravity = 'left'
    end
  end

  # The method below will fill in the applications sub-menu with a list
  # of all the applications that currently exist.

  def fillAppsMenu(menu)
    win = self
    begin
      menu.delete(0,'last')
    rescue
    end
    TkWinfo.interps.sort.each{|ip|
      begin
	if Tk.appsend(ip, false, 'info commands ruby') == ""
	  mode = 'Tcl'
	else
	  mode = 'Ruby'
	end
	menu.add('command', 'label'=>format("%s    (#{mode}/Tk)", ip),
		 'command'=>proc{win.newApp ip, mode})
      rescue
	menu.add('command', 'label'=>format("%s (unknown Tk)", ip),
		 'command'=>proc{win.newApp ip, mode}, 'state'=>'disabled')
      end
    }
    menu.add('command', 'label'=>format("local    (Ruby/Tk)"),
	     'command'=>proc{win.newApp 'local', 'Ruby'})
  end
end

Rmt.new

Tk.mainloop