import json
import os
import hashlib

blockchain_dir = os.curdir + '/blockchain/'


def get_hash(filename):
    file = open(blockchain_dir + filename, 'rb').read()
    return hashlib.md5(file).hexdigest()

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

def check_integrity():
    files = get_files()

    results = []

    for file in files[1:]:
        f = open(blockchain_dir + str(file))
        h = json.load(f)['hash']

        prev_file = str(file - 1)
        actual_hash = get_hash(prev_file)

        if h == actual_hash:
            res = 'ok'
        else:
            res = 'Corrupted'

         #print('block{} is: {}'.format(prev_file, res))

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

        return results

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

    files = get_files()
    prev_file = files [-1]

    filename = str(last_file + 1)

    prev_hash = get_hash(str(prec_file))


    #print(filename)

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

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

def main ():
    #write_block(name='oleg2', amount=7, to_whom= 'ksu')
    print(check_integrity())


if __name__ == '__main__':
    main()