<?php


function _getServerLoadLinuxData()
{
    if (is_readable("/proc/stat"))
    {
        $stats = @file_get_contents("/proc/stat");

        if ($stats !== false)
        {
            // Remove double spaces to make it easier to extract values with explode()
            $stats = preg_replace("/[[:blank:]]+/", " ", $stats);

            // Separate lines
            $stats = str_replace(array("\r\n", "\n\r", "\r"), "\n", $stats);
            $stats = explode("\n", $stats);

            // Separate values and find line for main CPU load
            foreach ($stats as $statLine)
            {
                $statLineData = explode(" ", trim($statLine));

                // Found!
                if
                (
                    (count($statLineData) >= 5) &&
                    ($statLineData[0] == "cpu")
                )
                {
                    return array(
                        $statLineData[1],
                        $statLineData[2],
                        $statLineData[3],
                        $statLineData[4],
                    );
                }
            }
        }
    }

    return null;
}
/* GET THÔNG TIN CPU */
function getServerLoad()
{
    $load = null;

    if (stristr(PHP_OS, "win"))
    {
        $cmd = "wmic cpu get loadpercentage /all";
        @exec($cmd, $output);

        if ($output)
        {
            foreach ($output as $line)
            {
                if ($line && preg_match("/^[0-9]+\$/", $line))
                {
                    $load = $line;
                    break;
                }
            }
        }
    }
    else
    {
        if (is_readable("/proc/stat"))
        {
            // Collect 2 samples - each with 1 second period
            // See: https://de.wikipedia.org/wiki/Load#Der_Load_Average_auf_Unix-Systemen
            $statData1 = _getServerLoadLinuxData();
            sleep(1);
            $statData2 = _getServerLoadLinuxData();

            if
            (
                (!is_null($statData1)) &&
                (!is_null($statData2))
            )
            {
                // Get difference
                $statData2[0] -= $statData1[0];
                $statData2[1] -= $statData1[1];
                $statData2[2] -= $statData1[2];
                $statData2[3] -= $statData1[3];

                // Sum up the 4 values for User, Nice, System and Idle and calculate
                // the percentage of idle time (which is part of the 4 values!)
                $cpuTime = $statData2[0] + $statData2[1] + $statData2[2] + $statData2[3];

                // Invert percentage to get CPU time, not idle time
                $load = 100 - ($statData2[3] * 100 / $cpuTime);
            }
        }
    }

    return $load;
}


/* GET THÔNG TIN RAM */
function getServerMemoryUsage($getPercentage=true)
{
    $memoryTotal = null;
    $memoryFree = null;

    if (stristr(PHP_OS, "win")) {
        // Get total physical memory (this is in bytes)
        $cmd = "wmic ComputerSystem get TotalPhysicalMemory";
        @exec($cmd, $outputTotalPhysicalMemory);

        // Get free physical memory (this is in kibibytes!)
        $cmd = "wmic OS get FreePhysicalMemory";
        @exec($cmd, $outputFreePhysicalMemory);

        if ($outputTotalPhysicalMemory && $outputFreePhysicalMemory) {
            // Find total value
            foreach ($outputTotalPhysicalMemory as $line) {
                if ($line && preg_match("/^[0-9]+\$/", $line)) {
                    $memoryTotal = $line;
                    break;
                }
            }

            // Find free value
            foreach ($outputFreePhysicalMemory as $line) {
                if ($line && preg_match("/^[0-9]+\$/", $line)) {
                    $memoryFree = $line;
                    $memoryFree *= 1024;  // convert from kibibytes to bytes
                    break;
                }
            }
        }
    }
    else
    {
        if (is_readable("/proc/meminfo"))
        {
            $stats = @file_get_contents("/proc/meminfo");

            if ($stats !== false) {
                // Separate lines
                $stats = str_replace(array("\r\n", "\n\r", "\r"), "\n", $stats);
                $stats = explode("\n", $stats);

                // Separate values and find correct lines for total and free mem
                foreach ($stats as $statLine) {
                    $statLineData = explode(":", trim($statLine));

                    //
                    // Extract size (TODO: It seems that (at least) the two values for total and free memory have the unit "kB" always. Is this correct?
                    //

                    // Total memory
                    if (count($statLineData) == 2 && trim($statLineData[0]) == "MemTotal") {
                        $memoryTotal = trim($statLineData[1]);
                        $memoryTotal = explode(" ", $memoryTotal);
                        $memoryTotal = $memoryTotal[0];
                        $memoryTotal *= 1024;  // convert from kibibytes to bytes
                    }

                    // Free memory
                    if (count($statLineData) == 2 && trim($statLineData[0]) == "MemFree") {
                        $memoryFree = trim($statLineData[1]);
                        $memoryFree = explode(" ", $memoryFree);
                        $memoryFree = $memoryFree[0];
                        $memoryFree *= 1024;  // convert from kibibytes to bytes
                    }
                }
            }
        }
    }

    if (is_null($memoryTotal) || is_null($memoryFree)) {
        return null;
    } else {
        if ($getPercentage) {
            return (100 - ($memoryFree * 100 / $memoryTotal));
        } else {
            return array(
                "total" => $memoryTotal,
                "free" => $memoryFree,
            );
        }
    }
}

function getNiceFileSize($bytes, $binaryPrefix=true)
{
    if ($binaryPrefix) {
        $unit=array('B','KiB','MiB','GiB','TiB','PiB');
        if ($bytes==0) return '0 ' . $unit[0];
        return @round($bytes/pow(1024,($i=floor(log($bytes,1024)))),2) .' '. (isset($unit[$i]) ? $unit[$i] : 'B');
    } else {
        $unit=array('B','KB','MB','GB','TB','PB');
        if ($bytes==0) return '0 ' . $unit[0];
        return @round($bytes/pow(1000,($i=floor(log($bytes,1000)))),2) .' '. (isset($unit[$i]) ? $unit[$i] : 'B');
    }
}