/*
Copyright 2019-2021 Intel Corporation

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/


//
// sysinfo is a helper module used to query various system metrics in a platform agnostic fashion
//


var PDH_FMT_LONG = 0x00000100;
var PDH_FMT_DOUBLE = 0x00000200;

var promise = require('promise');
if (process.platform == 'win32')
{
    var GM = require('_GenericMarshal');
    GM.kernel32 = GM.CreateNativeProxy('kernel32.dll');
    GM.kernel32.CreateMethod('GlobalMemoryStatusEx');       // https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex

    GM.pdh = GM.CreateNativeProxy('pdh.dll');
    GM.pdh.CreateMethod('PdhAddEnglishCounterA');           // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhaddenglishcountera
    GM.pdh.CreateMethod('PdhCloseQuery');                   // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhclosequery
    GM.pdh.CreateMethod('PdhCollectQueryData');             // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhcollectquerydata
    GM.pdh.CreateMethod('PdhGetFormattedCounterValue');     // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhgetformattedcountervalue
    GM.pdh.CreateMethod('PdhGetFormattedCounterArrayA');    // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhgetformattedcounterarraya
    GM.pdh.CreateMethod('PdhOpenQueryA');                   // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhopenquerya
    GM.pdh.CreateMethod('PdhRemoveCounter');                // https://learn.microsoft.com/en-us/windows/win32/api/pdh/nf-pdh-pdhremovecounter
}

//
// Windows Implementation for fetching CPU utilization
//
function windows_cpuUtilization()
{
    var p = new promise(function (res, rej) { this._res = res; this._rej = rej; });
    p.counter = GM.CreateVariable(16);
    p.cpu = GM.CreatePointer();
    p.cpuTotal = GM.CreatePointer();
    var err = 0;
    if ((err = GM.pdh.PdhOpenQueryA(0, 0, p.cpu).Val) != 0) { p._rej(err); return; }

    // This gets the CPU Utilization for each proc
    if ((err = GM.pdh.PdhAddEnglishCounterA(p.cpu.Deref(), GM.CreateVariable('\\Processor(*)\\% Processor Time'), 0, p.cpuTotal).Val) != 0) { p._rej(err); return; }

    if ((err = GM.pdh.PdhCollectQueryData(p.cpu.Deref()).Val != 0)) { p._rej(err); return; }
    p._timeout = setTimeout(function (po)
    {
        // Query in 100ms

        var u = { cpus: [] };
        var bufSize = GM.CreateVariable(4);
        var itemCount = GM.CreateVariable(4);
        var buffer, szName, item;
        var e;
        if ((e = GM.pdh.PdhCollectQueryData(po.cpu.Deref()).Val != 0)) { po._rej(e); return; /* Reject Promise if this fails */ }

        if ((e = GM.pdh.PdhGetFormattedCounterArrayA(po.cpuTotal.Deref(), PDH_FMT_DOUBLE, bufSize, itemCount, 0).Val) == -2147481646)
        {
            buffer = GM.CreateVariable(bufSize.toBuffer().readUInt32LE());
        }
        else
        {
            // Reject Promise if this failed
            po._rej(e);
            return;
        }
        if ((e = GM.pdh.PdhGetFormattedCounterArrayA(po.cpuTotal.Deref(), PDH_FMT_DOUBLE, bufSize, itemCount, buffer).Val) != 0) { po._rej(e); return;  /* reject promise on failuer */ }
        for(var i=0;i<itemCount.toBuffer().readUInt32LE();++i) // Enumerate the counter array
        {
            item = buffer.Deref(i * 24, 24);
            szName = item.Deref(0, GM.PointerSize).Deref();
            if (szName.String == '_Total')
            {
                u.total = item.Deref(16, 8).toBuffer().readDoubleLE();      // Add Value for TOTAL
            }
            else
            {
                u.cpus[parseInt(szName.String)] = item.Deref(16, 8).toBuffer().readDoubleLE();  // Add Value for CPU index
            }
        }

