src/eric7/Preferences/ConfigurationPages/EditorHighlightingStylesPage.py

# -*- coding: utf-8 -*-

# Copyright (c) 2006 - 2023 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing the Editor Highlighting Styles configuration page.
"""

import pathlib

from PyQt6.QtCore import QFile, QIODevice, Qt, pyqtSlot
from PyQt6.QtGui import QColor, QFont
from PyQt6.QtWidgets import (
    QColorDialog,
    QDialog,
    QFontDialog,
    QInputDialog,
    QMenu,
    QTreeWidgetItem,
)

from eric7.EricGui import EricPixmapCache
from eric7.EricWidgets import EricFileDialog, EricMessageBox
from eric7.EricXML.HighlightingStylesReader import HighlightingStylesReader
from eric7.Preferences.HighlightingStylesFile import HighlightingStylesFile
from eric7.QScintilla import Lexers

from ..SubstyleDefinitionDialog import SubstyleDefinitionDialog
from .ConfigurationPageBase import ConfigurationPageBase
from .Ui_EditorHighlightingStylesPage import Ui_EditorHighlightingStylesPage


class EditorHighlightingStylesPage(
    ConfigurationPageBase, Ui_EditorHighlightingStylesPage
):
    """
    Class implementing the Editor Highlighting Styles configuration page.
    """

    FAMILYONLY = 0
    SIZEONLY = 1
    FAMILYANDSIZE = 2
    FONT = 99

    StyleRole = Qt.ItemDataRole.UserRole + 1
    SubstyleRole = Qt.ItemDataRole.UserRole + 2

    def __init__(self, lexers):
        """
        Constructor

        @param lexers reference to the lexers dictionary
        @type dict
        """
        super().__init__()
        self.setupUi(self)
        self.setObjectName("EditorHighlightingStylesPage")

        self.defaultSubstylesButton.setIcon(EricPixmapCache.getIcon("editUndo"))
        self.addSubstyleButton.setIcon(EricPixmapCache.getIcon("plus"))
        self.deleteSubstyleButton.setIcon(EricPixmapCache.getIcon("minus"))
        self.editSubstyleButton.setIcon(EricPixmapCache.getIcon("edit"))
        self.copySubstyleButton.setIcon(EricPixmapCache.getIcon("editCopy"))

        self.__fontButtonMenu = QMenu()
        act = self.__fontButtonMenu.addAction(self.tr("Font"))
        act.setData(self.FONT)
        self.__fontButtonMenu.addSeparator()
        act = self.__fontButtonMenu.addAction(self.tr("Family and Size only"))
        act.setData(self.FAMILYANDSIZE)
        act = self.__fontButtonMenu.addAction(self.tr("Family only"))
        act.setData(self.FAMILYONLY)
        act = self.__fontButtonMenu.addAction(self.tr("Size only"))
        act.setData(self.SIZEONLY)
        self.__fontButtonMenu.triggered.connect(self.__fontButtonMenuTriggered)
        self.fontButton.setMenu(self.__fontButtonMenu)

        self.__allFontsButtonMenu = QMenu()
        act = self.__allFontsButtonMenu.addAction(self.tr("Font"))
        act.setData(self.FONT)
        self.__allFontsButtonMenu.addSeparator()
        act = self.__allFontsButtonMenu.addAction(self.tr("Family and Size only"))
        act.setData(self.FAMILYANDSIZE)
        act = self.__allFontsButtonMenu.addAction(self.tr("Family only"))
        act.setData(self.FAMILYONLY)
        act = self.__allFontsButtonMenu.addAction(self.tr("Size only"))
        act.setData(self.SIZEONLY)
        self.__allFontsButtonMenu.triggered.connect(self.__allFontsButtonMenuTriggered)
        self.allFontsButton.setMenu(self.__allFontsButtonMenu)

        self.lexer = None
        self.lexers = lexers

        # set initial values
        languages = sorted([""] + list(self.lexers))
        self.__populateLanguages(languages)

    def setMode(self, displayMode):
        """
        Public method to perform mode dependent setups.

