import time
from typing import Optional


class Tempo(object):
    _last_beat: float
    _override_beat: Optional[float] = None
    
    def __init__(self, bpm: float = 60):
        self._bpm: float = bpm
        self.update_last_beat()
    
    def set_bpm(self, bpm: float) -> None:
        self._bpm = bpm
    
    def get_bpm(self) -> float:
        return self._bpm
    
    def update_last_beat(self) -> None:
        self._last_beat = time.time()
    
    def get_beat_time(self) -> float:
        return 1000 / (self._bpm / 60)
    
    def get_beat_delay(self) -> Optional[float]:
        tick = self._override_beat
        if tick is None:
            return None
        self._override_beat = None
        return tick - self._last_beat
    
    def sync_beat(self):
        self._override_beat = time.time()
        
    def wait(self, beat_divider: int = 1):
        now = time.time()
        next_beat = self._last_beat + (self.get_beat_time() / beat_divider / 1000)
        wait_time = next_beat - now
        beat_delay = self.get_beat_delay()
        if beat_delay is not None:
            wait_time += beat_delay
        if wait_time > 0:
            time.sleep(wait_time)
        self.update_last_beat()
        return True