"""Decides what should be on screen right now, renders it, and only pushes to the panel when the rendered image actually changed. Design goals (in reaction to the InkyPi issues that motivated this rewrite): - One short tick (a few seconds), not a long sleep-until-interval -- config changes and manual actions take effect almost immediately, no signaling machinery needed. - Navidrome can preempt the rotation the instant something's playing, without needing to be "its turn" in a round-robin. - A screen is only ever fully re-rendered+pushed to hardware when its rendered image differs from what's currently displayed. """ import hashlib import logging import threading import time from pathlib import Path from PIL import Image logger = logging.getLogger(__name__) TICK_SECONDS = 5 MANUAL_OVERRIDE_SECONDS = 300 # how long "show this now" sticks before falling back to automatic PREVIEW_PATH = Path(__file__).resolve().parent / "web" / "static" / "preview.png" class ScreenCache: """Remembers a screen's last check() result so we don't re-poll faster than its own poll_interval, even if the rotation/tick cadence is tighter.""" def __init__(self): self.state = None self.checked_at: float = 0.0 def is_stale(self, poll_interval: int) -> bool: return (time.time() - self.checked_at) >= poll_interval class Scheduler: def __init__(self, config, screens: dict, display): self.config = config self.screens = screens self.display = display self._caches = {screen_id: ScreenCache() for screen_id in screens} self._rotation_index = 0 self._rotation_switched_at = time.time() self._last_image_hash: str | None = None self._manual_screen: str | None = None self._manual_until: float = 0.0 self._force_once = False self._wake = threading.Event() self._running = False self._thread: threading.Thread | None = None self._status_lock = threading.Lock() self._status = {"current_screen": None, "last_render_at": None, "last_display_write_at": None} # -------------------------------------------------------------- public def start(self): if self._thread and self._thread.is_alive(): return self._running = True self._thread = threading.Thread(target=self._run, daemon=True) self._thread.start() logger.info("Scheduler started") def stop(self): self._running = False self._wake.set() if self._thread: self._thread.join() def request_manual_refresh(self): self._force_once = True self._wake.set() def request_switch(self, screen_id: str): """Pin a screen for MANUAL_OVERRIDE_SECONDS. Navidrome priority can still preempt it if something starts playing -- that's the one thing this app promises to always show reliably -- but rotation won't.""" self._manual_screen = screen_id self._manual_until = time.time() + MANUAL_OVERRIDE_SECONDS self._wake.set() def request_resume_rotation(self): self._manual_screen = None self._wake.set() def get_status(self) -> dict: with self._status_lock: status = dict(self._status) manual_active = bool(self._manual_screen) and time.time() < self._manual_until status["manual_screen"] = self._manual_screen if manual_active else None status["manual_until"] = time.strftime("%H:%M:%S", time.localtime(self._manual_until)) if manual_active else None return status # ------------------------------------------------------------- internal def _run(self): while self._running: try: self._tick() except Exception: logger.exception("Scheduler tick failed") self._wake.wait(timeout=TICK_SECONDS) self._wake.clear() def _tick(self): screen_id, state, did_check = self._select_screen() screen = self.screens[screen_id] settings = self.config.get_screen_settings(screen_id) resolution = self.display.resolution image = screen.render(state, settings, resolution) image_hash = hashlib.sha256(image.tobytes()).hexdigest() self._save_preview(image) with self._status_lock: self._status["current_screen"] = screen_id self._status["last_render_at"] = time.time() if image_hash != self._last_image_hash or self._force_once: logger.info("Content changed (or forced) -- writing to display. screen=%s", screen_id) self.display.show(image) self.display.sleep() self._last_image_hash = image_hash self._force_once = False with self._status_lock: self._status["last_display_write_at"] = time.time() else: logger.debug("No change for screen=%s, skipping display write", screen_id) if did_check: self.config.save() def _select_screen(self) -> tuple[str, object, bool]: """Returns (screen_id, state, did_check_happen). Priority order: Navidrome-when-playing (if enabled) always wins -- that's the one thing this app promises to show reliably. Then a manual "show this now" pin, while it's still within its window. Then normal rotation. """ if self.config.get_navidrome_priority() and "navidrome" in self.screens: screen_id, state, checked = self._poll_screen("navidrome") if state is not None: return screen_id, state, checked if self._manual_screen: if time.time() < self._manual_until: return self._poll_screen(self._manual_screen) self._manual_screen = None # window expired return self._rotation_screen() def _rotation_screen(self) -> tuple[str, object, bool]: rotation = self.config.get_rotation() screen_ids = [s for s in rotation["screens"] if s in self.screens] if not screen_ids: # Nothing configured to rotate through -- fall back to whatever # exists so we're never stuck showing nothing. screen_ids = list(self.screens.keys()) now = time.time() # With rotation disabled, just pin to whatever's currently selected -- # never auto-advance. if rotation.get("enabled", True): interval_seconds = rotation["interval_minutes"] * 60 if now - self._rotation_switched_at >= interval_seconds: self._rotation_index = (self._rotation_index + 1) % len(screen_ids) self._rotation_switched_at = now screen_id = screen_ids[self._rotation_index % len(screen_ids)] return self._poll_screen(screen_id) def _poll_screen(self, screen_id: str) -> tuple[str, object, bool]: cache = self._caches[screen_id] screen = self.screens[screen_id] checked = False if cache.is_stale(screen.poll_interval): cache.state = self._check(screen_id) cache.checked_at = time.time() checked = True return screen_id, cache.state, checked def _check(self, screen_id: str): screen = self.screens[screen_id] settings = self.config.get_screen_settings(screen_id) try: return screen.check(settings) except Exception: logger.exception("check() failed for screen=%s", screen_id) return None def _save_preview(self, image: Image.Image): try: PREVIEW_PATH.parent.mkdir(parents=True, exist_ok=True) image.save(PREVIEW_PATH) except OSError: logger.exception("Could not write preview image")