#!/usr/bin/python

# Python code to read values from Smart Meter via SML (smart message language) 
# created: Alexander Kabza, Mar 1, 2016
# last mod: Alexander Kabza, 2020-03-01
# For documentation and further information see http://www.kabza.de/MyHome/SmartMeter/SmartMeter.html

import sys
import serial
import time
import datetime
import numpy as np


def writexml(t, E, E_feed, P):
    file = open('/var/www/html/SmartMeter.xml', 'w')
    file.write('<SmartMeter>' + 
    '<data name=\"timestamp\" value=\"' + t + '\"  valueunit=\"YYYY-MM-DD hh:mm:ss\"/>' + 
    '<data name=\"energy\" value=\"' + str(E) + '\" valueunit=\"mWh\"/>' + 
    '<data name=\"energy_feed\" value=\"' + str(E_feed) + '\" valueunit=\"mWh\"/>' + 
    '<data name=\"power\" value=\"' + str(P) + '\" valueunit=\"W\"/>' + 
    '</SmartMeter>') 
    file.close()


def writexml15(t, Start, Size, Pmin, Pave, Pmax, Pstddev):
    file = open('/var/www/html/SmartMeter15.xml', 'w')
    file.write('<SmartMeter>' + 
    '<data name=\"timestamp\" value=\"' + t + '\"  valueunit=\"YYYY-MM-DD hh:mm:ss\"/>' + 
    '<data name=\"start\" value=\"' + Start + '\"  valueunit=\"YYYY-MM-DD hh:mm:ss\"/>' + 
    '<data name=\"Size\" value=\"' + str(Size) + '\"  valueunit=\"\"/>' + 
    '<data name=\"15min_min\" value=\"' + str(Pmin) + '\" valueunit=\"W\"/>' + 
    '<data name=\"15min_ave\" value=\"' + str(Pave) + '\" valueunit=\"W\"/>' + 
    '<data name=\"15min_max\" value=\"' + str(Pmax) + '\" valueunit=\"W\"/>' + 
    '<data name=\"15min_stddev\" value=\"' + str(Pstddev) + '\" valueunit=\"W\"/>' + 
    '</SmartMeter>') 
    file.close()


def hex_to_int(hex):
    i = int(hex, 16)
    if i & 0x80000000:    # MSB set -> neg.
        return -((~i & 0xffffffff) + 1)
    else:
        return i




port = serial.Serial(
    port='/dev/ttyAMA0',
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS
)

#port.open();

start = '1b1b1b1b01010101'
end = '1b1b1b1b1a'

data = ''
a = np.empty(0, dtype=float)
now = datetime.datetime.now()
starttimestamp = (now.strftime("%Y-%m-%d ") + now.strftime("%H:%M:%S"))
prevminute = 321

while True:
    char = port.read()
    data = data + char.encode('HEX')
    pos = data.find(end)
    if (pos <> -1):
        for x in range(0, 3):       # read three more byte after end of SML message (checksum etc)
            char = port.read()
            data = data + char.encode('HEX')        
  
        now = datetime.datetime.now()
        timestamp = (now.strftime("%Y-%m-%d ") + now.strftime("%H:%M:%S"))
        result = timestamp

        #ExtendedOutput(data)
    
        search = '77078181c78203ff0101010104'
        pos = data.find(search)
        if (pos <> -1):
            pos = pos + len(search)
            value = data[pos:pos + 6]
            print 'Hersteller-ID:   ' + search + ': ' + value + ' = ' + value.decode('HEX')

        search = '77070100000009ff010101010b'
        pos = data.find(search)
        if (pos <> -1):
            pos = pos + len(search)
            value = data[pos:pos + 20]
            print 'Server-ID:       ' + search + ': ' + value

        energy = 0
        search = '77070100010800ff64'
        pos = data.find(search)
        if (pos <> -1):
            pos = pos + len(search) + 18   # skip 9 Bytes which may be different
            value = data[pos:pos + 16]
            try:
                energy = float(int(value, 16)) / 10
            except:
                energy = 0.0   
            print 'Total Bezug:     ' + search + ': ' + value + ' = ' + str(energy/1e6) + ' kWh'
        result = result + ";" + str(energy)
        
        energy_feed = 0
        search = '77070100020800ff64'
        pos = data.find(search)
        if (pos <> -1):
            pos = pos + len(search) + 18   # skip 9 Bytes which may be different
            value = data[pos:pos + 16]
            try:
                energy_feed = float(int(value, 16)) / 10
            except:
                energy_feed = 0.0
            print 'Total Lieferung: ' + search + ': ' + value + ' = ' + str(energy_feed/1e6) + ' kWh'
        result = result + ";" + str(energy_feed)
            
        power = 0
        search = '77070100100700ff0101621b52fe59'
        pos = data.find(search)
        if (pos <> -1):
            pos = pos + len(search)
            value = data[pos:pos + 16]
            try:
                power = float(hex_to_int(value)) / 100
            except:
                power = 0.0
            print 'Leistung:        ' + search + ': ' + value + ' = ' + str(power) + ' W'
        result = result + ";" + str(power)

        a = np.append(a, power)
        
        now = datetime.datetime.now()
        currentminute = now.minute
        if (currentminute % 15 == 0) and (prevminute <> currentminute):
            prevminute = currentminute
            writexml15(timestamp, starttimestamp, a.size, np.amin(a), np.average(a), np.amax(a), np.std(a)) 
            a = np.empty(0, dtype=float)
            now = datetime.datetime.now()
            starttimestamp = (now.strftime("%Y-%m-%d ") + now.strftime("%H:%M:%S"))
        
        writexml(timestamp, energy, energy_feed, power) 
                
        data = ''