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## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2016 The Qt Company Ltd.
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## This file is part of the Qt for Python examples of the Qt Toolkit.
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from PySide2 import QtCore, QtGui, QtWidgets

import application_rc

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()

        self.curFile = ''

        self.textEdit = QtWidgets.QTextEdit()
        self.setCentralWidget(self.textEdit)

        self.createActions()
        self.createMenus()
        self.createToolBars()
        self.createStatusBar()

        self.readSettings()

        self.textEdit.document().contentsChanged.connect(self.documentWasModified)

        self.setCurrentFile('')
        self.setUnifiedTitleAndToolBarOnMac(True)

    def closeEvent(self, event):
        if self.maybeSave():
            self.writeSettings()
            event.accept()
        else:
            event.ignore()

    def newFile(self):
        if self.maybeSave():
            self.textEdit.clear()
            self.setCurrentFile('')

    def open(self):
        if self.maybeSave():
            fileName, filtr = QtWidgets.QFileDialog.getOpenFileName(self)
            if fileName:
                self.loadFile(fileName)

    def save(self):
        if self.curFile:
            return self.saveFile(self.curFile)

        return self.saveAs()

    def saveAs(self):
        fileName, filtr = QtWidgets.QFileDialog.getSaveFileName(self)
        if fileName:
            return self.saveFile(fileName)

        return False

    def about(self):
        QtWidgets.QMessageBox.about(self, "About Application",
                "The <b>Application</b> example demonstrates how to write "
                "modern GUI applications using Qt, with a menu bar, "
                "toolbars, and a status bar.")

    def documentWasModified(self):
        self.setWindowModified(self.textEdit.document().isModified())

    def createActions(self):
        self.newAct = QtWidgets.QAction(QtGui.QIcon(':/images/new.png'), "&New",
                self, shortcut=QtGui.QKeySequence.New,
                statusTip="Create a new file", triggered=self.newFile)

        self.openAct = QtWidgets.QAction(QtGui.QIcon(':/images/open.png'),
                "&Open...", self, shortcut=QtGui.QKeySequence.Open,
                statusTip="Open an existing file", triggered=self.open)

        self.saveAct = QtWidgets.QAction(QtGui.QIcon(':/images/save.png'),
                "&Save", self, shortcut=QtGui.QKeySequence.Save,
                statusTip="Save the document to disk", triggered=self.save)

        self.saveAsAct = QtWidgets.QAction("Save &As...", self,
                shortcut=QtGui.QKeySequence.SaveAs,
                statusTip="Save the document under a new name",
                triggered=self.saveAs)

        self.exitAct = QtWidgets.QAction("E&xit", self, shortcut="Ctrl+Q",
                statusTip="Exit the application", triggered=self.close)

        self.cutAct = QtWidgets.QAction(QtGui.QIcon(':/images/cut.png'), "Cu&t",
                self, shortcut=QtGui.QKeySequence.Cut,
                statusTip="Cut the current selection's contents to the clipboard",
                triggered=self.textEdit.cut)

        self.copyAct = QtWidgets.QAction(QtGui.QIcon(':/images/copy.png'),
                "&Copy", self, shortcut=QtGui.QKeySequence.Copy,
                statusTip="Copy the current selection's contents to the clipboard",
                triggered=self.textEdit.copy)

        self.pasteAct = QtWidgets.QAction(QtGui.QIcon(':/images/paste.png'),
                "&Paste", self, shortcut=QtGui.QKeySequence.Paste,
                statusTip="Paste the clipboard's contents into the current selection",
                triggered=self.textEdit.paste)

        self.aboutAct = QtWidgets.QAction("&About", self,
                statusTip="Show the application's About box",
                triggered=self.about)

        self.aboutQtAct = QtWidgets.QAction("About &Qt", self,
                statusTip="Show the Qt library's About box",
                triggered=QtWidgets.qApp.aboutQt)

        self.cutAct.setEnabled(False)
        self.copyAct.setEnabled(False)
        self.textEdit.copyAvailable.connect(self.cutAct.setEnabled)
        self.textEdit.copyAvailable.connect(self.copyAct.setEnabled)

