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import IECore

import Gaffer
import GafferUI

## Abstract base class for toolbars representing nodes, typically
# used in the Viewer. Nodes may have up to four toolbars - one for
# each edge of the frame. See StandardNodeToolbar for a concrete
# implementation suitable for most purposes.
class NodeToolbar( GafferUI.Widget ) :

	def __init__( self, node, topLevelWidget, **kw ) :

		GafferUI.Widget.__init__( self, topLevelWidget, **kw )

		self.__node = node

		scriptNode = self.__node.scriptNode()
		self.__context = GafferUI.PlugValueWidget._PlugValueWidget__defaultContext( node )

	## Returns the node the toolbar represents.
	def node( self ) :

		return self.__node

	def getContext( self ) :

		return self.__context

	def setContext( self, context ) :

		self.__context = context

	## Creates a NodeToolbar instance for the specified node and edge.
	# Note that not all nodes have toolbars, so None may be returned.
	@classmethod
	def create( cls, node, edge = GafferUI.Edge.Top ) :

		# Try to create a toolbar using metadata.
		toolbarType = Gaffer.Metadata.value( node, "nodeToolbar:%s:type" % str( edge ).lower() )
		if toolbarType is not None :
			if toolbarType == "" :
				return None
			path = toolbarType.split( "." )
			toolbarClass = __import__( path[0] )
			for n in path[1:] :
				toolbarClass = getattr( toolbarClass, n )
			return toolbarClass( node )

		# Fall back to deprecated registry.
		if edge == GafferUI.Edge.Top :
			nodeHierarchy = IECore.RunTimeTyped.baseTypeIds( node.typeId() )
			for typeId in [ node.typeId() ] + nodeHierarchy :
				creator = cls.__creators.get( typeId, None )
				if creator is not None :
					return creator( node )

		return None

	__creators = {}
	## Registers a subclass of NodeToolbar to be used with a specific node type.
	## \deprecated. Use "nodeToolbar:top|bottom|left|right:type" metadata instead.
	@classmethod
	def registerCreator( cls, nodeClassOrTypeId, toolbarCreator ) :

		assert( callable( toolbarCreator ) )

		if isinstance( nodeClassOrTypeId, IECore.TypeId ) :
			nodeTypeId = nodeClassOrTypeId
		else :
			nodeTypeId = nodeClassOrTypeId.staticTypeId()

		cls.__creators[nodeTypeId] = toolbarCreator
