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"""Helper class to write Qt widget unittests."""

__authors__ = ["T. Vincent"]
__license__ = "MIT"
__date__ = "22/11/2023"


import gc
import logging
import unittest
import time
import functools
import sys
import os

_logger = logging.getLogger(__name__)

from silx.gui import qt
from silx.gui.qt import inspect as _inspect


if qt.BINDING == "PyQt5":
    from PyQt5.QtTest import QTest
elif qt.BINDING == "PySide6":
    from PySide6.QtTest import QTest
elif qt.BINDING == "PyQt6":
    from PyQt6.QtTest import QTest
else:
    raise ImportError("Unsupported Qt bindings")


def qWaitForWindowExposedAndActivate(window, timeout=None):
    """Waits until the window is shown in the screen.

    It also activates the window and raises it.

    See QTest.qWaitForWindowExposed for details.
    """
    if timeout is None:
        result = QTest.qWaitForWindowExposed(window)
    else:
        result = QTest.qWaitForWindowExposed(window, timeout)

    if result:
        # Makes sure window is active and on top
        window.activateWindow()
        window.raise_()

    return result


class TestCaseQt(unittest.TestCase):
    """Base class to write test for Qt stuff.

    It creates a QApplication before running the tests.
    WARNING: The QApplication is shared by all tests, which might have side
    effects.

    After each test, this class is checking for widgets remaining alive.
    To allow some widgets to remain alive at the end of a test, set the
    allowedLeakingWidgets attribute to the number of widgets that can remain
    alive at the end of the test.
    With PySide, this test is not run for now as it seems PySide
    is leaking widgets internally.

    All keyboard and mouse event simulation methods call qWait(20) after
    simulating the event (as QTest does on Mac OSX).
    This was introduced to fix issues with continuous integration tests
    running with Xvfb on Linux.
    """

    DEFAULT_TIMEOUT_WAIT = 100
    """Default timeout for qWait"""

    TIMEOUT_WAIT = 0
    """Extra timeout in millisecond to add to qSleep, qWait and
    qWaitForWindowExposed.

    Intended purpose is for debugging, to add extra time to waits in order to
    allow to view the tested widgets.
    """

    _qapp = None
    """Placeholder for QApplication"""

    @classmethod
    def exceptionHandler(cls, exceptionClass, exception, stack):
        import traceback

        message = "".join(traceback.format_tb(stack))
        template = "Traceback (most recent call last):\n{2}{0}: {1}"
        message = template.format(exceptionClass.__name__, exception, message)
        cls._exceptions.append(message)

    @classmethod
    def setUpClass(cls):
        """Makes sure Qt is inited"""
        cls._oldExceptionHook = sys.excepthook
        sys.excepthook = cls.exceptionHandler

        # Makes sure a QApplication exists and do it once for all
        if not qt.QApplication.instance():
            cls._qapp = qt.QApplication([])

    @classmethod
    def tearDownClass(cls):
        sys.excepthook = cls._oldExceptionHook

    def setUp(self):
        """Get the list of existing widgets."""
        self.allowedLeakingWidgets = 0
        if qt.BINDING == "PySide6":
            self.__previousWidgets = None
        else:
            self.__previousWidgets = self.qapp.allWidgets()
        self.__class__._exceptions = []

    def _currentTestSucceeded(self):
        if hasattr(self, "_feedErrorsToResult"):
            # Python 3.4 - 3.10  (These two methods have no side effects)
            result = self.defaultTestResult()
            if hasattr(self._outcome, "errors"):
                self._feedErrorsToResult(result, self._outcome.errors)
        elif hasattr(self._outcome, "result"):
            # Python 3.11+
            result = self._outcome.result

        if self._outcome is None:
            return True
        elif hasattr(self._outcome, "success"):
            # using pytest
            return self._outcome.success
        else:
            # using unittest
            return all(test != self for test, text in result.errors + result.failures)

    def _checkForUnreleasedWidgets(self):
        """Test fixture checking that no more widgets exists."""
        if self.__previousWidgets is None:
            return  # Do not test for leaking widgets with PySide

        gc.collect()

        widgets = [
            widget
            for widget in self.qapp.allWidgets()
            if (
                widget not in self.__previousWidgets
                and _inspect.createdByPython(widget)
            )
        ]
        self.__previousWidgets = None

        allowedLeakingWidgets = self.allowedLeakingWidgets
        self.allowedLeakingWidgets = 0

        if widgets and len(widgets) <= allowedLeakingWidgets:
            _logger.info(
                "%s: %d remaining widgets after test" % (self.id(), len(widgets))
            )

        if len(widgets) > allowedLeakingWidgets:
            raise RuntimeError("Test ended with widgets alive: %s" % str(widgets))

    def tearDown(self):
        self.qapp.processEvents()

        if len(self.__class__._exceptions) > 0:
            messages = "\n".join(self.__class__._exceptions)
            raise AssertionError("Exception occured in Qt thread:\n" + messages)

        if self._currentTestSucceeded():
            self._checkForUnreleasedWidgets()

    @property
    def qapp(self):
        """The QApplication currently running."""
        return qt.QApplication.instance()

    # Proxy to QTest

    Press = QTest.Press
    """Key press action code"""

    Release = QTest.Release
    """Key release action code"""

    Click = QTest.Click
    """Key click action code"""

    QTest = property(
        lambda self: QTest, doc="""The Qt QTest class from the used Qt binding."""
    )

    def keyClick(self, widget, key, modifier=qt.Qt.NoModifier, delay=-1):
        """Simulate clicking a key.

