#!/usr/bin/python3
import hashlib
import random
import sys

## That part was originally secrets.py --> now bcp is integrated into a single file program
"""Generate cryptographically strong pseudo-random numbers suitable for
managing secrets such as account authentication, tokens, and similar.

See PEP 506 for more information.
https://www.python.org/dev/peps/pep-0506/

Amit nem hasznalok belole azt kivettem!
Eredeti forras: https://raw.githubusercontent.com/python/cpython/3.7/Lib/secrets.py

"""

__all__ = ['choice', 'randbelow', 'randbits', 'SystemRandom',
           'token_bytes', 'token_hex', 'token_urlsafe',
           'compare_digest',
           ]

import base64
import binascii
import os

from hmac import compare_digest
from random import SystemRandom

_sysrand = SystemRandom()

randbits = _sysrand.getrandbits
choice = _sysrand.choice

DEFAULT_ENTROPY = 64  # number of bytes to return by default

def token_bytes(nbytes=None):
    """Return a random byte string containing *nbytes* bytes.
    >>> token_bytes(16)  #doctest:+SKIP
    b'\\xebr\\x17D*t\\xae\\xd4\\xe3S\\xb6\\xe2\\xebP1\\x8b'"""
    if nbytes is None:
        nbytes = DEFAULT_ENTROPY
    return os.urandom(nbytes)


def token_hex(nbytes=None):
    """Return a random text string, in hexadecimal.
    >>> token_hex(16)  #doctest:+SKIP
    'f9bf78b9a18ce6d46a0cd2b0b86df9da'"""
    return binascii.hexlify(token_bytes(nbytes)).decode('ascii')
## End of integrated secrets.py

# Az egyszeruseg kedveert, 1 tomb = 1 sor

blokklanc_file = os.getenv("HOME") + "/.blokklanc.pp"

# Eredet tomb letrehozasa ha nem letezik
if not os.path.exists(blokklanc_file):
    # Genezis/eredet tomb letrehozasa randommal, hogy ha ugyan az is ket szoveg, soha ne ugyan az legyen a kimenetel
    eredet = "Eredet."
    erand = token_hex(64)
    etomb_adat = eredet + erand
    etomb_hash = hashlib.sha512(etomb_adat.encode('utf-8')).hexdigest()
    print("Initializing...")
    print("Origin block: " + str(etomb_adat) + '||' + etomb_hash)
    # beirni eredetet
    ask_for_write = input("Save the first block into " + blokklanc_file + "? [y/n] ")
    if ask_for_write != "y":
        sys.exit()
    f = open(blokklanc_file,'w')
    f.write(str(etomb_adat) + etomb_hash)
    f.close()


# kiolvassa az utolso sort
def utolso_sor():
    blokk_file = open(blokklanc_file,'r')
    for sor in blokk_file:
        fb_sor = sor
    print("Utolsó tömb: " + fb_sor)
    return fb_sor

# hozzaad egy uj tombot
def uj_tomb(tomb_adat):
    utolso_tomb_hash = utolso_sor()
    uj_tomb = hashlib.sha512(utolso_tomb_hash.encode('utf-8')).hexdigest() + '||' + tomb_adat + '||'
    uj_tomb_hash = hashlib.sha512(uj_tomb.encode('utf-8')).hexdigest()
    fu = open(blokklanc_file,'a')
    fu.write('\n' + uj_tomb + uj_tomb_hash)

# ujraszamolja a blokklanc helyesseget
def teljes_lanc_ellenorzes():
    pass
teljes_lanc_ellenorzes()


# Kovetkezo letrehozasa
jegyzet = input("What do you want to add to the blockchain? ")
uj_tomb(jegyzet)
#print("Teszt: " + hashlib.sha512("teszt".encode('utf-8')).hexdigest())

# cut -d '|' -f 3 blokklanc.pp | egrep -v "^Eredet."