// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

#include "metrics/SystemInfo.h"
#include "utils/Log.h"

#include <dirent.h>
#include <nvml.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <fstream>
#include <iostream>
#include <string>
#include <utility>

namespace milvus {
namespace server {

void
SystemInfo::Init() {
    if (initialized_) {
        return;
    }

    initialized_ = true;

    // initialize CPU information
    FILE* file;
    struct tms time_sample;
    char line[128];
    last_cpu_ = times(&time_sample);
    last_sys_cpu_ = time_sample.tms_stime;
    last_user_cpu_ = time_sample.tms_utime;
    file = fopen("/proc/cpuinfo", "r");
    num_processors_ = 0;
    while (fgets(line, 128, file) != nullptr) {
        if (strncmp(line, "processor", 9) == 0) {
            num_processors_++;
        }
        if (strncmp(line, "physical", 8) == 0) {
            num_physical_processors_ = ParseLine(line);
        }
    }
    total_ram_ = GetPhysicalMemory();
    fclose(file);

    // initialize GPU information
    nvmlReturn_t nvmlresult;
    nvmlresult = nvmlInit();
    if (NVML_SUCCESS != nvmlresult) {
        SERVER_LOG_ERROR << "System information initilization failed";
        return;
    }
    nvmlresult = nvmlDeviceGetCount(&num_device_);
    if (NVML_SUCCESS != nvmlresult) {
        SERVER_LOG_ERROR << "Unable to get devidce number";
        return;
    }

    // initialize network traffic information
    std::pair<uint64_t, uint64_t> in_and_out_octets = Octets();
    in_octets_ = in_and_out_octets.first;
    out_octets_ = in_and_out_octets.second;
    net_time_ = std::chrono::system_clock::now();
}

uint64_t
SystemInfo::ParseLine(char* line) {
    // This assumes that a digit will be found and the line ends in " Kb".
    int i = strlen(line);
    const char* p = line;
    while (*p < '0' || *p > '9') {
        p++;
    }
    line[i - 3] = '\0';
    i = atoi(p);
    return static_cast<uint64_t>(i);
}

uint64_t
SystemInfo::GetPhysicalMemory() {
    struct sysinfo memInfo;
    sysinfo(&memInfo);
    uint64_t totalPhysMem = memInfo.totalram;
    // Multiply in next statement to avoid int overflow on right hand side...
    totalPhysMem *= memInfo.mem_unit;
    return totalPhysMem;
}

uint64_t
SystemInfo::GetProcessUsedMemory() {
    // Note: this value is in KB!
    FILE* file = fopen("/proc/self/status", "r");
    constexpr uint64_t line_length = 128;
    uint64_t result = -1;
    constexpr uint64_t KB_SIZE = 1024;
    char line[line_length];

    while (fgets(line, line_length, file) != nullptr) {
        if (strncmp(line, "VmRSS:", 6) == 0) {
            result = ParseLine(line);
            break;
        }
    }
    fclose(file);
    // return value in Byte
    return (result * KB_SIZE);
}

double
SystemInfo::MemoryPercent() {
    if (!initialized_) {
        Init();
    }

    double mem_used = static_cast<double>(GetProcessUsedMemory() * 100);
    return mem_used / static_cast<double>(total_ram_);
}

std::vector<double>
SystemInfo::CPUCorePercent() {
    std::vector<uint64_t> prev_work_time_array;
    std::vector<uint64_t> prev_total_time_array = getTotalCpuTime(prev_work_time_array);
    usleep(100000);
    std::vector<uint64_t> cur_work_time_array;
    std::vector<uint64_t> cur_total_time_array = getTotalCpuTime(cur_work_time_array);

    std::vector<double> cpu_core_percent;
    for (int i = 1; i < num_processors_; i++) {
        double total_cpu_time = cur_total_time_array[i] - prev_total_time_array[i];
        double cpu_work_time = cur_work_time_array[i] - prev_work_time_array[i];
        cpu_core_percent.push_back((cpu_work_time / total_cpu_time) * 100);
    }
    return cpu_core_percent;
}

std::vector<uint64_t>
SystemInfo::getTotalCpuTime(std::vector<uint64_t>& work_time_array) {
    std::vector<uint64_t> total_time_array;
    FILE* file = fopen("/proc/stat", "r");
    if (file == NULL) {
        SERVER_LOG_ERROR << "Could not open stat file";
        return total_time_array;
    }

    uint64_t user = 0, nice = 0, system = 0, idle = 0;
    uint64_t iowait = 0, irq = 0, softirq = 0, steal = 0, guest = 0, guestnice = 0;

    for (int i = 0; i < num_processors_; i++) {
        char buffer[1024];
        char* ret = fgets(buffer, sizeof(buffer) - 1, file);
        if (ret == NULL) {
            SERVER_LOG_ERROR << "Could not read stat file";
            fclose(file);
            return total_time_array;
        }

        sscanf(buffer, "cpu  %16lu %16lu %16lu %16lu %16lu %16lu %16lu %16lu %16lu %16lu", &user, &nice, &system, &idle,
               &iowait, &irq, &softirq, &steal, &guest, &guestnice);

