Adding initial camera functions

src/camera.py

@@ -0,0 +1,82 @@
+import logging
+import threading
+from collections.abc import Iterator
+
+logger = logging.getLogger(__name__)
+
+try:
+    from picamera2 import Picamera2
+    from picamera2.encoders import H264Encoder
+    from picamera2.outputs import FileOutput
+
+    PICAMERA_AVAILABLE = True
+except ImportError:
+    PICAMERA_AVAILABLE = False
+    logger.warning("picamera2 not available — running in mock mode")
+
+
+class StreamOutput:
+    """Thread-safe buffer that holds the latest H.264 frame."""
+
+    def __init__(self) -> None:
+        self.frame: bytes = b""
+        self.condition = threading.Condition()
+
+    def write(self, data: bytes) -> None:
+        with self.condition:
+            self.frame = data
+            self.condition.notify_all()
+
+
+class Camera:
+    def __init__(self) -> None:
+        self._picam: Picamera2 | None = None
+        self._output: StreamOutput | None = None
+        self._encoder: H264Encoder | None = None
+        self.running = False
+
+    def start(self) -> None:
+        if self.running:
+            return
+        if not PICAMERA_AVAILABLE:
+            logger.info("Mock camera started")
+            self.running = True
+            return
+
+        self._picam = Picamera2()
+        config = self._picam.create_video_configuration(
+            main={"size": (1280, 720)},
+        )
+        self._picam.configure(config)
+        self._output = StreamOutput()
+        self._encoder = H264Encoder(bitrate=2_000_000)
+        self._picam.start_recording(self._encoder, FileOutput(self._output))
+        self.running = True
+        logger.info("Camera started")
+
+    def stop(self) -> None:
+        if not self.running:
+            return
+        if self._picam:
+            self._picam.stop_recording()
+            self._picam.close()
+            self._picam = None
+        self.running = False
+        logger.info("Camera stopped")
+
+    def frames(self) -> Iterator[bytes]:
+        """Yield H.264 frames for multipart streaming."""
+        if not PICAMERA_AVAILABLE:
+            # yield a small empty frame in mock mode
+            while self.running:
+                yield b""
+                return
+        assert self._output is not None
+        while self.running:
+            with self._output.condition:
+                self._output.condition.wait()
+                frame = self._output.frame
+            yield frame
+
+
+camera = Camera()