WebBrowser/SpellCheck/InstallDictionariesDialog.py

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

# Copyright (c) 2017 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a dialog to install spell checking dictionaries.
"""

from __future__ import unicode_literals

from PyQt5.QtCore import pyqtSlot, Qt, QUrl
from PyQt5.QtWidgets import QDialog, QDialogButtonBox, QAbstractButton, \
    QListWidgetItem
from PyQt5.QtNetwork import QNetworkConfigurationManager, QNetworkRequest, \
    QNetworkReply

from E5Gui import E5MessageBox

from .Ui_InstallDictionariesDialog import Ui_InstallDictionariesDialog

from WebBrowser.WebBrowserWindow import WebBrowserWindow

import Preferences


class InstallDictionariesDialog(QDialog, Ui_InstallDictionariesDialog):
    """
    Class implementing a dialog to install spell checking dictionaries.
    """
    FilenameRole = Qt.UserRole
    
    def __init__(self, writeableDirectories, parent=None):
        """
        Constructor
        
        @param writeableDirectories list of writable directories
        @type list of str
        @param parent reference to the parent widget
        @type QWidget
        """
        super(InstallDictionariesDialog, self).__init__(parent)
        self.setupUi(self)
        
        self.__refreshButton = self.buttonBox.addButton(
            self.tr("Refresh"), QDialogButtonBox.ActionRole)
        self.__installButton = self.buttonBox.addButton(
            self.tr("Install Selected"), QDialogButtonBox.ActionRole)
        self.__installButton.setEnabled(False)
        self.__cancelButton = self.buttonBox.addButton(
            self.tr("Cancel"), QDialogButtonBox.ActionRole)
        self.__cancelButton.setEnabled(False)
        
        self.locationComboBox.addItems(writeableDirectories)
        
        self.dictionariesUrlEdit.setText(
            Preferences.getWebBrowser("SpellCheckDictionariesUrl"))
        
        if Preferences.getUI("DynamicOnlineCheck"):
            self.__networkConfigurationManager = \
                QNetworkConfigurationManager(self)
            self.__onlineStateChanged(
                self.__networkConfigurationManager.isOnline())
            self.__networkConfigurationManager.onlineStateChanged.connect(
                self.__onlineStateChanged)
        else:
            self.__networkConfigurationManager = None
            self.__onlineStateChanged(True)
        self.__replies = []
        
        self.__downloadCancelled = False
        self.__dictionariesToDownload = []
        
        self.__populateList()
    
    @pyqtSlot(bool)
    def __onlineStateChanged(self, online):
        """
        Private slot handling online state changes.
        
        @param online flag indicating the online status
        @type bool
        """
        self.__refreshButton.setEnabled(online)
        if online:
            msg = self.tr("Network Status: online")
        else:
            msg = self.tr("Network Status: offline")
        self.statusLabel.setText(msg)
    
    def __isOnline(self):
        """
        Private method to check the online status.
        
        @return flag indicating the online status
        @rtype bool
        """
        if self.__networkConfigurationManager is not None:
            return self.__networkConfigurationManager.isOnline()
        else:
            return True
    
    @pyqtSlot(QAbstractButton)
    def on_buttonBox_clicked(self, button):
        """
        Private slot to handle the click of a button of the button box.
        
        @param button reference to the button pressed
        @type QAbstractButton
        """
        if button == self.__refreshButton:
            self.__populateList()
        elif button == self.__cancelButton:
            self.__downloadCancel()
        elif button == self.__installButton:
            self.__installSelected()
    