        work_time_array.push_back(user + nice + system);
        total_time_array.push_back(user + nice + system + idle + iowait + irq + softirq + steal);
    }

    fclose(file);
    return total_time_array;
}

double
SystemInfo::CPUPercent() {
    if (!initialized_) {
        Init();
    }
    struct tms time_sample;
    clock_t now;
    double percent;

    now = times(&time_sample);
    if (now <= last_cpu_ || time_sample.tms_stime < last_sys_cpu_ || time_sample.tms_utime < last_user_cpu_) {
        // Overflow detection. Just skip this value.
        percent = -1.0;
    } else {
        percent = (time_sample.tms_stime - last_sys_cpu_) + (time_sample.tms_utime - last_user_cpu_);
        percent /= (now - last_cpu_);
        percent *= 100;
    }
    last_cpu_ = now;
    last_sys_cpu_ = time_sample.tms_stime;
    last_user_cpu_ = time_sample.tms_utime;

    return percent;
}

std::vector<uint64_t>
SystemInfo::GPUMemoryTotal() {
    // get GPU usage percent
    if (!initialized_)
        Init();
    std::vector<uint64_t> result;
    nvmlMemory_t nvmlMemory;
    for (int i = 0; i < num_device_; ++i) {
        nvmlDevice_t device;
        nvmlDeviceGetHandleByIndex(i, &device);
        nvmlDeviceGetMemoryInfo(device, &nvmlMemory);
        result.push_back(nvmlMemory.total);
    }
    return result;
}

std::vector<uint64_t>
SystemInfo::GPUTemperature() {
    if (!initialized_)
        Init();
    std::vector<uint64_t> result;
    for (int i = 0; i < num_device_; i++) {
        nvmlDevice_t device;
        nvmlDeviceGetHandleByIndex(i, &device);
        unsigned int temp;
        nvmlDeviceGetTemperature(device, NVML_TEMPERATURE_GPU, &temp);
        result.push_back(temp);
    }
    return result;
}

std::vector<float>
SystemInfo::CPUTemperature() {
    std::vector<float> result;
    std::string path = "/sys/class/hwmon/";

    DIR* dir = NULL;
    dir = opendir(path.c_str());
    if (!dir) {
        SERVER_LOG_ERROR << "Could not open hwmon directory";
        return result;
    }

    struct dirent* ptr = NULL;
    while ((ptr = readdir(dir)) != NULL) {
        std::string filename(path);
        filename.append(ptr->d_name);

        char buf[100];
        if (readlink(filename.c_str(), buf, 100) != -1) {
            std::string m(buf);
            if (m.find("coretemp") != std::string::npos) {
                std::string object = filename;
                object += "/temp1_input";
                FILE* file = fopen(object.c_str(), "r");
                if (file == nullptr) {
                    SERVER_LOG_ERROR << "Could not open temperature file";
                    return result;
                }
                float temp;
                fscanf(file, "%f", &temp);
                result.push_back(temp / 1000);
            }
        }
    }
    closedir(dir);
    return result;
}

std::vector<uint64_t>
SystemInfo::GPUMemoryUsed() {
    // get GPU memory used
    if (!initialized_)
        Init();

    std::vector<uint64_t> result;
    nvmlMemory_t nvmlMemory;
    for (int i = 0; i < num_device_; ++i) {
        nvmlDevice_t device;
        nvmlDeviceGetHandleByIndex(i, &device);
        nvmlDeviceGetMemoryInfo(device, &nvmlMemory);
        result.push_back(nvmlMemory.used);
    }
    return result;
}

std::pair<uint64_t, uint64_t>
SystemInfo::Octets() {
    pid_t pid = getpid();
    //    const std::string filename = "/proc/"+std::to_string(pid)+"/net/netstat";
    const std::string filename = "/proc/net/netstat";
    std::ifstream file(filename);
    std::string lastline = "";
    std::string line = "";
    while (true) {
        getline(file, line);
        if (file.fail()) {
            break;
        }
        lastline = line;
    }
    std::vector<size_t> space_position;
    size_t space_pos = lastline.find(" ");
    while (space_pos != std::string::npos) {
        space_position.push_back(space_pos);
        space_pos = lastline.find(" ", space_pos + 1);
    }
    // InOctets is between 6th and 7th " " and OutOctets is between 7th and 8th " "
    size_t inoctets_begin = space_position[6] + 1;
    size_t inoctets_length = space_position[7] - inoctets_begin;
    size_t outoctets_begin = space_position[7] + 1;
    size_t outoctets_length = space_position[8] - outoctets_begin;
    std::string inoctets = lastline.substr(inoctets_begin, inoctets_length);
    std::string outoctets = lastline.substr(outoctets_begin, outoctets_length);

    uint64_t inoctets_bytes = std::stoull(inoctets);
    uint64_t outoctets_bytes = std::stoull(outoctets);
    std::pair<uint64_t, uint64_t> res(inoctets_bytes, outoctets_bytes);
    return res;
}

}  // namespace server
}  // namespace milvus