    def createMenus(self):
        self.fileMenu = self.menuBar().addMenu("&File")
        self.fileMenu.addAction(self.newAct)
        self.fileMenu.addAction(self.openAct)
        self.fileMenu.addAction(self.saveAct)
        self.fileMenu.addAction(self.saveAsAct)
        self.fileMenu.addSeparator()
        self.fileMenu.addAction(self.exitAct)

        self.editMenu = self.menuBar().addMenu("&Edit")
        self.editMenu.addAction(self.cutAct)
        self.editMenu.addAction(self.copyAct)
        self.editMenu.addAction(self.pasteAct)

        self.menuBar().addSeparator()

        self.helpMenu = self.menuBar().addMenu("&Help")
        self.helpMenu.addAction(self.aboutAct)
        self.helpMenu.addAction(self.aboutQtAct)

    def createToolBars(self):
        self.fileToolBar = self.addToolBar("File")
        self.fileToolBar.addAction(self.newAct)
        self.fileToolBar.addAction(self.openAct)
        self.fileToolBar.addAction(self.saveAct)

        self.editToolBar = self.addToolBar("Edit")
        self.editToolBar.addAction(self.cutAct)
        self.editToolBar.addAction(self.copyAct)
        self.editToolBar.addAction(self.pasteAct)

    def createStatusBar(self):
        self.statusBar().showMessage("Ready")

    def readSettings(self):
        settings = QtCore.QSettings("Trolltech", "Application Example")
        pos = settings.value("pos", QtCore.QPoint(200, 200))
        size = settings.value("size", QtCore.QSize(400, 400))
        self.resize(size)
        self.move(pos)

    def writeSettings(self):
        settings = QtCore.QSettings("Trolltech", "Application Example")
        settings.setValue("pos", self.pos())
        settings.setValue("size", self.size())

    def maybeSave(self):
        if self.textEdit.document().isModified():
            ret = QtWidgets.QMessageBox.warning(self, "Application",
                    "The document has been modified.\nDo you want to save "
                    "your changes?",
                    QtWidgets.QMessageBox.Save | QtWidgets.QMessageBox.Discard |
                    QtWidgets.QMessageBox.Cancel)
            if ret == QtWidgets.QMessageBox.Save:
                return self.save()
            elif ret == QtWidgets.QMessageBox.Cancel:
                return False
        return True

    def loadFile(self, fileName):
        file = QtCore.QFile(fileName)
        if not file.open(QtCore.QFile.ReadOnly | QtCore.QFile.Text):
            QtWidgets.QMessageBox.warning(self, "Application",
                    "Cannot read file %s:\n%s." % (fileName, file.errorString()))
            return

        inf = QtCore.QTextStream(file)
        QtWidgets.QApplication.setOverrideCursor(QtCore.Qt.WaitCursor)
        self.textEdit.setPlainText(inf.readAll())
        QtWidgets.QApplication.restoreOverrideCursor()

        self.setCurrentFile(fileName)
        self.statusBar().showMessage("File loaded", 2000)

    def saveFile(self, fileName):
        file = QtCore.QFile(fileName)
        if not file.open(QtCore.QFile.WriteOnly | QtCore.QFile.Text):
            QtWidgets.QMessageBox.warning(self, "Application",
                    "Cannot write file %s:\n%s." % (fileName, file.errorString()))
            return False

        outf = QtCore.QTextStream(file)
        QtWidgets.QApplication.setOverrideCursor(QtCore.Qt.WaitCursor)

        # FIXME: Once file is out of scope, the file is empty, instead of having text.
        outf << self.textEdit.toPlainText()
        QtWidgets.QApplication.restoreOverrideCursor()

        self.setCurrentFile(fileName)
        self.statusBar().showMessage("File saved", 2000)
        return True

    def setCurrentFile(self, fileName):
        self.curFile = fileName
        self.textEdit.document().setModified(False)
        self.setWindowModified(False)

        if self.curFile:
            shownName = self.strippedName(self.curFile)
        else:
            shownName = 'untitled.txt'

        self.setWindowTitle("%s[*] - Application" % shownName)

    def strippedName(self, fullFileName):
        return QtCore.QFileInfo(fullFileName).fileName()


if __name__ == '__main__':

    import sys

    app = QtWidgets.QApplication(sys.argv)
    mainWin = MainWindow()
    mainWin.show()
    sys.exit(app.exec_())
