/*
 * Experiment.cpp
 *
 *  Created on: 16 maj 2016
 *      Author: oramus
 */

#include <stdlib.h>
#include <iostream>
#include <omp.h>

#include "Experiment.h"
#include "Distribution.h"

#define DEBUG_ON_

using namespace std;

Experiment::Experiment(int balls, int drawsNumber)
{
    this->balls = balls;
    this->drawsNumber = drawsNumber;

    hmax = 0; // wyznaczamy maksymalna sume
    hmin = 0; // i najmniejsza sume
    for (int i = 0; i < drawsNumber; i++)
    {
        hmax += balls - i;
        hmin += i + 1; // 1 + 2 + 3 + ... liczba losowan
    }

    cout << "Histogram min: " << hmin << " max: " << hmax << endl;

    histogram = new long[hmax + 1];

    for (long i = 0; i < hmax + 1; i++)
        histogram[i] = 0;
}

void Experiment::clearUsed(bool *used)
{
    for (int i = 0; i < balls; i++)
    {
        used[i] = false;
    }
}

long Experiment::singleExperimentResult(drand48_data *drandBuf, bool *used)
{
    long sum = 0;
    int ball;
    double p, randomBall, randomProbability;

    clearUsed(used);
    for (int i = 0; i < drawsNumber;)
    {
        drand48_r(drandBuf, &randomBall);
        ball = 1 + (int)((double)balls * randomBall);

        if (used[ball - 1])
            continue;

        p = Distribution::getProbability(i + 1, ball); // pobieramy prawdopodobienstwo wylosowania tej kuli

        drand48_r(drandBuf, &randomProbability);
        if (randomProbability < p) // akceptacja wyboru kuli z zadanym prawdopodobienstwem
        {
            #ifdef DEBUG_ON
            cout << "Dodano kule o numerze " << ball << endl;
            #endif
            used[ball - 1] = true;
            sum += ball; // kule maja numery od 1 do balls wlacznie
            i++;
        }
    }

    /// cout << "Suma = " << sum << endl;

    return sum;
}

Result *Experiment::calc(long experiments)
{
    #pragma omp parallel
    {
        long *privateHistogram = new long[hmax + 1];
        for (int i = 0; i < hmax + 1; i++)
        {
            privateHistogram[i] = 0;
        }
        bool *used = new bool[balls];

        struct drand48_data drandBuf;
        int seed = 1202107158 + omp_get_thread_num() * 1999;
        srand48_r(seed, &drandBuf);

        #pragma omp for schedule(dynamic)
        for (long l = 0; l < experiments; l++)
        {
            privateHistogram[singleExperimentResult(&drandBuf, used)]++;
        }

        #pragma omp critical
        {
            for (int i = 0; i < hmax + 1; i++)
            {
                histogram[i] += privateHistogram[i];
            }
        }
    }

    long maxID = 0;
    long maxN = 0;
    double sum = 0.0;
    long values = 0;

    #pragma omp parallel
    {
        long localMaxID = 0;
        long localMaxN = 0;
        double localSum = 0.0;
        long localValues = 0;

        #pragma omp for
        for (long idx = hmin; idx <= hmax; idx++)
        {
            if (localMaxN < histogram[idx])
            {
                localMaxN = histogram[idx];
                localMaxID = idx;
            }
            localSum += idx * histogram[idx];
            localValues += histogram[idx];
        }

        #pragma omp critical
        {
            if (localMaxN > maxN)
            {
                maxN = localMaxN;
                maxID = localMaxID;
            }
            sum += localSum;
            values += localValues;
        }
    }

    // indeks to wartosc, histogram -> liczba wystapien
    return new Result(maxID, maxN, sum / values, values);
}

Experiment::~Experiment()
{
    delete[] histogram;
}