/****************************************************************************
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
 
 http://www.cocos2d-x.org
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ****************************************************************************/

#include "platform/android/jni/ProcessCpuTracker.h"

#ifdef ANDROID
#include <jni.h>
#include <android/log.h>
#include <unistd.h>
#endif
#include <stdlib.h>
#include <vector>
#include <time.h>
#include <fcntl.h>
#include <sstream>

#ifdef ANDROID
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, "ProcessCpuTracker", __VA_ARGS__)
#else
#define LOGD printf
#endif

typedef struct _CpuInfo
{
    long userTime; // Unit: jiffies
    long niceTime;
    long systemTime;
    long idleTime;
    long ioWaitTime;
    long irqTime;
    long softIrqTime;
}CpuInfo;

// Return 0 means the end of buffer
static bool readLine(char* p, const char* end, char** next)
{
    if (p == NULL)
    {
        *next = NULL;
        return false;
    }

    while (*p != '\n' && p < end)
        ++p;

    if (*p == '\n')
    {// line break
        *p = '\0'; // Set to \0 to make a sub-sequence string
        *next = ++p;
        return true;
    }
    else
    {// end of buffer
        *next = NULL;
        return true;
    }
}

static std::vector<CpuInfo> readProcStat()
{
    std::vector<CpuInfo> cpuInfos;
    cpuInfos.reserve(13);
    char buffer[1024] = {0};

#ifdef ANDROID
    int fd = open("/proc/stat", O_RDONLY);

    if (fd < 0)
    {
        return cpuInfos;
    }

    const int len = read(fd, buffer, sizeof(buffer)-1);
    close(fd);

    if (len < 0) {
        LOGD("Unable to open process fd=%d", fd);
        return cpuInfos;
    }
    buffer[len] = 0;
#else
    FILE* fp = fopen("fonts/stat-huawei.txt", "rb");
    if (fp == NULL)
        return cpuInfos;
    fread(buffer, sizeof(buffer)-1, 1, fp);
    fclose(fp);
    size_t len = strlen(buffer);
#endif

    char* p = buffer;
    const char* end = p + len;
    char* next = NULL;
    int cpuIndex;
    const int COLUMN = sizeof(CpuInfo) / sizeof(long);
    size_t i = 0;

    while (readLine(p, end, &next))
    {
        // break if the line with no cpu prefix
        if (p[0] != 'c' || p[1] != 'p' || p[2] != 'u')
            break;

//        LOGD("%s\n", p);
        // Removes 'cpu%d' prefix
        p = p + 3;

        if (*p == ' ')
        { // The first line means the average cpu usage
            cpuIndex = 0;
        }
        else
        {
            cpuIndex = strtol(p, &p, 10) + 1;
        }

//        LOGD("cpu index: %d\n", cpuIndex);

        cpuInfos.resize(cpuIndex + 1);

        for (i = 0; i < COLUMN; ++i)
        {
            long value = strtol(p, &p, 10);
//            LOGD("%ld ", value);

            CpuInfo& info = cpuInfos[cpuIndex];
            long* e = (long*)&info + i;
            *e = value;
        }
//        LOGD("%s", "\n");

        p = next;
    }

    return cpuInfos;
}

void ProcessCpuTracker::update()
{
    static const int JIFFYMILLIS = 10;
    std::vector<CpuInfo> cpuInfos = readProcStat();
    if (!cpuInfos.empty())
    {
        if (_cpuTimeInfos.size() < cpuInfos.size())
        {
            _cpuTimeInfos.resize(cpuInfos.size());
        }

//        LOGD("cpuInfo size: %d", (int)cpuInfos.size());

