Helpviewer/Feeds/FeedsManager.py

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

# Copyright (c) 2011 - 2014 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a RSS feeds manager dialog.
"""

from PyQt4.QtCore import pyqtSlot, pyqtSignal, Qt, QUrl, QXmlStreamReader
from PyQt4.QtGui import QDialog, QIcon, QTreeWidgetItem, QMenu, QCursor, \
    QApplication
from PyQt4.QtNetwork import QNetworkRequest, QNetworkReply
from PyQt4.QtWebKit import QWebSettings

from E5Gui import E5MessageBox

from .Ui_FeedsManager import Ui_FeedsManager

import Preferences
import UI.PixmapCache


class FeedsManager(QDialog, Ui_FeedsManager):
    """
    Class implementing a RSS feeds manager dialog.
    
    @signal openUrl(QUrl, str) emitted to open a URL in the current tab
    @signal newUrl(QUrl, str) emitted to open a URL in a new tab
    """
    openUrl = pyqtSignal(QUrl, str)
    newUrl = pyqtSignal(QUrl, str)
    
    UrlStringRole = Qt.UserRole
    ErrorDataRole = Qt.UserRole + 1
    
    def __init__(self, parent=None):
        """
        Constructor
        
        @param parent reference to the parent widget (QWidget)
        """
        super().__init__(parent)
        self.setupUi(self)
        
        self.__wasShown = False
        self.__loaded = False
        self.__feeds = []
        self.__replies = {}  # dict key is the id of the request object
                             # dict value is a tuple of request and tree item
        
        self.feedsTree.setContextMenuPolicy(Qt.CustomContextMenu)
        self.feedsTree.customContextMenuRequested.connect(
            self.__customContextMenuRequested)
        self.feedsTree.itemActivated.connect(self.__itemActivated)
    
    def show(self):
        """
        Public slot to show the feeds manager dialog.
        """
        super().show()
        
        if not self.__wasShown:
            self.__enableButtons()
            self.on_reloadAllButton_clicked()
            self.__wasShown = True
    
    def addFeed(self, urlString, title, icon):
        """
        Public method to add a feed.
        
        @param urlString URL of the feed (string)
        @param title title of the feed (string)
        @param icon icon for the feed (QIcon)
        @return flag indicating a successful addition of the feed (boolean)
        """
        if urlString == "":
            return False
        
        if not self.__loaded:
            self.__load()
        
        # step 1: check, if feed was already added
        for feed in self.__feeds:
            if feed[0] == urlString:
                return False
        
        # step 2: add the feed
        if icon.isNull() or \
                icon == QIcon(QWebSettings.webGraphic(
                    QWebSettings.DefaultFrameIconGraphic)):
            icon = UI.PixmapCache.getIcon("rss16.png")
        feed = (urlString, title, icon)
        self.__feeds.append(feed)
        self.__addFeedItem(feed)
        self.__save()
        
        return True
    
    def __addFeedItem(self, feed):
        """
        Private slot to add a top level feed item.
        
        @param feed tuple containing feed info (URL, title, icon)
            (string, string, QIcon)
        """
        itm = QTreeWidgetItem(self.feedsTree, [feed[1]])
        itm.setIcon(0, feed[2])
        itm.setData(0, FeedsManager.UrlStringRole, feed[0])
    
    def __load(self):
        """
        Private method to load the feeds data.
        """
        self.__feeds = Preferences.getHelp("RssFeeds")
        self.__loaded = True
        
        # populate the feeds tree top level with the feeds
        self.feedsTree.clear()
        for feed in self.__feeds:
            self.__addFeedItem(feed)
    
    def __save(self):
        """
        Private method to store the feeds data.
        """
        if not self.__loaded:
            self.__load()
        
        Preferences.setHelp("RssFeeds", self.__feeds)
    
    @pyqtSlot()
    def on_reloadAllButton_clicked(self):
        """
        Private slot to reload all feeds.
        """
        if not self.__loaded:
            self.__load()
        
        for index in range(self.feedsTree.topLevelItemCount()):
            itm = self.feedsTree.topLevelItem(index)
            self.__reloadFeed(itm)
    
    @pyqtSlot()
    def on_reloadButton_clicked(self):
        """
        Private slot to reload the selected feed.
        """
        itm = self.feedsTree.selectedItems()[0]
        self.__reloadFeed(itm)
    
