#------------------------------------------------------------------------------
#
#  Copyright (c) 2006, Enthought, Inc.
#  All rights reserved.
#
#  This software is provided without warranty under the terms of the BSD
#  license included in enthought/LICENSE.txt and may be redistributed only
#  under the conditions described in the aforementioned license.  The license
#  is also available online at http://www.enthought.com/licenses/BSD.txt
#
#  Thanks for using Enthought open source!
#
#  Author: David C. Morrill
#  Date:   06/25/2006
#
#------------------------------------------------------------------------------

""" Defines the various editors for a drag-and-drop editor,
    for the wxPython user interface toolkit. A drag-and-drop editor represents
    its value as a simple image which, depending upon the editor style, can be
    a drag source only, a drop target only, or both a drag source and a drop
    target.
"""

#-------------------------------------------------------------------------------
#  Imports:
#-------------------------------------------------------------------------------

import wx
import numpy

from pickle \
    import load

from traits.api \
    import Bool

# FIXME: ToolkitEditorFactory is a proxy class defined here just for backward
# compatibility. The class has been moved to the
# traitsui.editors.dnd_editor file.
from traitsui.editors.dnd_editor \
    import ToolkitEditorFactory

from pyface.wx.drag_and_drop \
    import PythonDropSource, PythonDropTarget, clipboard

try:
    from apptools.io import File
except ImportError:
    File = None

try:
    from apptools.naming.api import Binding
except ImportError:
    Binding = None

from pyface.image_resource \
    import ImageResource

from .editor \
    import Editor

#-------------------------------------------------------------------------------
#  Constants:
#-------------------------------------------------------------------------------

# The image to use when the editor accepts files:
file_image = ImageResource( 'file' ).create_image()

# The image to use when the editor accepts objects:
object_image = ImageResource( 'object' ).create_image()

# The image to use when the editor is disabled:
inactive_image = ImageResource( 'inactive' ).create_image()

# String types:
string_type = ( str, str )

#-------------------------------------------------------------------------------
#  'SimpleEditor' class:
#-------------------------------------------------------------------------------

class SimpleEditor ( Editor ):
    """ Simply style of editor for a drag-and-drop editor, which is both a drag
        source and a drop target.
    """

    #---------------------------------------------------------------------------
    #  Trait definitions:
    #---------------------------------------------------------------------------

    # Is the editor a drop target?
    drop_target = Bool( True )

    # Is the editor a drag source?
    drag_source = Bool( True )

    #---------------------------------------------------------------------------
    #  Finishes initializing the editor by creating the underlying toolkit
    #  widget:
    #---------------------------------------------------------------------------

    def init ( self, parent ):
        """ Finishes initializing the editor by creating the underlying toolkit
            widget.
        """
        # Determine the drag/drop type:
        value         = self.value
        self._is_list = isinstance( value, list )
        self._is_file = (isinstance( value, string_type ) or
                         (self._is_list and (len( value ) > 0) and
                          isinstance( value[0], string_type )))

        # Get the right image to use:
        image = self.factory.image
        if image is not None:
            image = image.create_image()
            disabled_image = self.factory.disabled_image
            if disabled_image is not None:
                disabled_image = disabled_image.create_image()
        else:
            disabled_image = inactive_image
            image          = object_image
            if self._is_file:
                image = file_image

        self._image = image.ConvertToBitmap()
        if disabled_image is not None:
            self._disabled_image = disabled_image.ConvertToBitmap()
        else:
            data = numpy.reshape( numpy.fromstring( image.GetData(),
                                                    numpy.uint8 ),
                      ( -1, 3 ) ) * numpy.array( [ [ 0.297, 0.589, 0.114 ] ] )
            g = data[ :, 0 ] + data[ :, 1 ] + data[ :, 2 ]
            data[ :, 0 ] = data[ :, 1 ] = data[ :, 2 ] = g
            image.SetData( numpy.ravel( data.astype(numpy.uint8) ).tostring() )
            image.SetMaskColour( 0, 0, 0 )
            self._disabled_image = image.ConvertToBitmap()

        # Create the control and set up the event handlers:
        self.control = control = wx.Window( parent, -1,
                         size = wx.Size( image.GetWidth(), image.GetHeight() ) )
        self.set_tooltip()

        if self.drop_target:
            control.SetDropTarget( PythonDropTarget( self ) )

        wx.EVT_LEFT_DOWN( control, self._left_down )
        wx.EVT_LEFT_UP(   control, self._left_up )
        wx.EVT_MOTION(    control, self._mouse_move )
        wx.EVT_PAINT(     control, self._on_paint )

    #---------------------------------------------------------------------------
    #  Disposes of the contents of an editor:
    #---------------------------------------------------------------------------

    def dispose ( self ):
        """ Disposes of the contents of an editor.
        """
        control = self.control
        wx.EVT_LEFT_DOWN( control, None )
        wx.EVT_LEFT_UP(   control, None )
        wx.EVT_MOTION(    control, None )
        wx.EVT_PAINT(     control, None )

        super( SimpleEditor, self ).dispose()

    #---------------------------------------------------------------------------
    #  Updates the editor when the object trait changes external to the editor:
    #---------------------------------------------------------------------------

    def update_editor ( self ):
        """ Updates the editor when the object trait changes externally to the
            editor.
        """
        return