        @param displayMode mode of the configuration dialog
        @type ConfigurationMode
        """
        from ..ConfigurationDialog import ConfigurationMode

        if displayMode in (ConfigurationMode.SHELLMODE,):
            self.__populateLanguages(["Python3"])

    def save(self):
        """
        Public slot to save the Editor Highlighting Styles configuration.
        """
        for lexer in self.lexers.values():
            lexer.writeSettings()

    def __populateLanguages(self, languages):
        """
        Private method to populate the language selection box.

        @param languages list of languages to include in the language selector
        @type list of str
        """
        self.lexerLanguageComboBox.clear()
        for language in languages:
            self.lexerLanguageComboBox.addItem(
                Lexers.getLanguageIcon(language, False), language
            )
        self.on_lexerLanguageComboBox_activated(0)

    @pyqtSlot(int)
    def on_lexerLanguageComboBox_activated(self, index):
        """
        Private slot to fill the style combo of the source page.

        @param index index of the selected entry
        @type int
        """
        language = self.lexerLanguageComboBox.itemText(index)

        self.styleElementList.clear()
        self.styleGroup.setEnabled(False)
        self.lexer = None

        if not language:
            return

        try:
            self.lexer = self.lexers[language]
        except KeyError:
            return

        self.styleGroup.setEnabled(True)
        for description, styleNo, subStyleNo in self.lexer.getStyles():
            if subStyleNo >= 0:
                parent = self.styleElementList.findItems(
                    self.lexer.description(styleNo), Qt.MatchFlag.MatchExactly
                )[0]
                parent.setExpanded(True)
            else:
                parent = self.styleElementList
            itm = QTreeWidgetItem(parent, [description])
            itm.setData(0, self.StyleRole, styleNo)
            itm.setData(0, self.SubstyleRole, subStyleNo)
        self.__styleAllItems()
        self.styleElementList.setCurrentItem(self.styleElementList.topLevelItem(0))

    def __stylesForItem(self, itm):
        """
        Private method to get the style and sub-style number of the given item.

        @param itm reference to the item to extract the styles from
        @type QTreeWidgetItem
        @return tuple containing the style and sub-style numbers
        @rtype tuple of (int, int)
        """
        style = itm.data(0, self.StyleRole)
        substyle = itm.data(0, self.SubstyleRole)

        return (style, substyle)

    def __currentStyles(self):
        """
        Private method to get the styles of the current item.

        @return tuple containing the style and sub-style numbers
        @rtype tuple of (int, int)
        """
        itm = self.styleElementList.currentItem()
        # return default style, if no current item
        styles = (0, -1) if itm is None else self.__stylesForItem(itm)

        return styles

    def __styleOneItem(self, item, style, substyle):
        """
        Private method to style one item of the style element list.

        @param item reference to the item to be styled
        @type QTreeWidgetItem
        @param style base style number
        @type int
        @param substyle sub-style number
        @type int
        """
        colour = self.lexer.color(style, substyle)
        paper = self.lexer.paper(style, substyle)
        font = self.lexer.font(style, substyle)
        eolfill = self.lexer.eolFill(style, substyle)

        item.setFont(0, font)
        item.setBackground(0, paper)
        item.setForeground(0, colour)
        if eolfill:
            item.setCheckState(0, Qt.CheckState.Checked)
        else:
            item.setCheckState(0, Qt.CheckState.Unchecked)

    def __styleAllItems(self):
        """
        Private method to style all items of the style element list.
        """
        itm = self.styleElementList.topLevelItem(0)
        while itm is not None:
            style, substyle = self.__stylesForItem(itm)
            self.__styleOneItem(itm, style, substyle)
            itm = self.styleElementList.itemBelow(itm)

    def __styleSample(self, color, paper, font=None):
        """
        Private method to style the sample text.

        @param color foreground color for the sample
        @type QColor
        @param paper background color for the sample
        @type QColor
        @param font font for the sample (defaults to None)
        @type QFont (optional)
        """
        if font:
            self.sampleText.setFont(font)

        self.sampleText.setStyleSheet(
            "QLineEdit {{ color: {0}; background-color: {1}; }}".format(
                color.name(), paper.name()
            )
        )

    @pyqtSlot(QTreeWidgetItem, QTreeWidgetItem)
    def on_styleElementList_currentItemChanged(self, current, previous):
        """
        Private method to handle a change of the current row.

