/* *****************************************************************************
 * %{QMAKE_PROJECT_NAME}
 * Copyright (c) %YEAR% killerbee
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 * ****************************************************************************/
#ifndef VOTE_COUNT_H
#define VOTE_COUNT_H

#include <cstdint>
#include <iostream>
#include <numeric>
#include <vector>

#include <kblib/iterators.h>
#include <kblib/stats.h>

using kblib::max;

void print(std::vector<int16_t>& vec) {
	std::clog << "{";
	for (auto i : vec) {
		if (i != max) {
			std::clog << ' ' << i;
		} else {
			std::clog << " _";
		}
	}
	std::clog << " }\n";
}

inline std::uint64_t vote_count(std::int16_t min, std::int16_t total) {
	std::vector<int16_t> votes(total);
	std::uint64_t counter{};

	for (auto n : kblib::range(+min, total + 1)) {
		// std::clog << n << '/' << total << ":\n";
		std::iota(votes.begin(), votes.begin() + n, 1);
		std::fill(votes.begin() + n, votes.end(), max);
		do {
			print(votes);
			++counter;
		} while (std::next_permutation(votes.begin(), votes.end()));
	}

	return counter;
}

inline std::uint64_t factorial_div(std::int16_t x, std::int16_t d) {
	if (x < 0) {
		throw std::domain_error{"negative factorial"};
	}
	std::uint64_t counter{1};
	// bool first = true;
	for (auto i : kblib::range(d + 1, x + 1)) {
		// if (! std::exchange(first, false)) {
		//	std::cout << " * ";
		//}
		// std::cout << i;
		counter *= i;
	}
	// std::cout << '\n';
	return counter;
}

inline std::uint64_t vote_calc(std::int16_t min, std::int16_t total) {
	std::uint64_t counter{};
	for (auto n : kblib::range(0, total - min + 1)) {
		// const auto t_f = factorial(total);
		counter += factorial_div(total, n);
	}
	return counter;
}

#endif // VOTE_COUNT_H