import os, sys, json
from os import walk # for walking a directory

ERR = '''
ERROR:: Program requires three parameters!

ARGUMENTS::
	1. ngc file path
	2. json file path
	3. (e)xtract or (i)nsert or (d)elete
'''

def get_json_object(lines):
	jsonlines = []

	index = 0
	while index < len(lines):
		line = lines[index]
		if len(line) < 1:
			continue
		if line[0] == '%':
			break
		else:
			jsonlines.append(line[1:len(line)-1]) # get the line removing the semicolon
		index += 1
	string = '\n'.join(jsonlines)
	return string, json.loads(string)

def insert_json(lines, jsonlines):
	string = ' '.join(jsonlines)
	for line in reversed(jsonlines):
		lines.insert(0, ';' + line)
	return lines

def delete_json(lines):
	index = 0
	while index < len(lines):
		line = lines[index]
		if len(line) < 1:
			continue
		if line[0] == '%':
			break
		index += 1
	return lines[index : len(lines)-1]

def read_lines(path):
	lines = []
	with open(path) as f:
		lines = f.readlines()
	return lines	

def write_lines(path, lines):
	with open(path, "w") as f:
		f.write(''.join(lines))

def handle_arguments():
	args = sys.argv
	if len(args) == 1: 
		print ERR
		return
	elif len(args) < 4:
		print ERR
		return
	else:
		
		ngc_path = args[1]
		json_path = args[2]
		action = args[3]

		if action == 'e':
			string, obj = get_json_object(read_lines(ngc_path))
		elif action == 'i':
			jsonlines = read_lines(json_path)
			write_lines(ngc_path, insert_json(read_lines(ngc_path), jsonlines))
		elif action == 'd':
			write_lines(ngc_path, delete_json(read_lines(ngc_path)))
		else:
			print("ERROR:: unknown action " + action + "!")
			return

if __name__ == '__main__':
	handle_arguments()