        @param current reference to the current item
        @type QTreeWidgetItem
        @param previous reference to the previous item
        @type QTreeWidgetItem
        """
        if current is None:
            return

        style, substyle = self.__stylesForItem(current)
        colour = self.lexer.color(style, substyle)
        paper = self.lexer.paper(style, substyle)
        eolfill = self.lexer.eolFill(style, substyle)
        font = self.lexer.font(style, substyle)

        self.__styleSample(colour, paper, font=font)
        self.eolfillCheckBox.setChecked(eolfill)

        selectedOne = len(self.styleElementList.selectedItems()) == 1
        self.defaultSubstylesButton.setEnabled(
            selectedOne and substyle < 0 and self.lexer.isBaseStyle(style)
        )
        self.addSubstyleButton.setEnabled(
            selectedOne and substyle < 0 and self.lexer.isBaseStyle(style)
        )
        self.deleteSubstyleButton.setEnabled(selectedOne and substyle >= 0)
        self.editSubstyleButton.setEnabled(selectedOne and substyle >= 0)
        self.copySubstyleButton.setEnabled(selectedOne and substyle >= 0)

    @pyqtSlot()
    def on_foregroundButton_clicked(self):
        """
        Private method used to select the foreground colour of the selected
        style and lexer.
        """
        style, substyle = self.__currentStyles()
        colour = QColorDialog.getColor(self.lexer.color(style, substyle))
        if colour.isValid():
            paper = self.lexer.paper(style, substyle)
            self.__styleSample(colour, paper)
            for selItem in self.styleElementList.selectedItems():
                style, substyle = self.__stylesForItem(selItem)
                self.lexer.setColor(colour, style, substyle)
                selItem.setForeground(0, colour)

    @pyqtSlot()
    def on_backgroundButton_clicked(self):
        """
        Private method used to select the background colour of the selected
        style and lexer.
        """
        style, substyle = self.__currentStyles()
        paper = QColorDialog.getColor(self.lexer.paper(style, substyle))
        if paper.isValid():
            colour = self.lexer.color(style, substyle)
            self.__styleSample(colour, paper)
            for selItem in self.styleElementList.selectedItems():
                style, substyle = self.__stylesForItem(selItem)
                self.lexer.setPaper(paper, style, substyle)
                selItem.setBackground(0, paper)

    @pyqtSlot()
    def on_allBackgroundColoursButton_clicked(self):
        """
        Private method used to select the background colour of all styles of a
        selected lexer.
        """
        style, substyle = self.__currentStyles()
        paper = QColorDialog.getColor(self.lexer.paper(style, substyle))
        if paper.isValid():
            colour = self.lexer.color(style, substyle)
            self.__styleSample(colour, paper)

            itm = self.styleElementList.topLevelItem(0)
            while itm is not None:
                style, substyle = self.__stylesForItem(itm)
                self.lexer.setPaper(paper, style, substyle)
                itm = self.styleElementList.itemBelow(itm)
            self.__styleAllItems()

    def __changeFont(self, doAll, familyOnly, sizeOnly):
        """
        Private slot to change the highlighter font.

        @param doAll flag indicating to change the font for all styles
        @type bool
        @param familyOnly flag indicating to set the font family only
        @type bool
        @param sizeOnly flag indicating to set the font size only
        @type bool
        """

        def setFont(font, style, substyle, familyOnly, sizeOnly):
            """
            Local function to set the font.

            @param font font to be set
            @type QFont
            @param style style number
            @type int
            @param substyle sub-style number
            @type int
            @param familyOnly flag indicating to set the font family only
            @type bool
            @param sizeOnly flag indicating to set the font size only
            @type bool
            """
            if familyOnly or sizeOnly:
                newFont = QFont(self.lexer.font(style))
                if familyOnly:
                    newFont.setFamily(font.family())
                if sizeOnly:
                    newFont.setPointSize(font.pointSize())
                self.lexer.setFont(newFont, style, substyle)
            else:
                self.lexer.setFont(font, style, substyle)

        def setSampleFont(font, familyOnly, sizeOnly):
            """
            Local function to set the font of the sample text.

