#----------------------------------------------------------------------
# Name:        wx.lib.resizewidget
# Purpose:     Adds a resize handle to any widget, with support for
#              notifying parents when layout needs done.
#
# Author:      Robin Dunn
#
# Created:     12-June-2008
# Copyright:   (c) 2008-2020 by Total Control Software
# Licence:     wxWindows license
# Tags:        phoenix-port, unittest, documented, py3-port
#----------------------------------------------------------------------

"""
Reparents a given widget into a specialized panel that provides a resize
handle for the widget. When the user drags the resize handle the widget is
resized accordingly, and an event is sent to notify parents that they should
recalculate their layout.
"""

import wx
import wx.lib.newevent

#-----------------------------------------------------------------------------

# dimensions used for the handle
RW_THICKNESS = 4
RW_LENGTH = 12

# default colors for the handle
RW_PEN   = 'black'
RW_FILL  = '#A0A0A0'
RW_FILL2 = '#E0E0E0'

# An event and event binder that will notify the containers that they should
# redo the layout in whatever way makes sense for their particular content.
_RWLayoutNeededEvent, EVT_RW_LAYOUT_NEEDED = wx.lib.newevent.NewCommandEvent()


# TODO: Add a style flag that indicates that the ResizeWidget should
# try to adjust the layout itself by looking up the sizer and
# containment hierarchy.  Maybe also a style that says that it is okay
# to adjust the size of top-level windows too.

#-----------------------------------------------------------------------------

class ResizeWidget(wx.Panel):
    """
    Reparents a given widget into a specialized panel that provides a resize
    handle for the widget.

    """
    def __init__(self, *args, **kw):
        """
        Default class constructor.

        :param `args`: arguments will be passed on to the wx.Panel
        :param `kw`: key words will be passed on to the wx.Panel

        """
        wx.Panel.__init__(self, *args, **kw)
        self._init()

        self.Bind(wx.EVT_LEFT_DOWN, self.OnLeftDown)
        self.Bind(wx.EVT_LEFT_UP, self.OnLeftUp)
        self.Bind(wx.EVT_MOTION,  self.OnMouseMove)
        self.Bind(wx.EVT_LEAVE_WINDOW, self.OnMouseLeave)

        self.Bind(wx.EVT_SIZE, self.OnSize)
        self.Bind(wx.EVT_PAINT, self.OnPaint)


    def _init(self):
        self._managedChild = None
        self._bestSize = wx.Size(100, 25)
        self.InvalidateBestSize()
        self._resizeCursor = False
        self._dragPos = None
        self._resizeEnabled = True
        self._reparenting = False

        self.SetDimensions()
        self.SetColors()

    def SetDimensions(self, thickness=RW_THICKNESS, length=RW_LENGTH):
        """
        Set the dimensions of handles.

        :param `thickness`: the thickness of the handles
        :param `length`: the length of the handles

        """
        self.RW_THICKNESS = thickness
        self.RW_LENGTH = length

    def SetColors(self, pen=RW_PEN, fill=RW_FILL, fill2=RW_FILL2):
        """
        Set the colors of handles.

        :param `pen`: the pen color
        :param `fill`: the fill color
        :param `fill2`: the secondary fill color

        """
        self.RW_PEN   = pen
        self.RW_FILL  = fill
        self.RW_FILL2 = fill2

    def SetManagedChild(self, child):
        """
        Set a managed child.

        :param `child`: child to manage

        """
        self._reparenting = True
        child.Reparent(self)  # This calls AddChild, so do the rest of the init there
        self._reparenting = False
        self.AdjustToChild()

    def GetManagedChild(self):
        """Get the managed child."""
        return self._managedChild

    ManagedChild = property(GetManagedChild, SetManagedChild)


    def AdjustToChild(self):
        """Adjust the size to the child."""
        self.AdjustToSize(self._managedChild.GetEffectiveMinSize())


    def AdjustToSize(self, size):
        """
        Adjust to given size.

        :param `size`: size to adjust to.

        """
        size = wx.Size(*size)
        self._bestSize = size + (self.RW_THICKNESS, self.RW_THICKNESS)
        self.InvalidateBestSize()
        self.SetSize(self._bestSize)


    def EnableResize(self, enable=True):
        """
        Enable resizing.

        :param boolean `enable`: enable or disable resizing.

        """
        self._resizeEnabled = enable
        self.Refresh(False)


    def IsResizeEnabled(self):
        """Is resize enabled?"""
        return self._resizeEnabled


    #=== Event handler methods ===
    def OnLeftDown(self, evt):
        """
        Handles the ``wx.EVT_LEFT_DOWN`` event for :class:`ResizeWidget`.

        :param `evt`: a :class:`MouseEvent` event to be processed.

        """
        if self._hitTest(evt.GetPosition()) and self._resizeEnabled:
            self.CaptureMouse()
            self._dragPos = evt.GetPosition()


    def OnLeftUp(self, evt):
        """
        Handles the ``wx.EVT_LEFT_UP`` event for :class:`ResizeWidget`.

        :param `evt`: a :class:`MouseEvent` event to be processed.

        """
        if self.HasCapture():
            self.ReleaseMouse()
        self._dragPos = None


    def OnMouseMove(self, evt):
        """
        Handles the ``wx.EVT_MOTION`` event for :class:`ResizeWidget`.

        :param `evt`: a :class:`MouseEvent` event to be processed.