        See QTest.keyClick for details.
        """
        QTest.keyClick(widget, key, modifier, delay)
        self.qWait(20)

    def keyClicks(self, widget, sequence, modifier=qt.Qt.NoModifier, delay=-1):
        """Simulate clicking a sequence of keys.

        See QTest.keyClick for details.
        """
        QTest.keyClicks(widget, sequence, modifier, delay)
        self.qWait(20)

    def keyEvent(self, action, widget, key, modifier=qt.Qt.NoModifier, delay=-1):
        """Sends a Qt key event.

        See QTest.keyEvent for details.
        """
        QTest.keyEvent(action, widget, key, modifier, delay)
        self.qWait(20)

    def keyPress(self, widget, key, modifier=qt.Qt.NoModifier, delay=-1):
        """Sends a Qt key press event.

        See QTest.keyPress for details.
        """
        QTest.keyPress(widget, key, modifier, delay)
        self.qWait(20)

    def keyRelease(self, widget, key, modifier=qt.Qt.NoModifier, delay=-1):
        """Sends a Qt key release event.

        See QTest.keyRelease for details.
        """
        QTest.keyRelease(widget, key, modifier, delay)
        self.qWait(20)

    def mouseClick(self, widget, button, modifier=None, pos=None, delay=-1):
        """Simulate clicking a mouse button.

        See QTest.mouseClick for details.
        """
        if modifier is None:
            modifier = self.qapp.keyboardModifiers()
        pos = qt.QPoint(int(pos[0]), int(pos[1])) if pos is not None else qt.QPoint()
        QTest.mouseClick(widget, button, modifier, pos, delay)
        self.qWait(20)

    def mouseDClick(self, widget, button, modifier=None, pos=None, delay=-1):
        """Simulate double clicking a mouse button.

        See QTest.mouseDClick for details.
        """
        if modifier is None:
            modifier = self.qapp.keyboardModifiers()
        pos = qt.QPoint(int(pos[0]), int(pos[1])) if pos is not None else qt.QPoint()
        QTest.mouseDClick(widget, button, modifier, pos, delay)
        self.qWait(20)

    def mouseMove(self, widget, pos=None, delay=-1):
        """Simulate moving the mouse.

        See QTest.mouseMove for details.
        """
        pos = qt.QPoint(int(pos[0]), int(pos[1])) if pos is not None else qt.QPoint()
        QTest.mouseMove(widget, pos, delay)
        self.qWait(20)

    def mousePress(self, widget, button, modifier=None, pos=None, delay=-1):
        """Simulate pressing a mouse button.

        See QTest.mousePress for details.
        """
        if modifier is None:
            modifier = self.qapp.keyboardModifiers()
        pos = qt.QPoint(int(pos[0]), int(pos[1])) if pos is not None else qt.QPoint()
        QTest.mousePress(widget, button, modifier, pos, delay)
        self.qWait(20)

    def mouseRelease(self, widget, button, modifier=None, pos=None, delay=-1):
        """Simulate releasing a mouse button.

        See QTest.mouseRelease for details.
        """
        if modifier is None:
            modifier = self.qapp.keyboardModifiers()
        pos = qt.QPoint(int(pos[0]), int(pos[1])) if pos is not None else qt.QPoint()
        QTest.mouseRelease(widget, button, modifier, pos, delay)
        self.qWait(20)

    def qSleep(self, ms):
        """Sleep for ms milliseconds, blocking the execution of the test.

        See QTest.qSleep for details.
        """
        QTest.qSleep(int(ms) + self.TIMEOUT_WAIT)

    @classmethod
    def qWait(cls, ms=None):
        """Waits for ms milliseconds, events will be processed.

        See QTest.qWait for details.
        """
        if ms is None:
            ms = cls.DEFAULT_TIMEOUT_WAIT

        if qt.BINDING == "PySide6":
            # PySide has no qWait, provide a replacement
            timeout = int(ms)
            endTimeMS = int(time.time() * 1000) + timeout
            qapp = qt.QApplication.instance()
            while timeout > 0:
                qapp.processEvents(qt.QEventLoop.AllEvents, timeout)
                timeout = endTimeMS - int(time.time() * 1000)
        else:
            QTest.qWait(int(ms) + cls.TIMEOUT_WAIT)

    def qWaitForWindowExposed(self, window, timeout=None):
        """Waits until the window is shown in the screen.