        GM.pdh.PdhRemoveCounter(po.cpuTotal.Deref());
        GM.pdh.PdhCloseQuery(po.cpu.Deref());
        p._res(u);
    }, 100, p);

    return (p);
}

//
// Windows Implementation to fetch memory utilization
//
function windows_memUtilization()
{
    var info = GM.CreateVariable(64);
    info.Deref(0, 4).toBuffer().writeUInt32LE(64);
    GM.kernel32.GlobalMemoryStatusEx(info); // Fetch the memory Utilization Metrics

    var ret =
        {
            MemTotal: require('bignum').fromBuffer(info.Deref(8, 8).toBuffer(), { endian: 'little' }),  // Convert total to bignum type
            MemFree: require('bignum').fromBuffer(info.Deref(16, 8).toBuffer(), { endian: 'little' })   // Convert free to bignum type
        };

    // Calculate the remaining metrics, and convert to bignum type
    ret.percentFree = ((ret.MemFree.div(require('bignum')('1048576')).toNumber() / ret.MemTotal.div(require('bignum')('1048576')).toNumber()) * 100);//.toFixed(2);
    ret.percentConsumed = ((ret.MemTotal.sub(ret.MemFree).div(require('bignum')('1048576')).toNumber() / ret.MemTotal.div(require('bignum')('1048576')).toNumber()) * 100);//.toFixed(2);
    ret.MemTotal = ret.MemTotal.toString();
    ret.MemFree = ret.MemFree.toString();
    return (ret);
}

var cpuLastIdle = [];
var cpuLastSum = [];


//
// Linux Implementation of fetching the CPU Utilization, which uses procfs
//
function linux_cpuUtilization() {
    var ret = { cpus: [] };
    var info = require('fs').readFileSync('/proc/stat');  // fetch metrics from procfs
    var lines = info.toString().split('\n');
    var columns;
    var x, y;
    var cpuNo = 0;
    var currSum, currIdle, utilization;
    for (var i in lines) {
        columns = lines[i].split(' ');
        if (!columns[0].startsWith('cpu')) { break; }

        // Parse out the utilization metrics, calulcating the values if necessary
        x = 0, currSum = 0;
        while (columns[++x] == '');
        for (y = x; y < columns.length; ++y) { currSum += parseInt(columns[y]); }
        currIdle = parseInt(columns[3 + x]);

        var diffIdle = currIdle - cpuLastIdle[cpuNo];
        var diffSum = currSum - cpuLastSum[cpuNo];

        utilization = (100 - ((diffIdle / diffSum) * 100));

        cpuLastSum[cpuNo] = currSum;
        cpuLastIdle[cpuNo] = currIdle;

        if (!ret.total) {
            ret.total = utilization;
        } else {
            ret.cpus.push(utilization);
        }
        ++cpuNo;
    }

    var p = new promise(function (res, rej) { this._res = res; this._rej = rej; });
    p._res(ret);
    return (p);
}

//
// Linux implementation of memory utilization, using procfs
//
function linux_memUtilization()
{
    var ret = {};

    var info = require('fs').readFileSync('/proc/meminfo').toString().split('\n');
    var tokens;
    for(var i in info)
    {
        tokens = info[i].split(' ');
        switch(tokens[0])
        {
            case 'MemTotal:':
                ret.total = parseInt(tokens[tokens.length - 2]);
                break;
            case 'MemFree:':
                ret.free = parseInt(tokens[tokens.length - 2]);
                break;
        }
    }
    ret.percentFree = ((ret.free / ret.total) * 100);//.toFixed(2);
    ret.percentConsumed = (((ret.total - ret.free) / ret.total) * 100);//.toFixed(2);
    return (ret);
}

//
// macOS CPU Utilization, where we just use system utility 'top'
//
function macos_cpuUtilization()
{
    var ret = new promise(function (res, rej) { this._res = res; this._rej = rej; });
    var child = require('child_process').execFile('/bin/sh', ['sh']);
    child.stdout.str = '';
    child.stdout.on('data', function (chunk) { this.str += chunk.toString(); });
    child.stdin.write('top -l 1 | grep -E "^CPU"\nexit\n');
    child.waitExit();

    var lines = child.stdout.str.split('\n');
    if (lines[0].length > 0)
    {
        var usage = lines[0].split(':')[1];
        var bdown = usage.split(',');

        var tot = parseFloat(bdown[0].split('%')[0].trim()) + parseFloat(bdown[1].split('%')[0].trim());
        ret._res({total: tot, cpus: []});
    }
    else
    {
        ret._rej('parse error');
    }