    @pyqtSlot()
    def on_editButton_clicked(self):
        """
        Private slot to edit the selected feed.
        """
        itm = self.feedsTree.selectedItems()[0]
        origTitle = itm.text(0)
        origUrlString = itm.data(0, FeedsManager.UrlStringRole)
        
        feedToChange = None
        for feed in self.__feeds:
            if feed[0] == origUrlString:
                feedToChange = feed
                break
        if feedToChange:
            feedIndex = self.__feeds.index(feedToChange)
            
            from .FeedEditDialog import FeedEditDialog
            dlg = FeedEditDialog(origUrlString, origTitle)
            if dlg.exec_() == QDialog.Accepted:
                urlString, title = dlg.getData()
                for feed in self.__feeds:
                    if feed[0] == urlString:
                        E5MessageBox.critical(
                            self,
                            self.tr("Duplicate Feed URL"),
                            self.tr(
                                """A feed with the URL {0} exists already."""
                                """ Aborting...""".format(urlString)))
                        return
                
                self.__feeds[feedIndex] = (urlString, title, feedToChange[2])
                self.__save()
                
                itm.setText(0, title)
                itm.setData(0, FeedsManager.UrlStringRole, urlString)
                self.__reloadFeed(itm)
    
    @pyqtSlot()
    def on_deleteButton_clicked(self):
        """
        Private slot to delete the selected feed.
        """
        itm = self.feedsTree.selectedItems()[0]
        title = itm.text(0)
        res = E5MessageBox.yesNo(
            self,
            self.tr("Delete Feed"),
            self.tr(
                """<p>Do you really want to delete the feed"""
                """ <b>{0}</b>?</p>""".format(title)))
        if res:
            urlString = itm.data(0, FeedsManager.UrlStringRole)
            if urlString:
                feedToDelete = None
                for feed in self.__feeds:
                    if feed[0] == urlString:
                        feedToDelete = feed
                        break
                if feedToDelete:
                    self.__feeds.remove(feedToDelete)
                    self.__save()
                
                index = self.feedsTree.indexOfTopLevelItem(itm)
                if index != -1:
                    self.feedsTree.takeTopLevelItem(index)
                    del itm
    
    @pyqtSlot()
    def on_feedsTree_itemSelectionChanged(self):
        """
        Private slot to enable the various buttons depending on the selection.
        """
        self.__enableButtons()
    
    def __enableButtons(self):
        """
        Private slot to disable/enable various buttons.
        """
        selItems = self.feedsTree.selectedItems()
        if len(selItems) == 1 and \
           self.feedsTree.indexOfTopLevelItem(selItems[0]) != -1:
            enable = True
        else:
            enable = False
        
        self.reloadButton.setEnabled(enable)
        self.editButton.setEnabled(enable)
        self.deleteButton.setEnabled(enable)
    
    def __reloadFeed(self, itm):
        """
        Private method to reload the given feed.
        
        @param itm feed item to be reloaded (QTreeWidgetItem)
        """
        urlString = itm.data(0, FeedsManager.UrlStringRole)
        if urlString == "":
            return
        
        for child in itm.takeChildren():
            del child
        
        import Helpviewer.HelpWindow
        request = QNetworkRequest(QUrl(urlString))
        reply = Helpviewer.HelpWindow.HelpWindow.networkAccessManager()\
            .get(request)
        reply.finished.connect(self.__feedLoaded)
        self.__replies[id(reply)] = (reply, itm)
    
    def __feedLoaded(self):
        """
        Private slot to extract the loaded feed data.
        """
        reply = self.sender()
        if id(reply) not in self.__replies:
            return
        
        topItem = self.__replies[id(reply)][1]
        del self.__replies[id(reply)]
        
        if reply.error() == QNetworkReply.NoError:
            linkString = ""
            titleString = ""
            
            xml = QXmlStreamReader()
            xmlData = reply.readAll()
            xml.addData(xmlData)
            
            while not xml.atEnd():
                xml.readNext()
                if xml.isStartElement():
                    if xml.name() == "item":
                        linkString = xml.attributes().value("rss:about")
                    elif xml.name() == "link":
                        linkString = xml.attributes().value("href")
                    currentTag = xml.name()
                elif xml.isEndElement():
                    if xml.name() in ["item", "entry"]:
                        itm = QTreeWidgetItem(topItem)
                        itm.setText(0, titleString)
                        itm.setData(0, FeedsManager.UrlStringRole, linkString)
                        itm.setIcon(0, UI.PixmapCache.getIcon("rss16.png"))
                        