#-- Private Methods ------------------------------------------------------------

    #---------------------------------------------------------------------------
    #  Returns the processed version of a drag request's data:
    #---------------------------------------------------------------------------

    def _get_drag_data ( self, data ):
        """ Returns the processed version of a drag request's data.
        """
        if isinstance( data, list ):

            if Binding is not None and isinstance( data[0], Binding ):
                data = [ item.obj for item in data ]

            if File is not None and isinstance( data[0], File ):
                data = [ item.absolute_path for item in data ]
                if not self._is_file:
                    result = []
                    for file in data:
                        item = self._unpickle( file )
                        if item is not None:
                            result.append( item )
                    data = result

        else:
            if Binding is not None and isinstance( data, Binding ):
                data = data.obj

            if File is not None and isinstance( data, File ):
                data = data.absolute_path
                if not self._is_file:
                    object = self._unpickle( data )
                    if object is not None:
                        data = object

        return data

    #---------------------------------------------------------------------------
    #  Returns the unpickled version of a specified file (if possible):
    #---------------------------------------------------------------------------

    def _unpickle ( self, file_name ):
        """ Returns the unpickled version of a specified file (if possible).
        """
        fh = None
        try:
            fh     = file( file_name, 'rb' )
            object = load( fh )
        except:
            object = None

        if fh is not None:
            fh.close()

        return object

#-- wxPython Event Handlers ----------------------------------------------------

    def _on_paint ( self, event ):
        """ Called when the control needs repainting.
        """
        image   = self._image
        control = self.control
        if not control.IsEnabled():
            image = self._disabled_image

        wdx, wdy = control.GetClientSizeTuple()
        wx.PaintDC( control ).DrawBitmap( image,
            (wdx - image.GetWidth())  / 2, (wdy - image.GetHeight()) / 2, True )

    def _left_down ( self, event ):
        """ Handles the left mouse button being pressed.
        """
        if self.control.IsEnabled() and self.drag_source:
            self._x, self._y = event.GetX(), event.GetY()
            self.control.CaptureMouse()

        event.Skip()

    def _left_up ( self, event ):
        """ Handles the left mouse button being released.
        """
        if self._x is not None:
            self._x = None
            self.control.ReleaseMouse()

        event.Skip()

    def _mouse_move ( self, event ):
        """ Handles the mouse being moved.
        """
        if self._x is not None:
            if ((abs( self._x - event.GetX() ) +
                 abs( self._y - event.GetY() )) >= 3):
                self.control.ReleaseMouse()
                self._x = None
                if self._is_file:
                    FileDropSource(   self.control, self.value )
                else:
                    PythonDropSource( self.control, self.value )

        event.Skip()

#----- Drag and drop event handlers: -------------------------------------------

    #---------------------------------------------------------------------------
    #  Handles a Python object being dropped on the control:
    #---------------------------------------------------------------------------

    def wx_dropped_on ( self, x, y, data, drag_result ):
        """ Handles a Python object being dropped on the tree.
        """
        try:
            self.value = self._get_drag_data( data )
            return drag_result
        except:
            return wx.DragNone

    #---------------------------------------------------------------------------
    #  Handles a Python object being dragged over the control:
    #---------------------------------------------------------------------------

    def wx_drag_over ( self, x, y, data, drag_result ):
        """ Handles a Python object being dragged over the tree.
        """
        try:
            self.object.base_trait( self.name ).validate( self.object,
                                        self.name, self._get_drag_data( data ) )
            return drag_result
        except:
            return wx.DragNone

#-------------------------------------------------------------------------------
#  'CustomEditor' class:
#-------------------------------------------------------------------------------

class CustomEditor ( SimpleEditor ):
    """ Custom style of drag-and-drop editor, which is not a drag source.
    """
    #---------------------------------------------------------------------------
    #  Trait definitions:
    #---------------------------------------------------------------------------

    # Is the editor a drag source? This value overrides the default.
    drag_source = False

#-------------------------------------------------------------------------------
#  'ReadonlyEditor' class:
#-------------------------------------------------------------------------------

class ReadonlyEditor ( SimpleEditor ):
    """ Read-only style of drag-and-drop editor, which is not a drop target.
    """
    #---------------------------------------------------------------------------
    #  Trait definitions:
    #---------------------------------------------------------------------------

    # Is the editor a drop target? This value overrides the default.
    drop_target = False

#-------------------------------------------------------------------------------
#  'FileDropSource' class:
#-------------------------------------------------------------------------------

class FileDropSource ( wx.DropSource ):
    """ Represents a draggable file.
    """
    #---------------------------------------------------------------------------
    #  Initializes the object:
    #---------------------------------------------------------------------------

    def __init__ ( self, source, files ):
        """ Initializes the object.
        """
        self.handler    = None
        self.allow_move = True

        # Put the data to be dragged on the clipboard:
        clipboard.data        = files
        clipboard.source      = source
        clipboard.drop_source = self

        data_object = wx.FileDataObject()
        if isinstance( files, string_type ):
            files = [ files ]

        for file in files:
            data_object.AddFile( file )

        # Create the drop source and begin the drag and drop operation:
        super( FileDropSource, self ).__init__( source )
        self.SetData( data_object )
        self.result = self.DoDragDrop( True )

    #---------------------------------------------------------------------------
    #  Called when the data has been dropped:
    #---------------------------------------------------------------------------

    def on_dropped ( self, drag_result ):
        """ Called when the data has been dropped. """
        return

## EOF ########################################################################