    return (ret);
}

//
// macOS Memory Utilization, using system utility 'top'
//
function macos_memUtilization()
{
    var mem = { };
    var ret = new promise(function (res, rej) { this._res = res; this._rej = rej; });
    var child = require('child_process').execFile('/bin/sh', ['sh']);
    child.stdout.str = '';
    child.stdout.on('data', function (chunk) { this.str += chunk.toString(); });
    child.stdin.write('top -l 1 | grep -E "^Phys"\nexit\n');
    child.waitExit();

    var lines = child.stdout.str.split('\n');
    if (lines[0].length > 0)
    {
        var usage = lines[0].split(':')[1];
        var bdown = usage.split(',');

        mem.MemTotal = parseInt(bdown[0].trim().split(' ')[0]);
        mem.MemFree = parseInt(bdown[1].trim().split(' ')[0]);
        mem.percentFree = ((mem.MemFree / mem.MemTotal) * 100);//.toFixed(2);
        mem.percentConsumed = (((mem.MemTotal - mem.MemFree) / mem.MemTotal) * 100);//.toFixed(2);
        return (mem);
    }
    else
    {
        throw ('Parse Error');
    }
}

//
// Windows Implementation of fetching system thermals, using WMI and system utility 'wmic'
//
function windows_thermals()
{
    var ret = [];
    child = require('child_process').execFile(process.env['windir'] + '\\System32\\wbem\\wmic.exe', ['wmic', '/namespace:\\\\root\\wmi', 'PATH', 'MSAcpi_ThermalZoneTemperature', 'get', 'CurrentTemperature']);
    child.stdout.str = ''; child.stdout.on('data', function (c) { this.str += c.toString(); });
    child.stderr.str = ''; child.stderr.on('data', function (c) { this.str += c.toString(); });
    child.waitExit();

    if(child.stdout.str.trim!='')
    {
        var lines = child.stdout.str.trim().split('\r\n');
        for (var i = 1; i < lines.length; ++i)
        {
            if (lines[i].trim() != '') { ret.push(((parseFloat(lines[i]) / 10) - 273.15).toFixed(2)); }
        }
    }
    return (ret);
}

//
// Linux Implementation of fetching system thermals, from the filesystem
//
function linux_thermals()
{
    child = require('child_process').execFile('/bin/sh', ['sh']);
    child.stdout.str = ''; child.stdout.on('data', function (c) { this.str += c.toString(); });
    child.stderr.str = ''; child.stderr.on('data', function (c) { this.str += c.toString(); });
    child.stdin.write("cat /sys/class/thermal/thermal_zone*/temp | awk '{ print $0 / 1000 }'\nexit\n");
    child.waitExit();
    var ret = child.stdout.str.trim().split('\n');
    if (ret.length == 1 && ret[0] == '') { ret = []; }
    return (ret);
}

//
// macOS Implementation of fetching system thermals, using system utility 'powermetrics'
//
function macos_thermals()
{
    var ret = [];
    var child = require('child_process').execFile('/bin/sh', ['sh']);
    child.stdout.str = ''; child.stdout.on('data', function (c) { this.str += c.toString(); });
    child.stderr.on('data', function () { });
    child.stdin.write('powermetrics --help | grep SMC\nexit\n');
    child.waitExit();
    
    if (child.stdout.str.trim() != '')
    {
        child = require('child_process').execFile('/bin/sh', ['sh']);
        child.stdout.str = ''; child.stdout.on('data', function (c)
        {
            this.str += c.toString();
            var tokens = this.str.trim().split('\n');
            for (var i in tokens)
            {
                if (tokens[i].split(' die temperature: ').length > 1)
                {
                    ret.push(tokens[i].split(' ')[3]);
                    this.parent.kill();
                }
            }
        });
        child.stderr.str = ''; child.stderr.on('data', function (c) { this.str += c.toString(); });
        child.stdin.write('powermetrics -s smc\n');
        child.waitExit(5000);
    }
    return (ret);
}

switch(process.platform)
{
    case 'linux':
        module.exports = { cpuUtilization: linux_cpuUtilization, memUtilization: linux_memUtilization, thermals: linux_thermals };
        break;
    case 'win32':
        module.exports = { cpuUtilization: windows_cpuUtilization, memUtilization: windows_memUtilization, thermals: windows_thermals };
        break;
    case 'darwin':
        module.exports = { cpuUtilization: macos_cpuUtilization, memUtilization: macos_memUtilization, thermals: macos_thermals };
        break;
}