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

# Copyright (c) 2010 - 2020 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a dialog to show the output of the hg status command
process.
"""

import os

from PyQt5.QtCore import pyqtSlot, Qt, QSize
from PyQt5.QtGui import QTextCursor
from PyQt5.QtWidgets import (
    QWidget, QDialogButtonBox, QMenu, QHeaderView, QTreeWidgetItem
)

from E5Gui.E5Application import e5App
from E5Gui import E5MessageBox

from .Ui_HgStatusDialog import Ui_HgStatusDialog

from .HgDiffHighlighter import HgDiffHighlighter
from .HgDiffGenerator import HgDiffGenerator

import Preferences
import UI.PixmapCache


class HgStatusDialog(QWidget, Ui_HgStatusDialog):
    """
    Class implementing a dialog to show the output of the hg status command
    process.
    """
    def __init__(self, vcs, mq=False, parent=None):
        """
        Constructor
        
        @param vcs reference to the vcs object
        @param mq flag indicating to show a queue repo status (boolean)
        @param parent parent widget (QWidget)
        """
        super(HgStatusDialog, self).__init__(parent)
        self.setupUi(self)
        
        self.__toBeCommittedColumn = 0
        self.__statusColumn = 1
        self.__pathColumn = 2
        self.__lastColumn = self.statusList.columnCount()
        
        self.refreshButton = self.buttonBox.addButton(
            self.tr("Refresh"), QDialogButtonBox.ActionRole)
        self.refreshButton.setToolTip(
            self.tr("Press to refresh the status display"))
        self.refreshButton.setEnabled(False)
        self.buttonBox.button(QDialogButtonBox.Close).setEnabled(False)
        self.buttonBox.button(QDialogButtonBox.Cancel).setDefault(True)
        
        self.diff = None
        self.vcs = vcs
        self.vcs.committed.connect(self.__committed)
        self.__hgClient = self.vcs.getClient()
        self.__mq = mq
        
        self.statusList.headerItem().setText(self.__lastColumn, "")
        self.statusList.header().setSortIndicator(
            self.__pathColumn, Qt.AscendingOrder)
        
        font = Preferences.getEditorOtherFonts("MonospacedFont")
        self.diffEdit.setFontFamily(font.family())
        self.diffEdit.setFontPointSize(font.pointSize())
        
        self.diffHighlighter = HgDiffHighlighter(self.diffEdit.document())
        self.__diffGenerator = HgDiffGenerator(vcs, self)
        self.__diffGenerator.finished.connect(self.__generatorFinished)
        
        self.__selectedName = ""
        
        self.modifiedIndicators = [
            self.tr('added'),
            self.tr('modified'),
            self.tr('removed'),
        ]
        
        self.unversionedIndicators = [
            self.tr('not tracked'),
        ]
        
        self.missingIndicators = [
            self.tr('missing')
        ]
        
        self.status = {
            'A': self.tr('added'),
            'C': self.tr('normal'),
            'I': self.tr('ignored'),
            'M': self.tr('modified'),
            'R': self.tr('removed'),
            '?': self.tr('not tracked'),
            '!': self.tr('missing'),
        }
        
        self.__initActionsMenu()
        
        if mq:
            self.diffLabel.setVisible(False)
            self.diffEdit.setVisible(False)
            self.actionsButton.setEnabled(False)
            self.diffSplitter.setSizes([600, 0])
        else:
            self.diffSplitter.setSizes([300, 300])
    
    def __initActionsMenu(self):
        """
        Private method to initialize the actions menu.
        """
        self.__actionsMenu = QMenu()
        self.__actionsMenu.setTearOffEnabled(True)
        self.__actionsMenu.setToolTipsVisible(True)
        self.__actionsMenu.aboutToShow.connect(self.__showActionsMenu)
        
        self.__commitAct = self.__actionsMenu.addAction(
            self.tr("Commit"), self.__commit)
        self.__commitAct.setToolTip(self.tr("Commit the selected changes"))
        self.__commitSelectAct = self.__actionsMenu.addAction(
            self.tr("Select all for commit"), self.__commitSelectAll)
        self.__commitDeselectAct = self.__actionsMenu.addAction(
            self.tr("Unselect all from commit"), self.__commitDeselectAll)
        
