import json
import random
from jsonrpcclient import Request
from jsonrpcclient.http_client import HTTPClient
from contextlib import contextmanager
import sys, os
import argparse

#argparse
parser = argparse.ArgumentParser(prog='True Random Password Generator', description='Uses the random.org basic API with a free subscription to initialize a true random seed for the python random function to create -c passwords of -l length')
parser.add_argument('-a', '--apikey', default=os.environ['HOME']+'/.bin/.apikey' , type=str, help='path to a file which contains only a random.org api key')
parser.add_argument('-c', '--count', default='50', type=int, help='the number of passwords to generate')
parser.add_argument('-l', '--length', default='20', type=int, help='the length the generated passwords should have')
parser.add_argument('-s', '--seed', action='store_true', help='outputs the queried seed instead of initialzing the pseudo random vector')
args = parser.parse_args()


#Loading the .apikey file
try:
    with open (args.apikey, 'r') as f:
        apikey=f.readline()
except:
    print("Please provide a file that contains only your apikey with the -a option, if no option is provided the script assumes that the apikey file has this path: " + args.apikey)
    exit(1)


#Prevent program segments from blabbering to stdout/stderr
@contextmanager
def suppress_std_err_out():
    with open(os.devnull, "w") as devnull:
        old_stdout = sys.stdout
        sys.stdout = devnull
        old_stderr = sys.stderr
        sys.stderr = devnull
        try:
            yield
        finally:
           sys.stdout = old_stdout
           sys.stderr = old_stderr

#Blabbering program segment
with suppress_std_err_out():
    client = HTTPClient("https://api.random.org/json-rpc/2/invoke")
    response = client.send(Request("generateIntegers", apiKey=apikey,n="1",min='1',max="1000000000"))
    seed=response["random"]["data"]

#Filling the seed with a (true) random number
if not args.seed:
	characters="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789#_@!?+"
	char_lst = [x for x in characters]
	random.seed(int(seed[0]))
	#Building password
	for _ in range(0,args.count):
		pw_string=""
		for _ in range(0,args.length):
			pw_string += char_lst[random.randint(0, 67)]
	print(pw_string)
else:
	print("-------------------------------------------")
	print('Seed: '+str(seed[0]));

print("-------------------------------------------")
bit_uses_left=response["bitsLeft"] // response["bitsUsed"]
uses_left = bit_uses_left if bit_uses_left <  response["requestsLeft"] else response["requestsLeft"]
print("This apikey (with free api subscription) has another " + str(uses_left) + " uses left today")