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

# Copyright (c) 2017 - 2019 Detlev Offenbach <detlev@die-offenbachs.de>
#

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


import os
import io
import zipfile
import glob
import shutil

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_ManageDictionariesDialog import Ui_ManageDictionariesDialog

from WebBrowser.WebBrowserWindow import WebBrowserWindow

import Preferences


class ManageDictionariesDialog(QDialog, Ui_ManageDictionariesDialog):
    """
    Class implementing a dialog to install spell checking dictionaries.
    """
    FilenameRole = Qt.UserRole
    UrlRole = Qt.UserRole + 1
    DocumentationDirRole = Qt.UserRole + 2
    LocalesRole = Qt.UserRole + 3
    
    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(ManageDictionariesDialog, 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.__uninstallButton = self.buttonBox.addButton(
            self.tr("Uninstall Selected"), QDialogButtonBox.ActionRole)
        self.__uninstallButton.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)
        
        self.on_dictionariesList_itemSelectionChanged()
    
    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()
        elif button == self.__uninstallButton:
            self.__uninstallSelected()
    
    @pyqtSlot()
    def on_dictionariesList_itemSelectionChanged(self):
        """
        Private slot to handle a change of the selection.
        """
        self.__installButton.setEnabled(
            self.locationComboBox.count() > 0 and
            len(self.dictionariesList.selectedItems()) > 0 and
            self.__isOnline()
        )
        
        self.__uninstallButton.setEnabled(
            self.locationComboBox.count() > 0 and
            len([itm
                 for itm in self.dictionariesList.selectedItems()
                 if itm.checkState() == Qt.Checked
                 ])
        )
    
    @pyqtSlot(bool)
    def on_dictionariesUrlEditButton_toggled(self, checked):
        """
        Private slot to set the read only status of the dictionaries URL line
        edit.
        
        @param checked state of the push button (boolean)
        """
        self.dictionariesUrlEdit.setReadOnly(not checked)
    
    @pyqtSlot(str)
    def on_locationComboBox_currentTextChanged(self, txt):
        """
        Private slot to handle a change of the installation location.
        
        @param txt installation location
        @type str
        """
        self.__checkInstalledDictionaries()
    
    def __populateList(self):
        """
        Private method to populate the list of available plugins.
        """
        self.dictionariesList.clear()
        self.downloadProgress.setValue(0)
        
        url = self.dictionariesUrlEdit.text()
        
        if self.__isOnline():
            self.__refreshButton.setEnabled(False)
            self.__installButton.setEnabled(False)
            self.__uninstallButton.setEnabled(False)
            self.__cancelButton.setEnabled(True)
            
            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(
                lambda: self.__listFileDownloaded(reply))
            reply.downloadProgress.connect(self.__downloadProgress)
            self.__replies.append(reply)
        else:
            E5MessageBox.warning(
                self,
                self.tr("Error populating list of dictionaries"),
                self.tr(
                    """<p>Could not download the dictionaries list"""
                    """ from {0}.</p><p>Error: {1}</p>"""
                ).format(url, self.tr("Computer is offline.")))
    
    def __listFileDownloaded(self, reply):
        """
        Private method called, after the dictionaries list file has been
        downloaded from the Internet.
        
        @param reply reference to the network reply
        @type QNetworkReply
        """
        self.__refreshButton.setEnabled(True)
        self.__cancelButton.setEnabled(False)
        self.__onlineStateChanged(self.__isOnline())
        
        self.downloadProgress.setValue(0)
        
        if reply in self.__replies:
            self.__replies.remove(reply)
        reply.deleteLater()
        
        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.dictionariesUrlEdit.text(),
                             reply.errorString())
                )
            self.downloadProgress.setValue(0)
            return
        
        listFileData = reply.readAll()
        
        # 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."""
                )
            )
        
        if self.locationComboBox.count() == 0:
            # no writable locations available
            E5MessageBox.warning(
                self,
                self.tr("Error installing dictionaries"),
                self.tr(
                    """<p>None of the dictionary locations is writable by"""
                    """ you. Please download required dictionaries manually"""
                    """ and install them as administrator.</p>"""
                )
            )
        
        self.__checkInstalledDictionaries()
    
    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, url, documentationDir, locales):
        """
        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
        @param url download URL for the dictionary entry
        @type str
        @param documentationDir name of the directory containing the
            dictionary documentation
        @type str
        @param locales list of locales
        @type list of str
        """
        itm = QListWidgetItem(
            self.tr("{0} ({1})").format(short, " ".join(locales)),
            self.dictionariesList)
        itm.setCheckState(Qt.Unchecked)
        
        itm.setData(ManageDictionariesDialog.FilenameRole, filename)
        itm.setData(ManageDictionariesDialog.UrlRole, url)
        itm.setData(ManageDictionariesDialog.DocumentationDirRole,
                    documentationDir)
        itm.setData(ManageDictionariesDialog.LocalesRole, locales)
    
    def __checkInstalledDictionaries(self):
        """
        Private method to check all installed dictionaries.
        
