# Author: Paul Cunnane 2016
#
# This module borrows heavily from the Adafruit BME280 Python library
# and the Adafruit GPIO/I2C library. Original copyright notices are reproduced
# below.
#
# Those libraries were written for the Raspberry Pi. This modification is
# intended for the MicroPython and esp8266 boards.
#
# Copyright (c) 2014 Adafruit Industries
# Author: Tony DiCola
#
# Based on the BMP280 driver with BME280 changes provided by
# David J Taylor, Edinburgh (www.satsignal.eu)
#
# Based on Adafruit_I2C.py created by Kevin Townsend.
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

class Device:
    """Class for communicating with an I2C device.

    Allows reading and writing 8-bit, 16-bit, and byte array values to
    registers on the device."""

    def __init__(self, address, i2c):
        """Create an instance of the I2C device at the specified address using
        the specified I2C interface object."""
        self._address = address
        self._i2c = i2c

    def writeRaw8(self, value):
        """Write an 8-bit value on the bus (without register)."""
        buf = bytearray(1)
        buf[0] = value & 0xFF
        self._i2c.writeto(self._address, buf)

    def write8(self, register, value):
        """Write an 8-bit value to the specified register."""
        buf = bytearray(1)
        buf[0] = value & 0xFF
        self._i2c.writeto_mem(self._address, register, buf)

    def readRaw8(self):
        """Read an 8-bit value on the bus (without register)."""
        return int.from_bytes(self._i2c.readfrom(self._address, 1)) & 0xFF

    def readU8(self, register):
        """Read an unsigned byte from the specified register."""
        return int.from_bytes(
            self._i2c.readfrom_mem(self._address, register, 1)) & 0xFF

    def readS8(self, register):
        """Read a signed byte from the specified register."""
        result = self.readU8(register)
        if result > 127:
            result -= 256
        return result

    def readU16(self, register, little_endian=True):
        """Read an unsigned 16-bit value from the specified register, with the
        specified endianness (default little endian, or least significant byte
        first)."""
        result = int.from_bytes(
            self._i2c.readfrom_mem(self._address, register, 2)) & 0xFFFF
        if not little_endian:
            result = ((result << 8) & 0xFF00) + (result >> 8)
        return result

    def readS16(self, register, little_endian=True):
        """Read a signed 16-bit value from the specified register, with the
        specified endianness (default little endian, or least significant byte
        first)."""
        result = self.readU16(register, little_endian)
        if result > 32767:
            result -= 65536
        return result

    def readU16LE(self, register):
        """Read an unsigned 16-bit value from the specified register, in little
        endian byte order."""
        return self.readU16(register, little_endian=True)

    def readU16BE(self, register):
        """Read an unsigned 16-bit value from the specified register, in big
        endian byte order."""
        return self.readU16(register, little_endian=False)

    def readS16LE(self, register):
        """Read a signed 16-bit value from the specified register, in little
        endian byte order."""
        return self.readS16(register, little_endian=True)

    def readS16BE(self, register):
        """Read a signed 16-bit value from the specified register, in big
        endian byte order."""
        return self.readS16(register, little_endian=False)