# -*- coding: utf-8 -*-
#
# Copyright © Spyder Project Contributors
# Licensed under the terms of the MIT License
# (see spyder/__init__.py for details)

"""QPlainTextEdit base class"""

# pylint: disable=C0103
# pylint: disable=R0903
# pylint: disable=R0911
# pylint: disable=R0201

# Standard library imports
import os
import sys

# Third party imports
from qtpy.compat import to_qvariant
from qtpy.QtCore import QEvent, QPoint, Qt, Signal, Slot
from qtpy.QtGui import (QClipboard, QColor, QMouseEvent, QTextFormat,
                        QTextOption, QTextCursor)
from qtpy.QtWidgets import QApplication, QMainWindow, QPlainTextEdit, QToolTip

# Local imports
from spyder.config.gui import get_font
from spyder.config.manager import CONF
from spyder.py3compat import PY3, to_text_string
from spyder.widgets.calltip import CallTipWidget, ToolTipWidget
from spyder.widgets.mixins import BaseEditMixin
from spyder.plugins.editor.api.decoration import TextDecoration, DRAW_ORDERS
from spyder.plugins.editor.utils.decoration import TextDecorationsManager
from spyder.plugins.editor.widgets.completion import CompletionWidget
from spyder.plugins.outlineexplorer.api import is_cell_header


class TextEditBaseWidget(QPlainTextEdit, BaseEditMixin):
    """Text edit base widget"""
    BRACE_MATCHING_SCOPE = ('sof', 'eof')
    cell_separators = None
    focus_in = Signal()
    zoom_in = Signal()
    zoom_out = Signal()
    zoom_reset = Signal()
    focus_changed = Signal()
    sig_insert_completion = Signal(str)
    sig_eol_chars_changed = Signal(str)

    def __init__(self, parent=None):
        QPlainTextEdit.__init__(self, parent)
        BaseEditMixin.__init__(self)
        self.setAttribute(Qt.WA_DeleteOnClose)

        self.extra_selections_dict = {}

        # Code snippets
        self.code_snippets = True

        self.textChanged.connect(self.changed)
        self.cursorPositionChanged.connect(self.cursor_position_changed)

        self.indent_chars = " "*4
        self.tab_stop_width_spaces = 4

        # Code completion / calltips
        if parent is not None:
            mainwin = parent
            while not isinstance(mainwin, QMainWindow):
                mainwin = mainwin.parent()
                if mainwin is None:
                    break
            if mainwin is not None:
                parent = mainwin

        self.completion_widget = CompletionWidget(self, parent)
        self.codecompletion_auto = False
        self.setup_completion()

        self.calltip_widget = CallTipWidget(self, hide_timer_on=False)
        self.calltip_position = None
        self.tooltip_widget = ToolTipWidget(self, as_tooltip=True)

        self.highlight_current_cell_enabled = False

        # The color values may be overridden by the syntax highlighter
        # Highlight current line color
        self.currentline_color = QColor(Qt.red).lighter(190)
        self.currentcell_color = QColor(Qt.red).lighter(194)

        # Brace matching
        self.bracepos = None
        self.matched_p_color = QColor(Qt.green)
        self.unmatched_p_color = QColor(Qt.red)

        self.decorations = TextDecorationsManager(self)

    def setup_completion(self):
        size = CONF.get('main', 'completion/size')
        font = get_font()
        self.completion_widget.setup_appearance(size, font)

    def set_indent_chars(self, indent_chars):
        self.indent_chars = indent_chars

    def set_tab_stop_width_spaces(self, tab_stop_width_spaces):
        self.tab_stop_width_spaces = tab_stop_width_spaces
        self.update_tab_stop_width_spaces()

    def update_tab_stop_width_spaces(self):
        self.setTabStopWidth(self.fontMetrics().width(
                             ' ' * self.tab_stop_width_spaces))

    def set_palette(self, background, foreground):
        """
        Set text editor palette colors:
        background color and caret (text cursor) color
        """
        # Because QtStylsheet overrides QPalette and because some style do not
        # use the palette for all drawing (e.g. macOS styles), the background
        # and foreground color of each TextEditBaseWidget instance must be set
        # with a stylesheet extended with an ID Selector.
        # Fixes spyder-ide/spyder#2028, spyder-ide/spyder#8069 and
        # spyder-ide/spyder#9248.
        if not self.objectName():
            self.setObjectName(self.__class__.__name__ + str(id(self)))
        style = "QPlainTextEdit#%s {background: %s; color: %s;}" % \
                (self.objectName(), background.name(), foreground.name())
        self.setStyleSheet(style)

    # ---- Extra selections
    def get_extra_selections(self, key):
        """Return editor extra selections.

        Args:
            key (str) name of the extra selections group

        Returns:
            list of sourcecode.api.TextDecoration.
        """
        return self.extra_selections_dict.get(key, [])

    def set_extra_selections(self, key, extra_selections):
        """Set extra selections for a key.

