"""Project Euler - Problem 8 - http://projecteuler.net/problem=8"""
import sys
import time
import tools.timeutils as timeutils


a_thousand_digit_number = \
    int('73167176531330624919225119674426574742355349194934' +
        '96983520312774506326239578318016984801869478851843' +
        '85861560789112949495459501737958331952853208805511' +
        '12540698747158523863050715693290963295227443043557' +
        '66896648950445244523161731856403098711121722383113' +
        '62229893423380308135336276614282806444486645238749' +
        '30358907296290491560440772390713810515859307960866' +
        '70172427121883998797908792274921901699720888093776' +
        '65727333001053367881220235421809751254540594752243' +
        '52584907711670556013604839586446706324415722155397' +
        '53697817977846174064955149290862569321978468622482' +
        '83972241375657056057490261407972968652414535100474' +
        '82166370484403199890008895243450658541227588666881' +
        '16427171479924442928230863465674813919123162824586' +
        '17866458359124566529476545682848912883142607690042' +
        '24219022671055626321111109370544217506941658960408' +
        '07198403850962455444362981230987879927244284909188' +
        '84580156166097919133875499200524063689912560717606' +
        '05886116467109405077541002256983155200055935729725' +
        '71636269561882670428252483600823257530420752963450')


def compute_product(n):
    """
    Processes each chunk of 5 digits and returns the product of these 5 digits
    If there is a zero on the sequence, even at the most significative digit,
    e.g., the left-most digit, the result will be zero
    """
    a = 1
    for m in range(1, 6, 1):
        a *= n % 10
        n //= 10
    return a


def greatest_product(number):
    """
    Finds the greatest product of 5 consecutive digits in the 1000-digit number
    """
    largest = 1
    for n in range(1, 997, 1):
        product = compute_product(number % (10 ** 5))
        if product > largest:
            largest = product
        number //= 10
    print('largest is', largest)


def main():
    """Main entry point for the script"""
    start = time.time()
    greatest_product(a_thousand_digit_number)
    timeutils.elapsed_time(time.time() - start)


if __name__ == '__main__':
    sys.exit(main())
