test toggling comment in qtextedit

qtextedit_test.py

import os
import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4 import uic

import textwrap
from functools import partial


class MyWindow(QDialog):

    def __init__(self, parent=None):
        super(MyWindow, self).__init__(parent)
        layout = QVBoxLayout()

        textedit = QTextEdit()
        code = '''
            def myFunc(x):
                print 'x=%s' % x
                if 3>2:
                    print 'yeah!'

            myFunc(1)
            '''
        code = textwrap.dedent(code).strip()
        textedit.insertPlainText(code)
        font = QFont('Monospace')
        textedit.setFont(font)

        buttons_to_create = [
            ('Current Pos', partial(self.test, 'current_pos')),
            ('Add Single Line Comment', partial(self.test, 'single_line_comment')),
            ('Get Range', partial(self.test, 'get_range')),
            ('Load Range', partial(self.test, 'load_range')),
            ('Toggle Multi Line Comment', self.toggle_comment),
            ('Get char at current pos',
             partial(self.test, 'get_text_cur_pos')),
            # ('Tab', partial(self.test, 'tab')),
            # ('Shift + Tab', partial(self.test, 'shift_tab')),
            ('Tab', partial(self.tab, 'tab')),
            ('Shift + Tab', partial(self.tab, 'shift_tab')),
            ('Undo', partial(self.test, 'undo')),


        ]

        buttons = []
        for label, cmd in buttons_to_create:
            btn = QPushButton(label)
            btn.clicked.connect(cmd)
            buttons.append(btn)

        layout.addWidget(textedit)
        for btn in buttons:
            layout.addWidget(btn)

        self.setLayout(layout)

        self.textedit = textedit
        self.init()

        self.comment_string = '#'
        # self.last_change=None

        textedit.setLineWrapMode(QTextEdit.FixedPixelWidth)
        textedit.setLineWrapColumnOrWidth(600)

    def init(self):
        # self.moveToPosition(25)

        start_pos, end_pos = 21, 59
        cursor = self.textedit.textCursor()

        self.moveToPosition(start_pos)
        # self.textedit.setTextCursor(cursor)

        cursor = self.textedit.textCursor()
        cursor.movePosition(
            QTextCursor.Right, QTextCursor.KeepAnchor, end_pos-start_pos)
        self.textedit.setTextCursor(cursor)

        # test single text delete
        # self.moveToPosition(start_pos)
        # cursor = self.textedit.textCursor()
        # cursor.movePosition(QTextCursor.Right, QTextCursor.MoveAnchor, 20)
        # self.textedit.setTextCursor(cursor)

    def moveToPosition(self, pos):
        cursor = self.textedit.textCursor()
        cursor.movePosition(QTextCursor.Start, QTextCursor.MoveAnchor)
        cursor.movePosition(QTextCursor.Right, QTextCursor.MoveAnchor, pos)
        self.textedit.setTextCursor(cursor)



    def restore_selection(fn):

        from functools import wraps
        @wraps(fn)
        def wrapper(self,*args, **kw):
            
            print 'before'
            self.test('get_range')

            fn(self,*args, **kw)

            print 'after'
            self.test('load_range')

        return wrapper


    @restore_selection
    def toggle_comment(self,*args):
        self.last_change='toggle_comment'
        self.test('multi_line_comment')


    @restore_selection
    def tab(self,mode='tab',*args):
        self.test(mode)

    def position_in_block(self,cursor):
        # this can be replaced with cursor.positionInBlock after qt 4.7
        pos = cursor.position()-cursor.block().position()
        return pos


    def get_line_range(self,cursor,start_pos,end_pos):

        # if start_pos!=end_pos:
        # find which line is left most
        cursor.setPosition(end_pos)
        last_line = cursor.block().blockNumber()
        if cursor.atBlockStart() and start_pos != end_pos:
            last_line -= 1

        cursor.setPosition(start_pos)
        first_line = cursor.block().blockNumber()  
        
        return (first_line,last_line)    

    def get_min_indent(self,cursor,start_pos,first_line,last_line):
        # find the leftmost line and get its position
        cursor.setPosition(start_pos)
        indents = []
        for _line_nb in range(first_line, last_line+1):

            text = str(cursor.block().text())
            indent = len(text)-len(text.lstrip())
            # print 'line:',_line_nb,'indent:',indent
            indents.append(indent)
            cursor.movePosition(QTextCursor.NextBlock)

        min_indent = min(indents)
        print 'min_indent:', min_indent
        return min_indent

    def test(self, mode='current_pos'):
        cursor = self.textedit.textCursor()

        if mode == 'current_pos':
            print 'current pos:', cursor.position()
        elif mode == 'single_line_comment':

            cursor.movePosition(
                QTextCursor.StartOfBlock, QTextCursor.MoveAnchor)
            self.textedit.setTextCursor(cursor)
            cursor.insertText('# ')

        elif mode == 'get_range':
            start_pos, end_pos = [cursor.selectionStart(),
                                  cursor.selectionEnd()]
            print 'range:', start_pos, end_pos
            self.sel_range = (start_pos, end_pos)

        elif mode == 'load_range':
            start_pos, end_pos = self.sel_range
            print 'load range:', start_pos, end_pos
            self.moveToPosition(start_pos)

            cursor = self.textedit.textCursor()
            cursor.movePosition(
                QTextCursor.Right, QTextCursor.KeepAnchor, end_pos - start_pos)
            self.textedit.setTextCursor(cursor)

        elif mode == 'multi_line_comment':
            # find selected lines
            start_pos, end_pos = [cursor.selectionStart(),
                                  cursor.selectionEnd()]


            first_line,last_line = self.get_line_range(cursor,start_pos, end_pos)