        Also assign draw orders to leave current_cell and current_line
        in the backgrund (and avoid them to cover other decorations)

        NOTE: This will remove previous decorations added to  the same key.

        Args:
            key (str) name of the extra selections group.
            extra_selections (list of sourcecode.api.TextDecoration).
        """
        # use draw orders to highlight current_cell and current_line first
        draw_order = DRAW_ORDERS.get(key)
        if draw_order is None:
            draw_order = DRAW_ORDERS.get('on_top')

        for selection in extra_selections:
            selection.draw_order = draw_order

        self.clear_extra_selections(key)
        self.extra_selections_dict[key] = extra_selections

    def update_extra_selections(self):
        """Add extra selections to DecorationsManager.

        TODO: This method could be remove it and decorations could be
        added/removed in set_extra_selections/clear_extra_selections.
        """
        extra_selections = []

        for key, extra in list(self.extra_selections_dict.items()):
            extra_selections.extend(extra)
        self.decorations.add(extra_selections)

    def clear_extra_selections(self, key):
        """Remove decorations added through set_extra_selections.

        Args:
            key (str) name of the extra selections group.
        """
        for decoration in self.extra_selections_dict.get(key, []):
            self.decorations.remove(decoration)
        self.extra_selections_dict[key] = []

    def changed(self):
        """Emit changed signal"""
        self.modificationChanged.emit(self.document().isModified())


    #------Highlight current line
    def highlight_current_line(self):
        """Highlight current line"""
        selection = TextDecoration(self.textCursor())
        selection.format.setProperty(QTextFormat.FullWidthSelection,
                                     to_qvariant(True))
        selection.format.setBackground(self.currentline_color)
        selection.cursor.clearSelection()
        self.set_extra_selections('current_line', [selection])
        self.update_extra_selections()

    def unhighlight_current_line(self):
        """Unhighlight current line"""
        self.clear_extra_selections('current_line')

    #------Highlight current cell
    def highlight_current_cell(self):
        """Highlight current cell"""
        if self.cell_separators is None or \
          not self.highlight_current_cell_enabled:
            return
        cursor, whole_file_selected, whole_screen_selected =\
            self.select_current_cell_in_visible_portion()
        selection = TextDecoration(cursor)
        selection.format.setProperty(QTextFormat.FullWidthSelection,
                                     to_qvariant(True))
        selection.format.setBackground(self.currentcell_color)

        if whole_file_selected:
            self.clear_extra_selections('current_cell')
        elif whole_screen_selected:
            has_cell_separators = False
            for oedata in self.outlineexplorer_data_list():
                if oedata.def_type == oedata.CELL:
                    has_cell_separators = True
                    break
            if has_cell_separators:
                self.set_extra_selections('current_cell', [selection])
                self.update_extra_selections()
            else:
                self.clear_extra_selections('current_cell')
        else:
            self.set_extra_selections('current_cell', [selection])
            self.update_extra_selections()

    def unhighlight_current_cell(self):
        """Unhighlight current cell"""
        self.clear_extra_selections('current_cell')

    #------Brace matching
    def find_brace_match(self, position, brace, forward):
        start_pos, end_pos = self.BRACE_MATCHING_SCOPE
        if forward:
            bracemap = {'(': ')', '[': ']', '{': '}'}
            text = self.get_text(position, end_pos)
            i_start_open = 1
            i_start_close = 1
        else:
            bracemap = {')': '(', ']': '[', '}': '{'}
            text = self.get_text(start_pos, position)
            i_start_open = len(text)-1
            i_start_close = len(text)-1

        while True:
            if forward:
                i_close = text.find(bracemap[brace], i_start_close)
            else:
                i_close = text.rfind(bracemap[brace], 0, i_start_close+1)
            if i_close > -1:
                if forward:
                    i_start_close = i_close+1
                    i_open = text.find(brace, i_start_open, i_close)
                else:
                    i_start_close = i_close-1
                    i_open = text.rfind(brace, i_close, i_start_open+1)
                if i_open > -1:
                    if forward:
                        i_start_open = i_open+1
                    else:
                        i_start_open = i_open-1
                else:
                    # found matching brace
                    if forward:
                        return position+i_close
                    else:
                        return position-(len(text)-i_close)
            else:
                # no matching brace
                return