        Note: A dictionary is assumed to be installed, if at least one of its
        binary dictionaries (*.bdic) is found in the selected dictionaries
        location.
        """
        if self.locationComboBox.currentText():
            installedLocales = {
                os.path.splitext(os.path.basename(dic))[0]
                for dic in glob.glob(
                    os.path.join(self.locationComboBox.currentText(), "*.bdic")
                )
            }
            
            for row in range(self.dictionariesList.count()):
                itm = self.dictionariesList.item(row)
                locales = set(itm.data(ManageDictionariesDialog.LocalesRole))
                if locales.intersection(installedLocales):
                    itm.setCheckState(Qt.Checked)
                else:
                    itm.setCheckState(Qt.Unchecked)
        else:
            for row in range(self.dictionariesList.count()):
                itm = self.dictionariesList.item(row)
                itm.setCheckState(Qt.Unchecked)
    
    def __installSelected(self):
        """
        Private method to install the selected dictionaries.
        """
        if self.__isOnline() and bool(self.locationComboBox.currentText()):
            self.__dictionariesToDownload = [
                itm.data(ManageDictionariesDialog.UrlRole)
                for itm in self.dictionariesList.selectedItems()
            ]
            
            self.__refreshButton.setEnabled(False)
            self.__installButton.setEnabled(False)
            self.__uninstallButton.setEnabled(False)
            self.__cancelButton.setEnabled(True)
            
            self.__downloadCancelled = False
            
            self.__downloadDictionary()
    
    def __downloadDictionary(self):
        """
        Private slot to download a dictionary.
        """
        if self.__isOnline():
            if self.__dictionariesToDownload:
                url = self.__dictionariesToDownload.pop(0)
                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(
                    lambda: self.__installDictionary(reply))
                reply.downloadProgress.connect(self.__downloadProgress)
                self.__replies.append(reply)
            else:
                self.__installationFinished()
        else:
            E5MessageBox.warning(
                self,
                self.tr("Error downloading dictionary file"),
                self.tr(
                    """<p>Could not download the requested dictionary file"""
                    """ from {0}.</p><p>Error: {1}</p>"""
                ).format(url, self.tr("Computer is offline.")))
            
            self.__installationFinished()
    
    def __installDictionary(self, reply):
        """
        Private slot to install the downloaded dictionary.
        
        @param reply reference to the network reply
        @type QNetworkReply
        """
        if reply in self.__replies:
            self.__replies.remove(reply)
        reply.deleteLater()
        
        if reply.error() != QNetworkReply.NoError:
            if not self.__downloadCancelled:
                E5MessageBox.warning(
                    self,
                    self.tr("Error downloading dictionary file"),
                    self.tr(
                        """<p>Could not download the requested dictionary"""
                        """ file from {0}.</p><p>Error: {1}</p>"""
                    ).format(reply.url(), reply.errorString())
                )
            self.downloadProgress.setValue(0)
            return
        
        archiveData = reply.readAll()
        archiveFile = io.BytesIO(bytes(archiveData))
        archive = zipfile.ZipFile(archiveFile, "r")
        if archive.testzip() is not None:
            E5MessageBox.critical(
                self,
                self.tr("Error downloading dictionary"),
                self.tr(
                    """<p>The downloaded dictionary archive is invalid."""
                    """ Skipping it.</p>""")
            )
        else:
            installDir = self.locationComboBox.currentText()
            archive.extractall(installDir)
        
        if self.__dictionariesToDownload:
            self.__downloadDictionary()
        else:
            self.__installationFinished()
    
    def __installationFinished(self):
        """
        Private method called after all selected dictionaries have been
        installed.
        """
        self.__refreshButton.setEnabled(True)
        self.__cancelButton.setEnabled(False)
        self.__onlineStateChanged(self.__isOnline())
        
        self.dictionariesList.clearSelection()
        self.downloadProgress.setValue(0)
        
        self.__checkInstalledDictionaries()
    
    def __uninstallSelected(self):
        """
        Private method to uninstall the selected dictionaries.
        """
        installLocation = self.locationComboBox.currentText()
        if not installLocation:
            return
        
        itemsToDelete = [
            itm
            for itm in self.dictionariesList.selectedItems()
            if itm.checkState() == Qt.Checked
        ]
        for itm in itemsToDelete:
            documentationDir = itm.data(
                ManageDictionariesDialog.DocumentationDirRole)
            shutil.rmtree(os.path.join(installLocation, documentationDir),
                          True)
            
            locales = itm.data(ManageDictionariesDialog.LocalesRole)
            for locale in locales:
                bdic = os.path.join(installLocation, locale + ".bdic")
                try:
                    os.remove(bdic)
                except OSError:
                    # ignore silently
                    pass
        
        self.dictionariesList.clearSelection()
        
        self.__checkInstalledDictionaries()
