Source code for qtdraw.util.qt_event_util

"""
Control Qt event loop.

This module provides functions to control Qt event loop.

See also,

- [use Qt from Jupyter NB](https://qiita.com/Hanjin_Liu/items/9df684920727f8a784c4)
- [exception hook](https://timlehr.com/python-exception-hooks-with-qt-message-box/)
"""

import sys
import logging
from IPython.core import ultratb
from PySide6.QtCore import QObject, Signal, Qt, QLoggingCategory
from PySide6.QtGui import QFont
from PySide6.QtWidgets import QApplication
from qtdraw.widget.message_box import MessageBox
from qtdraw.util.util import set_latex_setting, create_style_sheet
from qtdraw.core.pyvista_widget_setting import default_preference
from qtdraw import __top_dir__


# ==================================================


def gui_qt():
    """
    Execute gui magic command for qtconsole.
    """
    try:
        from IPython import get_ipython
    except ImportError:
        get_ipython = lambda: False

    shell = get_ipython()

    if shell and shell.active_eventloop != "qt":
        shell.enable_gui("qt")



# ==================================================


def get_qt_application(latex=True):
    """
    Get Qt application.

    Args:
        latex (bool, optional): use latex setting ?

    Returns:
        - (QApplication) -- Qt application.

    Note:
        - call this before super().__init__() in __init__() of QMainWindow class as follows.
            - self.app = get_qt_application()
            - ExceptionHook()
    """
    # suppress logging message concerning japanese IM.
    QLoggingCategory.setFilterRules("qt.qpa.keymapper=false")

    # initial LaTeX setting.
    if latex:
        set_latex_setting()

    gui_qt()
    app = QApplication.instance()
    if app is None:
        app = QApplication([])

    # for high-resolution setting.
    app.setAttribute(Qt.AA_EnableHighDpiScaling)
    app.setAttribute(Qt.AA_UseHighDpiPixmaps)

    style = default_preference["general"]["style"]
    font = default_preference["general"]["font"]
    size = default_preference["general"]["size"]
    app.setStyle(style)
    app.setFont(QFont(font))
    app.setStyleSheet(create_style_sheet(size))

    return app



# ==================================================


class ExceptionHook(QObject):
    msg_signal = Signal(str)

    # ==================================================
    def __init__(self, parent=None):
        """
        Exception hook.

        Args:
            parent (QObject, optional): parent.

        Note:
            - call this before super().__init__() in __init__() of QMainWindow class as follows.
                - self.app = get_qt_application()
                - ExceptionHook()
        """
        super().__init__(parent)

        # hook the exception handler of the Python interpreter.
        sys.excepthook = self.hook

        # connection.
        self.msg_signal.connect(lambda x: MessageBox(x, "Exception Message"))

    # ==================================================


    def hook(self, type, value, traceback):
        """
        Callback for uncaught exceptions.

        Args:
            type (Any): type of exception.
            value (Any): arguments.
            traceback (TraceBack): traceback.
        """
        if issubclass(type, KeyboardInterrupt):
            sys.__excepthook__(type, value, traceback)  # ignore keyboard interrupt for console applications.
        else:
            bar = "---------------------------------------------------------------------------"
            handler = ultratb.VerboseTB(color_scheme="NoColor", long_header=False)
            log_msg = handler.text(type, value, traceback)
            log_msg += "\n" + bar
            simple = "\n" + bar + "\n" + ultratb.SyntaxTB().text(type, value, traceback) + bar
            self.msg_signal.emit(log_msg)
            logging.critical(simple)


    # ==================================================


    def reset(self):
        """
        Reset exception hook.
        """
        sys.excepthook = sys.__excepthook__