    def __highlight(self, positions, color=None, cancel=False):
        if cancel:
            self.clear_extra_selections('brace_matching')
            return
        extra_selections = []
        for position in positions:
            if position > self.get_position('eof'):
                return
            selection = TextDecoration(self.textCursor())
            selection.format.setBackground(color)
            selection.cursor.clearSelection()
            selection.cursor.setPosition(position)
            selection.cursor.movePosition(QTextCursor.NextCharacter,
                                          QTextCursor.KeepAnchor)
            extra_selections.append(selection)
        self.set_extra_selections('brace_matching', extra_selections)
        self.update_extra_selections()

    def cursor_position_changed(self):
        """Brace matching"""
        if self.bracepos is not None:
            self.__highlight(self.bracepos, cancel=True)
            self.bracepos = None
        cursor = self.textCursor()
        if cursor.position() == 0:
            return
        cursor.movePosition(QTextCursor.PreviousCharacter,
                            QTextCursor.KeepAnchor)
        text = to_text_string(cursor.selectedText())
        pos1 = cursor.position()
        if text in (')', ']', '}'):
            pos2 = self.find_brace_match(pos1, text, forward=False)
        elif text in ('(', '[', '{'):
            pos2 = self.find_brace_match(pos1, text, forward=True)
        else:
            return
        if pos2 is not None:
            self.bracepos = (pos1, pos2)
            self.__highlight(self.bracepos, color=self.matched_p_color)
        else:
            self.bracepos = (pos1,)
            self.__highlight(self.bracepos, color=self.unmatched_p_color)


    #-----Widget setup and options
    def set_codecompletion_auto(self, state):
        """Set code completion state"""
        self.codecompletion_auto = state

    def set_wrap_mode(self, mode=None):
        """
        Set wrap mode
        Valid *mode* values: None, 'word', 'character'
        """
        if mode == 'word':
            wrap_mode = QTextOption.WrapAtWordBoundaryOrAnywhere
        elif mode == 'character':
            wrap_mode = QTextOption.WrapAnywhere
        else:
            wrap_mode = QTextOption.NoWrap
        self.setWordWrapMode(wrap_mode)


    #------Reimplementing Qt methods
    @Slot()
    def copy(self):
        """
        Reimplement Qt method
        Copy text to clipboard with correct EOL chars
        """
        if self.get_selected_text():
            QApplication.clipboard().setText(self.get_selected_text())

    def toPlainText(self):
        """
        Reimplement Qt method
        Fix PyQt4 bug on Windows and Python 3
        """
        # Fix what appears to be a PyQt4 bug when getting file
        # contents under Windows and PY3. This bug leads to
        # corruptions when saving files with certain combinations
        # of unicode chars on them (like the one attached on
        # spyder-ide/spyder#1546).
        if os.name == 'nt' and PY3:
            text = self.get_text('sof', 'eof')
            return text.replace('\u2028', '\n').replace('\u2029', '\n')\
                       .replace('\u0085', '\n')
        else:
            return super(TextEditBaseWidget, self).toPlainText()

    def keyPressEvent(self, event):
        text, key = event.text(), event.key()
        ctrl = event.modifiers() & Qt.ControlModifier
        meta = event.modifiers() & Qt.MetaModifier
        # Use our own copy method for {Ctrl,Cmd}+C to avoid Qt
        # copying text in HTML. See spyder-ide/spyder#2285.
        if (ctrl or meta) and key == Qt.Key_C:
            self.copy()
        else:
            super(TextEditBaseWidget, self).keyPressEvent(event)

    #------Text: get, set, ...
    def get_selection_as_executable_code(self, cursor=None):
        """Return selected text as a processed text,
        to be executable in a Python/IPython interpreter"""
        ls = self.get_line_separator()

        _indent = lambda line: len(line)-len(line.lstrip())

        line_from, line_to = self.get_selection_bounds(cursor)
        text = self.get_selected_text(cursor)
        if not text:
            return

        lines = text.split(ls)
        if len(lines) > 1:
            # Multiline selection -> eventually fixing indentation
            original_indent = _indent(self.get_text_line(line_from))
            text = (" "*(original_indent-_indent(lines[0])))+text

        # If there is a common indent to all lines, find it.
        # Moving from bottom line to top line ensures that blank
        # lines inherit the indent of the line *below* it,
        # which is the desired behavior.
        min_indent = 999
        current_indent = 0
        lines = text.split(ls)
        for i in range(len(lines)-1, -1, -1):
            line = lines[i]
            if line.strip():
                current_indent = _indent(line)
                min_indent = min(current_indent, min_indent)
            else:
                lines[i] = ' ' * current_indent
        if min_indent:
            lines = [line[min_indent:] for line in lines]

