/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include "UUID.hpp"
#include <ctime>

namespace OpenVulkano
{
	UUID GenerateTimePrefixedCustomUUID()
	{
		UUID uuid = UUID::generate();

		uuid.time_low = 0;
		uuid.time_mid = 0;
		time_t now = time(nullptr);
		struct tm* timeinfo = localtime(&now);

		// Extract time components
		uint32_t year = timeinfo->tm_year % 100;  // Get last two digits of year
		uint32_t month = timeinfo->tm_mon + 1;    // Month is 0-based
		uint32_t day = timeinfo->tm_mday;
		uint32_t hour = timeinfo->tm_hour;
		uint16_t minute = timeinfo->tm_min;
		uint16_t second = timeinfo->tm_sec;

		// Each decimal digit takes 4 bits in the final hex number
		uuid.time_low |= (year / 10) << 28;
		uuid.time_low |= (year % 10) << 24;
		uuid.time_low |= (month / 10) << 20;
		uuid.time_low |= (month % 10) << 16;
		uuid.time_low |= (day / 10) << 12;
		uuid.time_low |= (day % 10) << 8;
		uuid.time_low |= (hour / 10) << 4;
		uuid.time_low |= (hour % 10) << 0;
		uuid.time_mid |= (minute / 10) << 12;
		uuid.time_mid |= (minute % 10) << 8;
		uuid.time_mid |= (second / 10) << 4;
		uuid.time_mid |= (second % 10) << 0;

		// Set version to custom
		uuid.time_hiv &= ~(static_cast<uint16_t>(uuid.version()) << 12);
		uuid.time_hiv |= 8 << 12;

		return uuid;
	}
}