#!/usr/bin/env python
#
# This code is for Grove - 3-Axis Digital Accelerometer(+/-16g)
#
# which is a low power high performance 3-axis linear accelerometer belonging
# to the "nano" family, with digital I2C serial interface standard output.
#
# This is the library for Grove Base Hat which used to connect grove sensors for raspberry pi.
#

'''
## License

The MIT License (MIT)

Grove Base Hat for the Raspberry Pi, used to connect grove sensors.
Copyright (C) 2018  Seeed Technology Co.,Ltd. 

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.
'''
import smbus
import time
import json
 
bus = smbus.SMBus(1)
 
# ADXL345 device address
ADXL345_DEVICE = 0x53
 
# ADXL345 constants
EARTH_GRAVITY_MS2   = 9.80665
SCALE_MULTIPLIER    = 0.004
 
DATA_FORMAT         = 0x31
BW_RATE             = 0x2C
POWER_CTL           = 0x2D
 
BW_RATE_1600HZ      = 0x0F
BW_RATE_800HZ       = 0x0E
BW_RATE_400HZ       = 0x0D
BW_RATE_200HZ       = 0x0C
BW_RATE_100HZ       = 0x0B
BW_RATE_50HZ        = 0x0A
BW_RATE_25HZ        = 0x09
 
RANGE_2G            = 0x00
RANGE_4G            = 0x01
RANGE_8G            = 0x02
RANGE_16G           = 0x03
 
MEASURE             = 0x08
AXES_DATA           = 0x32
 
class ADXL345:
 
    address = None
 
    def __init__(self, address = ADXL345_DEVICE):
        self.address = address
        self.setBandwidthRate(BW_RATE_100HZ)
        self.setRange(RANGE_2G)
        self.enableMeasurement()
 
    def enableMeasurement(self):
        bus.write_byte_data(self.address, POWER_CTL, MEASURE)
 
    def setBandwidthRate(self, rate_flag):
        bus.write_byte_data(self.address, BW_RATE, rate_flag)
 
    # set the measurement range for 10-bit readings
    def setRange(self, range_flag):
        value = bus.read_byte_data(self.address, DATA_FORMAT)
 
        value &= ~0x0F;
        value |= range_flag;
        value |= 0x08;
 
        bus.write_byte_data(self.address, DATA_FORMAT, value)
 
    # returns the current reading from the sensor for each axis
    #
    # parameter gforce:
    #    False (default): result is returned in m/s^2
    #    True           : result is returned in gs
    def getAxes(self, gforce = False):
        bytes = bus.read_i2c_block_data(self.address, AXES_DATA, 6)
 
        x = bytes[0] | (bytes[1] << 8)
        if(x & (1 << 16 - 1)):
            x = x - (1<<16)
 
        y = bytes[2] | (bytes[3] << 8)
        if(y & (1 << 16 - 1)):
            y = y - (1<<16)
 
        z = bytes[4] | (bytes[5] << 8)
        if(z & (1 << 16 - 1)):
            z = z - (1<<16)
 
        x = x * SCALE_MULTIPLIER
        y = y * SCALE_MULTIPLIER
        z = z * SCALE_MULTIPLIER
 
        if gforce == False:
            x = x * EARTH_GRAVITY_MS2
            y = y * EARTH_GRAVITY_MS2
            z = z * EARTH_GRAVITY_MS2
 
        x = round(x, 4)
        y = round(y, 4)
        z = round(z, 4)
 
        return {"x": x, "y": y, "z": z}
 
if __name__ == "__main__":
    # if run directly we'll just create an instance of the class and output
    # the current readings
    adxl345 = ADXL345()
 
    while True:
        axes = adxl345.getAxes(True)
        print(json.dumps({"x":'{:.3f}'.format(axes['x']), "y":'{:.3f}'.format(axes['y']), "z":'{:.3f}'.format(axes['z'])}))
        # print "ADXL345 on address 0x%x:" % (adxl345.address)
        # print "   x = %.3fG" % ( axes['x'] )
        # print "   y = %.3fG" % ( axes['y'] )
        # print "   z = %.3fG" % ( axes['z'] )
        time.sleep(1)