            @param font font to be set (QFont)
            @param familyOnly flag indicating to set the font family only
                (boolean)
            @param sizeOnly flag indicating to set the font size only (boolean
            """
            if familyOnly or sizeOnly:
                style, substyle = self.__currentStyles()
                newFont = QFont(self.lexer.font(style, substyle))
                if familyOnly:
                    newFont.setFamily(font.family())
                if sizeOnly:
                    newFont.setPointSize(font.pointSize())
                self.sampleText.setFont(newFont)
            else:
                self.sampleText.setFont(font)

        style, substyle = self.__currentStyles()
        options = (
            QFontDialog.FontDialogOption.MonospacedFonts
            if self.monospacedButton.isChecked()
            else QFontDialog.FontDialogOption(0)
        )
        font, ok = QFontDialog.getFont(
            self.lexer.font(style, substyle), self, "", options
        )
        if ok:
            setSampleFont(font, familyOnly, sizeOnly)
            if doAll:
                itm = self.styleElementList.topLevelItem(0)
                while itm is not None:
                    style, substyle = self.__stylesForItem(itm)
                    setFont(font, style, substyle, familyOnly, sizeOnly)
                    itm = self.styleElementList.itemBelow(itm)
                self.__styleAllItems()
            else:
                for selItem in self.styleElementList.selectedItems():
                    style, substyle = self.__stylesForItem(selItem)
                    setFont(font, style, substyle, familyOnly, sizeOnly)
                    itmFont = self.lexer.font(style, substyle)
                    selItem.setFont(0, itmFont)

    def __fontButtonMenuTriggered(self, act):
        """
        Private slot used to select the font of the selected style and lexer.

        @param act reference to the triggering action
        @type QAction
        """
        if act is None:
            return

        familyOnly = act.data() in [self.FAMILYANDSIZE, self.FAMILYONLY]
        sizeOnly = act.data() in [self.FAMILYANDSIZE, self.SIZEONLY]
        self.__changeFont(False, familyOnly, sizeOnly)

    def __allFontsButtonMenuTriggered(self, act):
        """
        Private slot used to change the font of all styles of a selected lexer.

        @param act reference to the triggering action
        @type QAction
        """
        if act is None:
            return

        familyOnly = act.data() in [self.FAMILYANDSIZE, self.FAMILYONLY]
        sizeOnly = act.data() in [self.FAMILYANDSIZE, self.SIZEONLY]
        self.__changeFont(True, familyOnly, sizeOnly)

    @pyqtSlot(bool)
    def on_eolfillCheckBox_clicked(self, on):
        """
        Private method used to set the eolfill for the selected style and
        lexer.

        @param on flag indicating enabled or disabled state
        @type bool
        """
        style, substyle = self.__currentStyles()
        checkState = Qt.CheckState.Checked if on else Qt.CheckState.Unchecked
        for selItem in self.styleElementList.selectedItems():
            style, substyle = self.__stylesForItem(selItem)
            self.lexer.setEolFill(on, style, substyle)
            selItem.setCheckState(0, checkState)

    @pyqtSlot()
    def on_allEolFillButton_clicked(self):
        """
        Private method used to set the eolfill for all styles of a selected
        lexer.
        """
        on = self.tr("Enabled")
        off = self.tr("Disabled")
        selection, ok = QInputDialog.getItem(
            self,
            self.tr("Fill to end of line"),
            self.tr("Select fill to end of line for all styles"),
            [on, off],
            0,
            False,
        )
        if ok:
            enabled = selection == on
            self.eolfillCheckBox.setChecked(enabled)

            itm = self.styleElementList.topLevelItem(0)
            while itm is not None:
                style, substyle = self.__stylesForItem(itm)
                self.lexer.setEolFill(enabled, style, substyle)
                itm = self.styleElementList.itemBelow(itm)
            self.__styleAllItems()

    @pyqtSlot()
    def on_defaultButton_clicked(self):
        """
        Private method to set the current style to its default values.
        """
        for selItem in self.styleElementList.selectedItems():
            style, substyle = self.__stylesForItem(selItem)
            self.__setToDefault(style, substyle)
        self.on_styleElementList_currentItemChanged(
            self.styleElementList.currentItem(), None
        )
        self.__styleAllItems()

    @pyqtSlot()
    def on_allDefaultButton_clicked(self):
        """
        Private method to set all styles to their default values.
        """
        itm = self.styleElementList.topLevelItem(0)
        while itm is not None:
            style, substyle = self.__stylesForItem(itm)
            self.__setToDefault(style, substyle)
            itm = self.styleElementList.itemBelow(itm)
        self.on_styleElementList_currentItemChanged(
            self.styleElementList.currentItem(), None
        )
        self.__styleAllItems()

    def __setToDefault(self, style, substyle):
        """
        Private method to set a specific style to its default values.