        # Remove any leading whitespace or comment lines
        # since they confuse the reserved word detector that follows below
        lines_removed = 0
        while lines:
            first_line = lines[0].lstrip()
            if first_line == '' or first_line[0] == '#':
                lines_removed += 1
                lines.pop(0)
            else:
                break

        # Add an EOL character after the last line of code so that it gets
        # evaluated automatically by the console and any quote characters
        # are separated from the triple quotes of runcell
        lines.append(ls)

        # Add removed lines back to have correct traceback line numbers
        leading_lines_str = ls * lines_removed

        return leading_lines_str + ls.join(lines)

    def get_cell_as_executable_code(self, cursor=None):
        """Return cell contents as executable code."""
        if cursor is None:
            cursor = self.textCursor()
        ls = self.get_line_separator()
        cursor, whole_file_selected = self.select_current_cell(cursor)
        line_from, line_to = self.get_selection_bounds(cursor)
        # Get the block for the first cell line
        start = cursor.selectionStart()
        block = self.document().findBlock(start)
        if not is_cell_header(block) and start > 0:
            block = self.document().findBlock(start - 1)
        # Get text
        text = self.get_selection_as_executable_code(cursor)
        if text is not None:
            text = ls * line_from + text
        return text, block

    def is_cell_separator(self, cursor=None, block=None):
        """Return True if cursor (or text block) is on a block separator"""
        assert cursor is not None or block is not None
        if cursor is not None:
            cursor0 = QTextCursor(cursor)
            cursor0.select(QTextCursor.BlockUnderCursor)
            text = to_text_string(cursor0.selectedText())
        else:
            text = to_text_string(block.text())
        if self.cell_separators is None:
            return False
        else:
            return text.lstrip().startswith(self.cell_separators)

    def select_current_cell(self, cursor=None):
        """
        Select cell under cursor.

        cell = group of lines separated by CELL_SEPARATORS
        returns the textCursor and a boolean indicating if the
        entire file is selected.
        """
        if cursor is None:
            cursor = self.textCursor()
        cursor.movePosition(QTextCursor.StartOfBlock)
        cur_pos = prev_pos = cursor.position()

        # Moving to the next line that is not a separator, if we are
        # exactly at one of them
        while self.is_cell_separator(cursor):
            cursor.movePosition(QTextCursor.NextBlock)
            prev_pos = cur_pos
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                return cursor, False
        prev_pos = cur_pos
        # If not, move backwards to find the previous separator
        while not self.is_cell_separator(cursor):
            cursor.movePosition(QTextCursor.PreviousBlock)
            prev_pos = cur_pos
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                if self.is_cell_separator(cursor):
                    return cursor, False
                else:
                    break
        cursor.setPosition(prev_pos)
        cell_at_file_start = cursor.atStart()
        # Once we find it (or reach the beginning of the file)
        # move to the next separator (or the end of the file)
        # so we can grab the cell contents
        while not self.is_cell_separator(cursor):
            cursor.movePosition(QTextCursor.NextBlock,
                                QTextCursor.KeepAnchor)
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                cursor.movePosition(QTextCursor.EndOfBlock,
                                    QTextCursor.KeepAnchor)
                break
            prev_pos = cur_pos
        cell_at_file_end = cursor.atEnd()
        return cursor, cell_at_file_start and cell_at_file_end

    def select_current_cell_in_visible_portion(self):
        """Select cell under cursor in the visible portion of the file
        cell = group of lines separated by CELL_SEPARATORS
        returns
         -the textCursor
         -a boolean indicating if the entire file is selected
         -a boolean indicating if the entire visible portion of the file is selected"""
        cursor = self.textCursor()
        cursor.movePosition(QTextCursor.StartOfBlock)
        cur_pos = prev_pos = cursor.position()

        beg_pos = self.cursorForPosition(QPoint(0, 0)).position()
        bottom_right = QPoint(self.viewport().width() - 1,
                              self.viewport().height() - 1)
        end_pos = self.cursorForPosition(bottom_right).position()