    @pyqtSlot()
    def on_dictionariesList_itemSelectionChanged(self):
        """
        Private slot to handle a change of the selection.
        """
        self.__installButton.setEnabled(
            len(self.dictionariesList.selectedItems()) > 0)
    
    def __populateList(self):
        """
        Private method to populate the list of available plugins.
        """
        self.dictionariesList.clear()
        self.downloadProgress.setValue(0)
        
        if self.__isOnline():
            self.__refreshButton.setEnabled(False)
            self.__installButton.setEnabled(False)
            self.__cancelButton.setEnabled(True)
            
            url = self.dictionariesUrlEdit.text()
            self.statusLabel.setText(url)
            
            self.__downloadCancelled = False
            
            request = QNetworkRequest(QUrl(url))
            request.setAttribute(QNetworkRequest.CacheLoadControlAttribute,
                                 QNetworkRequest.AlwaysNetwork)
            reply = WebBrowserWindow.networkManager().get(request)
            reply.finished.connect(self.__listFileDownloaded)
            reply.downloadProgress.connect(self.__downloadProgress)
            self.__replies.append(reply)
    
    def __listFileDownloaded(self):
        """
        Private method called, after the dictionaries list file has been
        downloaded from the Internet.
        """
        self.__refreshButton.setEnabled(True)
        self.__cancelButton.setEnabled(False)
        self.__onlineStateChanged(self.__isOnline())
        
        reply = self.sender()
        if reply in self.__replies:
            self.__replies.remove(reply)
        if reply.error() != QNetworkReply.NoError:
            if not self.__downloadCancelled:
                E5MessageBox.warning(
                    self,
                    self.tr("Error downloading dictionaries list"),
                    self.tr(
                        """<p>Could not download the dictionaries list"""
                        """ from {0}.</p><p>Error: {1}</p>"""
                    ).format(self.repositoryUrlEdit.text(),
                             reply.errorString())
                )
            self.downloadProgress.setValue(0)
            reply.deleteLater()
            return
        
        listFileData = reply.readAll()
        reply.deleteLater()
        
        # extract the dictionaries
        from E5XML.SpellCheckDictionariesReader import \
            SpellCheckDictionariesReader
        reader = SpellCheckDictionariesReader(listFileData, self.addEntry)
        reader.readXML()
        url = Preferences.getWebBrowser("SpellCheckDictionariesUrl")
        if url != self.dictionariesUrlEdit.text():
            self.dictionariesUrlEdit.setText(url)
            E5MessageBox.warning(
                self,
                self.tr("Dictionaries URL Changed"),
                self.tr(
                    """The URL of the spell check dictionaries has"""
                    """ changed. Select the "Refresh" button to get"""
                    """ the new dictionaries list."""))
    
    def __downloadCancel(self):
        """
        Private slot to cancel the current download.
        """
        if self.__replies:
            reply = self.__replies[0]
            self.__downloadCancelled = True
            self.__dictionariesToDownload = []
            reply.abort()
    
    def __downloadProgress(self, done, total):
        """
        Private slot to show the download progress.
        
        @param done number of bytes downloaded so far
        @type int
        @param total total bytes to be downloaded
        @type int
        """
        if total:
            self.downloadProgress.setMaximum(total)
            self.downloadProgress.setValue(done)
    
    def addEntry(self, short, filename):
        """
        Public method to add an entry to the list.
        
        @param short data for the description field
        @type str
        @param filename data for the filename field
        @type str
        """
        itm = QListWidgetItem(short, self.dictionariesList)
        itm.setData(InstallDictionariesDialog.FilenameRole, filename)
    
    def __installSelected(self):
        """
        Private method to install the selected dictionaries.
        """
        self.__dictionariesToDownload = [
            itm.data(InstallDictionariesDialog.FilenameRole)
            for itm in self.dictionariesList.selectedItems()
        ]
        
        self.__refreshButton.setEnabled(False)
        self.__installButton.setEnabled(False)
        self.__cancelButton.setEnabled(True)
        
        self.__downloadCancelled = False
        
        self.__downloadDictionary()
    
    def __downloadDictionary(self):
        """
        Private slot to download a dictionary.
        """
        # TODO: implement this
        # use __installDictionary as finish slot
    
    def __installDictionary(self):
        """
        Private slot to install the downloaded dictionary.
        """
        # TODO: implement this
        
        if not bool(self.__dictionariesToDownload):
            self.__installationFinished()
    
    def __installationFinished(self):
        """
        Private method called after all selected dictionaries have been
        installed.
        """
        # TODO: implement this