import datetime
import bcrypt

# the taste of summer strawberries
straw = "le goût des fraises d'été"

# summer
ete = "été"

def bytes2hex(byte_array: bytes):
    '''converts the byte_array into a string like [41 43 54]:
    a series of pairs of hexadecimal digits, surrounded by square brackets'''
    if type(byte_array) != bytes:
        raise TypeError('argument is not an array of bytes', byte_array)
    hex = ' '.join( format(b, '02x') for b in byte_array )
    return f'[{hex}]'

def demo_encode_decode(x: str):
    '''convert the argument (a string) into an array of bytes by
    encoding as UTF8, and convert back, printing results to
    demonstrate encoding and decoding.'''
    if type(x) != str:
        raise TypeError('argument is not a string', x)
    print(f'encoding x: {x}')
    b = x.encode('utf-8')
    y = b.decode('utf-8')
    print('x', x, type(x))
    print('b', b, type(b))
    print('y', y, type(y))
    print(bytes2hex(b))
    print('are x and y equal?', x==y)

def bcrypt_string(input_string, prior=None, encoding='utf8'):
    if prior is None:
        prior = bcrypt.gensalt()
    else:
        prior = prior.encode(encoding)
    x = input_string.encode(encoding)
    y = bcrypt.hashpw(x, prior)
    output_string = y.decode(encoding)
    return output_string

def bcrypt_timing(min_work=12, max_work=18):
    '''Bcrypt a particular string with a variety of work factors'''
    last_time = datetime.datetime.now()
    for i in range(min_work, max_work):
        # work factor is embedded in the salt part of the string
        salt = bcrypt.gensalt(rounds=i)
        h = bcrypt.hashpw('secret'.encode('utf8'), salt)
        now = datetime.datetime.now()
        time_diff = now - last_time
        last_time = now
        seconds = (time_diff.seconds +
                   (time_diff.microseconds / float(1_000_000)))
        print(f"hashing 'secret' with work {i} takes {seconds} seconds")

def signup(passwd, encoding='utf8'):
    '''Returns an encrypted password, as a string, suitable for
    storing in a database.'''
    prior = bcrypt.gensalt()
    x = passwd.encode(encoding)
    y = bcrypt.hashpw(x, prior)
    output_string = y.decode(encoding)
    return output_string

def login(passwd, prior, encoding='utf8'):
    '''Returns true/false as to whether the user entered the correct
    password, given that the value stored in the database is 'prior'.'''
    p = prior.encode(encoding)
    x = passwd.encode(encoding)
    y = bcrypt.hashpw(x, p)
    output_string = y.decode(encoding)
    print(passwd, prior, x, y, output_string, sep="\n")
    return prior == output_string