        @param style style number
        @type int
        @param substyle sub-style number
        @type int
        """
        self.lexer.setColor(self.lexer.defaultColor(style, substyle), style, substyle)
        self.lexer.setPaper(self.lexer.defaultPaper(style, substyle), style, substyle)
        self.lexer.setFont(self.lexer.defaultFont(style, substyle), style, substyle)
        self.lexer.setEolFill(
            self.lexer.defaultEolFill(style, substyle), style, substyle
        )

    #######################################################################
    ## Importing and exporting of styles
    #######################################################################

    @pyqtSlot()
    def on_importButton_clicked(self):
        """
        Private slot to import styles to be selected.
        """
        self.__importStyles(importAll=False)

    @pyqtSlot()
    def on_exportButton_clicked(self):
        """
        Private slot to export styles to be selected.
        """
        self.__exportStyles(exportAll=False)

    @pyqtSlot()
    def on_importAllButton_clicked(self):
        """
        Private slot to import the styles of all lexers.
        """
        self.__importStyles(importAll=True)

    @pyqtSlot()
    def on_exportAllButton_clicked(self):
        """
        Private slot to export the styles of all lexers.
        """
        self.__exportStyles(exportAll=True)

    def __exportStyles(self, exportAll=False):
        """
        Private method to export the styles of selectable lexers.

        @param exportAll flag indicating to export all styles without asking
            (defaults to False)
        @type bool (optional)
        """
        from eric7.Globals import getConfig

        from .EditorHighlightingStylesSelectionDialog import (
            EditorHighlightingStylesSelectionDialog,
        )

        stylesDir = getConfig("ericStylesDir")

        lexerNames = list(self.lexers)
        if not exportAll:
            if self.lexer:
                preselect = [self.lexer.language()]
            else:
                preselect = []
            dlg = EditorHighlightingStylesSelectionDialog(
                lexerNames, forImport=False, preselect=preselect
            )
            if dlg.exec() == QDialog.DialogCode.Accepted:
                lexerNames = dlg.getLexerNames()
            else:
                # Cancelled by user
                return

        lexers = [self.lexers[name] for name in lexerNames]

        fn, selectedFilter = EricFileDialog.getSaveFileNameAndFilter(
            self,
            self.tr("Export Highlighting Styles"),
            stylesDir,
            self.tr("Highlighting Styles File (*.ehj)"),
            "",
            EricFileDialog.DontConfirmOverwrite,
        )

        if not fn:
            return

        fpath = pathlib.Path(fn)
        if not fpath.suffix:
            ex = selectedFilter.split("(*")[1].split(")")[0]
            if ex:
                fpath = fpath.with_suffix(ex)

        ok = (
            EricMessageBox.yesNo(
                self,
                self.tr("Export Highlighting Styles"),
                self.tr(
                    """<p>The highlighting styles file <b>{0}</b> exists"""
                    """ already. Overwrite it?</p>"""
                ).format(fpath),
            )
            if fpath.exists()
            else True
        )

        if ok:
            highlightingStylesFile = HighlightingStylesFile()
            highlightingStylesFile.writeFile(str(fpath), lexers)

    def __importStyles(self, importAll=False):
        """
        Private method to import the styles of lexers to be selected.

        @param importAll flag indicating to import all styles without asking
            (defaults to False)
        @type bool (optional)
        """
        from eric7.Globals import getConfig

        stylesDir = getConfig("ericStylesDir")

        fn = EricFileDialog.getOpenFileName(
            self,
            self.tr("Import Highlighting Styles"),
            stylesDir,
            self.tr(
                "Highlighting Styles File (*.ehj);;"
                "XML Highlighting Styles File (*.e6h *.e4h)"
            ),
        )