        self.__actionsMenu.addSeparator()
        
        self.__addAct = self.__actionsMenu.addAction(
            self.tr("Add"), self.__add)
        self.__addAct.setToolTip(self.tr("Add the selected files"))
        self.__lfAddLargeAct = self.__actionsMenu.addAction(
            self.tr("Add as Large Files"), lambda: self.__lfAdd("large"))
        self.__lfAddLargeAct.setToolTip(self.tr(
            "Add the selected files as a large files using the 'Large Files'"
            " extension"))
        self.__lfAddNormalAct = self.__actionsMenu.addAction(
            self.tr("Add as Normal Files"), lambda: self.__lfAdd("normal"))
        self.__lfAddNormalAct.setToolTip(self.tr(
            "Add the selected files as a normal files using the 'Large Files'"
            " extension"))
        
        self.__actionsMenu.addSeparator()
        
        self.__diffAct = self.__actionsMenu.addAction(
            self.tr("Differences"), self.__diff)
        self.__diffAct.setToolTip(self.tr(
            "Shows the differences of the selected entry in a"
            " separate dialog"))
        self.__sbsDiffAct = self.__actionsMenu.addAction(
            self.tr("Differences Side-By-Side"), self.__sbsDiff)
        self.__sbsDiffAct.setToolTip(self.tr(
            "Shows the differences of the selected entry side-by-side in"
            " a separate dialog"))
        
        self.__actionsMenu.addSeparator()
        
        self.__revertAct = self.__actionsMenu.addAction(
            self.tr("Revert"), self.__revert)
        self.__revertAct.setToolTip(self.tr(
            "Reverts the changes of the selected files"))
        
        self.__actionsMenu.addSeparator()
        
        self.__forgetAct = self.__actionsMenu.addAction(
            self.tr("Forget missing"), self.__forget)
        self.__forgetAct.setToolTip(self.tr(
            "Forgets about the selected missing files"))
        self.__restoreAct = self.__actionsMenu.addAction(
            self.tr("Restore missing"), self.__restoreMissing)
        self.__restoreAct.setToolTip(self.tr(
            "Restores the selected missing files"))
        
        self.__actionsMenu.addSeparator()

        self.__commitMergeAct = self.__actionsMenu.addAction(
            self.tr("Commit Merge"), self.__commitMerge)
        self.__commitMergeAct.setToolTip(self.tr("Commit all the merged"
                                                 " changes."))
        self.__abortMergeAct = self.__actionsMenu.addAction(
            self.tr("Abort Merge"), self.__abortMerge)
        self.__commitMergeAct.setToolTip(self.tr("Abort an uncommitted merge "
                                                 "and lose all changes"))

        self.__actionsMenu.addSeparator()
        
        act = self.__actionsMenu.addAction(
            self.tr("Adjust column sizes"), self.__resizeColumns)
        act.setToolTip(self.tr(
            "Adjusts the width of all columns to their contents"))
        
        self.actionsButton.setIcon(
            UI.PixmapCache.getIcon("actionsToolButton.png"))
        self.actionsButton.setMenu(self.__actionsMenu)
    
    def closeEvent(self, e):
        """
        Protected slot implementing a close event handler.
        
        @param e close event (QCloseEvent)
        """
        if self.__hgClient.isExecuting():
            self.__hgClient.cancel()
        
        if self.__mq:
            self.vcs.getPlugin().setPreferences(
                "MqStatusDialogGeometry", self.saveGeometry())
            self.vcs.getPlugin().setPreferences(
                "MqStatusDialogSplitterState", self.diffSplitter.saveState())
        else:
            self.vcs.getPlugin().setPreferences(
                "StatusDialogGeometry", self.saveGeometry())
            self.vcs.getPlugin().setPreferences(
                "StatusDialogSplitterState", self.diffSplitter.saveState())
        
        e.accept()
    
    def show(self):
        """
        Public slot to show the dialog.
        """
        super(HgStatusDialog, self).show()
        
        if self.__mq:
            geom = self.vcs.getPlugin().getPreferences(
                "MqStatusDialogGeometry")
        else:
            geom = self.vcs.getPlugin().getPreferences(
                "StatusDialogGeometry")
        if geom.isEmpty():
            s = QSize(800, 600)
            self.resize(s)
        else:
            self.restoreGeometry(geom)
        
