#!/usr/bin/env python


#############################################################################
##
## Copyright (C) 2012 Riverbank Computing Limited.
## Copyright (C) 2012 Digia Plc
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
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## modification, are permitted provided that the following conditions are
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##   * Redistributions of source code must retain the above copyright
##     notice, this list of conditions and the following disclaimer.
##   * Redistributions in binary form must reproduce the above copyright
##     notice, this list of conditions and the following disclaimer in
##     the documentation and/or other materials provided with the
##     distribution.
##   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
##     the names of its contributors may be used to endorse or promote
##     products derived from this software without specific prior written
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## $QT_END_LICENSE$
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#############################################################################


# This is only needed for Python v2 but is harmless for Python v3.
import sip
sip.setapi('QString', 2)

from PyQt4 import QtCore, QtGui

import customcompleter_rc


class TextEdit(QtGui.QTextEdit):
    def __init__(self, parent=None):
        super(TextEdit, self).__init__(parent)

        self._completer = None

        self.setPlainText(
                "This TextEdit provides autocompletions for words that have "
                "more than 3 characters. You can trigger autocompletion "
                "using %s" % QtGui.QKeySequence("Ctrl+E").toString(
                        QtGui.QKeySequence.NativeText))

    def setCompleter(self, c):
        if self._completer is not None:
            self._completer.activated.disconnect()

        self._completer = c

        c.setWidget(self)
        c.setCompletionMode(QtGui.QCompleter.PopupCompletion)
        c.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        c.activated.connect(self.insertCompletion)

    def completer(self):
        return self._completer

    def insertCompletion(self, completion):
        if self._completer.widget() is not self:
            return

        tc = self.textCursor()
        extra = len(completion) - len(self._completer.completionPrefix())
        tc.movePosition(QtGui.QTextCursor.Left)
        tc.movePosition(QtGui.QTextCursor.EndOfWord)
        tc.insertText(completion[-extra:])
        self.setTextCursor(tc)

    def textUnderCursor(self):
        tc = self.textCursor()
        tc.select(QtGui.QTextCursor.WordUnderCursor)

        return tc.selectedText()

    def focusInEvent(self, e):
        if self._completer is not None:
            self._completer.setWidget(self)

        super(TextEdit, self).focusInEvent(e)

    def keyPressEvent(self, e):
        if self._completer is not None and self._completer.popup().isVisible():
            # The following keys are forwarded by the completer to the widget.
            if e.key() in (QtCore.Qt.Key_Enter, QtCore.Qt.Key_Return, QtCore.Qt.Key_Escape, QtCore.Qt.Key_Tab, QtCore.Qt.Key_Backtab):
                e.ignore()
                # Let the completer do default behavior.
                return

        isShortcut = ((e.modifiers() & QtCore.Qt.ControlModifier) != 0 and e.key() == QtCore.Qt.Key_E)
        if self._completer is None or not isShortcut:
            # Do not process the shortcut when we have a completer.
            super(TextEdit, self).keyPressEvent(e)

        ctrlOrShift = e.modifiers() & (QtCore.Qt.ControlModifier | QtCore.Qt.ShiftModifier)
        if self._completer is None or (ctrlOrShift and len(e.text()) == 0):
            return

        eow = "~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="
        hasModifier = (e.modifiers() != QtCore.Qt.NoModifier) and not ctrlOrShift
        completionPrefix = self.textUnderCursor()

        if not isShortcut and (hasModifier or len(e.text()) == 0 or len(completionPrefix) < 3 or e.text()[-1] in eow):
            self._completer.popup().hide()
            return

        if completionPrefix != self._completer.completionPrefix():
            self._completer.setCompletionPrefix(completionPrefix)
            self._completer.popup().setCurrentIndex(
                    self._completer.completionModel().index(0, 0))

        cr = self.cursorRect()
        cr.setWidth(self._completer.popup().sizeHintForColumn(0) + self._completer.popup().verticalScrollBar().sizeHint().width())
        self._completer.complete(cr)


class MainWindow(QtGui.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        self.createMenu()

        self.completingTextEdit = TextEdit()
        self.completer = QtGui.QCompleter(self)
        self.completer.setModel(self.modelFromFile(':/resources/wordlist.txt'))
        self.completer.setModelSorting(
                QtGui.QCompleter.CaseInsensitivelySortedModel)
        self.completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self.completer.setWrapAround(False)
        self.completingTextEdit.setCompleter(self.completer)

        self.setCentralWidget(self.completingTextEdit)
        self.resize(500, 300)
        self.setWindowTitle("Completer")

    def createMenu(self):
        exitAction = QtGui.QAction("Exit", self)
        aboutAct = QtGui.QAction("About", self)
        aboutQtAct = QtGui.QAction("About Qt", self)

        exitAction.triggered.connect(QtGui.qApp.quit)
        aboutAct.triggered.connect(self.about)
        aboutQtAct.triggered.connect(QtGui.qApp.aboutQt)

        fileMenu = self.menuBar().addMenu("File")
        fileMenu.addAction(exitAction)

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

    def modelFromFile(self, fileName):
        f = QtCore.QFile(fileName)
        if not f.open(QtCore.QFile.ReadOnly):
            return QtGui.QStringListModel(self.completer)

        QtGui.QApplication.setOverrideCursor(
                QtGui.QCursor(QtCore.Qt.WaitCursor))

        words = []
        while not f.atEnd():
            line = f.readLine().trimmed()
            if line.length() != 0:
                try:
                    line = str(line, encoding='ascii')
                except TypeError:
                    line = str(line)

                words.append(line)

        QtGui.QApplication.restoreOverrideCursor()

        return QtGui.QStringListModel(words, self.completer)

    def about(self):
        QtGui.QMessageBox.about(self, "About",
                "This example demonstrates the different features of the "
                "QCompleter class.")


if __name__ == '__main__':

    import sys

    app = QtGui.QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())
