use bytes::{equal};
use fmt;
use io;
use os;
use strconv;
use strings::{cut, fromutf8_unsafe, rtrim, split, toutf8};

fn u64revdigits(u: u64) ([]u8, size) = {
	static let buf: [64]u8 = [0...];

	let length = 0z;

	for (u > 0u64) {
		buf[length] = (u % 10): u8;
		length += 1;
		u /= 10;
	};

	return (buf, length);
};

fn has_repeating_seq(num: u64) bool = {
	if (num < 11) return false;

	let (num_bytes, digits) = u64revdigits(num);

	for (let i: u8 = 2; i <= digits; i += 1) {
		if (digits % i == 0) {
			let chunk_size = digits / i;
			let first_chunk: []u8 = num_bytes[..chunk_size];

			let valid_seq = true;

			for (let j: u8 = 1; j < i; j += 1) {
				let chunk = num_bytes[chunk_size * j..chunk_size * (j + 1)];

				if (!equal(chunk, first_chunk)) {
					valid_seq = false;
					break;
				};
			};

			if (valid_seq) return true;
		};
	};

	return false;
};

export fn main() void = {
	let handle = os::open("input.txt")!;
	defer io::close(handle)!;

	let buf = io::drain(handle) as []u8;
	defer free(buf);

	let range_strings = split(fromutf8_unsafe(buf), ",")!;
	defer free(range_strings);

	let answer: u64 = 0;

	for (let i: size = 0; i < len(range_strings); i += 1) {
		let range_ends = cut(rtrim(range_strings[i], '\n'), "-");

		let start = strconv::stou64(range_ends.0)!;
		let end = strconv::stou64(range_ends.1)!;

		for (let num = start; num <= end; num += 1) {
			if (has_repeating_seq(num)) answer += num;
		};
	};

	fmt::printfln("Answer: {}", answer)!;
};