        # Moving to the next line that is not a separator, if we are
        # exactly at one of them
        while self.is_cell_separator(cursor):
            cursor.movePosition(QTextCursor.NextBlock)
            prev_pos = cur_pos
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                return cursor, False, False
        prev_pos = cur_pos
        # If not, move backwards to find the previous separator
        while not self.is_cell_separator(cursor)\
          and cursor.position() >= beg_pos:
            cursor.movePosition(QTextCursor.PreviousBlock)
            prev_pos = cur_pos
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                if self.is_cell_separator(cursor):
                    return cursor, False, False
                else:
                    break
        cell_at_screen_start = cursor.position() <= beg_pos
        cursor.setPosition(prev_pos)
        cell_at_file_start = cursor.atStart()
        # Selecting cell header
        if not cell_at_file_start:
            cursor.movePosition(QTextCursor.PreviousBlock)
            cursor.movePosition(QTextCursor.NextBlock,
                                QTextCursor.KeepAnchor)
        # Once we find it (or reach the beginning of the file)
        # move to the next separator (or the end of the file)
        # so we can grab the cell contents
        while not self.is_cell_separator(cursor)\
          and cursor.position() <= end_pos:
            cursor.movePosition(QTextCursor.NextBlock,
                                QTextCursor.KeepAnchor)
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                cursor.movePosition(QTextCursor.EndOfBlock,
                                    QTextCursor.KeepAnchor)
                break
            prev_pos = cur_pos
        cell_at_file_end = cursor.atEnd()
        cell_at_screen_end = cursor.position() >= end_pos
        return cursor,\
               cell_at_file_start and cell_at_file_end,\
               cell_at_screen_start and cell_at_screen_end

    def go_to_next_cell(self):
        """Go to the next cell of lines"""
        cursor = self.textCursor()
        cursor.movePosition(QTextCursor.NextBlock)
        cur_pos = prev_pos = cursor.position()
        while not self.is_cell_separator(cursor):
            # Moving to the next code cell
            cursor.movePosition(QTextCursor.NextBlock)
            prev_pos = cur_pos
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                return
        self.setTextCursor(cursor)

    def go_to_previous_cell(self):
        """Go to the previous cell of lines"""
        cursor = self.textCursor()
        cur_pos = prev_pos = cursor.position()

        if self.is_cell_separator(cursor):
            # Move to the previous cell
            cursor.movePosition(QTextCursor.PreviousBlock)
            cur_pos = prev_pos = cursor.position()

        while not self.is_cell_separator(cursor):
            # Move to the previous cell or the beginning of the current cell
            cursor.movePosition(QTextCursor.PreviousBlock)
            prev_pos = cur_pos
            cur_pos = cursor.position()
            if cur_pos == prev_pos:
                return

        self.setTextCursor(cursor)

    def get_line_count(self):
        """Return document total line number"""
        return self.blockCount()

    def __save_selection(self):
        """Save current cursor selection and return position bounds"""
        cursor = self.textCursor()
        return cursor.selectionStart(), cursor.selectionEnd()

    def __restore_selection(self, start_pos, end_pos):
        """Restore cursor selection from position bounds"""
        cursor = self.textCursor()
        cursor.setPosition(start_pos)
        cursor.setPosition(end_pos, QTextCursor.KeepAnchor)
        self.setTextCursor(cursor)

    def __duplicate_line_or_selection(self, after_current_line=True):
        """Duplicate current line or selected text"""
        cursor = self.textCursor()
        cursor.beginEditBlock()
        start_pos, end_pos = self.__save_selection()
        if to_text_string(cursor.selectedText()):
            cursor.setPosition(end_pos)
            # Check if end_pos is at the start of a block: if so, starting
            # changes from the previous block
            cursor.movePosition(QTextCursor.StartOfBlock,
                                QTextCursor.KeepAnchor)
            if not to_text_string(cursor.selectedText()):
                cursor.movePosition(QTextCursor.PreviousBlock)
                end_pos = cursor.position()

        cursor.setPosition(start_pos)
        cursor.movePosition(QTextCursor.StartOfBlock)
        while cursor.position() <= end_pos:
            cursor.movePosition(QTextCursor.EndOfBlock, QTextCursor.KeepAnchor)
            if cursor.atEnd():
                cursor_temp = QTextCursor(cursor)
                cursor_temp.clearSelection()
                cursor_temp.insertText(self.get_line_separator())
                break
            cursor.movePosition(QTextCursor.NextBlock, QTextCursor.KeepAnchor)
        text = cursor.selectedText()
        cursor.clearSelection()

        if not after_current_line:
            # Moving cursor before current line/selected text
            cursor.setPosition(start_pos)
            cursor.movePosition(QTextCursor.StartOfBlock)
            start_pos += len(text)
            end_pos += len(text)

        cursor.insertText(text)
        cursor.endEditBlock()
        self.setTextCursor(cursor)
        self.__restore_selection(start_pos, end_pos)

    def duplicate_line(self):
        """
        Duplicate current line or selected text
        Paste the duplicated text *after* the current line/selected text
        """
        self.__duplicate_line_or_selection(after_current_line=True)

    def copy_line(self):
        """
        Copy current line or selected text
        Paste the duplicated text *before* the current line/selected text
        """
        self.__duplicate_line_or_selection(after_current_line=False)

    def __move_line_or_selection(self, after_current_line=True):
        """Move current line or selected text"""
        cursor = self.textCursor()
        cursor.beginEditBlock()
        start_pos, end_pos = self.__save_selection()
        last_line = False