        """
        # set or reset the drag cursor
        pos = evt.GetPosition()
        if self._hitTest(pos) and self._resizeEnabled:
            if not self._resizeCursor:
                self.SetCursor(wx.Cursor(wx.CURSOR_SIZENWSE))
                self._resizeCursor = True
        else:
            if self._resizeCursor:
                self.SetCursor(wx.Cursor(wx.CURSOR_ARROW))
                self._resizeCursor = False

        # determine if a new size is needed
        if evt.Dragging() and self._dragPos is not None:
            delta = self._dragPos - pos
            newSize = self.GetSize() - delta.Get()
            self._adjustNewSize(newSize)
            if newSize != self.GetSize():
                self.SetSize(newSize)
                self._dragPos = pos
                self._bestSize = newSize
                self.InvalidateBestSize()
                self._sendEvent()


    def _sendEvent(self):
        event = _RWLayoutNeededEvent(self.GetId())
        event.SetEventObject(self)
        self.GetEventHandler().ProcessEvent(event)


    def _adjustNewSize(self, newSize):
        if newSize.width < self.RW_LENGTH:
            newSize.width = self.RW_LENGTH
        if newSize.height < self.RW_LENGTH:
            newSize.height = self.RW_LENGTH

        if self._managedChild:
            minsize = self._managedChild.GetMinSize()
            if minsize.width != -1 and newSize.width - self.RW_THICKNESS < minsize.width:
                newSize.width = minsize.width + self.RW_THICKNESS
            if minsize.height != -1 and newSize.height - self.RW_THICKNESS < minsize.height:
                newSize.height = minsize.height + self.RW_THICKNESS
            maxsize = self._managedChild.GetMaxSize()
            if maxsize.width != -1 and newSize.width - self.RW_THICKNESS > maxsize.width:
                newSize.width = maxsize.width + self.RW_THICKNESS
            if maxsize.height != -1 and newSize.height - self.RW_THICKNESS > maxsize.height:
                newSize.height = maxsize.height + self.RW_THICKNESS


    def OnMouseLeave(self, evt):
        """
        Handles the ``wx.EVT_LEAVE_WINDOW`` event for :class:`ResizeWidget`.

        :param `evt`: a :class:`MouseEvent` event to be processed.

        """
        if self._resizeCursor:
            self.SetCursor(wx.Cursor(wx.CURSOR_ARROW))
            self._resizeCursor = False


    def OnSize(self, evt):
        """
        Handles the ``wx.EVT_SIZE`` event for :class:`ResizeWidget`.

        :param `evt`: a :class:`wx.SizeEvent` event to be processed.

        """
        if not self._managedChild:
            return
        sz = self.GetSize()
        cr = wx.Rect((0, 0), sz - (self.RW_THICKNESS, self.RW_THICKNESS))
        self._managedChild.SetRect(cr)
        r1 = wx.Rect(0, cr.height, sz.width, self.RW_THICKNESS)
        r2 = wx.Rect(cr.width, 0, self.RW_THICKNESS, sz.height)
        self.RefreshRect(r1)
        self.RefreshRect(r2)


    def OnPaint(self, evt):
        """
        Handles the ``wx.EVT_PAINT`` event for :class:`ResizeWidget`.

        :param `evt`: a :class:`PaintEvent` event to be processed.

        """
        # draw the resize handle
        dc = wx.PaintDC(self)
        w, h = self.GetSize()
        points = [ (w - 1,                 h - self.RW_LENGTH),
                   (w - self.RW_THICKNESS, h - self.RW_LENGTH),
                   (w - self.RW_THICKNESS, h - self.RW_THICKNESS),
                   (w - self.RW_LENGTH,    h - self.RW_THICKNESS),
                   (w - self.RW_LENGTH,    h - 1),
                   (w - 1,                 h - 1),
                   (w - 1,                 h - self.RW_LENGTH),
                   ]
        dc.SetPen(wx.Pen(self.RW_PEN, 1))
        if self._resizeEnabled:
            fill = self.RW_FILL
        else:
            fill = self.RW_FILL2
        dc.SetBrush(wx.Brush(fill))
        dc.DrawPolygon(points)


    def _hitTest(self, pos):
        # is the position in the area to be used for the resize handle?
        w, h = self.GetSize()
        if ( w - self.RW_THICKNESS <= pos.x <= w
             and h - self.RW_LENGTH <= pos.y <= h ):
            return True
        if ( w - self.RW_LENGTH <= pos.x <= w
             and h - self.RW_THICKNESS <= pos.y <= h ):
            return True
        return False


    #=== Overridden virtuals from the base class ===
    def AddChild(self, child):
        """
        Add the child to manage.

        :param `child`: the child to manage.

        """
        assert self._managedChild is None, "Already managing a child widget, can only do one"
        self._managedChild = child
        wx.Panel.AddChild(self, child)

        # This little hack is needed because if this AddChild was called when
        # the widget was first created, then the OOR values will get reset
        # after this function call, and so the Python proxy object saved in
        # the window may be different than the child object we have now, so we
        # need to reset which proxy object we're using.  Look for it by ID.
        def _doAfterAddChild(self, id):
            if not self:
                return
            child = self.FindWindow(id)
            self._managedChild = child
            self.AdjustToChild()
            self._sendEvent()
        if self._reparenting:
            _doAfterAddChild(self, child.GetId())
        else:
            wx.CallAfter(_doAfterAddChild, self, child.GetId())

    def RemoveChild(self, child):
        """
        Remove the managed child.

        :param `child`: child to remove.

        """
        self._init()
        wx.Panel.RemoveChild(self, child)


    def DoGetBestSize(self):
        """Return the best size."""
        return self._bestSize


#-----------------------------------------------------------------------------