            # If the selection contains only commented lines and surrounding
            # whitespace, uncomment. Otherwise, comment.
            is_comment_or_whitespace = True
            at_least_one_comment = False
            for _line_nb in range(first_line, last_line+1):

                text = str(cursor.block().text()).lstrip()
                print 'dealing text:', text

                is_comment = text.startswith(self.comment_string)
                is_whitespace = (text == '')
                is_comment_or_whitespace *= (is_comment or is_whitespace)
                if is_comment:
                    at_least_one_comment = True
                cursor.movePosition(QTextCursor.NextBlock)



            min_indent = self.get_min_indent(cursor,start_pos,first_line,last_line)

            cursor.beginEditBlock()

            if is_comment_or_whitespace and at_least_one_comment:
                print 'need to uncomment'

                cursor.setPosition(start_pos)
                for _line_nb in range(first_line, last_line+1):

                    if _line_nb==first_line:
                        self.moveToPosition(start_pos)
                        if self.position_in_block(cursor)>min_indent:
                            start_pos-=2

                    cursor.movePosition(QTextCursor.StartOfLine)

                    cursor.movePosition(
                        QTextCursor.Right, QTextCursor.MoveAnchor, min_indent)

                    self.textedit.setTextCursor(cursor)
                    cursor.deleteChar()
                    end_pos-=1

                    next_char = cursor.block().text()[self.position_in_block(cursor)]
                    print 'next char:', next_char

                    if next_char == ' ':
                        cursor.deleteChar()
                        end_pos-=1

                    cursor.movePosition(QTextCursor.NextBlock)

                    self.sel_range=(start_pos,end_pos)


            else:
                print 'need to comment'
                cursor.setPosition(start_pos)
                for _line_nb in range(first_line, last_line+1):

                    if _line_nb==first_line:
                        self.moveToPosition(start_pos)
                        
                        if self.position_in_block(cursor)>min_indent:
                            start_pos+=2


                    cursor.movePosition(QTextCursor.StartOfLine)

                    cursor.movePosition(
                        QTextCursor.Right, QTextCursor.MoveAnchor, min_indent)

                    self.textedit.setTextCursor(cursor)
                    cursor.insertText('%s ' % self.comment_string)
                    end_pos+=2

                    cursor.movePosition(QTextCursor.NextBlock)

                    self.sel_range=(start_pos,end_pos)

            cursor.endEditBlock()


        elif mode == 'get_text_cur_pos':
            print 'get cur pos text'
            cursor = self.textedit.textCursor()

            positionInBlock = self.position_in_block(cursor)
            print 'block pos:', positionInBlock
            print 'block text:', cursor.block().text()
            print cursor.block().text()[positionInBlock]

        elif mode == 'tab':
            print 'tab'
            start_pos, end_pos = [cursor.selectionStart(),
                  cursor.selectionEnd()]

            start_pos+=4

            # get last first line
            first_line,last_line = self.get_line_range(cursor,start_pos, end_pos)

            # indent 4 spaces
            for _line_nb in range(first_line, last_line+1):
                cursor.movePosition(QTextCursor.StartOfLine)
                self.textedit.setTextCursor(cursor)
                cursor.insertText(' '*4)
                end_pos+=4

                cursor.movePosition(QTextCursor.NextBlock)

            self.sel_range=(start_pos,end_pos)

        elif mode == 'shift_tab':
            print 'shift_tab'
            start_pos, end_pos = [cursor.selectionStart(),
                  cursor.selectionEnd()]

            # get last first line
            first_line,last_line = self.get_line_range(cursor,start_pos, end_pos)

            for _line_nb in range(first_line, last_line+1):

                cursor.movePosition(QTextCursor.StartOfLine)

                if _line_nb==first_line:

                    for i in range(4):
                        next_char = cursor.block().text()[self.position_in_block(cursor)]
                        if next_char == ' ':
                            cursor.deleteChar()
                            start_pos-=1
                            end_pos-=1

                else:
                    for i in range(4):
                        next_char = cursor.block().text()[self.position_in_block(cursor)]
                        if next_char == ' ':
                            cursor.deleteChar()
                            end_pos-=1

                
                self.textedit.setTextCursor(cursor)
                cursor.movePosition(QTextCursor.NextBlock)

            self.sel_range=(start_pos,end_pos)
        elif mode == 'undo':
            print 'undo'
            # if self.last_change=='toggle_comment':
                # self.toggle_comment()
            self.textedit.undo()


def main():
    if qApp.applicationName().startsWith('Maya'):
        global win
        try:
            win.close()
        except:
            pass
        win = MyWindow(getMayaWindow())
    else:
        app = QApplication(sys.argv)
        win = MyWindow()
        win.show()
        sys.exit(app.exec_())

if __name__ == "__main__":
    main()