#include "Metrics.hpp"

#include <chrono>

std::unordered_map<MetricVariable, Metric*> Metrics::m_Metrics = {};
std::vector<MetricVariable> Metrics::m_Variables = {
    MetricVariable::GameLoop,
    MetricVariable::PacketHandling,
    MetricVariable::UpdateEntities,
    MetricVariable::UpdateSpawners,
    MetricVariable::Physics,
    MetricVariable::UpdateReplica,
    MetricVariable::Ghosting,
    MetricVariable::CPUTime,
    MetricVariable::Sleep,
    MetricVariable::Frame,
};

void Metrics::AddMeasurement(MetricVariable variable, int64_t value) 
{   
    const auto& iter = m_Metrics.find(variable);

    Metric* metric;

    if (iter == m_Metrics.end())
    {
        metric = new Metric();

        m_Metrics[variable] = metric;
    }
    else
    {
        metric = iter->second;
    }

    AddMeasurement(metric, value);
}

void Metrics::AddMeasurement(Metric* metric, int64_t value) 
{
    const auto index = metric->measurementIndex;

    metric->measurements[index] = value;

    if (metric->max == -1 || value > metric->max)
    {
        metric->max = value;
    }
    else if (metric->min == -1 || metric->min > value)
    {
        metric->min = value;
    }

    if (metric->measurementSize < MAX_MEASURMENT_POINTS)
    {
        metric->measurementSize++;
    }

    metric->measurementIndex = (index + 1) % MAX_MEASURMENT_POINTS;
}

const Metric* Metrics::GetMetric(MetricVariable variable)
{
    const auto& iter = m_Metrics.find(variable);

    if (iter == m_Metrics.end())
    {
        return nullptr;
    }

    Metric* metric = iter->second;

    int64_t average = 0;

    for (size_t i = 0; i < metric->measurementSize; i++)
    {
        average += metric->measurements[i];
    }

    average /= metric->measurementSize;

    metric->average = average;
    
    return metric;
}

void Metrics::StartMeasurement(MetricVariable variable) 
{
    const auto& iter = m_Metrics.find(variable);

    Metric* metric;

    if (iter == m_Metrics.end())
    {
        metric = new Metric();

        m_Metrics[variable] = metric;
    }
    else
    {
        metric = iter->second;
    }

    metric->activeMeasurement = std::chrono::high_resolution_clock::now();
}

void Metrics::EndMeasurement(MetricVariable variable) 
{
    const auto end = std::chrono::high_resolution_clock::now();

    const auto& iter = m_Metrics.find(variable);

    if (iter == m_Metrics.end())
    {
        return;
    }

    Metric* metric = iter->second;

    const auto elapsed = end - metric->activeMeasurement;

    const auto nanoseconds = std::chrono::duration_cast<std::chrono::nanoseconds>(elapsed).count();

    AddMeasurement(metric, nanoseconds);
}

float Metrics::ToMiliseconds(int64_t nanoseconds) 
{
    return (float) nanoseconds / 1e6;
}

std::string Metrics::MetricVariableToString(MetricVariable variable) 
{
    switch (variable)
    {
    case MetricVariable::GameLoop:
        return "GameLoop";
    case MetricVariable::PacketHandling:
        return "PacketHandling";
    case MetricVariable::UpdateEntities:
        return "UpdateEntities";
    case MetricVariable::UpdateSpawners:
        return "UpdateSpawners";
    case MetricVariable::Physics:
        return "Physics";
    case MetricVariable::UpdateReplica:
        return "UpdateReplica";
    case MetricVariable::Sleep:
        return "Sleep";
    case MetricVariable::CPUTime:
        return "CPUTime";
    case MetricVariable::Frame:
        return "Frame";
    case MetricVariable::Ghosting:
        return "Ghosting";
    
    default:
        return "Invalid";
    }
}

const std::vector<MetricVariable>& Metrics::GetAllMetrics() 
{
    return m_Variables;
}

void Metrics::Clear() 
{
    for (const auto& pair : m_Metrics)
    {
        delete pair.second;
    }
    
    m_Metrics.clear();
}

/* RSS Memory utilities
 *
 * Author:  David Robert Nadeau
 * Site:    http://NadeauSoftware.com/
 * License: Creative Commons Attribution 3.0 Unported License
 *          http://creativecommons.org/licenses/by/3.0/deed.en_US
 */


