"""ParenMatch -- for parenthesis matching.

When you hit a right paren, the cursor should move briefly to the left
paren. Paren here is used generically; the matching applies to
parentheses, square brackets, and curly braces.
"""
from idlelib.hyperparser import HyperParser
from idlelib.config import idleConf

_openers = {')':'(',']':'[','}':'{'}
CHECK_DELAY = 100 # milliseconds

class ParenMatch:
 """Highlight matching openers and closers, (), [], and {}.

 There are three supported styles of paren matching. When a right
 paren (opener) is typed:

 opener -- highlight the matching left paren (closer);
 parens -- highlight the left and right parens (opener and closer);
 expression -- highlight the entire expression from opener to closer.
 (For back compatibility, 'default' is a synonym for 'opener').

 Flash-delay is the maximum milliseconds the highlighting remains.
 Any cursor movement (key press or click) before that removes the
 highlight. If flash-delay is 0, there is no maximum.

 TODO:
 - Augment bell() with mismatch warning in status window.
 - Highlight when cursor is moved to the right of a closer.
 This might be too expensive to check.
 """

 RESTORE_VIRTUAL_EVENT_NAME = "<<parenmatch-check-restore>>"
 # We want the restore event be called before the usual return and
 # backspace events.
 RESTORE_SEQUENCES = ("<KeyPress>", "<ButtonPress>",
 "<Key-Return>", "<Key-BackSpace>")

 def __init__(self, editwin):
 self.editwin = editwin
 self.text = editwin.text
 # Bind the check-restore event to the function restore_event,
 # so that we can then use activate_restore (which calls event_add)
 # and deactivate_restore (which calls event_delete).
 editwin.text.bind(self.RESTORE_VIRTUAL_EVENT_NAME,
 self.restore_event)
 self.counter = 0
 self.is_restore_active = 0

 @classmethod
 def reload(cls):
 cls.STYLE = idleConf.GetOption(
 'extensions','ParenMatch','style', default='opener')
 cls.FLASH_DELAY = idleConf.GetOption(
 'extensions','ParenMatch','flash-delay', type='int',default=500)
 cls.BELL = idleConf.GetOption(
 'extensions','ParenMatch','bell', type='bool', default=1)
 cls.HILITE_CONFIG = idleConf.GetHighlight(idleConf.CurrentTheme(),
 'hilite')

 def activate_restore(self):
 "Activate mechanism to restore text from highlighting."
 if not self.is_restore_active:
 for seq in self.RESTORE_SEQUENCES:
 self.text.event_add(self.RESTORE_VIRTUAL_EVENT_NAME, seq)
 self.is_restore_active = True

 def deactivate_restore(self):
 "Remove restore event bindings."
 if self.is_restore_active:
 for seq in self.RESTORE_SEQUENCES:
 self.text.event_delete(self.RESTORE_VIRTUAL_EVENT_NAME, seq)
 self.is_restore_active = False

 def flash_paren_event(self, event):
 "Handle editor 'show surrounding parens' event (menu or shortcut)."
 indices = (HyperParser(self.editwin, "insert")
 .get_surrounding_brackets())
 self.finish_paren_event(indices)
 return "break"

 def paren_closed_event(self, event):
 "Handle user input of closer."
 # If user bound non-closer to <<paren-closed>>, quit.
 closer = self.text.get("insert-1c")
 if closer not in _openers:
 return
 hp = HyperParser(self.editwin, "insert-1c")
 if not hp.is_in_code():
 return
 indices = hp.get_surrounding_brackets(_openers[closer], True)
 self.finish_paren_event(indices)
 return # Allow calltips to see ')'

 def finish_paren_event(self, indices):
 if indices is None and self.BELL:
 self.text.bell()
 return
 self.activate_restore()
 # self.create_tag(indices)
 self.tagfuncs.get(self.STYLE, self.create_tag_expression)(self, indices)
 # self.set_timeout()
 (self.set_timeout_last if self.FLASH_DELAY else
 self.set_timeout_none)()

 def restore_event(self, event=None):
 "Remove effect of doing match."
 self.text.tag_delete("paren")
 self.deactivate_restore()
 self.counter += 1 # disable the last timer, if there is one.

 def handle_restore_timer(self, timer_count):
 if timer_count == self.counter:
 self.restore_event()

 # any one of the create_tag_XXX methods can be used depending on
 # the style

 def create_tag_opener(self, indices):
 """Highlight the single paren that matches"""
 self.text.tag_add("paren", indices[0])
 self.text.tag_config("paren", self.HILITE_CONFIG)

 def create_tag_parens(self, indices):
 """Highlight the left and right parens"""
 if self.text.get(indices[1]) in (')', ']', '}'):
 rightindex = indices[1]+"+1c"
 else:
 rightindex = indices[1]
 self.text.tag_add("paren", indices[0], indices[0]+"+1c", rightindex+"-1c", rightindex)
 self.text.tag_config("paren", self.HILITE_CONFIG)

 def create_tag_expression(self, indices):
 """Highlight the entire expression"""
 if self.text.get(indices[1]) in (')', ']', '}'):
 rightindex = indices[1]+"+1c"
 else:
 rightindex = indices[1]
 self.text.tag_add("paren", indices[0], rightindex)
 self.text.tag_config("paren", self.HILITE_CONFIG)

 tagfuncs = {
 'opener': create_tag_opener,
 'default': create_tag_opener,
 'parens': create_tag_parens,
 'expression': create_tag_expression,
 }

 # any one of the set_timeout_XXX methods can be used depending on
 # the style

 def set_timeout_none(self):
 """Highlight will remain until user input turns it off
 or the insert has moved"""
 # After CHECK_DELAY, call a function which disables the "paren" tag
 # if the event is for the most recent timer and the insert has changed,
 # or schedules another call for itself.
 self.counter += 1
 def callme(callme, self=self, c=self.counter,
 index=self.text.index("insert")):
 if index != self.text.index("insert"):
 self.handle_restore_timer(c)
 else:
 self.editwin.text_frame.after(CHECK_DELAY, callme, callme)
 self.editwin.text_frame.after(CHECK_DELAY, callme, callme)

 def set_timeout_last(self):
 """The last highlight created will be removed after FLASH_DELAY millisecs"""
 # associate a counter with an event; only disable the "paren"
 # tag if the event is for the most recent timer.
 self.counter += 1
 self.editwin.text_frame.after(
 self.FLASH_DELAY,
 lambda self=self, c=self.counter: self.handle_restore_timer(c))


ParenMatch.reload()


if __name__ == '__main__':
 from unittest import main
 main('idlelib.idle_test.test_parenmatch', verbosity=2)