        if self.__mq:
            diffSplitterState = self.vcs.getPlugin().getPreferences(
                "MqStatusDialogSplitterState")
        else:
            diffSplitterState = self.vcs.getPlugin().getPreferences(
                "StatusDialogSplitterState")
        if diffSplitterState is not None:
            self.diffSplitter.restoreState(diffSplitterState)
    
    def __resort(self):
        """
        Private method to resort the tree.
        """
        self.statusList.sortItems(
            self.statusList.sortColumn(),
            self.statusList.header().sortIndicatorOrder())
    
    def __resizeColumns(self):
        """
        Private method to resize the list columns.
        """
        self.statusList.header().resizeSections(QHeaderView.ResizeToContents)
        self.statusList.header().setStretchLastSection(True)
    
    def __generateItem(self, status, path):
        """
        Private method to generate a status item in the status list.
        
        @param status status indicator (string)
        @param path path of the file or directory (string)
        """
        statusText = self.status[status]
        itm = QTreeWidgetItem(self.statusList, [
            "",
            statusText,
            path,
        ])
        
        itm.setTextAlignment(1, Qt.AlignHCenter)
        itm.setTextAlignment(2, Qt.AlignLeft)
    
        if status in "AMR":
            itm.setFlags(itm.flags() | Qt.ItemIsUserCheckable)
            itm.setCheckState(self.__toBeCommittedColumn, Qt.Checked)
        else:
            itm.setFlags(itm.flags() & ~Qt.ItemIsUserCheckable)
        
        if statusText not in self.__statusFilters:
            self.__statusFilters.append(statusText)
        
    def start(self, fn):
        """
        Public slot to start the hg status command.
        
        @param fn filename(s)/directoryname(s) to show the status of
            (string or list of strings)
        """
        self.errorGroup.hide()
        self.intercept = False
        self.args = fn
        
        self.actionsButton.setEnabled(False)
        
        self.statusFilterCombo.clear()
        self.__statusFilters = []
        self.statusList.clear()
        
        if self.__mq:
            self.setWindowTitle(
                self.tr("Mercurial Queue Repository Status"))
        else:
            self.setWindowTitle(self.tr('Mercurial Status'))
        
        args = self.vcs.initCommand("status")
        if self.__mq:
            args.append('--mq')
            if isinstance(fn, list):
                self.dname, fnames = self.vcs.splitPathList(fn)
            else:
                self.dname, fname = self.vcs.splitPath(fn)
        else:
            if self.vcs.hasSubrepositories():
                args.append("--subrepos")
            
            if isinstance(fn, list):
                self.dname, fnames = self.vcs.splitPathList(fn)
                self.vcs.addArguments(args, fn)
            else:
                self.dname, fname = self.vcs.splitPath(fn)
                args.append(fn)
        
        # find the root of the repo
        repodir = self.dname
        while not os.path.isdir(os.path.join(repodir, self.vcs.adminDir)):
            repodir = os.path.dirname(repodir)
            if os.path.splitdrive(repodir)[1] == os.sep:
                return
        
        self.refreshButton.setEnabled(False)
        
        out, err = self.__hgClient.runcommand(args)
        if err:
            self.__showError(err)
        if out:
            for line in out.splitlines():
                self.__processOutputLine(line)
                if self.__hgClient.wasCanceled():
                    break
        self.__finish()
    
    def __finish(self):
        """
        Private slot called when the process finished or the user pressed
        the button.
        """
        self.refreshButton.setEnabled(True)
        
        self.buttonBox.button(QDialogButtonBox.Close).setEnabled(True)
        self.buttonBox.button(QDialogButtonBox.Cancel).setEnabled(False)
        self.buttonBox.button(QDialogButtonBox.Close).setDefault(True)
        self.buttonBox.button(QDialogButtonBox.Close).setFocus(
            Qt.OtherFocusReason)
        
        self.__statusFilters.sort()
        self.__statusFilters.insert(0, "<{0}>".format(self.tr("all")))
        self.statusFilterCombo.addItems(self.__statusFilters)
        
        if not self.__mq:
            self.actionsButton.setEnabled(True)
        
        self.__resort()
        self.__resizeColumns()
        
        self.__refreshDiff()
    
    def on_buttonBox_clicked(self, button):
        """
        Private slot called by a button of the button box clicked.
        
