from Components.HTMLSkin import *
from Components.GUISkin import *

import sys

class Screen(dict, HTMLSkin, GUISkin):
	""" bla """

	def __init__(self, session):
		self.skinName = self.__class__.__name__
		self.session = session
		GUISkin.__init__(self)
		
		self.onClose = [ ]
		self.onExecBegin = [ ]
		self.onShown = [ ]
		
		self.onShow = [ ]
		self.onHide = [ ]
		
		self.execing = False
		self.shown = False
		
		# in order to support screens *without* a help,
		# we need the list in every screen. how ironic.
		self.helpList = [ ]
		
	def execBegin(self):
		self.active_components = [ ]
		for x in self.onExecBegin:
			x()
			if self.session.current_dialog != self:
				return

#		assert self.session == None, "a screen can only exec once per time"
#		self.session = session

		for (name, val) in self.items():
			val.execBegin()
			if self.session.current_dialog != self:
				return
			self.active_components.append(val)

		self.execing = True
	
		for x in self.onShown:
			x()
	
	def execEnd(self):
#		for (name, val) in self.items():
		for val in self.active_components:
			val.execEnd()
		del self.active_components
#		assert self.session != None, "execEnd on non-execing screen!"
#		self.session = None
		self.execing = False
	
	# never call this directly - it will be called from the session!
	def doClose(self):
		self.hide()
		for x in self.onClose:
			x()
		
		# fixup circular references
		del self.helpList
		GUISkin.close(self)
		
		del self.session
		for (name, val) in self.items():
			val.destroy()
			del self[name]
		
		# really delete all elements now
		self.__dict__.clear()
	
	def close(self, *retval):
		self.session.close(*retval)

	def setFocus(self, o):
		self.instance.setFocus(o.instance)

	def show(self):
		if self.shown:
			return
		self.shown = True
		self.instance.show()
		for x in self.onShow:
			x()
		for (name, val) in self.items():
			if isinstance(val, GUIComponent):
				val.onShow()

	def hide(self):
		if not self.shown:
			return
		self.shown = False
		self.instance.hide()
		for x in self.onHide:
			x()
		for (name, val) in self.items():
			if isinstance(val, GUIComponent):
				val.onHide()