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"""PySide6 Multimedia Camera Example"""

import os
import sys
from PySide6.QtCore import QDate, QDir, QStandardPaths, Qt, QUrl, Slot
from PySide6.QtGui import QAction, QGuiApplication, QDesktopServices, QIcon
from PySide6.QtGui import QImage, QPixmap
from PySide6.QtWidgets import (QApplication, QHBoxLayout, QLabel,
    QMainWindow, QPushButton, QTabWidget, QToolBar, QVBoxLayout, QWidget)
from PySide6.QtMultimedia import (QCamera, QImageCapture,
                                  QCameraDevice, QMediaCaptureSession,
                                  QMediaDevices)
from PySide6.QtMultimediaWidgets import QVideoWidget


class ImageView(QWidget):
    def __init__(self, previewImage, fileName):
        super().__init__()

        self._file_name = fileName

        main_layout = QVBoxLayout(self)
        self._image_label = QLabel()
        self._image_label.setPixmap(QPixmap.fromImage(previewImage))
        main_layout.addWidget(self._image_label)

        top_layout = QHBoxLayout()
        self._file_name_label = QLabel(QDir.toNativeSeparators(fileName))
        self._file_name_label.setTextInteractionFlags(Qt.TextBrowserInteraction)

        top_layout.addWidget(self._file_name_label)
        top_layout.addStretch()
        copy_button = QPushButton("Copy")
        copy_button.setToolTip("Copy file name to clipboard")
        top_layout.addWidget(copy_button)
        copy_button.clicked.connect(self.copy)
        launch_button = QPushButton("Launch")
        launch_button.setToolTip("Launch image viewer")
        top_layout.addWidget(launch_button)
        launch_button.clicked.connect(self.launch)
        main_layout.addLayout(top_layout)

    @Slot()
    def copy(self):
        QGuiApplication.clipboard().setText(self._file_name_label.text())

    @Slot()
    def launch(self):
        QDesktopServices.openUrl(QUrl.fromLocalFile(self._file_name))


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

        self._capture_session = None
        self._camera = None
        self._camera_info = None
        self._image_capture = None

        available_cameras = QMediaDevices.videoInputs()
        if available_cameras:
            self._camera_info = available_cameras[0]
            self._camera = QCamera(self._camera_info)
            self._camera.errorOccurred.connect(self._camera_error)
            self._image_capture = QImageCapture(self._camera)
            self._image_capture.imageCaptured.connect(self.image_captured)
            self._image_capture.imageSaved.connect(self.image_saved)
            self._image_capture.errorOccurred.connect(self._capture_error)
            self._capture_session = QMediaCaptureSession()
            self._capture_session.setCamera(self._camera)
            self._capture_session.setImageCapture(self._image_capture)

        self._current_preview = QImage()

        tool_bar = QToolBar()
        self.addToolBar(tool_bar)

        file_menu = self.menuBar().addMenu("&File")
        shutter_icon = QIcon(os.path.join(os.path.dirname(__file__),
                            "shutter.svg"))
        self._take_picture_action = QAction(shutter_icon, "&Take Picture", self,
                                            shortcut="Ctrl+T",
                                            triggered=self.take_picture)
        self._take_picture_action.setToolTip("Take Picture")
        file_menu.addAction(self._take_picture_action)
        tool_bar.addAction(self._take_picture_action)

        exit_action = QAction(QIcon.fromTheme("application-exit"), "E&xit",
                              self, shortcut="Ctrl+Q", triggered=self.close)
        file_menu.addAction(exit_action)

        about_menu = self.menuBar().addMenu("&About")
        about_qt_action = QAction("About &Qt", self, triggered=qApp.aboutQt)
        about_menu.addAction(about_qt_action)

        self._tab_widget = QTabWidget()
        self.setCentralWidget(self._tab_widget)

        self._camera_viewfinder = QVideoWidget()
        self._tab_widget.addTab(self._camera_viewfinder, "Viewfinder")

        if self._camera and self._camera.error() == QCamera.NoError:
            name = self._camera_info.description()
            self.setWindowTitle(f"PySide6 Camera Example ({name})")
            self.show_status_message(f"Starting: '{name}'")
            self._capture_session.setVideoOutput(self._camera_viewfinder)
            self._take_picture_action.setEnabled(self._image_capture.isReadyForCapture())
            self._image_capture.readyForCaptureChanged.connect(self._take_picture_action.setEnabled)
            self._camera.start()
        else:
            self.setWindowTitle("PySide6 Camera Example")
            self._take_picture_action.setEnabled(False)
            self.show_status_message("Camera unavailable")

    def show_status_message(self, message):
        self.statusBar().showMessage(message, 5000)

    def closeEvent(self, event):
        if self._camera and self._camera.isActive():
            self._camera.stop()
        event.accept()

    def next_image_file_name(self):
        pictures_location = QStandardPaths.writableLocation(QStandardPaths.PicturesLocation)
        date_string = QDate.currentDate().toString("yyyyMMdd")
        pattern = f"{pictures_location}/pyside6_camera_{date_string}_{{:03d}}.jpg"
        n = 1
        while True:
            result = pattern.format(n)
            if not os.path.exists(result):
                return result
            n = n + 1
        return None

    @Slot()
    def take_picture(self):
        self._current_preview = QImage()
        self._image_capture.captureToFile(self.next_image_file_name())

    @Slot(int, QImage)
    def image_captured(self, id, previewImage):
        self._current_preview = previewImage

    @Slot(int, str)
    def image_saved(self, id, fileName):
        index = self._tab_widget.count()
        image_view = ImageView(self._current_preview, fileName)
        self._tab_widget.addTab(image_view, f"Capture #{index}")
        self._tab_widget.setCurrentIndex(index)

    @Slot(int, QImageCapture.Error, str)
    def _capture_error(self, id, error, error_string):
        print(error_string, file=sys.stderr)
        self.show_status_message(error_string)

    @Slot(QCamera.Error, str)
    def _camera_error(self, error, error_string):
        print(error_string, file=sys.stderr)
        self.show_status_message(error_string)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    main_win = MainWindow()
    available_geometry = main_win.screen().availableGeometry()
    main_win.resize(available_geometry.width() / 3, available_geometry.height() / 2)
    main_win.show()
    sys.exit(app.exec())
