import time
import os, sys
from datetime import datetime
import RPi.GPIO as GPIO
import matplotlib.pyplot as plt

class SousVide:
    '''
    target: Float. Target temperature in degree Celsius
    interval: Float. Time between measurements in seconds
    timeFrame: int. Length of history in view in minutes
    '''
    def __init__(self, target=50.0, interval=5.0, timeFrame=60):
        now = datetime.now().replace(microsecond=0).time()
        print "SousVide started at " + str(now)
        print "Init target temperature set at " + str(target) + " degree Celsius"

        # Set the correct GPIO pin to 'off'
        GPIO.setmode(GPIO.BOARD)
        GPIO.setup(36, GPIO.OUT)
        GPIO.output(36, GPIO.LOW)

        # Search for the sensor
        busDir = "/sys/bus/w1/devices/"
        self.sensDir = ""
        try:
            for root, dirs, files in os.walk(busDir):
                for d in dirs:
                    if d.startswith('w1_bus_master'):
                        continue
                    else:
                        self.sensDir = busDir + d + "/"
                        print "Found sensor!"
        except Exception as e:
            print e
            print "Error: Thermo sensor not found."
            print "Exiting..."
            sys.exit()
            

        # Heater
        self.heaterStatus = False
        
        # Temperature
        self.interval = interval # in seconds
        self.frameSize = int(timeFrame * 60 / self.interval)
        self.tempHistory = [1.0] * self.frameSize
        self.tempHistoryTime = [str(now)] * self.frameSize
        self.heaterHistory = [0] * self.frameSize
        self.curTemp = 0.0
        self.target = target

        # Plotting
        self.plotFrameSize = self.frameSize
        self.figure, self.ax = plt.subplots()
        self.ax2 = self.ax.twinx()
        plt.xticks(range(self.plotFrameSize), self.tempHistoryTime, rotation=45)
        #plt.locator_params(axis='x', nbins=5)
        self.plotLine, = self.ax.plot(range(self.plotFrameSize), self.tempHistory, "r-")
        self.plotLineH, = self.ax2.plot(range(self.plotFrameSize), self.heaterHistory, "b-")

        plt.title("Temp. History")
        plt.grid(True)
        
        self.ax.set_ylabel('Degree (C)')
        self.ax.set_xlabel('Time')
        self.ax.set_ylim((20,(self.target + 15)))

        self.ax2.set_ylabel('Heater (On/Off)')
        self.ax2.set_xlabel('Time')
        self.ax2.set_ylim([-1,2])
        self.ax2.set_yticks(range(4), ["", "Off", "On" , ""])
        
        plt.show(block=False)
        print "Initial plot created"
        print "Start measuring..."


    def getTemp(self):
    	""" Read sensor data and return temperature float """
        sensData = open(self.sensDir + "w1_slave", "r").read()
        sensData = sensData.split("\n")[1]
        temp = sensData[sensData.find("t=")+2:]
        return float(temp)


    def plotTemp(self):
        plt.xticks(range(self.plotFrameSize), self.tempHistoryTime[-(self.plotFrameSize):], rotation=45)
        self.plotLine.set_xdata(range(self.plotFrameSize))
        self.plotLine.set_ydata(self.tempHistory[-(self.plotFrameSize):])
        self.plotLineH.set_ydata(self.heaterHistory[-(self.plotFrameSize):])
        self.figure.canvas.draw()


    def enableHeater(self):
        GPIO.output(36, GPIO.HIGH)
        self.heaterStatus = True


    def disableHeater(self):
        GPIO.output(36, GPIO.LOW)
        self.heaterStatus = False

        
    def cook(self):
        try:
            while 1:
                now = datetime.now().replace(microsecond=0).time()
                self.curTemp = self.getTemp() / 1000
                print "Temperature is: " + str(self.curTemp) + " C"
                
                self.tempHistory.append(self.curTemp)
                self.tempHistoryTime.append(str(now))

                if (self.curTemp < self.target) and not self.heaterStatus:
                    diff = self.target - self.curTemp
                    print "Temperature difference to target temp. is: " + str(diff)
                    print ">> Activate heater"
                    
                    self.enableHeater()

                elif (self.curTemp >= self.target) and self.heaterStatus:
                    diff = self.target - self.curTemp
                    print "Temperature difference to target temp. is: " + str(diff)
                    print ">> Deactivate heater"

                    self.disableHeater()

                else:
                    print ""

                self.heaterHistory.append(int(self.heaterStatus))

                self.plotTemp()
                time.sleep(self.interval)
                
        except KeyboardInterrupt:
            GPIO.output(36, GPIO.LOW)
            print ""
            print "Thanks for cooking with me."
            print "Adios!"
            GPIO.cleanup()


    def brokenPipe(self):
    	# not sure if this works, not tried yet...
    	with open('error.log', 'a') as eLog:
    			elog.write(str(datetime.now()) + "\n")
    			elog.write("Died at", self.curTemp, "degrees.\n" )
    	GPIO.output(36, GPIO.LOW)
        print ""
        print "SSH connection died. Trying not to heat until boiling :("
        print "Ciao"
        GPIO.cleanup()


# Lets go
sv = SousVide(target=58.0, interval=5.0, timeFrame=60)
sv.cook()

# This is basically just for the case the SSH connection dies...
import atexit
atexit.register(sv.brokenPipe())