import time


class SHT41:
    DEFAULT_ADDR = 0x44
    CMD_MEASURE_HIGH_PRECISION = 0xFD

    def __init__(self, i2c, addr=DEFAULT_ADDR):
        self.i2c = i2c
        self.addr = addr
        # Soft reset
        self.i2c.writeto(self.addr, b"\x94")
        time.sleep(0.01)

    def read_values(self):
        # Trigger high precision measurement
        self.i2c.writeto(self.addr, bytes([self.CMD_MEASURE_HIGH_PRECISION]))
        # Conversion takes up to 8.2ms
        time.sleep(0.01)

        # 6 bytes: [Temp_MSB, Temp_LSB, CRC, Hum_MSB, Hum_LSB, CRC]
        data = self.i2c.readfrom(self.addr, 6)

        raw_t = (data[0] << 8) | data[1]
        raw_h = (data[3] << 8) | data[4]

        # Sensirion SHT4x conversion equations
        temp = -45.0 + 175.0 * (raw_t / 65535.0)
        hum = -6.0 + 125.0 * (raw_h / 65535.0)
        hum = max(0.0, min(hum, 100.0))

        return {
            "temperature": round(temp, 2),
            "humidity": round(hum, 2),
            "pressure": None,
        }