        if not fn:
            return

        if fn.endswith(".ehj"):
            # new JSON based file
            highlightingStylesFile = HighlightingStylesFile()
            styles = highlightingStylesFile.readFile(fn)
            if not styles:
                return
        else:
            # old XML based file
            f = QFile(fn)
            if f.open(QIODevice.OpenModeFlag.ReadOnly):
                reader = HighlightingStylesReader(f, self.lexers)
                styles = reader.readXML()
                f.close()
                if not styles:
                    return
            else:
                EricMessageBox.critical(
                    self,
                    self.tr("Import Highlighting Styles"),
                    self.tr(
                        "<p>The highlighting styles file <b>{0}</b> could not"
                        " be read.</p><p>Reason: {1}</p>"
                    ).format(fn, f.errorString()),
                )
                return

        self.__applyStyles(styles, importAll=importAll)
        self.on_lexerLanguageComboBox_activated(
            self.lexerLanguageComboBox.currentIndex()
        )

    def __applyStyles(self, stylesList, importAll=False):
        """
        Private method to apply the imported styles to this dialog.

        @param stylesList list of imported lexer styles
        @type list of dict
        @param importAll flag indicating to import all styles without asking
            (defaults to False)
        @type bool (optional)
        """
        from .EditorHighlightingStylesSelectionDialog import (
            EditorHighlightingStylesSelectionDialog,
        )

        lexerNames = [d["name"] for d in stylesList if d["name"] in self.lexers]

        if not importAll:
            dlg = EditorHighlightingStylesSelectionDialog(lexerNames, forImport=True)
            if dlg.exec() == QDialog.DialogCode.Accepted:
                lexerNames = dlg.getLexerNames()
            else:
                # Cancelled by user
                return

        for lexerDict in stylesList:
            if lexerDict["name"] in lexerNames:
                lexer = self.lexers[lexerDict["name"]]
                for styleDict in lexerDict["styles"]:
                    style = styleDict["style"]
                    substyle = styleDict["substyle"]
                    lexer.setColor(QColor(styleDict["color"]), style, substyle)
                    lexer.setPaper(QColor(styleDict["paper"]), style, substyle)
                    font = QFont()
                    font.fromString(styleDict["font"])
                    lexer.setFont(font, style, substyle)
                    lexer.setEolFill(styleDict["eolfill"], style, substyle)
                    if substyle >= 0:
                        # description and words can only be set for sub-styles
                        lexer.setDescription(styleDict["description"], style, substyle)
                        lexer.setWords(styleDict["words"], style, substyle)

    #######################################################################
    ## Methods to save and restore the state
    #######################################################################

    def saveState(self):
        """
        Public method to save the current state of the widget.

        @return list containing the index of the selected lexer language
            and a tuple containing the index of the parent selected lexer
            entry and the index of the selected entry
        @rtype list of [int, tuple of (int, int)]
        """
        itm = self.styleElementList.currentItem()
        if itm:
            parent = itm.parent()
            if parent is None:
                currentData = (None, self.styleElementList.indexOfTopLevelItem(itm))
            else:
                currentData = (
                    self.styleElementList.indexOfTopLevelItem(parent),
                    parent.indexOfChild(itm),
                )

            savedState = [
                self.lexerLanguageComboBox.currentIndex(),
                currentData,
            ]
        else:
            savedState = []
        return savedState

    def setState(self, state):
        """
        Public method to set the state of the widget.

        @param state state data generated by saveState
        @type list of [int, tuple of (int, int)]
        """
        if state:
            self.lexerLanguageComboBox.setCurrentIndex(state[0])
            self.on_lexerLanguageComboBox_activated(
                self.lexerLanguageComboBox.currentIndex()
            )

            parentIndex, index = state[1]
            if parentIndex is None:
                itm = self.styleElementList.topLevelItem(index)
            else:
                parent = self.styleElementList.topLevelItem(parentIndex)
                itm = parent.child(index)
            self.styleElementList.setCurrentItem(itm)

    #######################################################################
    ## Methods to add, delete and edit sub-styles and their definitions
    #######################################################################

    @pyqtSlot()
    def on_addSubstyleButton_clicked(self):
        """
        Private slot to add a new sub-style.
        """
        style, substyle = self.__currentStyles()
        dlg = SubstyleDefinitionDialog(self.lexer, style, substyle, parent=self)
        if dlg.exec() == QDialog.DialogCode.Accepted:
            description, words = dlg.getData()
            substyle = self.lexer.addSubstyle(style)
            self.lexer.setDescription(description, style, substyle)
            self.lexer.setWords(words, style, substyle)

            parent = self.styleElementList.findItems(
                self.lexer.description(style), Qt.MatchFlag.MatchExactly
            )[0]
            parent.setExpanded(True)
            itm = QTreeWidgetItem(parent, [description])
            itm.setData(0, self.StyleRole, style)
            itm.setData(0, self.SubstyleRole, substyle)
            self.__styleOneItem(itm, style, substyle)