        # ------ Select text

        # Get selection start location
        cursor.setPosition(start_pos)
        cursor.movePosition(QTextCursor.StartOfBlock)
        start_pos = cursor.position()

        # Get selection end location
        cursor.setPosition(end_pos)
        if not cursor.atBlockStart() or end_pos == start_pos:
            cursor.movePosition(QTextCursor.EndOfBlock)
            cursor.movePosition(QTextCursor.NextBlock)
        end_pos = cursor.position()

        # Check if selection ends on the last line of the document
        if cursor.atEnd():
            if not cursor.atBlockStart() or end_pos == start_pos:
                last_line = True

        # ------ Stop if at document boundary

        cursor.setPosition(start_pos)
        if cursor.atStart() and not after_current_line:
            # Stop if selection is already at top of the file while moving up
            cursor.endEditBlock()
            self.setTextCursor(cursor)
            self.__restore_selection(start_pos, end_pos)
            return

        cursor.setPosition(end_pos, QTextCursor.KeepAnchor)
        if last_line and after_current_line:
            # Stop if selection is already at end of the file while moving down
            cursor.endEditBlock()
            self.setTextCursor(cursor)
            self.__restore_selection(start_pos, end_pos)
            return

        # ------ Move text

        sel_text = to_text_string(cursor.selectedText())
        cursor.removeSelectedText()


        if after_current_line:
            # Shift selection down
            text = to_text_string(cursor.block().text())
            sel_text = os.linesep + sel_text[0:-1]  # Move linesep at the start
            cursor.movePosition(QTextCursor.EndOfBlock)
            start_pos += len(text)+1
            end_pos += len(text)
            if not cursor.atEnd():
                end_pos += 1
        else:
            # Shift selection up
            if last_line:
                # Remove the last linesep and add it to the selected text
                cursor.deletePreviousChar()
                sel_text = sel_text + os.linesep
                cursor.movePosition(QTextCursor.StartOfBlock)
                end_pos += 1
            else:
                cursor.movePosition(QTextCursor.PreviousBlock)
            text = to_text_string(cursor.block().text())
            start_pos -= len(text)+1
            end_pos -= len(text)+1

        cursor.insertText(sel_text)

        cursor.endEditBlock()
        self.setTextCursor(cursor)
        self.__restore_selection(start_pos, end_pos)

    def move_line_up(self):
        """Move up current line or selected text"""
        self.__move_line_or_selection(after_current_line=False)

    def move_line_down(self):
        """Move down current line or selected text"""
        self.__move_line_or_selection(after_current_line=True)

    def go_to_new_line(self):
        """Go to the end of the current line and create a new line"""
        self.stdkey_end(False, False)
        self.insert_text(self.get_line_separator())

    def extend_selection_to_complete_lines(self):
        """Extend current selection to complete lines"""
        cursor = self.textCursor()
        start_pos, end_pos = cursor.selectionStart(), cursor.selectionEnd()
        cursor.setPosition(start_pos)
        cursor.setPosition(end_pos, QTextCursor.KeepAnchor)
        if cursor.atBlockStart():
            cursor.movePosition(QTextCursor.PreviousBlock,
                                QTextCursor.KeepAnchor)
            cursor.movePosition(QTextCursor.EndOfBlock,
                                QTextCursor.KeepAnchor)
        self.setTextCursor(cursor)

    def delete_line(self):
        """Delete current line."""
        cursor = self.textCursor()
        if self.has_selected_text():
            self.extend_selection_to_complete_lines()
            start_pos, end_pos = cursor.selectionStart(), cursor.selectionEnd()
            cursor.setPosition(start_pos)
        else:
            start_pos = end_pos = cursor.position()
        cursor.beginEditBlock()
        cursor.setPosition(start_pos)
        cursor.movePosition(QTextCursor.StartOfBlock)
        while cursor.position() <= end_pos:
            cursor.movePosition(QTextCursor.EndOfBlock, QTextCursor.KeepAnchor)
            if cursor.atEnd():
                break
            cursor.movePosition(QTextCursor.NextBlock, QTextCursor.KeepAnchor)
        cursor.removeSelectedText()
        cursor.endEditBlock()
        self.ensureCursorVisible()
        self.document_did_change()

    def set_selection(self, start, end):
        cursor = self.textCursor()
        cursor.setPosition(start)
        cursor.setPosition(end, QTextCursor.KeepAnchor)
        self.setTextCursor(cursor)