        @param button button that was clicked (QAbstractButton)
        """
        if button == self.buttonBox.button(QDialogButtonBox.Close):
            self.close()
        elif button == self.buttonBox.button(QDialogButtonBox.Cancel):
            self.__hgClient.cancel()
        elif button == self.refreshButton:
            self.on_refreshButton_clicked()
    
    def __processOutputLine(self, line):
        """
        Private method to process the lines of output.
        
        @param line output line to be processed (string)
        """
        if line[0] in "ACIMR?!" and line[1] == " ":
            status, path = line.strip().split(" ", 1)
            self.__generateItem(status, path)
    
    def __showError(self, out):
        """
        Private slot to show some error.
        
        @param out error to be shown (string)
        """
        self.errorGroup.show()
        self.errors.insertPlainText(out)
        self.errors.ensureCursorVisible()
    
    @pyqtSlot()
    def on_refreshButton_clicked(self):
        """
        Private slot to refresh the status display.
        """
        selectedItems = self.statusList.selectedItems()
        if len(selectedItems) == 1:
            self.__selectedName = selectedItems[0].text(self.__pathColumn)
        else:
            self.__selectedName = ""
        
        self.start(self.args)
    
    @pyqtSlot(str)
    def on_statusFilterCombo_activated(self, txt):
        """
        Private slot to react to the selection of a status filter.
        
        @param txt selected status filter (string)
        """
        if txt == "<{0}>".format(self.tr("all")):
            for topIndex in range(self.statusList.topLevelItemCount()):
                topItem = self.statusList.topLevelItem(topIndex)
                topItem.setHidden(False)
        else:
            for topIndex in range(self.statusList.topLevelItemCount()):
                topItem = self.statusList.topLevelItem(topIndex)
                topItem.setHidden(topItem.text(self.__statusColumn) != txt)
    
    @pyqtSlot()
    def on_statusList_itemSelectionChanged(self):
        """
        Private slot to act upon changes of selected items.
        """
        self.__generateDiffs()
    
    ###########################################################################
    ## Menu handling methods
    ###########################################################################
    
    def __showActionsMenu(self):
        """
        Private slot to prepare the actions button menu before it is shown.
        """
        if self.vcs.canCommitMerge(self.dname):
            self.__commitMergeAct.setEnabled(True)
            self.__abortMergeAct.setEnabled(True)

            self.__addAct.setEnabled(False)
            self.__diffAct.setEnabled(False)
            self.__sbsDiffAct.setEnabled(False)
            self.__revertAct.setEnabled(False)
            self.__forgetAct.setEnabled(False)
            self.__restoreAct.setEnabled(False)
            self.__commitAct.setEnabled(False)
            self.__commitSelectAct.setEnabled(False)
            self.__commitDeselectAct.setEnabled(False)

            self.__lfAddLargeAct.setEnabled(False)
            self.__lfAddNormalAct.setEnabled(False)

        else:
            self.__commitMergeAct.setEnabled(False)
            self.__abortMergeAct.setEnabled(False)

            modified = len(self.__getModifiedItems())
            unversioned = len(self.__getUnversionedItems())
            missing = len(self.__getMissingItems())
            commitable = len(self.__getCommitableItems())
            commitableUnselected = len(self.__getCommitableUnselectedItems())
    
            self.__addAct.setEnabled(unversioned)
            self.__diffAct.setEnabled(modified)
            self.__sbsDiffAct.setEnabled(modified == 1)
            self.__revertAct.setEnabled(modified)
            self.__forgetAct.setEnabled(missing)
            self.__restoreAct.setEnabled(missing)
            self.__commitAct.setEnabled(commitable)
            self.__commitSelectAct.setEnabled(commitableUnselected)
            self.__commitDeselectAct.setEnabled(commitable)
            
            if self.vcs.isExtensionActive("largefiles"):
                enable = bool(unversioned)
            else:
                enable = False
            self.__lfAddLargeAct.setEnabled(enable)
            self.__lfAddNormalAct.setEnabled(enable)
    
