import serial   # Not a standard Python library. This will need to be installed
                # using 'pip install PySerial'
import csv
from datetime import datetime as dt
from collections import deque   # Used for circular array

#portname = input('Enter COM Port name: ')   
#baud = input('Baud Rate: ')
portname = 'COM3'  # Change to suit port allocation/ Linux/Windows
baud = 9600
buffer = deque([],10)       # Circular array, empty, size: 10
timebuffer = deque([],10)   # Another...

# Set up CSV file with name as current YYYY-MM-DD-HH-MM.csv
filename = str(dt.now().strftime('%Y-%m-%d-%H%M') + '.csv')
#filename = 'test.csv'
myCSV = open(filename, 'a', newline = '') # Open my file object for appending ('a')
myWriter = csv.writer(myCSV, dialect = 'excel')

# Attempt to open serial port
try:
    ser = serial.Serial(portname, baud, timeout = 1)
    if ser.isOpen():    # Courtesy message, print date & time, serial port name
        print((ser.port) + ' is open...')
        print('START data collection.  Press [Ctrl]+[C] to abort.')
        # Write Date & time to CSV
        myWriter.writerow([dt.now().isoformat(' '),'START data collection'])
# Catch exceptions: wrong name, baud, serial errors etc
except NameError:
    print('Fail.... NameError')
except ValueError:
    print('ValueError: Param(s) out of range.')
except serial.SerialException:
    print('Serial Exception at ' + dt.now().isoformat(' '))
    
try:
    ser.reset_input_buffer()
    for n in range(10):         # Loop x10
        readIN = ser.read(1)    # Read IN 1 byte
        if len(readIN) != 0:    # If data read from Rx buffer
            buffer.append(ord(readIN))  # Add to deque circular array
            #print(ord(readIN))
            timebuffer.append(dt.now().isoformat(' '))
#    for n in range(10):
#        print(timebuffer[n],buffer[n])
    while ser.readable():
        ser.reset_input_buffer()    # Clear Rx buffer
        data = ser.read(1)          # Read 1 byte
        buffer.append(ord(ser.read(1)))
        timebuffer.append(dt.now().isoformat(' '))
        if len(data)>0:
            #print(ord(data))   # For debugging only
            #print(~ord(data) & 255)    #   Bitwise inversion of 'data'
            buffer.append(ord(data))
            timebuffer.append(dt.now().isoformat(' '))
            # If current result is +- 1 from last result
            if (buffer[9] > buffer[8] + 1) or (buffer[9] < (buffer[8]-1)):
                print(dt.now().isoformat(' '), buffer[9])
                # Save last 10 results & timestamps to file
                for n in range(10):
                    print(timebuffer[n], buffer[n])
                    myWriter.writerow([dt.now().isoformat(' '), buffer[n]])
# Catch serial port errors
except serial.SerialException:
    pass
# Wait for <Ctrl>+<X>
except (KeyboardInterrupt, SystemExit):
    pass

# Close file
myWriter.writerow([dt.now().isoformat(' '),'END data collection'])
myCSV.close()

# Close serial port
try:
    ser.close()
    ser.__del__()
except NameError:
    print('No open port to close')
#exit()