#!/usr/bin/python
# ---------------------------------------------------------------------
#    ___  ___  _ ____
#   / _ \/ _ \(_) __/__  __ __
#  / , _/ ___/ /\ \/ _ \/ // /
# /_/|_/_/  /_/___/ .__/\_, /
#                /_/   /___/
#
#           bh1750.py
# Read data from a BH1750 digital light sensor.
#
# Author : Matt Hawkins
# Date   : 26/06/2018
#
# For more information please visit :
# https://www.raspberrypi-spy.co.uk/?s=bh1750
#
# ---------------------------------------------------------------------
import smbus
import time
import writefile
import datetime

# Define some constants from the datasheet

DEVICE = 0x23  # Default device I2C address

POWER_DOWN = 0x00  # No active state
POWER_ON = 0x01  # Power on
RESET = 0x07  # Reset data register value

# Start measurement at 4lx resolution. Time typically 16ms.
CONTINUOUS_LOW_RES_MODE = 0x13
# Start measurement at 1lx resolution. Time typically 120ms
CONTINUOUS_HIGH_RES_MODE_1 = 0x10
# Start measurement at 0.5lx resolution. Time typically 120ms
CONTINUOUS_HIGH_RES_MODE_2 = 0x11
# Start measurement at 1lx resolution. Time typically 120ms
# Device is automatically set to Power Down after measurement.
ONE_TIME_HIGH_RES_MODE_1 = 0x20
# Start measurement at 0.5lx resolution. Time typically 120ms
# Device is automatically set to Power Down after measurement.
ONE_TIME_HIGH_RES_MODE_2 = 0x21
# Start measurement at 1lx resolution. Time typically 120ms
# Device is automatically set to Power Down after measurement.
ONE_TIME_LOW_RES_MODE = 0x23

# bus = smbus.SMBus(0) # Rev 1 Pi uses 0
bus = smbus.SMBus(1)  # Rev 2 Pi uses 1


def convertToNumber(data):
    # Simple function to convert 2 bytes of data
    # into a decimal number. Optional parameter 'decimals'
    # will round to specified number of decimal places.
    result = (data[1] + (256 * data[0])) / 1.2
    return (result)


def readLight(addr=DEVICE):
    # Read data from I2C interface
    data = bus.read_i2c_block_data(addr, ONE_TIME_HIGH_RES_MODE_1)
    return convertToNumber(data)


def main(Luz_ant):

    suma_luz = 0
    suma_ant = Luz_ant

    try:

        lightLevel = readLight()
        suma_luz = float(lightLevel)

        if suma_luz > 0:

            # Enviamos a la web cuando hay cambios del +-5%

            if suma_luz > suma_ant+(suma_ant*5/100) or suma_luz < suma_ant - (suma_ant*5/100):

                # Generamos la hora
                utc = datetime.datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S')

                suma_ant = suma_luz
                print("LUZ")
                print("---")
                print(utc)
                print("L " + str(suma_luz))
                print("")

                # Redondeamos a 2 decimales para que la BBDD guarde bien los datos
                writefile.setfile("luz", round(suma_luz, 2))

        else:
            print("error Revisa el Sistema de Fotoresistor")

        time.sleep(5)
    except (KeyboardInterrupt, SystemExit):
        raise

    return(suma_ant)


if __name__ == "__main__":
    main()