scan.py

from time import sleep
import threading


class ScanManger:
    def __init__(self, servoManager, bltManager, sweepRate=10):
        self.servoManager = servoManager
        self.bltManager = bltManager
        self.sweepRate = sweepRate  # angle changes in sec

        # distance reading per angle (0..180). -1 means out of range / not yet scanned
        self.distances = [-1] * 181

        self.angle = 0
        self.direction = 1  # +1 sweeps 0 -> 180, -1 sweeps 180 -> 0

        self._lock = threading.Lock()
        self._running = False
        self._thread = None

    def _record(self):
        """Move servo to current angle, settle, then store the latest distance."""
        self.servoManager.move(self.angle)
        sleep(1.0 / self.sweepRate)

        d = self.bltManager.latest_distance
        with self._lock:
            self.distances[self.angle] = -1 if d is None else d

    def _step(self):
        """Advance the sweep by one angle, recording a distance, bouncing at the ends."""
        self._record()

        self.angle += self.direction
        if self.angle > 180:
            self.angle = 179
            self.direction = -1
        elif self.angle < 0:
            self.angle = 1
            self.direction = 1

    def _sweep_loop(self):
        while self._running:
            self._step()

    def start(self):
        """Begin sweeping in the background."""
        if self._running:
            return
        self._running = True
        self._thread = threading.Thread(target=self._sweep_loop, daemon=True)
        self._thread.start()
        print("[msg] >>> scanning started.")

    def stop(self):
        self._running = False
        print("[msg] >>> scanning stopped.")

    def get_distances(self):
        """Snapshot of the per-angle distances (the display layer reads this)."""
        with self._lock:
            return list(self.distances)

    def get_distance(self, angle):
        with self._lock:
            return self.distances[angle]