#!/usr/bin/env python3
"""
Simple script to stream a G-code file to a GRBL controller.
"""
import os
import time

import serial

def stream(filename):
	"""Opens the given filename and streams it to GRBL."""
	usbs = [dev for dev in os.listdir("/dev/") if dev.startswith("ttyUSB")]
	for usb in usbs:
		try:
			s = serial.Serial(os.path.join("/dev/", usb), 115200)
			break
		except serial.serialutil.SerialException:
			continue
	else:
		print("Could not find any USB connections. Exiting.")
		return

	with open(filename, 'r') as file:
		data = file.read().splitlines()
	len_cmds = len(data)
	progress = []

	# Wake up grbl
	s.write(b"\r\n\r\n")
	time.sleep(2)   # Wait for grbl to initialize 
	s.flushInput()  # Flush startup text in serial input

	for n, line in enumerate(data):
		l = line.strip().encode("utf-8") # Strip all EOL characters for consistency
		# print('Sending: ' + str(l))
		s.write(l + b"\n") # Send g-code block to grbl
		grbl_out = s.readline() # Wait for grbl response with carriage return
		# print('Receive: ' + str(grbl_out).strip())
		percent = int(n/len_cmds*100)
		if not int(n/len_cmds) % 5:
			if not percent in progress:
				print(str(percent) + "%")
				progress.append(percent)

	s.close()


if __name__ == "__main__":
	import argparse

	parser = argparse.ArgumentParser(
		description="Streams the G-code file to GRBL.")
	parser.add_argument(
		"filename",
		help="The file to stream.")
	args = parser.parse_args()

	stream(args.filename)