import json
import os
from os import listdir
import hashlib

block_dir = os.curdir + '/blockchain/'  # ./blockchain/


def get_files():
    files = os.listdir(block_dir)
    return sorted([int(i) for i in files])


def get_hash(filename):
    file = open(block_dir + filename, 'rb').read()     # читаем бинарно
    return hashlib.md5(file).hexdigest()


def check_integrity():

    files = get_files()
    result = []

    for file in files[1:]:  # минуем генезис блок
        f = open(block_dir + str(file))
        hash = json.load(f)['hash']   # читаем хеш

        prev_file = str(file - 1)
        actual_hash = get_hash(prev_file)    # получаем новый блок и проверяем хеш

        if hash == actual_hash:
            res = 'Ok'
        else:
            res = 'Corrupted'

        result.append({'block': prev_file, 'result': res})

    return result


def write_block(name, amount, to_whom, prev_hash=''):

    files = get_files()
    prev_file = files[-1]   # сортируем номерные файлы
    file_name = str(prev_file + 1)

    prev_hash = get_hash(str(prev_file))

    data = {'name': name,
            'amount': amount,
            'to_whom': to_whom,
            'hash': prev_hash
            }

    with open(block_dir + file_name, 'w') as file:
        json.dump(data, file, indent=4, ensure_ascii=False)


def main():
    write_block(name='name', amount=0, to_whom='name')
    print(check_integrity())


if __name__ == '__main__':
    main()