import Tkinter

PREFIX = "tkController"

class Controller(object):
   def __init__(self, master=None):
      if master is None:
         master = Tkinter._default_root
      assert master is not None
      self.tag = PREFIX + str(id(self))
      def bind(event, handler):
         master.bind_class(self.tag, event, handler)
      self.create(bind)

   def install(self, widget):
      widgetclass = widget.winfo_class()
      # remove widget class bindings and other controllers
      tags = [self.tag]
      for tag in widget.bindtags():
         if tag != widgetclass and tag[:len(PREFIX)] != PREFIX:
            tags.append(tag)
      widget.bindtags(tuple(tags))

   def create(self, handle):
      # override if necessary
      # the default implementation looks for decorated methods
      for key in dir(self):
         method = getattr(self, key)
         if hasattr(method, "tkevent") and callable(method):
            for eventSequence in method.tkevent:
               handle(eventSequence, method)

def bind(*events):
   def decorator(func):
      func.tkevent = events
      return func
   return decorator

class KBController( Controller ):
   def __init__( self ):
      Controller.__init__( self )
      self._alt     = False
      self._control = False
      self._lock    = False
      self._meta    = False
      self._shift   = False
   
   @bind("<KeyPress>")      # type 2
   def KeyPress(self, event):
      if event.keysym in ('Alt_L', 'Alt_R'):
         self._alt = True
      elif event.keysym in ('Control_L', 'Control_R'):
         self._control = True
      elif event.keysym == 'Caps_Lock':
         self._lock = True
      elif event.keysym in ('Meta_L', 'Meta_R'):
         self._meta = True
      elif event.keysym in ( 'Shift_L', 'Shift_R'):
         self._shift = True
      elif (len(event.char) > 0) and (32 <= ord(event.char) <= 127):
         self.onTypedCharacterKey( event )
      else:
         self.onTypedSpecialKey( event )

   @bind("<KeyRelease>")   # type 3
   def KeyRelease( self, event ):
      if event.keysym in ('Alt_L', 'Alt_R'):
         self._alt = False
      elif event.keysym in ('Control_L', 'Control_R'):
         self._control = False
      elif event.keysym == 'Caps_Lock':
         self._lock = False
      elif event.keysym in ('Meta_L', 'Meta_R'):
         self._meta = False
      elif event.keysym in ('Shift_L', 'Shift_R'):
         self._shift = False
   
   def onTypedCharacterKey( self, event ):
      '''Override to handle typing of any printable keyboard character,
      Typed character is in event.char (which accounts for shift).'''
      pass
   
   def onTypedSpecialKey( self, event ):
      '''Override to handle typing of any special characters (tab, \n, backspace,
      delete, home, prior, insert, etc.  Any any key combinations involving
      Alt or Control.'''
      pass


class EnhancedTextController( KBController ):
   def __init__( self ):
      KBController.__init__( self )
      self._insert_x_pos    = None
   
   def onTypedCharacterKey( self, event ):
      try:
         event.widget.sel_delete( )
      except:
         pass
      
      event.widget.insert( 'insert', event.char )
      event.widget.sel_clear( )
      
      self._insert_x_pos = event.widget.bbox( 'insert' )[0]
   
   def moveCarrot( self, event ):
      widget = event.widget
      
      if self._shift:
         if not widget.sel_isAnchorSet():
            widget.sel_setAnchor( 'insert' )
      else:
         widget.sel_clear( )
      
      if event.keysym in ( 'Home', 'KP_Home' ):
         if self._control:
            # Move to beginning of text
            widget.mark_set( 'insert', '1.0' )
         else:
            # Move to front of line
            widget.mark_set( 'insert', widget.dline_start('insert') )
      elif event.keysym in ( 'End', 'KP_End' ):
         if self._control:
            # Move to end of text
            widget.mark_set( 'insert', 'end' )
         else:
            # Move to end of line
            widget.mark_set( 'insert', widget.dline_end('insert') )
      elif event.keysym == 'Right':
         if self._control:
            # Move by word
            currentPos = widget.index( 'insert' )
            maxPos     = widget.index( 'end wordstart' )
            
            if currentPos == maxPos:
               return
            
            offset = 1
            while widget.compare( currentPos, '==', widget.index('insert') ):
               widget.mark_set( 'insert', 'insert wordend +%dc wordstart' % offset )
               offset += 1
         else:
            # Move by character
            widget.mark_set( 'insert', 'insert +1 chars' )
      elif event.keysym == 'Left':
         if self._control:
            # Move by word
            currentPos = widget.index( 'insert' )
            minPos     = widget.index( '1.0 wordstart' )
            
