#include <numeric>
#include <cassert>
#include <algorithm>
#include <array>
#include "toolbox.hpp"

namespace asp {
	static constexpr size_t N_TIMES = 10;
	static constexpr std::array<const char* const, N_TIMES> time_formats = { "ns", "us", "ms", "s", "m", "h", "j", "w", "M", "y" };
	static constexpr std::array<uint16_t, N_TIMES> time_numbers = { 1, 1000, 1000, 1000, 60, 60, 24, 7, 4, 12 };
	static const uint64_t total_time = std::accumulate(time_numbers.begin(), time_numbers.end(), uint64_t(1), std::multiplies<uint64_t>());

	static constexpr size_t N_BYTES = 7;
	static constexpr std::array<const char*, N_BYTES> bytes_formats = { "", "K", "M", "G", "P", "E", "Z" }; //, "Y" };
	static constexpr uint64_t total_bytes = uint64_t(1)<<(10 * (N_BYTES - 1));

	/**
	 * @brief Format the time in seconds in human readable format.
	 *
	 * @param time Time in seconds
	 * @return std::string The formatted human readable string.
	 */
	std::string format_time(const uint64_t time) noexcept {
		return time < 2 ? std::to_string(time) + "s" : format_time_ns(time * (uint64_t)1e9);
	}

	/**
	 * @brief Format the time in nanoseconds in human readable format.
	 *
	 * @param time Time in nanoseconds
	 * @return std::string The formatted human readable string.
	 */
	std::string format_byte_size(uint64_t bytes) noexcept {
		if (bytes == 0)
			return "0B";
		uint64_t prod = total_bytes;

		std::string s = "";
		uint64_t res;
		for (size_t i = N_BYTES; i > 0; --i) {
			if (bytes >= prod) {
				res = bytes / prod;
				bytes %= prod;
				s += std::to_string(res) + bytes_formats[i - 1] + "B ";
			}
			prod /= uint64_t(1)<<10;
		}

		if (s.back() == ' ')
			s.pop_back();

		return s;
	}

	/**
	 * @brief Format the time in nanoseconds in human readable format.
	 *
	 * @param time Time in nanoseconds
	 * @return std::string The formatted human readable string.
	 */
	std::string format_time_ns(uint64_t time) noexcept {
		if (time == 0)
			return "0ns";
		uint64_t prod = total_time;

		std::string s = "";
		uint64_t res;
		for (size_t i = N_TIMES; i > 0; --i) {
			if (time >= prod) {
				res = time / prod;
				time %= prod;
				s += std::to_string(res) + time_formats[i - 1] + " ";
			}
			prod /= time_numbers[i - 1];
		}

		if (s.back() == ' ')
			s.pop_back();

		return s;
	}

	/**
	 * @brief Run some unitary tests on format functions
	 *
	 */
	void toolbox_unit_test(void) noexcept {
		assert(std::string("0B")  == format_byte_size(uint64_t(0)));
		assert(std::string("1B")  == format_byte_size(uint64_t(1)));
		assert(std::string("1KB") == format_byte_size(uint64_t(1)<<10));
		assert(std::string("1MB") == format_byte_size(uint64_t(1)<<20));
		assert(std::string("1GB") == format_byte_size(uint64_t(1)<<30));
		assert(std::string("1PB") == format_byte_size(uint64_t(1)<<40));
		assert(std::string("1EB") == format_byte_size(uint64_t(1)<<50));
		assert(std::string("1ZB") == format_byte_size(uint64_t(1)<<60));
		//assert(std::string("1YB") == format_byte_size(uint64_t(1)<<70));
		// UINT64_MAX == 18446744073709551615I64u == -1
		assert(std::string("15ZB 1023EB 1023PB 1023GB 1023MB 1023KB 1023B") == format_byte_size(uint64_t(-1)));

		assert(std::string("0s") == format_time(uint64_t(0)));
		assert(std::string("1s") == format_time(uint64_t(1)));
		assert(std::string("1m") == format_time(uint64_t(60)));
		assert(std::string("1h") == format_time(uint64_t(3600)));
		assert(std::string("1j") == format_time(uint64_t(86400)));
		assert(std::string("1w") == format_time(uint64_t(604800)));
		assert(std::string("1M") == format_time(uint64_t(2419200)));
		assert(std::string("1y") == format_time(uint64_t(29030400)));

		assert(std::string("0ns") == format_time_ns(uint64_t(0)));
		assert(std::string("1ns") == format_time_ns(uint64_t(1)));
		assert(std::string("1us") == format_time_ns(uint64_t(1e3)));
		assert(std::string("1ms") == format_time_ns(uint64_t(1e6)));
		assert(std::string("1s") == format_time_ns(uint64_t(1e9)));
		assert(std::string("1m") == format_time_ns(uint64_t(6e10)));
		assert(std::string("1h") == format_time_ns(uint64_t(36e11)));
		assert(std::string("1j") == format_time_ns(uint64_t(864e11)));
		assert(std::string("1w") == format_time_ns(uint64_t(6048e11)));
		assert(std::string("1M") == format_time_ns(uint64_t(24192e11)));
		assert(std::string("1y") == format_time_ns(uint64_t(290304e11)));
		// UINT64_MAX == 18446744073709551615I64u == -1
		assert(std::string("635y 5M 3j 23h 34m 33s 709ms 551us 615ns") == format_time_ns(uint64_t(-1)));
	}

	std::string thousand_sep(const uint64_t& k, const char& sep) noexcept {
		std::string s = "", n = std::to_string(k);

		uint8_t c = 0;
		for (int64_t i = int64_t(n.size()) - 1; i >= 0; --i) {
			++c;
			s.push_back(n[i]);
			if (c == 3) {
				s.push_back(sep);
				c = 0;
			}
		}

		std::reverse(s.begin(), s.end());

		if (s.size() % 4 == 0)
			s.erase(s.begin());

		return s;
	}

	std::string thousand_sep(const uint64_t& k) noexcept {
		return thousand_sep(k, ',');
	}

	void print_separator(const char* const title) noexcept {
		#define S(N) std::string(N, '-').c_str()
		constexpr size_t SEPARATOR_SIZE = W_NAME + W_TIME + W_FTIME + 6 + 6;
		char separator[SEPARATOR_SIZE];
		sprintf(separator, "|%s|%s|%s|\n", S(W_NAME + 2), S(W_TIME + 2), S(W_FTIME + 2));
		printf("| %-" STR(W_NAME) "s | %-" STR(W_TIME) "s | %-" STR(W_FTIME) "s	| \n%s", title, "Time spent(ns)", "Formatted time spent", separator);
		#undef S
	}
}