from idlelib.delegator import Delegator
from idlelib.redirector import WidgetRedirector


class Percolator:

 def __init__(self, text):
 # XXX would be nice to inherit from Delegator
 self.text = text
 self.redir = WidgetRedirector(text)
 self.top = self.bottom = Delegator(text)
 self.bottom.insert = self.redir.register("insert", self.insert)
 self.bottom.delete = self.redir.register("delete", self.delete)
 self.filters = []

 def close(self):
 while self.top is not self.bottom:
 self.removefilter(self.top)
 self.top = None
 self.bottom.setdelegate(None)
 self.bottom = None
 self.redir.close()
 self.redir = None
 self.text = None

 def insert(self, index, chars, tags=None):
 # Could go away if inheriting from Delegator
 self.top.insert(index, chars, tags)

 def delete(self, index1, index2=None):
 # Could go away if inheriting from Delegator
 self.top.delete(index1, index2)

 def insertfilter(self, filter):
 # Perhaps rename to pushfilter()?
 assert isinstance(filter, Delegator)
 assert filter.delegate is None
 filter.setdelegate(self.top)
 self.top = filter

 def removefilter(self, filter):
 # XXX Perhaps should only support popfilter()?
 assert isinstance(filter, Delegator)
 assert filter.delegate is not None
 f = self.top
 if f is filter:
 self.top = filter.delegate
 filter.setdelegate(None)
 else:
 while f.delegate is not filter:
 assert f is not self.bottom
 f.resetcache()
 f = f.delegate
 f.setdelegate(filter.delegate)
 filter.setdelegate(None)


def _percolator(parent): # htest #
 import tkinter as tk

 class Tracer(Delegator):
 def __init__(self, name):
 self.name = name
 Delegator.__init__(self, None)

 def insert(self, *args):
 print(self.name, ": insert", args)
 self.delegate.insert(*args)

 def delete(self, *args):
 print(self.name, ": delete", args)
 self.delegate.delete(*args)

 box = tk.Toplevel(parent)
 box.title("Test Percolator")
 x, y = map(int, parent.geometry().split('+')[1:])
 box.geometry("+%d+%d" % (x, y + 175))
 text = tk.Text(box)
 p = Percolator(text)
 pin = p.insertfilter
 pout = p.removefilter
 t1 = Tracer("t1")
 t2 = Tracer("t2")

 def toggle1():
 (pin if var1.get() else pout)(t1)
 def toggle2():
 (pin if var2.get() else pout)(t2)

 text.pack()
 var1 = tk.IntVar(parent)
 cb1 = tk.Checkbutton(box, text="Tracer1", command=toggle1, variable=var1)
 cb1.pack()
 var2 = tk.IntVar(parent)
 cb2 = tk.Checkbutton(box, text="Tracer2", command=toggle2, variable=var2)
 cb2.pack()

if __name__ == "__main__":
 from unittest import main
 main('idlelib.idle_test.test_percolator', verbosity=2, exit=False)

 from idlelib.idle_test.htest import run
 run(_percolator)