#! /usr/bin/env python
# -*- coding: utf-8 -*-

import subprocess
import time
import datetime
import RPi.GPIO as GPIO
import math
import Si7021
import pigpio

MIN_FEUCHTE_INNEN=65
MAX_FEUCHTE_INNEN=70
MAX_TEMP_INNEN=26
MIN_TEMP_INNEN=15
ABS_DIFF_LOWTEMP=3
ABS_DIFF_HIGHTEMP=1
TEMP_LOW_HIGH=13

#Feuchteberechnung
a = 6.112
b = 17.67
c = 243.5
def svp(t):
    svp = a * math.exp((b*t)/(c+t))
    return svp
def vp(rh, t):
    vp = rh/100. * svp(t)
    return vp
# Compute the absolute humidity in g/m³
def ah(rh, t):
    mw = 18.016 # kg/kmol (Molekulargewicht des Wasserdampfes)
    rs = 8314.3 # J/(kmol*K) (universelle Gaskonstante)
    ah = 10**5 * mw/rs * vp(rh, t)/(t + 273.15)
    return ah

def fan_on():
    GPIO.output(12, GPIO.LOW)
    print("FAN ON")

def fan_off():
    GPIO.output(12, GPIO.HIGH)
    print("FAN OFF")

def sensor_off():
    GPIO.output(32, GPIO.HIGH)
    GPIO.output(36, GPIO.HIGH)
    GPIO.output(37, GPIO.HIGH)
    print("SENSOR OFF")

def read_sensor(pin):
    #print pin
    GPIO.output(pin, GPIO.LOW)
    time.sleep(1)
    pi = pigpio.pi()
    s = Si7021.sensor(pi)
    s.set_resolution(0)
    temp = s.temperature()
    humi = s.humidity()
    s.cancel()
    pi.stop()
    GPIO.output(pin, GPIO.HIGH)
    time.sleep(1)
    return (humi, temp)

def main():
    print "Feuchtesteuerung V0.2"
    print"Init"
    time.sleep(1)
    # Mount xfer from nas for logging
    subprocess.call(["/home/pi/./smbmount.sh"])

    # Disable GPIO Warnings
    GPIO.setwarnings(False)
    # RPi.GPIO Layout verwenden (wie Pin-Nummern)
    GPIO.setmode(GPIO.BOARD)
    # Pin 12 (GPIO 18) auf Output setzen
    GPIO.setup(12, GPIO.OUT)
    # Pin 28 (GPIO    1) auf Output setzen
    GPIO.setup(32, GPIO.OUT)
    # Pin 32 (GPIO 12) auf Output setzen
    GPIO.setup(36, GPIO.OUT)
    # Pin 36 (GPIO 16) auf Output setzen
    GPIO.setup(37, GPIO.OUT)

    # Datei für Messwerte erstellen
    file = datetime.datetime.now().isoformat()
    f = open('/mnt/ramdisk/'+file+'.log', 'w')
    f.write('Zeitstempel;Innen-Temp1;Innen-Temp2;Außen-Temp;rel-Feuchte1;rel-Feuchte2;rel-Außen;abs-Feuchte1;abs-Feuchte2;abs-Außen;abs-Diff;Lüfterfreigabe;Lüftersperre;Lüfterstatus\n')
    f.close()

    fan_off()
    sensor_off()

    fan_lock = 0
    fan_status = 0
    fan_enable = 0
    fan_count = 0
    time_count = 0
    restart_counter=0

    print "running"

    while 1:
        # Zähler für Zeitsteuerung
        time_count += 1
        # Zähler für Lüfterinterval
        fan_count += 1
        # akteullen Zeitstempel speichern
        timestamp = datetime.datetime.now().isoformat()

        # Sensoren abfragen
        rha, ta = read_sensor(32)
        #print rha, ta
        rhi1, ti1 = read_sensor(36)
        #print rhi1, ti1
        rhi2, ti2 = read_sensor(37)
        #print rhi2, ti2