    def __commit(self):
        """
        Private slot to handle the Commit context menu entry.
        """
        if self.__mq:
            self.vcs.vcsCommit(self.dname, "", mq=True)
        else:
            names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                     for itm in self.__getCommitableItems()]
            if not names:
                E5MessageBox.information(
                    self,
                    self.tr("Commit"),
                    self.tr("""There are no entries selected to be"""
                            """ committed."""))
                return
            
            if Preferences.getVCS("AutoSaveFiles"):
                vm = e5App().getObject("ViewManager")
                for name in names:
                    vm.saveEditor(name)
            self.vcs.vcsCommit(names, '')
    
    def __committed(self):
        """
        Private slot called after the commit has finished.
        """
        if self.isVisible():
            self.on_refreshButton_clicked()
            self.vcs.checkVCSStatus()
    
    def __commitSelectAll(self):
        """
        Private slot to select all entries for commit.
        """
        self.__commitSelect(True)
    
    def __commitDeselectAll(self):
        """
        Private slot to deselect all entries from commit.
        """
        self.__commitSelect(False)
    
    def __add(self):
        """
        Private slot to handle the Add context menu entry.
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getUnversionedItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Add"),
                self.tr("""There are no unversioned entries"""
                        """ available/selected."""))
            return
        
        self.vcs.vcsAdd(names)
        self.on_refreshButton_clicked()
        
        project = e5App().getObject("Project")
        for name in names:
            project.getModel().updateVCSStatus(name)
        self.vcs.checkVCSStatus()
    
    def __lfAdd(self, mode):
        """
        Private slot to add a file to the repository.
        
        @param mode add mode (string one of 'normal' or 'large')
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getUnversionedItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Add"),
                self.tr("""There are no unversioned entries"""
                        """ available/selected."""))
            return
        
        self.vcs.getExtensionObject("largefiles").hgAdd(
            names, mode)
        self.on_refreshButton_clicked()
        
        project = e5App().getObject("Project")
        for name in names:
            project.getModel().updateVCSStatus(name)
        self.vcs.checkVCSStatus()
    
    def __forget(self):
        """
        Private slot to handle the Remove context menu entry.
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getMissingItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Remove"),
                self.tr("""There are no missing entries"""
                        """ available/selected."""))
            return
        
        self.vcs.hgForget(names)
        self.on_refreshButton_clicked()
    
    def __revert(self):
        """
        Private slot to handle the Revert context menu entry.
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getModifiedItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Revert"),
                self.tr("""There are no uncommitted changes"""
                        """ available/selected."""))
            return
        
        self.vcs.hgRevert(names)
        self.raise_()
        self.activateWindow()
        self.on_refreshButton_clicked()
        
        project = e5App().getObject("Project")
        for name in names:
            project.getModel().updateVCSStatus(name)
        self.vcs.checkVCSStatus()
    
    def __restoreMissing(self):
        """
        Private slot to handle the Restore Missing context menu entry.
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getMissingItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Revert"),
                self.tr("""There are no missing entries"""
                        """ available/selected."""))
            return
        
        self.vcs.hgRevert(names)
        self.on_refreshButton_clicked()
        self.vcs.checkVCSStatus()
        
    def __diff(self):
        """
        Private slot to handle the Diff context menu entry.
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getModifiedItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Differences"),
                self.tr("""There are no uncommitted changes"""
                        """ available/selected."""))
            return
        
        if self.diff is None:
            from .HgDiffDialog import HgDiffDialog
            self.diff = HgDiffDialog(self.vcs)
        self.diff.show()
        self.diff.start(names, refreshable=True)
    
    def __sbsDiff(self):
        """
        Private slot to handle the Diff context menu entry.
        """
        names = [os.path.join(self.dname, itm.text(self.__pathColumn))
                 for itm in self.__getModifiedItems()]
        if not names:
            E5MessageBox.information(
                self,
                self.tr("Side-by-Side Diff"),
                self.tr("""There are no uncommitted changes"""
                        """ available/selected."""))
            return
        elif len(names) > 1:
            E5MessageBox.information(
                self,
                self.tr("Side-by-Side Diff"),
                self.tr("""Only one file with uncommitted changes"""
                        """ must be selected."""))
            return
        
        self.vcs.hgSbsDiff(names[0])
    
    def __getCommitableItems(self):
        """
        Private method to retrieve all entries the user wants to commit.
        