            if currentPos == minPos:
               return
            
            offset = 2
            widget.mark_set( 'insert', 'insert wordstart' )
            while widget.compare( currentPos, '==', widget.index('insert') ):
               widget.mark_set( 'insert', 'insert -%dc wordstart' % offset )
               offset += 1
         else:
            # Move by character
            widget.mark_set( 'insert', 'insert -1 chars' )
      elif event.keysym == 'Down':
         if self._control:
            # Move by Paragraph
            widget.mark_set( 'insert', 'insert +1 lines' )
         else:
            # Move by line
            widget.mark_set( 'insert', widget.dline_next( 'insert', useThisX=self._insert_x_pos ) )
      elif event.keysym == 'Up':
         if self._control:
            # Move by Paragraph
            widget.mark_set( 'insert', 'insert -1 lines' )
            pass
         else:
            # Move by line
            widget.mark_set( 'insert', widget.dline_prev( 'insert', useThisX=self._insert_x_pos ) )
      elif event.keysym == 'Prior':
         if self._control:
            pass
         else:
            # Move by page
            event.widget.yview_scroll( -1, 'pages' )
      elif event.keysym == 'Next':
         if self._control:
            pass
         else:
            # Move by page
            event.widget.yview_scroll( 1, 'pages' )
      
      widget.see( 'insert' )
      
      if event.keysym not in ('Up','Down'):
         self._insert_x_pos = event.widget.bbox( 'insert' )[0]

   def typeSpecial( self, event ):
      widget = event.widget
      
      if event.keysym in ( 'Return', 'Enter', 'KP_Enter' ):
         try:
            widget.sel_delete( )
         finally:
            widget.insert( 'insert', '\n' )
      elif event.keysym == 'Tab':
         widget.insert( 'insert', '\t' )
      elif event.keysym == 'BackSpace':
         try:
            widget.sel_delete( )
         except:
            widget.delete( 'insert -1 char', 'insert' )
      elif event.keysym in ( 'Delete', 'KP_Delete' ):
         try:
            widget.sel_delete( )
         except:
            widget.delete( 'insert', 'insert +1 char' )
      
      widget.sel_clear()
      self._insert_x_pos = event.widget.bbox( 'insert' )[0]

   def onTypedSpecialKey( self, event ):
      widget = event.widget
      
      if event.keysym in ( 'Return','Enter','KP_Enter','Tab','BackSpace','Delete','Insert' ):
         self.typeSpecial( event )
      
      elif event.keysym in ( 'Up', 'Down', 'Left', 'Right', 'Home', 'End', 'Prior', 'Next'
                             'KP_Up', 'KP_Down', 'KP_Left', 'KP_Right', 'KP_Home', 'KP_End', 'KP_Prior', 'KP_Next' ):
         self.moveCarrot( event )
      
      elif self._control:
         if event.keysym == 'a':
            # select all
            self._selectionAnchor = '1.0'
            widget.mark_set( 'insert', 'end' )
         elif event.keysym == 'c':
            # copy
            try:
               widget.clipboard_append( widget.get( 'sel.first', 'sel.last' ) )
            except:
               pass
         elif event.keysym == 'r':
            # Redo
            try:
               widget.edit_redo( )
            except:
               pass
            widget.sel_clear( )
         elif event.keysym == 'v':
            # paste
            try:
               widget.mark_set( 'insert', 'sel.first' )
               widget.delete( 'sel.first', 'sel.last' )
            except:
               pass
            
            widget.insert( 'insert', widget.clipboard_get( ) )
            self.sel_clear( )
         elif event.keysym == 'x':
            # cut
            try:
               widget.clipboard_append( widget.get( 'sel.first', 'sel.last' ) )
               widget.delete( 'sel.first', 'sel.last' )
               widget.ins_updateTags( )
            except:
               pass
            widget.sel_clear( )
         elif event.keysym == 'z':
            # Undo
            try:
               widget.edit_undo( )
            except:
               pass
            self.sel_clear( )
         
         self._insert_x_pos = event.widget.bbox( 'insert' )[0]

   @bind( '<ButtonPress-1>' )
   def click( self, event ):
      event.widget.focus_set( )
      
      if not self._shift and not self._control:
         event.widget.sel_clear( )
         event.widget.sel_setAnchor( 'current' )
      
      self._insert_x_pos = event.x
   
   @bind( '<B1-Motion>', '<Shift-Button1-Motion>' )
   def dragSelection( self, event ):
      widget = event.widget
      
      if event.y < 0:
         widget.yview_scroll( -1, 'units' )
      elif event.y >= widget.winfo_height():
         widget.yview_scroll( 1, 'units' )
      
      if not widget.sel_isAnchorSet( ):
         widget.self_setAnchor( '@%d,%d' % (event.x+2, event.y) )
      
      widget.mark_set( 'insert', '@%d,%d' % (event.x+2, event.y) )
      self._insert_x_pos = event.x
   
   @bind( '<ButtonRelease-1>' )
   def moveCarrot_deselect( self, event ):
      widget = event.widget
      
      widget.grab_release()
      widget.mark_set( 'insert', 'current' )
      self._insert_x_pos = event.x
   
   @bind( '<Double-ButtonPress-1>' )
   def selectWord( self, event ):
      event.widget.sel_setAnchor( 'insert wordstart' )
      event.widget.mark_set( 'insert', 'insert wordend' )
      self._insert_x_pos = event.x
   