    def truncate_selection(self, position_from):
        """Unselect read-only parts in shell, like prompt"""
        position_from = self.get_position(position_from)
        cursor = self.textCursor()
        start, end = cursor.selectionStart(), cursor.selectionEnd()
        if start < end:
            start = max([position_from, start])
        else:
            end = max([position_from, end])
        self.set_selection(start, end)

    def restrict_cursor_position(self, position_from, position_to):
        """In shell, avoid editing text except between prompt and EOF"""
        position_from = self.get_position(position_from)
        position_to = self.get_position(position_to)
        cursor = self.textCursor()
        cursor_position = cursor.position()
        if cursor_position < position_from or cursor_position > position_to:
            self.set_cursor_position(position_to)

    #------Code completion / Calltips
    def hide_tooltip_if_necessary(self, key):
        """Hide calltip when necessary"""
        try:
            calltip_char = self.get_character(self.calltip_position)
            before = self.is_cursor_before(self.calltip_position,
                                           char_offset=1)
            other = key in (Qt.Key_ParenRight, Qt.Key_Period, Qt.Key_Tab)
            if calltip_char not in ('?', '(') or before or other:
                QToolTip.hideText()
        except (IndexError, TypeError):
            QToolTip.hideText()

    def select_completion_list(self):
        """Completion list is active, Enter was just pressed"""
        self.completion_widget.item_selected()

    def insert_completion(self, completion, completion_position):
        """Insert a completion into the editor.

        completion_position is where the completion was generated.

        The replacement range is computed using the (LSP) completion's
        textEdit field if it exists. Otherwise, we replace from the
        start of the word under the cursor.
        """
        if not completion:
            return

        cursor = self.textCursor()

        has_selected_text = self.has_selected_text()
        selection_start, selection_end = self.get_selection_start_end()

        if isinstance(completion, dict) and 'textEdit' in completion:
            cursor.setPosition(completion['textEdit']['range']['start'])
            cursor.setPosition(completion['textEdit']['range']['end'],
                               QTextCursor.KeepAnchor)
            text = to_text_string(completion['textEdit']['newText'])
        else:
            text = completion
            if isinstance(completion, dict):
                text = completion['insertText']
            text = to_text_string(text)

            # Get word on the left of the cursor.
            result = self.get_current_word_and_position(completion=True)
            if result is not None:
                current_text, start_position = result
                end_position = start_position + len(current_text)
                # Check if the completion position is in the expected range
                if not start_position <= completion_position <= end_position:
                    return
                cursor.setPosition(start_position)
                # Remove the word under the cursor
                cursor.setPosition(end_position,
                                   QTextCursor.KeepAnchor)
            else:
                # Check if we are in the correct position
                if cursor.position() != completion_position:
                    return

        if has_selected_text:
            self.sig_will_remove_selection.emit(selection_start, selection_end)

        cursor.removeSelectedText()
        self.setTextCursor(cursor)

        # Add text
        if self.code_snippets:
            self.sig_insert_completion.emit(text)
        else:
            self.insert_text(text)
        self.document_did_change()

    def is_completion_widget_visible(self):
        """Return True is completion list widget is visible"""
        return self.completion_widget.isVisible()

    def hide_completion_widget(self):
        """Hide completion widget and tooltip."""
        self.completion_widget.hide()
        QToolTip.hideText()

    #------Standard keys
    def stdkey_clear(self):
        if not self.has_selected_text():
            self.moveCursor(QTextCursor.NextCharacter, QTextCursor.KeepAnchor)
        self.remove_selected_text()

    def stdkey_backspace(self):
        if not self.has_selected_text():
            self.moveCursor(QTextCursor.PreviousCharacter,
                            QTextCursor.KeepAnchor)
        self.remove_selected_text()

    def __get_move_mode(self, shift):
        return QTextCursor.KeepAnchor if shift else QTextCursor.MoveAnchor

    def stdkey_up(self, shift):
        self.moveCursor(QTextCursor.Up, self.__get_move_mode(shift))

    def stdkey_down(self, shift):
        self.moveCursor(QTextCursor.Down, self.__get_move_mode(shift))

    def stdkey_tab(self):
        self.insert_text(self.indent_chars)

