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--
-- All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
-- its licensors.
--
-- For complete copyright and license terms please see the LICENSE at the root of this
-- distribution (the "License"). All use of this software is governed by the License,
-- or, if provided, by the license below or the license accompanying this file. Do not
-- remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
--
--
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-- DropTargetCrossCanvas - script for a drop target element that can be dropped on from other
-- canvases. This script is designed to be used with DraggableCrossCanvasElement
----------------------------------------------------------------------------------------------------
local DropTargetCrossCanvas = 
{
    Properties = 
    {
	},
}

function DropTargetCrossCanvas:OnActivate()
	self.dropTargetHandler = UiDropTargetNotificationBus.Connect(self, self.entityId)
end

function DropTargetCrossCanvas:OnDeactivate()
	self.dropTargetHandler:Disconnect()
end

function DropTargetCrossCanvas:OnDropHoverStart(draggable)
	if (UiDraggableBus.Event.IsProxy(draggable)) then
		if (UiElementBus.Event.GetNumChildElements(self.entityId) <= 0) then
			UiDraggableBus.Event.SetDragState(draggable, eUiDragState_Valid)
			UiDropTargetBus.Event.SetDropState(self.entityId, eUiDropState_Valid)
		else
			UiDraggableBus.Event.SetDragState(draggable, eUiDragState_Invalid)
			UiDropTargetBus.Event.SetDropState(self.entityId, eUiDropState_Invalid)
		end
	end
end

function DropTargetCrossCanvas:OnDropHoverEnd(draggable)
	if (UiDraggableBus.Event.IsProxy(draggable)) then
		UiDraggableBus.Event.SetDragState(draggable, eUiDragState_Normal)
		UiDropTargetBus.Event.SetDropState(self.entityId, eUiDropState_Normal)
	else
		UiDraggableBus.Event.SetDragState(draggable, eUiDragState_Normal)
		UiDropTargetBus.Event.SetDropState(self.entityId, eUiDropState_Normal)
	end
end

function DropTargetCrossCanvas:OnDrop(draggable)
	if (not UiDraggableBus.Event.IsProxy(draggable)) then
		if (UiElementBus.Event.GetNumChildElements(self.entityId) <= 0) then
			local myCanvasEntity = UiElementBus.Event.GetCanvas(self.entityId)
			local draggableCanvasEntity = UiElementBus.Event.GetCanvas(draggable)
			if (myCanvasEntity == draggableCanvasEntity) then
				UiElementBus.Event.Reparent(draggable, self.entityId, EntityId())
			else
				-- clone the draggable and remove it from its original canvas
				UiCanvasBus.Event.CloneElement(myCanvasEntity, draggable, self.entityId, EntityId())
				UiElementBus.Event.DestroyElement(draggable)
			end
		end
	end
end

return DropTargetCrossCanvas