import digitalio
import time

from car_os.system_clock import SystemClock

    
class PPSClock:
    def __init__(self, pin):
        self._system_clock = SystemClock()
        self.pin = pin
        self.gpio = digitalio.DigitalInOut(self.pin)
        self.gpio.direction = digitalio.Direction.INPUT
        self.previous_value = self.gpio.value
        self.current_value = self.gpio.value
        self._pps_timestamp = 0
        self._pps_time_ns = time.monotonic_ns()
        self.gps_set = False
        self._pps_offset = [0, 0, 0, 0]
        self._gps_utc = [0, 0, 0]
        self._system_time = (0, 0, 0, 0)
        self._previous_timestamp = 0
        self._previous_utc_h = 0
        
    def update(self):
        self._system_clock.update()
        self.current_value = self.gpio.value
        if not self.current_value and self.previous_value:
            self._pps_timestamp = self._system_clock.utc_timestamp
            self._gps_utc[2] = self._gps_utc[2] + 1
            self._pps_time_ns = time.monotonic_ns()
        self.previous_value = self.current_value
        current_timestamp = self.utc_timestamp
        if self._previous_utc_h == 23 and self.utc_time[0] == 0:
            current_timestamp += 86400
        delta = current_timestamp - self._previous_timestamp
        self._previous_timestamp = current_timestamp
        self._previous_utc_h = self.utc_time[0]
        return max(0, delta)
    
    def update_utc_from_gps(self, gps):
        self._gps_utc[0] = gps.time[0]
        self._gps_utc[1] = gps.time[1]
        self._gps_utc[2] = gps.time[2]
        gps.time_updated = False
        self.gps_set = True
    
    def update_gps_fixed(self, has_fix):
        self.gps_set = has_fix
    
    @property
    def utc_time(self):
        s = self._system_clock.utc_timestamp - self._pps_timestamp
        ns = s % 1
        s = int(s - ns)
        m, s = divmod(self._gps_utc[2] + s, 60)
        h, m = divmod(self._gps_utc[1] + m, 60)
        _, h = divmod(self._gps_utc[0] + h, 24)
        return (h, m, s, ns*1e9)
    
    @property
    def utc_timestamp(self):
        return self.utc_time[0] * 3600 + self.utc_time[1] * 60 + self.utc_time[2] + (self.utc_time[3] / 1_000_000_000)

    @property
    def update_time_ns(self):
        return self._pps_time_ns