from PySide6.QtCore import QObject, QTimer, Signal, Slot, QMutex, QMutexLocker
from PySide6.QtGui import QImage, QPixmap
import cv2

from .base_camera import BaseCamera


class CameraController(QObject):
    """
    A QObject worker for handling camera operations in a separate thread.
    This object should be moved to a QThread.
    """
    frame_ready = Signal(QPixmap)
    photo_ready = Signal(QPixmap)
    error_occurred = Signal(str)

    def __init__(self, parent: QObject | None = None) -> None:
        super().__init__(parent)
        self.camera: BaseCamera | None = None
        self.timer: QTimer | None = None
        self.fps = 15
        self.is_streaming = False
        self.is_connected = False
        self._camera_mutex = QMutex()

    @Slot()
    def run(self):
        """
        Initializes resources in the worker thread.
        This should be connected to the QThread.started signal.
        """
        self.timer = QTimer()
        self.timer.timeout.connect(self._update_frame)

    @Slot(BaseCamera, int)
    def set_camera(self, camera: BaseCamera, fps: int = 15) -> None:
        with QMutexLocker(self._camera_mutex):
            if self.is_streaming:
                self.stop_stream()
            if self.is_connected:
                self.stop_camera()

            self.camera = camera
            self.fps = fps

    @Slot()
    def start_camera(self) -> None:
        with QMutexLocker(self._camera_mutex):
            if self.camera is None or self.is_connected:
                return

            if self.camera.connect():
                self.is_connected = True
            else:
                self.is_connected = False
                self.error_occurred.emit(self.camera.get_error_msg())

    @Slot()
    def stop_camera(self) -> None:
        with QMutexLocker(self._camera_mutex):
            if self.is_streaming:
                self.stop_stream()

            if self.camera is not None and self.is_connected:
                self.camera.disconnect()

            self.is_connected = False

    @Slot()
    def start_stream(self):
        with QMutexLocker(self._camera_mutex):
            if not self.is_connected or self.is_streaming or self.timer is None:
                return

            self.is_streaming = True
            self.timer.setInterval(int(1000 / self.fps))
            self.timer.start()

    @Slot()
    def stop_stream(self) -> None:
        with QMutexLocker(self._camera_mutex):
            if not self.is_streaming or self.timer is None:
                return
            
            self.is_streaming = False
            self.timer.stop()

    def _update_frame(self) -> None:
        # This method is called by the timer, which is in the same thread.
        # A mutex is still good practice for accessing the shared camera object.
        with QMutexLocker(self._camera_mutex):
            if self.camera is None or not self.is_connected or not self.is_streaming:
                return
        
            ret, frame = self.camera.get_frame()

            if not ret:
                error_msg = self.camera.get_error_msg()
                if error_msg:
                    self.error_occurred.emit(error_msg)
                return

        if frame is not None:
            # Process the frame and emit it.
            rgb_image = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
            h, w, ch = rgb_image.shape
            qimg = QImage(rgb_image.data, w, h, ch * w, QImage.Format.Format_RGB888)
            pixmap = QPixmap.fromImage(qimg)
            self.frame_ready.emit(pixmap)