import os


def run_loop(runtime, client, queue, *, clock, sleep, iterations=None,
             sync_every=150, heartbeat_every=900, flush_every=300,
             frame_interval=0.0, zones_for=None):
    # `runtime` may be a single PipelineRuntime or a list of them (multi-camera). All
    # cameras share this loop, one shared clock read per tick, and the periodic
    # sync/heartbeat/flush. A per-camera step exception is counted, never fatal.
    runtimes = list(runtime) if isinstance(runtime, (list, tuple)) else [runtime]
    if zones_for is None:
        from edge.zones import zones_from_config
        zones_for = lambda cfg, rt: zones_from_config(cfg)
    counters = {"frames": 0, "syncs": 0, "beats": 0, "flushes": 0, "errors": 0}
    i = 0
    while iterations is None or i < iterations:
        i += 1
        now = clock()  # one timestamp per tick, shared across cameras
        for rt in runtimes:
            try:
                rt.step(now)
                counters["frames"] += 1
            except Exception:
                counters["errors"] += 1
        try:
            if sync_every and i % sync_every == 0:
                cfg = client.fetch_config()
                if cfg is not None:
                    for rt in runtimes:
                        rt.apply_zones(zones_for(cfg, rt))
                    counters["syncs"] += 1
            if heartbeat_every and i % heartbeat_every == 0:
                if client.send_heartbeat({"fps": 0.0, "frames": counters["frames"]}):
                    counters["beats"] += 1
            if flush_every and i % flush_every == 0:
                queue.flush()
                counters["flushes"] += 1
        except Exception:
            counters["errors"] += 1
        if frame_interval:
            sleep(frame_interval)
    return counters


def parse_cameras(env, default_camera_id):
    """CAMERAS='backend:device:camera_id,...' -> [(backend, device, camera_id), ...].
    When CAMERAS is unset, fall back to a single camera from
    CAMERA_BACKEND + {UVC,CSI}_DEVICE (using default_camera_id)."""
    raw = (env.get("CAMERAS") or "").strip()
    if raw:
        cams = []
        for spec in raw.split(","):
            spec = spec.strip()
            if not spec:
                continue
            parts = [p.strip() for p in spec.split(":")]
            if len(parts) != 3:
                raise ValueError(f"bad CAMERAS entry {spec!r} (want backend:device:camera_id)")
            cams.append((parts[0].lower(), parts[1], parts[2]))
        if not cams:
            raise ValueError("CAMERAS is set but has no valid entries")  # never monitor zero cameras
        return cams
    backend = (env.get("CAMERA_BACKEND") or "uvc").lower()
    device = env.get("CSI_DEVICE" if backend == "csi" else "UVC_DEVICE") or "0"
    return [(backend, device, default_camera_id)]


def main() -> None:  # pragma: no cover (integration entrypoint, exercised on device)
    import time
    from dataclasses import replace
    from edge.config import load_config
    from edge.cloudclient import CloudClient
    from edge.alert import PostClient
    from edge.queue import OfflineQueue
    from edge.runtime import PipelineRuntime
    from edge.zones import zones_from_config

    def build_source(backend, device):
        if backend == "csi":
            from edge.adapters.picamera_source import PiCameraSource
            return PiCameraSource(int(device))
        from edge.adapters.uvc_source import UvcSource
        return UvcSource(int(device))

    def build_pose():
        # POSE_BACKEND: "hailo" (Pi5 + Hailo-8, needs HAILO_HEF) or CPU "movenet"
        # (needs MOVENET_ONNX). One shared adapter serves every camera (the Hailo
        # device / onnxruntime session is reused per frame, round-robin across cams).
        if os.environ.get("POSE_BACKEND", "movenet").lower() == "hailo":
            from edge.adapters.hailo_pose import HailoPoseAdapter
            return HailoPoseAdapter(os.environ["HAILO_HEF"])
        from edge.adapters.movenet_pose import MoveNetPoseAdapter
        return MoveNetPoseAdapter(os.environ["MOVENET_ONNX"])

    cfg = load_config(dict(os.environ))
    nonce = lambda: os.urandom(8).hex()
    now = time.time
    base = cfg.cafe24_url.rstrip("/")
    client = CloudClient(base, cfg.device_id, cfg.secret, nonce, now)
    post = PostClient(base + "/api/events", cfg.device_id, cfg.secret, nonce, now)
    queue = OfflineQueue(os.environ.get("QUEUE_DB", "queue.db"), post)

    pose = build_pose()  # shared across cameras
    runtimes = []
    for backend, device, cam in parse_cameras(dict(os.environ), cfg.camera_id):
        # Per-camera config so events are stamped with that camera's id.
        cam_cfg = replace(cfg, camera_id=cam, engine=replace(cfg.engine, camera_id=cam))
        runtimes.append(PipelineRuntime(cam_cfg, build_source(backend, device), pose, queue))

    run_loop(runtimes, client, queue, clock=now, sleep=time.sleep, iterations=None,
             frame_interval=1.0 / float(os.environ.get("TARGET_FPS", "12")),
             zones_for=lambda c, rt: zones_from_config(c, rt.camera_id))