"""LSM6DS3 accelerometer / gyroscope over I2C (MicroPython)."""

import struct

WHO_AM_I_REG = 0x0F
WHO_AM_I_LSM6DS3 = 0x69

CTRL1_XL = 0x10
CTRL2_G = 0x11
OUT_TEMP_L = 0x20

# Default CTRL1_XL = 0x60: 104 Hz ODR, ±2 g, anti-aliasing filter BW ~100 Hz
# Default CTRL2_G = 0x40: 104 Hz ODR, 245 dps full scale
_DEFAULT_XL = b"\x60"
_DEFAULT_G = b"\x40"

# LSB scaling for default full-scale settings above
_G_PER_LSB = 0.000061
_DPS_PER_LSB = 0.00875


def is_lsm6ds3(who_am_i: int) -> bool:
    return who_am_i == WHO_AM_I_LSM6DS3


class LSM6DS3:
    def __init__(self, i2c, addr=0x6A):
        self.i2c = i2c
        self.addr = addr

    def who_am_i(self) -> int:
        return self.i2c.readfrom_mem(self.addr, WHO_AM_I_REG, 1)[0]

    def configure(self, ctrl1_xl=_DEFAULT_XL, ctrl2_g=_DEFAULT_G) -> None:
        self.i2c.writeto_mem(self.addr, CTRL1_XL, ctrl1_xl)
        self.i2c.writeto_mem(self.addr, CTRL2_G, ctrl2_g)

    def read_raw(self):
        """Returns (temp_raw, gx, gy, gz, ax, ay, az) as signed 16-bit values."""
        data = self.i2c.readfrom_mem(self.addr, OUT_TEMP_L, 14)
        return struct.unpack("<hhhhhhh", data)

    def read(self):
        """
        Scaled readings for default ±2 g / 245 dps configuration.

        Returns:
            temp_c: float, degrees C
            accel_g: (ax, ay, az) in g
            gyro_dps: (gx, gy, gz) in degrees per second
        """
        temp, gx, gy, gz, ax, ay, az = self.read_raw()
        temp_c = 25.0 + temp / 16.0
        accel_g = (
            ax * _G_PER_LSB,
            ay * _G_PER_LSB,
            az * _G_PER_LSB,
        )
        gyro_dps = (
            gx * _DPS_PER_LSB,
            gy * _DPS_PER_LSB,
            gz * _DPS_PER_LSB,
        )
        return temp_c, accel_g, gyro_dps