<?php

/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
 */

declare(strict_types=1);

namespace pocketmine\utils;

use pocketmine\thread\ThreadManager;
use function count;
use function exec;
use function fclose;
use function file;
use function file_get_contents;
use function function_exists;
use function getmypid;
use function getmyuid;
use function hexdec;
use function memory_get_usage;
use function posix_kill;
use function preg_match;
use function proc_close;
use function proc_open;
use function stream_get_contents;
use function strpos;
use function trim;

final class Process{

	private function __construct(){
		//NOOP
	}

	/**
	 * @return int[]
	 * @phpstan-return array{int,int,int}
	 */
	public static function getAdvancedMemoryUsage(){
		$reserved = memory_get_usage();
		$VmSize = null;
		$VmRSS = null;
		if(Utils::getOS() === Utils::OS_LINUX || Utils::getOS() === Utils::OS_ANDROID){
			$status = @file_get_contents("/proc/self/status");
			if($status === false) throw new AssumptionFailedError("/proc/self/status should always be accessible");

			// the numbers found here should never be bigger than PHP_INT_MAX, so we expect them to always be castable to int
			if(preg_match("/VmRSS:[ \t]+([0-9]+) kB/", $status, $matches) > 0){
				$VmRSS = ((int) $matches[1]) * 1024;
			}

			if(preg_match("/VmSize:[ \t]+([0-9]+) kB/", $status, $matches) > 0){
				$VmSize = ((int) $matches[1]) * 1024;
			}
		}

		//TODO: more OS

		if($VmRSS === null){
			$VmRSS = memory_get_usage();
		}

		if($VmSize === null){
			$VmSize = memory_get_usage(true);
		}

		return [$reserved, $VmRSS, $VmSize];
	}

	public static function getMemoryUsage() : int{
		return self::getAdvancedMemoryUsage()[1];
	}

	/**
	 * @return int[]
	 */
	public static function getRealMemoryUsage() : array{
		$stack = 0;
		$heap = 0;

		if(Utils::getOS() === Utils::OS_LINUX || Utils::getOS() === Utils::OS_ANDROID){
			$mappings = @file("/proc/self/maps");
			if($mappings === false) throw new AssumptionFailedError("/proc/self/maps should always be accessible");
			foreach($mappings as $line){
				if(preg_match("#([a-z0-9]+)\\-([a-z0-9]+) [rwxp\\-]{4} [a-z0-9]+ [^\\[]*\\[([a-zA-z0-9]+)\\]#", trim($line), $matches) > 0){
					if(strpos($matches[3], "heap") === 0){
						$heap += (int) hexdec($matches[2]) - (int) hexdec($matches[1]);
					}elseif(strpos($matches[3], "stack") === 0){
						$stack += (int) hexdec($matches[2]) - (int) hexdec($matches[1]);
					}
				}
			}
		}

		return [$heap, $stack];
	}

	public static function getThreadCount() : int{
		if(Utils::getOS() === Utils::OS_LINUX || Utils::getOS() === Utils::OS_ANDROID){
			$status = @file_get_contents("/proc/self/status");
			if($status === false) throw new AssumptionFailedError("/proc/self/status should always be accessible");
			if(preg_match("/Threads:[ \t]+([0-9]+)/", $status, $matches) > 0){
				return (int) $matches[1];
			}
		}

		//TODO: more OS

		return count(ThreadManager::getInstance()->getAll()) + 2; //MainLogger + Main Thread
	}

	public static function kill(int $pid, bool $subprocesses) : void{
		$logger = \GlobalLogger::get();
		if($logger instanceof MainLogger){
			$logger->syncFlushBuffer();
		}
		switch(Utils::getOS()){
			case Utils::OS_WINDOWS:
				exec("taskkill.exe /F " . ($subprocesses ? "/T " : "") . "/PID $pid > NUL 2> NUL");
				break;
			case Utils::OS_MACOS:
			case Utils::OS_LINUX:
			default:
				if($subprocesses){
					$pid = -$pid;
				}
				if(function_exists("posix_kill")){
					posix_kill($pid, 9); //SIGKILL
				}else{
					exec("kill -9 $pid > /dev/null 2>&1");
				}
		}
	}

	/**
	 * @param string      $command Command to execute
	 * @param string|null $stdout Reference parameter to write stdout to
	 * @param string|null $stderr Reference parameter to write stderr to
	 *
	 * @return int process exit code
	 */
	public static function execute(string $command, string &$stdout = null, string &$stderr = null) : int{
		$process = proc_open($command, [
			["pipe", "r"],
			["pipe", "w"],
			["pipe", "w"]
		], $pipes);

		if($process === false){
			$stderr = "Failed to open process";
			$stdout = "";

			return -1;
		}

		$stdout = stream_get_contents($pipes[1]);
		$stderr = stream_get_contents($pipes[2]);

		foreach($pipes as $p){
			fclose($p);
		}

		return proc_close($process);
	}

	public static function pid() : int{
		$result = getmypid();
		if($result === false){
			throw new \LogicException("getmypid() doesn't work on this platform");
		}
		return $result;
	}

	public static function uid() : int{
		$result = getmyuid();
		if($result === false){
			throw new \LogicException("getmyuid() doesn't work on this platform");
		}
		return $result;
	}
}