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

# Copyright (c) 2009 - 2024 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a window for showing the QtHelp TOC.
"""

from PyQt6.QtCore import Qt, QUrl, pyqtSignal, pyqtSlot
from PyQt6.QtGui import QClipboard, QGuiApplication
from PyQt6.QtWidgets import QApplication, QMenu, QVBoxLayout, QWidget


class HelpTocWidget(QWidget):
    """
    Class implementing a window for showing the QtHelp TOC.

    @signal escapePressed() emitted when the ESC key was pressed
    @signal openUrl(QUrl, str) emitted to open an entry in the current tab
    @signal newTab(QUrl, str) emitted to open an entry in a new tab
    @signal newBackgroundTab(QUrl, str) emitted to open an entry in a
        new background tab
    @signal newWindow(QUrl, str) emitted to open an entry in a new window
    """

    escapePressed = pyqtSignal()
    openUrl = pyqtSignal(QUrl)
    newTab = pyqtSignal(QUrl)
    newBackgroundTab = pyqtSignal(QUrl)
    newWindow = pyqtSignal(QUrl)

    def __init__(self, engine, internal=False, parent=None):
        """
        Constructor

        @param engine reference to the help engine
        @type QHelpEngine
        @param internal flag indicating the internal help viewer
        @type bool
        @param parent reference to the parent widget
        @type QWidget
        """
        super().__init__(parent)

        self.__engine = engine
        self.__expandDepth = -2

        self.__internal = internal

        self.__tocWidget = self.__engine.contentWidget()
        self.__tocWidget.setContextMenuPolicy(Qt.ContextMenuPolicy.CustomContextMenu)
        self.__tocWidget.setSortingEnabled(True)
        self.__tocWidget.setExpandsOnDoubleClick(False)

        self.__layout = QVBoxLayout(self)
        if internal:
            # no margins for the internal variant
            self.__layout.setContentsMargins(0, 0, 0, 0)
        self.__layout.addWidget(self.__tocWidget)

        self.__tocWidget.customContextMenuRequested.connect(self.__showContextMenu)
        self.__tocWidget.linkActivated.connect(self.__linkActivated)

        model = self.__tocWidget.model()
        model.contentsCreated.connect(self.__contentsCreated)

    @pyqtSlot(QUrl)
    def __linkActivated(self, url):
        """
        Private slot handling the activation of an entry.

        @param url URL of the activated entry
        @type QUrl
        """
        if not url.isEmpty() and url.isValid():
            buttons = QApplication.mouseButtons()
            modifiers = QApplication.keyboardModifiers()

            if buttons & Qt.MouseButton.MiddleButton:
                self.newTab.emit(url)
            else:
                if modifiers & (
                    Qt.KeyboardModifier.ControlModifier
                    | Qt.KeyboardModifier.ShiftModifier
                ) == (
                    Qt.KeyboardModifier.ControlModifier
                    | Qt.KeyboardModifier.ShiftModifier
                ):
                    self.newBackgroundTab.emit(url)
                elif modifiers & Qt.KeyboardModifier.ControlModifier:
                    self.newTab.emit(url)
                elif (
                    modifiers & Qt.KeyboardModifier.ShiftModifier
                    and not self.__internal
                ):
                    self.newWindow.emit(url)
                else:
                    self.openUrl.emit(url)

    def __contentsCreated(self):
        """
        Private slot to be run after the contents was generated.
        """
        self.__tocWidget.sortByColumn(0, Qt.SortOrder.AscendingOrder)
        self.__expandTOC()

    def __expandTOC(self):
        """
        Private slot to expand the table of contents.
        """
        if self.__expandDepth > -2:
            self.expandToDepth(self.__expandDepth)
            self.__expandDepth = -2

    def expandToDepth(self, depth):
        """
        Public slot to expand the table of contents to a specific depth.

        @param depth depth to expand to
        @type int
        """
        self.__expandDepth = depth
        if depth == -1:
            self.__tocWidget.expandAll()
        else:
            self.__tocWidget.expandToDepth(depth)

    def focusInEvent(self, evt):
        """
        Protected method handling focus in events.

        @param evt reference to the focus event object
        @type QFocusEvent
        """
        if evt.reason() != Qt.FocusReason.MouseFocusReason:
            self.__tocWidget.setFocus()

    def keyPressEvent(self, evt):
        """
        Protected method handling key press events.

        @param evt reference to the key press event
        @type QKeyEvent
        """
        if evt.key() == Qt.Key.Key_Escape:
            self.escapePressed.emit()

    def syncToContent(self, url):
        """
        Public method to sync the TOC to the displayed page.

        @param url URL of the displayed page
        @type QUrl
        @return flag indicating a successful synchronization
        @rtype bool
        """
        idx = self.__tocWidget.indexOf(url)
        if not idx.isValid():
            return False
        self.__tocWidget.setCurrentIndex(idx)
        return True

    def __showContextMenu(self, pos):
        """
        Private slot showing the context menu.

        @param pos position to show the menu at
        @type QPoint
        """
        if not self.__tocWidget.indexAt(pos).isValid():
            return

        model = self.__tocWidget.model()
        itm = model.contentItemAt(self.__tocWidget.currentIndex())
        link = itm.url()
        if link.isEmpty() or not link.isValid():
            return

        menu = QMenu()
        curTab = menu.addAction(self.tr("Open Link"))
        if self.__internal:
            newTab = menu.addAction(self.tr("Open Link in New Page"))
            newBackgroundTab = menu.addAction(self.tr("Open Link in Background Page"))
        else:
            newTab = menu.addAction(self.tr("Open Link in New Tab"))
            newBackgroundTab = menu.addAction(self.tr("Open Link in Background Tab"))
            newWindow = menu.addAction(self.tr("Open Link in New Window"))
        menu.addSeparator()
        copyLink = menu.addAction(self.tr("Copy URL to Clipboard"))
        menu.move(self.__tocWidget.mapToGlobal(pos))

        act = menu.exec()
        if act == curTab:
            self.openUrl.emit(link)
        elif act == newTab:
            self.newTab.emit(link)
        elif act == newBackgroundTab:
            self.newBackgroundTab.emit(link)
        elif not self.__internal and act == newWindow:
            self.newWindow.emit(link)
        elif act == copyLink:
            # copy the URL to both clipboard areas
            QGuiApplication.clipboard().setText(
                link.toString(), QClipboard.Mode.Clipboard
            )
            QGuiApplication.clipboard().setText(
                link.toString(), QClipboard.Mode.Selection
            )