        @return list of all items, the user has checked
        """
        commitableItems = []
        for index in range(self.statusList.topLevelItemCount()):
            itm = self.statusList.topLevelItem(index)
            if itm.checkState(self.__toBeCommittedColumn) == Qt.Checked:
                commitableItems.append(itm)
        return commitableItems
    
    def __getCommitableUnselectedItems(self):
        """
        Private method to retrieve all entries the user may commit but hasn't
        selected.
        
        @return list of all items, the user has checked
        """
        items = []
        for index in range(self.statusList.topLevelItemCount()):
            itm = self.statusList.topLevelItem(index)
            if (
                itm.flags() & Qt.ItemIsUserCheckable and
                itm.checkState(self.__toBeCommittedColumn) == Qt.Unchecked
            ):
                items.append(itm)
        return items
    
    def __getModifiedItems(self):
        """
        Private method to retrieve all entries, that have a modified status.
        
        @return list of all items with a modified status
        """
        modifiedItems = []
        for itm in self.statusList.selectedItems():
            if itm.text(self.__statusColumn) in self.modifiedIndicators:
                modifiedItems.append(itm)
        return modifiedItems
    
    def __getUnversionedItems(self):
        """
        Private method to retrieve all entries, that have an unversioned
        status.
        
        @return list of all items with an unversioned status
        """
        unversionedItems = []
        for itm in self.statusList.selectedItems():
            if itm.text(self.__statusColumn) in self.unversionedIndicators:
                unversionedItems.append(itm)
        return unversionedItems
    
    def __getMissingItems(self):
        """
        Private method to retrieve all entries, that have a missing status.
        
        @return list of all items with a missing status
        """
        missingItems = []
        for itm in self.statusList.selectedItems():
            if itm.text(self.__statusColumn) in self.missingIndicators:
                missingItems.append(itm)
        return missingItems
    
    def __commitSelect(self, selected):
        """
        Private slot to select or deselect all entries.
        
        @param selected commit selection state to be set (boolean)
        """
        for index in range(self.statusList.topLevelItemCount()):
            itm = self.statusList.topLevelItem(index)
            if itm.flags() & Qt.ItemIsUserCheckable:
                if selected:
                    itm.setCheckState(self.__toBeCommittedColumn, Qt.Checked)
                else:
                    itm.setCheckState(self.__toBeCommittedColumn, Qt.Unchecked)
    
    def __commitMerge(self):
        """
        Private slot to handle the Commit Merge context menu entry.
        """
        self.vcs.vcsCommit(self.dname, self.tr('Merge'), merge=True)
        self.__committed()

    def __abortMerge(self):
        """
        Private slot used to abort an uncommitted merge.
        """
        self.vcs.hgAbortMerge(self.dname)
        self.__committed()

    ###########################################################################
    ## Diff handling methods below
    ###########################################################################
    
    def __generateDiffs(self):
        """
        Private slot to generate diff outputs for the selected item.
        """
        self.diffEdit.clear()
        self.diffHighlighter.regenerateRules()
        
        if not self.__mq:
            selectedItems = self.statusList.selectedItems()
            if len(selectedItems) == 1:
                fn = os.path.join(self.dname,
                                  selectedItems[0].text(self.__pathColumn))
                self.__diffGenerator.start(fn)
    
    def __generatorFinished(self):
        """
        Private slot connected to the finished signal of the diff generator.
        """
        diff = self.__diffGenerator.getResult()[0]
        
        if diff:
            for line in diff[:]:
                if line.startswith("@@ "):
                    break
                else:
                    diff.pop(0)
            self.diffEdit.setPlainText("".join(diff))
        
        tc = self.diffEdit.textCursor()
        tc.movePosition(QTextCursor.Start)
        self.diffEdit.setTextCursor(tc)
        self.diffEdit.ensureCursorVisible()
    
    def __refreshDiff(self):
        """
        Private method to refresh the diff output after a refresh.
        """
        if self.__selectedName and not self.__mq:
            for index in range(self.statusList.topLevelItemCount()):
                itm = self.statusList.topLevelItem(index)
                if itm.text(self.__pathColumn) == self.__selectedName:
                    itm.setSelected(True)
                    break
        
        self.__selectedName = ""
