#!/usr/bin/python3

#
# load some data into the Flash on the test board
#

# read in the command args


from argparse import ArgumentParser
import serial
import string
#import binascii
import time
from datetime import datetime

parser = ArgumentParser()
parser.add_argument("-f", "--file", dest="filename",
			help="write report to FILE", metavar="FILE")

parser.add_argument("-p", "--port", dest="port", default="/dev/ttyACM0",
			help="serial port device")

parser.add_argument("-t", "--test",
                    action="store_true", dest="test", default=False,
                    help="load a default page")

args = parser.parse_args()
print ("args:%s:%s" % (type(args),str(args)))

page = bytearray(256)

# https://stackoverflow.com/questions/69369408/calculating-crc16-in-python-for-modbus
def modbusCrc(msg:str) -> int:
    crc = 0xFFFF
    for n in range(len(msg)) :
        crc ^= msg[n]
        for i in range(8) :
            if crc & 1 :
                crc >>= 1
                crc ^= 0xA001
            else :
                crc >>= 1
    return crc


def print_page (data) :
	ascii = ""
	print ("00 : ", end="")
	printable = string.ascii_letters + string.digits + string.punctuation + " "
	for b in range(256) :
		if b > 0 and b % 16 == 0 :
			print (": %s\n%02X : " % (ascii,b), end="")
			ascii = ""
		if chr(data[b]) in printable :
			ascii += chr(data[b])
		else :
			ascii += "."
		print ("%02X " % (data[b]), end="")
	print (": %s" % (ascii))

def open_port () :
	port = serial.Serial (args.port, 115200, timeout=1, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE)
	time.sleep(1)
	text = ""
	print ("init.")
	while True :
		bytesToRead = port.inWaiting()
		if bytesToRead > 0 : 
			print ("bytes =",bytesToRead)
			text += port.read(bytesToRead).decode()
			print ("text = %s = \"%s\"" % (type(text),text))
			time.sleep(0.1)
			if "code.py" in text or "REPL" in text :
				print ("send ctrl<d>")
				port.write( b'\x04' );
				time.sleep (3)
		else :
			break
	return port

def read_port (port, stop=False) :		# get one line from the serial port
	text = ""
	cnt = 250
	while True :					# wait for something to arrive
		bytesToRead = port.inWaiting()
		if bytesToRead > 0 :
			break
		else :
			time.sleep(0.1)
			cnt -= 1
			if cnt == 0 : 
				return ""
	cnt = 5
	while (cnt > 0) :			# read the line
		bytesToRead = port.inWaiting()
		if bytesToRead > 0 :
			#print ("bytes =", bytesToRead, end=" ")
			ch = port.read(1).decode()
			if ch == "\r" or ch == "\n" : 		# we get both CR and LF
				if stop :
					break
				else :
					continue
			text += ch.upper()
		else :
			time.sleep (0.05)
			cnt -= 1
	#print (f"read_port()  text = \"{text}\"")
	return text

def check_connection (port) :
	ok = False
	for tries in range(10) :
		print ("sending AT")
		port.write("AT\r".encode())		# what is writen gets echoed
		time.sleep(0.5)
		text = read_port (port)
		print ("   ",text)
		ok = (text == "OK ATTENTION") 
		if ok : break					# stop trying when OK
		time.sleep(1)					# one second between tries
	return ok

def write_test_page () :
	port = open_port()
	ok = check_connection(port)
	print ("ok =",ok)
	if ok :
		port.write("WRITE\r".encode())
		resp = read_port (port)
		print (f"WRITE = \"{resp}\"")
		ok = (resp == "OK")
	if ok :
		port.write ("ADDRESS:0\r".encode())
		resp = read_port (port)
		print (f"ADDRESS = \"{resp}\"")
		ok = (resp == "OK")
	if ok :
		for x in range(16) :
			def my_hex (num) :
				return hex(num)[2:]				# remove the '0x'
			text = ",".join(map(my_hex,page[(x * 16):(x * 16)+16]))
			text += "\r"
			port.write(text.encode())
			resp = read_port (port)
			print (f"DATA = \"{resp}\"")
			ok = resp.startswith("OK")
			if not ok : break
	if ok :
		port.write (f"CRC:{hex(crc)}\r".encode())
		resp = read_port (port)
		print (f"CRC = \"{resp}\"")
		ok = resp.startswith("OK")
	port.close()

def read_page (page) :
	port = open_port()
	ok = check_connection(port)
	print ("ok =",ok)
	if ok :
		port.write ("READ\r".encode())
		resp = read_port (port)
		print (f"READ = \"{resp}\"")
		ok = resp.startswith("OK")
	if ok :
		print (f"reading page {page}")
		port.write (f"ADDRESS:{page}\r".encode())
		arr = []
		while len(arr) < 256 :
			resp = read_port (port, stop=True)
			if len(resp) == 0 : continue
			arr += [int(h.strip(),16) for h in resp.split(",")]
		print_page (arr)


def erase_chip () :
	port = open_port()
	ok = check_connection(port)
	print ("ok =",ok)
	if ok :
		port.write ("ERASE\r".encode())
		resp = read_port (port)
		print (f"ERASE = \"{resp}\"")
		ok = resp.startswith("OK")
	


if args.test :
	print ("testing")
	for x in range(256) :			# a page of number from 0 -> 0xFF
		if x < 128 :
			page[x] = x;
		else :
			page[x] = 0xFF;
	now = datetime.now().strftime("%d/%m/%Y %H:%M:%S")
	for n in range(len(now)) :
		page[n + 0xA0] = ord(now[n])
	print_page (page)
	crc = modbusCrc(page)		# work out the crc for the page
	print ("crc = $%04X" % (crc))
	print ("port =",args.port)
	erase = input("Do you want to erase chip [y/N] ?")
	if erase.upper() == "Y" :
		erase_chip()
	write = input("Do you want to write page zero [y/N] ?")
	if write.upper() == "Y" :
		write_test_page()
	read_page (0)
	
else :
	print ("not testing")