# -*- coding: utf-8 -*-
# Copyright © 2005 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 implements functions that unindent line(s) in a gtksourceview
buffer.

@author: Lateef Alabi-Oki
@organization: The Scribes Project
@copyright: Copyright © 2005 Lateef Alabi-Oki
@license: GNU GPLv2 or Later
@contact: mystilleef@gmail.com
"""

def unindent(sourceview):
	"""
	Unident lines in a gtksourceview buffer.

	@param sourceview: The container for the gtksourceview buffer.
	@type textbuffer: A gtksourceview.SoureView object.

	@param lines_unindented: A list of lines unindented
	@type lines_unindented: A List object.
	"""
	lines_unindented = []
	sourceview.set_property("editable", False)
	sourcebuffer = sourceview.get_property("buffer")
	cursor_iterator = sourcebuffer.get_iter_at_mark(sourcebuffer.get_insert())
	line_number = cursor_iterator.get_line()
	try:
		begin_selection, end_selection = sourcebuffer.get_selection_bounds()
		if begin_selection.get_line() == end_selection.get_line():
			sourcebuffer.begin_user_action()
			result = unindent_line(sourceview, begin_selection.get_line())
			sourcebuffer.end_user_action()
			if result:
				lines_unindented.append(line_number)
		else:
			use_response = False
			begining_line = begin_selection.get_line()
			end_line = end_selection.get_line()
			if end_line - begining_line > 1000:
				use_response = True
				from SCRIBES.utils import response
			sourcebuffer.begin_user_action()
			for line in range(begining_line, end_line+1):
				if use_response:
					response()
				result = unindent_line(sourceview, line)
				if result:
					lines_unindented.append(line)
			sourcebuffer.end_user_action()
	except ValueError:
		sourcebuffer.begin_user_action()
		result = unindent_line(sourceview, line_number)
		sourcebuffer.end_user_action()
		if result:
			lines_unindented.append(line_number)
	sourceview.set_property("editable", True)
	return lines_unindented

def unindent_line(sourceview, line_number):
	"""
	Unindent a line in a gtksourceview buffer.

	The unindentation algorithm is based on tab stops. Lines are unidented to
	the nearest tab stop. During the unindentation process, all spaces are
	converted to tab characters. If spaces are used for indentation, then all
	tab characters are converted to spaces.

	@param sourceview: The container of the gtksourceview buffer.
	@type sourceview: A gtksourceview.SoureView object.

	@return: Return True if line was successfully unindented.
	@rtype: A Boolean object.
	"""
	sourcebuffer = sourceview.get_property("buffer")
	use_spaces = sourceview.get_property("insert-spaces-instead-of-tabs")
	tab_width = sourceview.get_property("tabs-width")
	begin_position = sourcebuffer.get_iter_at_line(line_number)
	transition_position = begin_position.copy()
	space_list = []
	tab_list = []
	while True:
		if transition_position.get_char() in (" "):
			space_list.append(" ")
		elif transition_position.get_char() in ("\t"):
			tab_list.append("\t")
		else:
			break
		transition_position.forward_char()
	if transition_position.equal(begin_position):
		return False
	number_of_spaces = len(space_list)
	number_of_tabs = len(tab_list)
	if use_spaces:
		new_spaces = []
		if number_of_tabs:
			for space in range(tab_width * number_of_tabs):
				new_spaces.append(" ")
		if number_of_spaces:
			new_spaces += space_list
		total_number_of_spaces = len(new_spaces)
		if total_number_of_spaces % tab_width:
			for space in range(total_number_of_spaces % tab_width):
				new_spaces.remove(" ")
		else:
			for space in range(tab_width):
				new_spaces.remove(" ")
		string = "".join(new_spaces)
	else:
		if not number_of_spaces:
			tab_list.remove("\t")
		else:
			if number_of_spaces > tab_width:
				tabs = number_of_spaces / tab_width
				tab_list.append("\t" * tabs)
		string = "".join(tab_list)
	sourcebuffer.delete(begin_position, transition_position)
	begin_position = sourcebuffer.get_iter_at_line(line_number)
	sourcebuffer.insert(begin_position, string)
	return True