# -*- coding: utf-8 -*-
# Copyright © 2007 Lateef Alabi-Oki
#
# This file is part of Scribes.
#
# Scribes is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# Scribes is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Scribes; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
# USA

"""
This module documents a class that monitors the buffer for potential
words for automatic completions.

@author: Lateef Alabi-Oki
@organization: The Scribes Project
@copyright: Copyright © 2007 Lateef Alabi-Oki
@license: GNU GPLv2 or Later
@contact: mystilleef@gmail.com
"""

class CompletionMonitor(object):
	"""
	This class creates an object that monitors the buffer for words for
	automatic completion.
	"""

	def __init__(self, manager, editor):
		"""
		Initialize object.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param manager: Reference to the CompletionManager instance.
		@type manager: A CompletionManager object.

		@param editor: Reference to the text editor.
		@type editor: An Editor object.
		"""
		self.__init_attributes(manager, editor)
		from gobject import idle_add, PRIORITY_LOW
		idle_add(self.__precompile_methods, priority=PRIORITY_LOW)
		self.__signal_id_1 = self.__manager.connect("destroy", self.__destroy_cb)
		self.__signal_id_2 = self.__manager.connect("update", self.__update_cb)
		self.__signal_id_3 = editor.textbuffer.connect_after("insert-text", self.__insert_text_cb)
		self.__signal_id_4 = editor.textview.connect("undo", self.__generic_cb)
		self.__signal_id_5 = editor.textview.connect("redo", self.__generic_cb)
		self.__signal_id_6 = editor.textview.connect("paste-clipboard", self.__generic_cb)
		self.__signal_id_7 = editor.textview.connect_after("undo", self.__generic_cb)
		self.__signal_id_8 = editor.textview.connect_after("redo", self.__generic_cb)
		self.__signal_id_9 = editor.textview.connect_after("paste-clipboard", self.__generic_cb)
		self.__signal_id_10 = editor.textview.connect("key-press-event", self.__key_press_event_cb)
		self.__signal_id_11 = manager.connect("is-visible", self.__is_visible_cb)

	def __init_attributes(self, manager, editor):
		"""
		Initialize data attributes.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param manager: Reference to the CompletionManager instance.
		@type manager: A CompletionManager object.

		@param editor: Reference to the text editor.
		@type editor: An Editor object.
		"""
		self.__editor = editor
		self.__manager = manager
		self.__completion_window_is_visible = False
		self.__dictionary = self.__create_completion_dictionary()
		self.__signal_id_1 = self.__signal_id_2 = self.__signal_id_3 = None
		self.__signal_id_4 = self.__signal_id_5 = self.__signal_id_6 = None
		self.__signal_id_7 = self.__signal_id_8 = self.__signal_id_9 = None
		return

########################################################################
#
#						Helper Methods
#
########################################################################

	def __check_buffer(self):
		"""
		Check the buffer for words for completion.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.
		"""
		try:
			word = self.__editor.get_word_before_cursor()
			if word:
				matches = self.__find_matches(word)
				if matches:
					self.__manager.emit("match-found", matches)
				else:
					self.__manager.emit("no-match-found")
			else:
				self.__manager.emit("no-match-found")
		except:
			self.__manager.emit("no-match-found")
		return False

	def __find_matches(self, word):
		"""
		Return a list of words that match against keys in the completion
		dictionary.

		Words found are ranked based on their number of occurrence in
		the buffer.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param word: Word to match against the completion dictionary.
		@type word: A String object.

		@return: A list of words that start with word.
		@rtype: A List object.
		"""
		from operator import not_, ne
		dictionary = self.__dictionary.get_dictionary()
		if not_(dictionary): return None
		match_list = [list(items) for items in dictionary.items() \
				if items[0].startswith(word) and ne(items[0], word)]
		if not_(match_list): return None
		match_list.sort(self.__sort_matches_occurrence_only)
		matches = [items[0] for items in match_list]
		return matches

	def __sort_matches(self, x, y):
		"""
		Sort matches based on word length and occurrence.

		Shorter words appear higher on the list. If words have the same
		length, the word with a higher occurrence appears higher on the
		list.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param x: First comparison item.
		@type x: A List object.

		@param y: Second comparison item.
		@type y: A List object.