        See QTest.qWaitForWindowExposed for details.
        """
        result = qWaitForWindowExposedAndActivate(window, timeout)

        if self.TIMEOUT_WAIT:
            QTest.qWait(self.TIMEOUT_WAIT)

        return result

    def exposeAndClose(self, widget):
        """Wait for expose a widget, flag it delete on close, and close it."""
        self.qWaitForWindowExposed(widget)
        self.qapp.processEvents()
        widget.setAttribute(qt.Qt.WA_DeleteOnClose)
        widget.close()

    _qobject_destroyed = False

    @classmethod
    def _aboutToDestroy(cls):
        cls._qobject_destroyed = True

    @classmethod
    def qWaitForDestroy(cls, ref):
        """
        Wait for Qt object destruction.

        Use a weakref as parameter to avoid any strong references to the
        object.

        It have to be used as following. Removing the reference to the object
        before calling the function looks to be expected, else
        :meth:`deleteLater` will not work.

        .. code-block:: python

            ref = weakref.ref(self.obj)
            self.obj = None
            self.qWaitForDestroy(ref)

        :param weakref ref: A weakref to an object to avoid any reference
        :return: True if the object was destroyed
        :rtype: bool
        """
        cls._qobject_destroyed = False
        qobject = ref()
        if qobject is None:
            return True
        qobject.destroyed.connect(cls._aboutToDestroy)
        qobject.deleteLater()
        qobject = None
        for _ in range(10):
            if cls._qobject_destroyed:
                break
            cls.qWait(10)
        else:
            _logger.debug("Object was not destroyed")

        return ref() is None

    def logScreenShot(self, level=logging.ERROR):
        """Take a screenshot and log it into the logging system if the
        logger is enabled for the expected level.

        The screenshot is stored in the directory "./build/test-debug", and
        the logging system only log the path to this file.

        :param level: Logging level
        """
        if not _logger.isEnabledFor(level):
            return
        basedir = os.path.abspath(os.path.join("build", "test-debug"))
        if not os.path.exists(basedir):
            os.makedirs(basedir)
        filename = "Screenshot_%s.png" % self.id()
        filename = os.path.join(basedir, filename)

        screen = self.qapp.primaryScreen()
        pixmap = screen.grabWindow(0)
        pixmap.save(filename)
        _logger.log(level, "Screenshot saved at %s", filename)


class SignalListener(object):
    """Util to listen a Qt event and store parameters"""

    def __init__(self):
        self.__calls = []

    def __call__(self, *args, **kargs):
        self.__calls.append((args, kargs))

    def clear(self):
        """Clear stored data"""
        self.__calls = []

    def callCount(self):
        """
        Returns how many times the listener was called.

        :rtype: int
        """
        return len(self.__calls)

    def arguments(self, callIndex=None, argumentIndex=None):
        """Returns positional arguments optionally filtered by call count id
        or argument index.

        :param int callIndex: Index of the called data
        :param int argumentIndex: Index of the positional argument.
        """
        if callIndex is not None:
            result = self.__calls[callIndex][0]
            if argumentIndex is not None:
                result = result[argumentIndex]
        else:
            result = [x[0] for x in self.__calls]
            if argumentIndex is not None:
                result = [x[argumentIndex] for x in result]
        return result

    def karguments(self, callIndex=None, argumentName=None):
        """Returns positional arguments optionally filtered by call count id
        or name of the keyword argument.

        :param int callIndex: Index of the called data
        :param int argumentName: Name of the keyword argument.
        """
        if callIndex is not None:
            result = self.__calls[callIndex][1]
            if argumentName is not None:
                result = result[argumentName]
        else:
            result = [x[1] for x in self.__calls]
            if argumentName is not None:
                result = [x[argumentName] for x in result]
        return result

    def partial(self, *args, **kargs):
        """Returns a new partial object which when called will behave like this
        listener called with the positional arguments args and keyword
        arguments keywords. If more arguments are supplied to the call, they
        are appended to args. If additional keyword arguments are supplied,
        they extend and override keywords.
        """
        return functools.partial(self, *args, **kargs)


def getQToolButtonFromAction(action):
    """Return a QToolButton corresponding to a QAction.

    :param QAction action: The QAction from which to get QToolButton.
    :return: A QToolButton associated to action or None.
    """
    if qt.BINDING in ("PySide6", "PyQt6"):
        widgets = action.associatedObjects()
    else:
        widgets = action.associatedWidgets()

    for widget in widgets:
        if isinstance(widget, qt.QToolButton):
            return widget
    return None


def findChildren(parent, kind, name=None):
    if qt.BINDING == "PySide6" and name is not None:
        result = []
        for obj in parent.findChildren(kind):
            if obj.objectName() == name:
                result.append(obj)
        return result
    else:
        return parent.findChildren(kind, name=name)