    @pyqtSlot()
    def on_deleteSubstyleButton_clicked(self):
        """
        Private slot to delete the selected sub-style.
        """
        style, substyle = self.__currentStyles()
        ok = EricMessageBox.yesNo(
            self,
            self.tr("Delete Sub-Style"),
            self.tr(
                """<p>Shall the sub-style <b>{0}</b> really be deleted?</p>"""
            ).format(self.lexer.description(style, substyle)),
        )
        if ok:
            self.lexer.delSubstyle(style, substyle)

            itm = self.styleElementList.currentItem()
            parent = itm.parent()
            index = parent.indexOfChild(itm)
            parent.takeChild(index)
            del itm

    @pyqtSlot()
    def on_editSubstyleButton_clicked(self):
        """
        Private slot to edit the selected sub-style entry.
        """
        style, substyle = self.__currentStyles()
        dlg = SubstyleDefinitionDialog(self.lexer, style, substyle, parent=self)
        if dlg.exec() == QDialog.DialogCode.Accepted:
            description, words = dlg.getData()
            self.lexer.setDescription(description, style, substyle)
            self.lexer.setWords(words, style, substyle)

            itm = self.styleElementList.currentItem()
            itm.setText(0, description)

    @pyqtSlot()
    def on_copySubstyleButton_clicked(self):
        """
        Private slot to copy the selected sub-style.
        """
        style, substyle = self.__currentStyles()
        newSubstyle = self.lexer.addSubstyle(style)

        description = self.tr("{0} - Copy").format(
            self.lexer.description(style, substyle)
        )
        self.lexer.setDescription(description, style, newSubstyle)
        self.lexer.setWords(self.lexer.words(style, substyle), style, newSubstyle)
        self.lexer.setColor(self.lexer.color(style, substyle), style, newSubstyle)
        self.lexer.setPaper(self.lexer.paper(style, substyle), style, newSubstyle)
        self.lexer.setFont(self.lexer.font(style, substyle), style, newSubstyle)
        self.lexer.setEolFill(self.lexer.eolFill(style, substyle), style, newSubstyle)

        parent = self.styleElementList.findItems(
            self.lexer.description(style), Qt.MatchFlag.MatchExactly
        )[0]
        parent.setExpanded(True)
        itm = QTreeWidgetItem(parent, [description])
        itm.setData(0, self.StyleRole, style)
        itm.setData(0, self.SubstyleRole, newSubstyle)
        self.__styleOneItem(itm, style, newSubstyle)

    @pyqtSlot()
    def on_defaultSubstylesButton_clicked(self):
        """
        Private slot to reset all substyles to default values.
        """
        style, substyle = self.__currentStyles()
        ok = EricMessageBox.yesNo(
            self,
            self.tr("Reset Sub-Styles to Default"),
            self.tr(
                "<p>Do you really want to reset all defined sub-styles of"
                " <b>{0}</b> to the default values?</p>"
                ""
            ).format(self.lexer.description(style, substyle)),
        )
        if ok:
            # 1. reset sub-styles
            self.lexer.loadDefaultSubStyles(style)

            # 2. delete all existing sub-style items
            parent = self.styleElementList.currentItem()
            while parent.childCount() > 0:
                itm = parent.takeChild(0)  # __IGNORE_WARNING__
                del itm

            # 3. create the new list of sub-style items
            for description, _, substyle in self.lexer.getSubStyles(style):
                itm = QTreeWidgetItem(parent, [description])
                itm.setData(0, self.StyleRole, style)
                itm.setData(0, self.SubstyleRole, substyle)
                self.__styleOneItem(itm, style, substyle)


def create(dlg):
    """
    Module function to create the configuration page.

    @param dlg reference to the configuration dialog
    @type ConfigurationDialog
    @return reference to the instantiated page
    @rtype ConfigurationPageBase
    """
    page = EditorHighlightingStylesPage(dlg.getLexers())
    return page