                        linkString = ""
                        titleString = ""
                elif xml.isCharacters() and not xml.isWhitespace():
                    if currentTag == "title":
                        titleString = xml.text()
                    elif currentTag == "link":
                        linkString += xml.text()
            
            if topItem.childCount() == 0:
                itm = QTreeWidgetItem(topItem)
                itm.setText(0, self.tr("Error fetching feed"))
                itm.setData(0, FeedsManager.UrlStringRole, "")
                itm.setData(0, FeedsManager.ErrorDataRole,
                            str(xmlData, encoding="utf-8"))
            
            topItem.setExpanded(True)
        else:
            linkString = ""
            titleString = reply.errorString()
            itm = QTreeWidgetItem(topItem)
            itm.setText(0, titleString)
            itm.setData(0, FeedsManager.UrlStringRole, linkString)
            topItem.setExpanded(True)
    
    def __customContextMenuRequested(self, pos):
        """
        Private slot to handle the context menu request for the bookmarks tree.
        
        @param pos position the context menu was requested (QPoint)
        """
        itm = self.feedsTree.currentItem()
        if itm is None:
            return
        
        if self.feedsTree.indexOfTopLevelItem(itm) != -1:
            return
        
        urlString = itm.data(0, FeedsManager.UrlStringRole)
        if urlString:
            menu = QMenu()
            menu.addAction(
                self.tr("&Open"), self.__openMessageInCurrentTab)
            menu.addAction(
                self.tr("Open in New &Tab"), self.__openMessageInNewTab)
            menu.addSeparator()
            menu.addAction(self.tr("&Copy URL to Clipboard"),
                           self.__copyUrlToClipboard)
            menu.exec_(QCursor.pos())
        else:
            errorString = itm.data(0, FeedsManager.ErrorDataRole)
            if errorString:
                menu = QMenu()
                menu.addAction(
                    self.tr("&Show error data"), self.__showError)
                menu.exec_(QCursor.pos())
    
    def __itemActivated(self, itm, column):
        """
        Private slot to handle the activation of an item.
        
        @param itm reference to the activated item (QTreeWidgetItem)
        @param column column of the activation (integer)
        """
        if self.feedsTree.indexOfTopLevelItem(itm) != -1:
            return
        
        self.__openMessage(
            QApplication.keyboardModifiers() &
            Qt.ControlModifier == Qt.ControlModifier)
        
    def __openMessageInCurrentTab(self):
        """
        Private slot to open a feed message in the current browser tab.
        """
        self.__openMessage(False)
    
    def __openMessageInNewTab(self):
        """
        Private slot to open a feed message in a new browser tab.
        """
        self.__openMessage(True)
    
    def __openMessage(self, newTab):
        """
        Private method to open a feed message.
        
        @param newTab flag indicating to open the feed message in a new tab
            (boolean)
        """
        itm = self.feedsTree.currentItem()
        if itm is None:
            return
        
        urlString = itm.data(0, FeedsManager.UrlStringRole)
        if urlString:
            title = itm.text(0)
            
            if newTab:
                self.newUrl.emit(QUrl(urlString), title)
            else:
                self.openUrl.emit(QUrl(urlString), title)
        else:
            errorString = itm.data(0, FeedsManager.ErrorDataRole)
            if errorString:
                self.__showError()
    
    def __copyUrlToClipboard(self):
        """
        Private slot to copy the URL of the selected item to the clipboard.
        """
        itm = self.feedsTree.currentItem()
        if itm is None:
            return
        
        if self.feedsTree.indexOfTopLevelItem(itm) != -1:
            return
        
        urlString = itm.data(0, FeedsManager.UrlStringRole)
        if urlString:
            QApplication.clipboard().setText(urlString)
    
    def __showError(self):
        """
        Private slot to show error info for a failed load operation.
        """
        itm = self.feedsTree.currentItem()
        if itm is None:
            return
        
        errorStr = itm.data(0, FeedsManager.ErrorDataRole)
        if errorStr:
            E5MessageBox.critical(
                self,
                self.tr("Error loading feed"),
                "{0}".format(errorStr))