#!/usr/bin/python

# sudo apt-get install python3-rpi.gpio
from RPi import GPIO
from datetime import datetime
import time

ss = 0 # start time stamp
ls = 0 # last time stamp 

# returns the elapsed milliseconds since the start of the program
def millis():
    dt = datetime.now() 
    ms =  dt.minute * 60 *1000 + dt.second * 1000 + dt.microsecond / 1000
    return int(ms)

def mark(tick):
    print("\t", end="")
    for i in range(tick):
        if i > 100:
            break
        if i == 34:
            print (">", end="")
        elif i== 42:
            print ("<", end="")
        elif i== 56:
            print (">", end="")
        elif i== 68:
            print ("<", end="")
        elif i== 100:
            print ("%", end="")
        else:
            print (".", end="")
    print()
            
            
        

channel = 24
GPIO.setmode(GPIO.BCM)
GPIO.setup(channel, GPIO.IN, pull_up_down=GPIO.PUD_UP)


def main():
    global ss,ls,channel
    try:
        while True:
            success = GPIO.wait_for_edge(channel, GPIO.FALLING, timeout = 50)
            if success is None:
                continue
            print("start")
            ss=0
            while not success is  None:
                ls = millis() 
                if ss == 0:
                    ss= ls
                # wait for up to 5 seconds for a rising edge (timeout is in milliseconds)
                success = GPIO.wait_for_edge(channel, GPIO.RISING, timeout=1000)
                ts1 = millis()
                
                print ('H {} {} ' . format(ts1-ss, ts1-ls), end="")
                mark(ts1-ls)
                ls = ts1
                if not success is None:
                    success = GPIO.wait_for_edge(channel, GPIO.FALLING, timeout=1000)
                    if not success is None:
                        ts2 = millis()
                        print ('L {} {} ' . format(ts2-ss, ts2-ls), end="" )
                        mark(ts2-ls)

    except KeyboardInterrupt: # does not work if it runs in background.
        print ("\nQuit")

if __name__ == '__main__':
    main()
    GPIO.cleanup()