#!/usr/bin/env python3
"""
Created on 13 Jan 2018

@author: David Doblas Jiménez
@email: daviddoji@pm.me

Solution for problem 17 of Project Euler
https://projecteuler.net/problem=17
"""

from utils import timeit


def num2letters(num):
    nums = {
        0: "",
        1: "one",
        2: "two",
        3: "three",
        4: "four",
        5: "five",
        6: "six",
        7: "seven",
        8: "eight",
        9: "nine",
        10: "ten",
        11: "eleven",
        12: "twelve",
        13: "thirteen",
        14: "fourteen",
        15: "fifteen",
        16: "sixteen",
        17: "seventeen",
        18: "eighteen",
        19: "nineteen",
        20: "twenty",
        30: "thirty",
        40: "forty",
        50: "fifty",
        60: "sixty",
        70: "seventy",
        80: "eighty",
        90: "ninety",
        100: "hundred",
        1000: "thousand",
    }

    if num <= 20:
        return len(nums[num])
    elif num < 100:
        tens, units = divmod(num, 10)
        return len(nums[tens * 10]) + num2letters(units)
    elif num < 1000:
        hundreds, rest = divmod(num, 100)
        if rest:
            return (
                num2letters(hundreds) + len(nums[100]) + len("and") + num2letters(rest)
            )
        else:
            return num2letters(hundreds) + len(nums[100])
    else:
        thousands, rest = divmod(num, 1000)
        return num2letters(thousands) + len(nums[1000])


@timeit("Problem 17")
def compute():
    """
    If the numbers 1 to 5 are written out in words: one, two, three, four,
    five, then there are 3 + 3 + 5 + 4 + 4 = 19 letters used in total.

    If all the numbers from 1 to 1000 (one thousand) inclusive were written
    out in words, how many letters would be used?

    NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and
    forty-two) contains 23 letters and 115 (one hundred and fifteen) contains
    20 letters. The use of "and" when writing out numbers is in compliance
    with British usage.
    """
    n = 1000
    letters = 0
    for num in range(1, n + 1):
        letters += num2letters(num)
    return letters


if __name__ == "__main__":

    print(f"Result for Problem 17: {compute()}")