        for (size_t i = 0, len = cpuInfos.size(); i < len; ++i)
        {
            CpuTimeInfo& cpuTimeInfo = _cpuTimeInfos[i];
            const CpuInfo& cpuInfo = cpuInfos[i];
            // Total user time is user + nice time.
            const long usertime = (cpuInfo.userTime + cpuInfo.niceTime) * JIFFYMILLIS;
            // Total system time is simply system time.
            const long systemtime = cpuInfo.systemTime * JIFFYMILLIS;
            // Total idle time is simply idle time.
            const long idletime = cpuInfo.idleTime * JIFFYMILLIS;
            // Total irq time is iowait + irq + softirq time.
            const long iowaittime = cpuInfo.ioWaitTime * JIFFYMILLIS;
            const long irqtime = cpuInfo.irqTime * JIFFYMILLIS;
            const long softirqtime = cpuInfo.softIrqTime * JIFFYMILLIS;
            // This code is trying to avoid issues with idle time going backwards,
            // but currently it gets into situations where it triggers most of the time. :(
            if (false || (usertime >= cpuTimeInfo.mBaseUserTime && systemtime >= cpuTimeInfo.mBaseSystemTime
                         && iowaittime >= cpuTimeInfo.mBaseIoWaitTime && irqtime >= cpuTimeInfo.mBaseIrqTime
                         && softirqtime >= cpuTimeInfo.mBaseSoftIrqTime && idletime >= cpuTimeInfo.mBaseIdleTime)) {
                cpuTimeInfo.mRelUserTime = usertime - cpuTimeInfo.mBaseUserTime;
                cpuTimeInfo.mRelSystemTime = systemtime - cpuTimeInfo.mBaseSystemTime;
                cpuTimeInfo.mRelIoWaitTime = iowaittime - cpuTimeInfo.mBaseIoWaitTime;
                cpuTimeInfo.mRelIrqTime = irqtime - cpuTimeInfo.mBaseIrqTime;
                cpuTimeInfo.mRelSoftIrqTime = softirqtime - cpuTimeInfo.mBaseSoftIrqTime;
                cpuTimeInfo.mRelIdleTime = idletime - cpuTimeInfo.mBaseIdleTime;
//                if (true) {
//                    LOGD("CPU%d, Total U: %ld, N:%ld S:%ld I:%ld W:%ld Q:%ld O:%ld\n",
//                         (int)i,
//                         cpuInfo.userTime,
//                         cpuInfo.niceTime,
//                         cpuInfo.systemTime,
//                         cpuInfo.idleTime,
//                         cpuInfo.ioWaitTime,
//                         cpuInfo.irqTime,
//                         cpuInfo.softIrqTime
//                         );
//                    LOGD("CPU%d, Rel U:%ld, S:%ld, I:%ld, Q:%ld\n",
//                        (int)i,
//                        cpuTimeInfo.mRelUserTime,
//                        cpuTimeInfo.mRelSystemTime,
//                        cpuTimeInfo.mRelIdleTime,
//                        cpuTimeInfo.mRelIrqTime
//                        );
//                    if (cpuTimeInfo.mRelUserTime < 0
//                        || cpuTimeInfo.mRelSystemTime < 0
//                        || cpuTimeInfo.mRelIdleTime < 0
//                        || cpuTimeInfo.mRelIrqTime < 0)
//                    {
//                        LOGD("CPU%d,base U:%ld, S:%ld, I:%ld, Q:%ld\n",
//                        (int)i,
//                        cpuTimeInfo.mBaseUserTime,
//                        cpuTimeInfo.mBaseSystemTime,
//                        cpuTimeInfo.mBaseIdleTime,
//                        cpuTimeInfo.mBaseIrqTime
//                        );
//                    }
//                }
                cpuTimeInfo.mBaseUserTime = usertime;
                cpuTimeInfo.mBaseSystemTime = systemtime;
                cpuTimeInfo.mBaseIoWaitTime = iowaittime;
                cpuTimeInfo.mBaseIrqTime = irqtime;
                cpuTimeInfo.mBaseSoftIrqTime = softirqtime;
                cpuTimeInfo.mBaseIdleTime = idletime;
            } else {