    def stdkey_home(self, shift, ctrl, prompt_pos=None):
        """Smart HOME feature: cursor is first moved at
        indentation position, then at the start of the line"""
        move_mode = self.__get_move_mode(shift)
        if ctrl:
            self.moveCursor(QTextCursor.Start, move_mode)
        else:
            cursor = self.textCursor()
            if prompt_pos is None:
                start_position = self.get_position('sol')
            else:
                start_position = self.get_position(prompt_pos)
            text = self.get_text(start_position, 'eol')
            indent_pos = start_position+len(text)-len(text.lstrip())
            if cursor.position() != indent_pos:
                cursor.setPosition(indent_pos, move_mode)
            else:
                cursor.setPosition(start_position, move_mode)
            self.setTextCursor(cursor)

    def stdkey_end(self, shift, ctrl):
        move_mode = self.__get_move_mode(shift)
        if ctrl:
            self.moveCursor(QTextCursor.End, move_mode)
        else:
            self.moveCursor(QTextCursor.EndOfBlock, move_mode)

    def stdkey_pageup(self):
        pass

    def stdkey_pagedown(self):
        pass

    def stdkey_escape(self):
        pass


    #----Qt Events
    def mousePressEvent(self, event):
        """Reimplement Qt method"""
        if sys.platform.startswith('linux') and event.button() == Qt.MidButton:
            self.calltip_widget.hide()
            self.setFocus()
            event = QMouseEvent(QEvent.MouseButtonPress, event.pos(),
                                Qt.LeftButton, Qt.LeftButton, Qt.NoModifier)
            QPlainTextEdit.mousePressEvent(self, event)
            QPlainTextEdit.mouseReleaseEvent(self, event)
            # Send selection text to clipboard to be able to use
            # the paste method and avoid the strange spyder-ide/spyder#1445.
            # NOTE: This issue seems a focusing problem but it
            # seems really hard to track
            mode_clip = QClipboard.Clipboard
            mode_sel = QClipboard.Selection
            text_clip = QApplication.clipboard().text(mode=mode_clip)
            text_sel = QApplication.clipboard().text(mode=mode_sel)
            QApplication.clipboard().setText(text_sel, mode=mode_clip)
            self.paste()
            QApplication.clipboard().setText(text_clip, mode=mode_clip)
        else:
            self.calltip_widget.hide()
            QPlainTextEdit.mousePressEvent(self, event)

    def focusInEvent(self, event):
        """Reimplemented to handle focus"""
        self.focus_changed.emit()
        self.focus_in.emit()
        self.highlight_current_cell()
        QPlainTextEdit.focusInEvent(self, event)

    def focusOutEvent(self, event):
        """Reimplemented to handle focus"""
        self.focus_changed.emit()
        QPlainTextEdit.focusOutEvent(self, event)

    def wheelEvent(self, event):
        """Reimplemented to emit zoom in/out signals when Ctrl is pressed"""
        # This feature is disabled on MacOS, see spyder-ide/spyder#1510.
        if sys.platform != 'darwin':
            if event.modifiers() & Qt.ControlModifier:
                if hasattr(event, 'angleDelta'):
                    if event.angleDelta().y() < 0:
                        self.zoom_out.emit()
                    elif event.angleDelta().y() > 0:
                        self.zoom_in.emit()
                elif hasattr(event, 'delta'):
                    if event.delta() < 0:
                        self.zoom_out.emit()
                    elif event.delta() > 0:
                        self.zoom_in.emit()
                return
        QPlainTextEdit.wheelEvent(self, event)
        self.hide_completion_widget()
        self.highlight_current_cell()

    def position_widget_at_cursor(self, widget):
        # Retrieve current screen height
        desktop = QApplication.desktop()
        srect = desktop.availableGeometry(desktop.screenNumber(widget))

        left, top, right, bottom = (srect.left(), srect.top(),
                                    srect.right(), srect.bottom())
        ancestor = widget.parent()
        if ancestor:
            left = max(left, ancestor.x())
            top = max(top, ancestor.y())
            right = min(right, ancestor.x() + ancestor.width())
            bottom = min(bottom, ancestor.y() + ancestor.height())

        point = self.cursorRect().bottomRight()
        point = self.calculate_real_position(point)
        point = self.mapToGlobal(point)
        # Move to left of cursor if not enough space on right
        widget_right = point.x() + widget.width()
        if widget_right > right:
            point.setX(point.x() - widget.width())
        # Push to right if not enough space on left
        if point.x() < left:
            point.setX(left)

        # Moving widget above if there is not enough space below
        widget_bottom = point.y() + widget.height()
        x_position = point.x()
        if widget_bottom > bottom:
            point = self.cursorRect().topRight()
            point = self.mapToGlobal(point)
            point.setX(x_position)
            point.setY(point.y() - widget.height())

        if ancestor is not None:
            # Useful only if we set parent to 'ancestor' in __init__
            point = ancestor.mapFromGlobal(point)

        widget.move(point)

    def calculate_real_position(self, point):
        return point