#if defined(_WIN32)
#include <windows.h>
#include <psapi.h>

#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
#include <unistd.h>
#include <sys/resource.h>

#if defined(__APPLE__) && defined(__MACH__)
#include <mach/mach.h>

#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
#include <fcntl.h>
#include <procfs.h>

#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
#include <stdio.h>

#endif

#else
#error "Cannot define getPeakRSS( ) or getCurrentRSS( ) for an unknown OS."
#endif

/**
 * Returns the peak (maximum so far) resident set size (physical
 * memory use) measured in bytes, or zero if the value cannot be
 * determined on this OS.
 */
size_t Metrics::GetPeakRSS()
{
#if defined(_WIN32)
    /* Windows -------------------------------------------------- */
    PROCESS_MEMORY_COUNTERS info;
    GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
    return (size_t)info.PeakWorkingSetSize;

#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
    /* AIX and Solaris ------------------------------------------ */
    struct psinfo psinfo;
    int fd = -1;
    if ( (fd = open( "/proc/self/psinfo", O_RDONLY )) == -1 )
        return (size_t)0L;      /* Can't open? */
    if ( read( fd, &psinfo, sizeof(psinfo) ) != sizeof(psinfo) )
    {
        close( fd );
        return (size_t)0L;      /* Can't read? */
    }
    close( fd );
    return (size_t)(psinfo.pr_rssize * 1024L);

#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
    /* BSD, Linux, and OSX -------------------------------------- */
    struct rusage rusage;
    getrusage( RUSAGE_SELF, &rusage );
#if defined(__APPLE__) && defined(__MACH__)
    return (size_t)rusage.ru_maxrss;
#else
    return (size_t)(rusage.ru_maxrss * 1024L);
#endif

#else
    /* Unknown OS ----------------------------------------------- */
    return (size_t)0L;          /* Unsupported. */
#endif

}

/**
 * Returns the current resident set size (physical memory use) measured
 * in bytes, or zero if the value cannot be determined on this OS.
 */
size_t Metrics::GetCurrentRSS()
{
#if defined(_WIN32)
    /* Windows -------------------------------------------------- */
    PROCESS_MEMORY_COUNTERS info;
    GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
    return (size_t)info.WorkingSetSize;

#elif defined(__APPLE__) && defined(__MACH__)
    /* OSX ------------------------------------------------------ */
    struct mach_task_basic_info info;
    mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
    if ( task_info( mach_task_self( ), MACH_TASK_BASIC_INFO,
        (task_info_t)&info, &infoCount ) != KERN_SUCCESS )
        return (size_t)0L;      /* Can't access? */
    return (size_t)info.resident_size;

#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
    /* Linux ---------------------------------------------------- */
    long rss = 0L;
    FILE* fp = NULL;
    if ( (fp = fopen( "/proc/self/statm", "r" )) == NULL )
        return (size_t)0L;      /* Can't open? */
    if ( fscanf( fp, "%*s%ld", &rss ) != 1 )
    {
        fclose( fp );
        return (size_t)0L;      /* Can't read? */
    }
    fclose( fp );
    return (size_t)rss * (size_t)sysconf( _SC_PAGESIZE);

#else
    /* AIX, BSD, Solaris, and Unknown OS ------------------------ */
    return (size_t)0L;          /* Unsupported. */
#endif

}

size_t Metrics::GetProcessID() 
{
#if defined(_WIN32)
    return GetCurrentProcessId();
#else
    return getpid();
#endif
}