		@return: Returns 0, 1, -1 depending on importance
		@rtype: A Integer object.
		"""
		from operator import gt, lt, eq
		if lt(len(x[0]), len(y[0])): return -1
		if gt(len(x[0]), len(y[0])): return 1
		if eq(len(x[0]), len(y[0])):
			if lt(x[1], y[1]): return 1
			if gt(x[1], y[1]): return -1
		return 0

	def __sort_matches_occurrence_only(self, x, y):
		from operator import gt, lt
		if lt(x[1], y[1]): return 1
		if gt(x[1], y[1]): return -1
		return 0

	def __precompile_methods(self):
		try:
			from psyco import bind
			bind(self.__check_buffer)
			bind(self.__find_matches)
			bind(self.__sort_matches_occurrence_only)
			bind(self.__insert_text_cb)
			bind(self.__key_press_event_cb)
		except ImportError:
			pass
		except:
			pass
		return False

	def __create_completion_dictionary(self):
		"""
		Create a completion dictionary.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.
		"""
		try:
			from SCRIBES.Exceptions import GlobalStoreObjectDoesNotExistError
			dictionary = self.__editor.get_global_object("WordCompletionDictionary")
		except GlobalStoreObjectDoesNotExistError:
			from CompletionDictionary import CompletionDictionary
			self.__editor.add_global_object("WordCompletionDictionary", CompletionDictionary())
			dictionary = self.__editor.get_global_object("WordCompletionDictionary")
		return dictionary

	def __update_dictionary(self, dictionary):
		self.__dictionary.update(dictionary)
		return False

########################################################################
#
#						Signal and Event Handlers
#
########################################################################

	def __insert_text_cb(self, textbuffer, iterator, text, length):
		"""
		Handles callback when the "insert-text" signal is emitted.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param textbuffer: The text editor's buffer
		@type textbuffer: A ScribesTextBuffer object.
		"""
		try:
			from operator import gt
			if gt(length, 1): raise ValueError
			from gobject import idle_add, source_remove, PRIORITY_LOW, timeout_add
			try:
				source_remove(self.__insert_text_id)
			except:
				pass
			if self.__completion_window_is_visible:
				self.__insert_text_id = idle_add(self.__check_buffer, priority=PRIORITY_LOW)
			else:
				self.__insert_text_id = timeout_add(500, self.__check_buffer, priority=PRIORITY_LOW)
		except ValueError:
			self.__manager.emit("no-match-found")
		return False

	def __generic_cb(self, *args):
		"""
		A generic callback method.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param *args: Irrelevant arguments.
		@type *args: A List object.
		"""
		self.__manager.emit("no-match-found")
		from gobject import source_remove
		try:
			source_remove(self.__insert_text_id)
		except:
			pass
		return False

	def __update_cb(self, manager, dictionary):
		"""
		Handles callback when the "update" signal is emitted.

		@param self: Reference to the CompletionMonitor instance.
		@type self: An CompletionMonitor object.

		@param manager: Reference to the CompletionManager.
		@type manager: An CompletionManager object.
		"""
		try:
			from gobject import timeout_add, PRIORITY_LOW, source_remove
			source_remove(self.__dictionary_timer)
		except:
			pass
		self.__dictionary_timer = timeout_add(1000, self.__update_dictionary, dictionary, priority=PRIORITY_LOW)
		return

	def __key_press_event_cb(self, textview, event):
		"""
		Handles callback when the "key-press-event" is emitted.

		@param self: Reference to the CompletionMonitor instance.
		@type self: A CompletionMonitor object.

		@param textview: The text editor's buffer container.
		@type textview: A textview object.
		"""
		from operator import eq, contains
		from gtk import keysyms
		hide_keys = (keysyms.BackSpace, keysyms.space, keysyms.Tab, keysyms.Escape)
		if contains(hide_keys, event.keyval): self.__manager.emit("no-match-found")
		return False

	def __is_visible_cb(self, manager, visibility):
		self.__completion_window_is_visible = visibility
		return False

	def __destroy_cb(self, manager):
		"""
		Handles callback when the "destroy" signal is emitted.

		@param self: Reference to the CompletionMonitor instance.
		@type self: An CompletionMonitor object.

		@param manager: Reference to the CompletionManager.
		@type manager: An CompletionManager object.
		"""
		self.__editor.disconnect_signal(self.__signal_id_1, self.__manager)
		self.__editor.disconnect_signal(self.__signal_id_2, self.__manager)
		self.__editor.disconnect_signal(self.__signal_id_3, self.__editor.textbuffer)
		self.__editor.disconnect_signal(self.__signal_id_4, self.__editor.textview)
		self.__editor.disconnect_signal(self.__signal_id_5, self.__editor.textview)
		self.__editor.disconnect_signal(self.__signal_id_6, self.__editor.textview)
		self.__editor.disconnect_signal(self.__signal_id_7, self.__editor.textview)
		self.__editor.disconnect_signal(self.__signal_id_8, self.__editor.textview)
		self.__editor.disconnect_signal(self.__signal_id_9, self.__editor.textview)
		self.__editor.disconnect_signal(self.__signal_id_10, self.__editor.textview)
		del self
		self = None
		return