   @bind( '<Triple-ButtonPress-1>' )
   def selectLine( self, event ):
      event.widget.sel_setAnchor( 'insert linestart' )
      event.widget.mark_set( 'insert', 'insert lineend' )
      self._insert_x_pos = event.x
   
   @bind( '<Button1-Leave>' )
   def scrollView( self, event ):
      widget = event.widget
      
      if event.y < 0:
         widget.yview_scroll( -1, 'units' )
      elif event.y >= widget.winfo_height():
         widget.yview_scroll( 1, 'units' )
      
      widget.grab_set( )
   
   @bind( '<MouseWheel>' )
   def wheelScroll( self, event ):
      widget = event.widget
      
      if event.delta < 0:
         widget.yview_scroll( 1, 'units' )
      else:
         widget.yview_scroll( -1, 'units' )
   

class EnhancedText( Tkinter.Text ):
   def __init__( self, parent, **options ):
      Tkinter.Text.__init__( self, parent, **options )
      
      controller = EnhancedTextController( )
      controller.install( self )

   # Selection Operations
   def sel_clear( self ):
      try:
         self.tag_remove( 'sel', '1.0', 'end' )
      except:
         pass
      
      try:
         self.mark_unset( 'sel.anchor', 'sel.first', 'sel.last' )
      except:
         pass
   
   def sel_setAnchor( self, index ):
      self.mark_set( 'sel.anchor', index )
   
   def sel_isAnchorSet( self ):
      try:
         self.index( 'sel.anchor' )
         return True
      except:
         return False

   def sel_isSelection( self ):
      try:
         self.index( 'sel.first' )
         return True
      except:
         return False

   def sel_update( self ):
      if widget.compare( 'sel.anchor', '<', 'insert' ):
         widget.mark_set( 'sel.first', 'sel.anchor' )
         widget.mark_set( 'sel.last', 'insert' )
      elif widget.compare( 'sel.anchor', '>', 'insert' ):
         widget.mark_set( 'sel.first', 'insert' )
         widget.mark_set( 'sel.last', 'sel.anchor' )
      else:
         return
      
      widget.tag_remove( 'sel', '1.0', 'end' )
      widget.tag_add( 'sel', 'sel.first', 'sel.last' )
   
   def sel_delete( self ):
      try:
         Tkinter.Text.delete( self, 'sel.first', 'sel.last' )
      except:
         pass
      self.sel_clear( )
   
   # Display Lines
   def dline_prev( self, index, useThisX=None ):
      x,y,width,height = self.bbox( index )
      if (y-height) < 0:
         self.yview_scroll( -1, 'units' )
         x,y,width,height = self.bbox( index )
      
      if useThisX:
         x = useThisX
      
      insertIndex = self.index( index )
      newY = y - height
      newIndex = self.index( '@%d,%d' % ( x, newY ) )
      while (self.compare( newIndex, '==', insertIndex)) and (self.compare( newIndex, '>', '1.0' )):
         newY -= height
         newIndex = self.index( '@%d,%d' % ( x, newY ) )
      return newIndex
   
   def dline_next( self, index, useThisX=None ):
      x,y,width,height = self.bbox( index )
      insertIndex = self.index( index )
      
      if useThisX:
         x = useThisX
      
      newY = y + height
      newIndex = self.index( '@%d,%d' % ( x, newY ) )
      while (self.compare( newIndex, '==', insertIndex)) and (self.compare( newIndex, '<', 'end -1 chars' )):
         newY += height
         newIndex = self.index( '@%d,%d' % ( x, newY ) )
      
      return newIndex
   
   def dline_start( self, index ):
      x,y,width,height = self.bbox( index )
      return self.index( '@%d,%d' % (0, y) )
   
   def dline_end( self, index ):
      x,y,width,height = self.bbox( index )
      return self.index( '@%d,%d' % ( self.winfo_width(), y ) )

   # Overloads
   def mark_set( self, name, index ):
      Tkinter.Text.mark_set( self, name, index )
      
      if name == 'insert':
         try:
            if self.compare( 'sel.anchor', '<', 'insert' ):
               self.mark_set( 'sel.first', 'sel.anchor' )
               self.mark_set( 'sel.last', 'insert' )
            elif self.compare( 'sel.anchor', '>', 'insert' ):
               self.mark_set( 'sel.first', 'insert' )
               self.mark_set( 'sel.last', 'sel.anchor' )
            else:
               return
            
            self.tag_remove( 'sel', '1.0', 'end' )
            self.tag_add( 'sel', 'sel.first', 'sel.last' )
         except:
            pass


sample = '''zero one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen twenty.
twenty-one twenty-two twenty-three twenty-four twenty-five twenty-six twenty-seven.
thirty-one thirty-two thirty-three thirty-four thirty-five thirty-six thirty-seven thirty-eight.'''

root = Tkinter.Tk()
text = EnhancedText( root )
text.pack()

text.insert( 'end', sample )

root.mainloop()