//                if (usertime < cpuTimeInfo.mBaseUserTime)
//                {
//                    LOGD("ERROR: usertime: %ld, base: %ld", usertime, cpuTimeInfo.mBaseUserTime);
//                }
//
//                if (systemtime < cpuTimeInfo.mBaseSystemTime)
//                {
//                    LOGD("ERROR: systemtime: %ld, base: %ld", systemtime, cpuTimeInfo.mBaseSystemTime);
//                }
//
//                if (iowaittime < cpuTimeInfo.mBaseIoWaitTime)
//                {
//                    LOGD("ERROR: iowaittime: %ld, base: %ld", iowaittime, cpuTimeInfo.mBaseIoWaitTime);
//                }
//
//                if (irqtime < cpuTimeInfo.mBaseIrqTime)
//                {
//                    LOGD("ERROR: irqtime: %ld, base: %ld", irqtime, cpuTimeInfo.mBaseIrqTime);
//                }
//
//                if (softirqtime < cpuTimeInfo.mBaseSoftIrqTime)
//                {
//                    LOGD("ERROR: softirqtime: %ld, base: %ld", softirqtime, cpuTimeInfo.mBaseSoftIrqTime);
//                }
//
//                if (idletime < cpuTimeInfo.mBaseIdleTime)
//                {
//                    LOGD("ERROR: idletime: %ld, base: %ld", idletime, cpuTimeInfo.mBaseIdleTime);
//                }

                if (usertime > 0 || idletime > 0)
                {
                    cpuTimeInfo.mBaseUserTime = usertime;
                    cpuTimeInfo.mBaseSystemTime = systemtime;
                    cpuTimeInfo.mBaseIoWaitTime = iowaittime;
                    cpuTimeInfo.mBaseIrqTime = irqtime;
                    cpuTimeInfo.mBaseSoftIrqTime = softirqtime;
                    cpuTimeInfo.mBaseIdleTime = idletime;
                }

                cpuTimeInfo.mRelUserTime = 0;
                cpuTimeInfo.mRelSystemTime = 0;
                cpuTimeInfo.mRelIoWaitTime = 0;
                cpuTimeInfo.mRelIrqTime = 0;
                cpuTimeInfo.mRelSoftIrqTime = 0;
                cpuTimeInfo.mRelIdleTime = 0;
                LOGD("CPU: %d, /proc/stats has gone backwards; skipping CPU update\n", (int)i);
            }
        }
    }
}

static long printRatio(std::stringstream& ss, long numerator, long denominator) {
    long hundreds = 0;
    if (denominator > 0)
    {
        long thousands = (numerator*1000)/denominator;
        hundreds = thousands/10;
        ss << hundreds;
        if (hundreds < 10) {
            long remainder = thousands - (hundreds*10);

            if (remainder != 0) {
                ss << '.';
                ss << remainder;
            }
        }
    }
    else
    {
        ss << '0';
    }
    ss << " ";

    return hundreds;
}

static long printProcessCPU(std::stringstream& ss, long totalTime, long user)
{   
    return printRatio(ss, user, totalTime);
}

void ProcessCpuTracker::printCurrentState()
{
    std::stringstream ss;
    long totalCpuUsage = 0;
    for (size_t i = 0, len = _cpuTimeInfos.size(); i < len; ++i)
    {
        CpuTimeInfo& cpuTimeInfo = _cpuTimeInfos[i];
        const long totalTime = cpuTimeInfo.mRelUserTime + cpuTimeInfo.mRelSystemTime + cpuTimeInfo.mRelIoWaitTime
        + cpuTimeInfo.mRelIrqTime + cpuTimeInfo.mRelSoftIrqTime + cpuTimeInfo.mRelIdleTime;

//        if (totalTime <= 0)
//        {
//            LOGD("cjh totalTime, i=%d: %ld mRelUserTime: %ld, mRelSystemTime: %ld, mRelIoWaitTime: %ld, mRelIrqTime: %ld, mRelSoftIrqTime: %ld, mRelIdleTime: %ld",
//                (int)i,
//                totalTime,
//                cpuTimeInfo.mRelUserTime,
//                cpuTimeInfo.mRelSystemTime,
//                cpuTimeInfo.mRelIoWaitTime,
//                cpuTimeInfo.mRelIrqTime,
//                cpuTimeInfo.mRelSoftIrqTime,
//                cpuTimeInfo.mRelIdleTime
//            );
//        }

        const long preCoreUsage = printProcessCPU(ss, totalTime, cpuTimeInfo.mRelUserTime);
        if (i > 0)
        {
            totalCpuUsage += preCoreUsage;
        }
    }

    ss << "T:";
    ss << totalCpuUsage;
    std::string str = ss.str();
    LOGD("CPU: %s", str.c_str());
}