        # Prüfe auf fehlerhafte Sensorwerte
        if rha is None or ta is None or rha > 120:
            print "rha error"
            # Warte bis zur nächsten Messung
            time.sleep(53.35)
            continue
        if rhi1 is None or ti1 is None or rhi1 > 120:
            print "rhi1 error"
            # Warte bis zur nächsten Messung
            time.sleep(53.35)
            continue
        if rhi2 is None or ti2 is None or rhi2 > 120:
            print "rhi2 error"
            # Warte bis zur nächsten Messung
            time.sleep(53.35)
            continue

        # Absolute Feuchte berechnen
        ahi1 = ah(rhi1,ti1)
        ahi2 = ah(rhi2,ti2)
        aha = ah(rha,ta)
        ti = ti1
        rhi = rhi1
        ahi = ahi1
        if ahi1 < ahi2:
            ti = ti2
            rhi = rhi2
            ahi = ahi2

        rhi = round(rhi,1)
        ti    = round(ti,1)
        ahi = round(ahi,1)
        rhi1 = round(rhi1,1)
        ti1    = round(ti1,1)
        ahi1 = round(ahi1,1)
        rhi2 = round(rhi2,1)
        ti2    = round(ti2,1)
        ahi2 = round(ahi2,1)
        rha = round(rha,1)
        ta    = round(ta,1)
        aha = round(aha,1)
        diff = ahi - aha

        # Lüfterstatus prüfen
        if GPIO.input(12):
            fan_status_real = 0
        else:
            fan_status_real = 1

        # Feuchte Differenz prüfen
        if (ahi - aha) > ABS_DIFF_LOWTEMP or ( (ahi - aha) > ABS_DIFF_HIGHTEMP and ta > TEMP_LOW_HIGH ):
            # draußen trockener: grundsätzliche Lüfterfreigabe
            if fan_enable < 3:
                fan_enable += 1
            # Zusatzbedingungen prüfen:
            if rhi < MIN_FEUCHTE_INNEN or ti < MIN_TEMP_INNEN or ti > MAX_TEMP_INNEN:
                fan_enable = 0
                #print "trocken genug oder zu warm/kalt innen"
            if rhi > MAX_FEUCHTE_INNEN:
                if fan_enable < 3:
                    fan_enable += 1
                #print "zu feucht"
        # feuchter draußen: Lüfterfreigabe AUS
        else:
            fan_enable = 0

        # Prüfe 20 minütige Lüftersperre, Lüfter aus
        if fan_lock > 0:
            if not fan_count % 20:
                fan_count = 0
                if fan_status == 1:
                    fan_off()
                    fan_status = 0
                else:
                    fan_lock -= 1

        # Lüfter einschalten
        if fan_lock == 0:
            if fan_enable > 2:
                if fan_status == 0 and fan_status_real == 0:
                    fan_on()
                    fan_status = 1
                    fan_lock = 2
                    fan_count = 0

        # Lüfterstatus prüfen
        if GPIO.input(12):
            fan_status_real = 0
        else:
            fan_status_real = 1

        # Messwerte abspeichern
        f = open('/mnt/ramdisk/'+file+'.log', 'a')
        f.write(timestamp)
        f.write(';')
        f.write(str(ti1))
        f.write(';')
        f.write(str(ti2))
        f.write(';')
        if ta < 10:
            f.write(' ')
        f.write(str(ta))
        f.write(';')
        f.write(str(rhi1))
        f.write(';')
        f.write(str(rhi2))
        f.write(';')
        f.write(str(rha))
        f.write(';')
        if ahi1 < 10:
            f.write(' ')
        f.write(str(ahi1))
        f.write(';')
        if ahi2 < 10:
            f.write(' ')
        f.write(str(ahi2))
        f.write(';')
        if aha < 10:
            f.write(' ')
        f.write(str(aha))
        f.write(';')
        if diff >= 0:
            f.write(' ')
        f.write(str(diff))
        f.write(';')
        f.write(str(fan_enable))
        f.write(';')
        f.write(str(fan_lock))
        f.write(';')
        if fan_status_real == 1:
            f.write('EIN')
        else:
            f.write('AUS')
        f.write('\n')
        f.close()

        # Daten alle 10 Minuten auf NAS synchroniseren
        if not time_count % 10:
            subprocess.Popen(["/home/pi/./syncdata.sh"])

        # Warte bis zur nächsten Messung
        time.sleep(53.35)

if __name__ == '__main__':
    main()