#include "task_2.h"
#include <cassert>          // assert
#include <cmath>
#include <fstream>
#include <omp.h>

tuple<double, double> min_max_par(const vector<double> &v) {
    int min_val = v[0];
    int max_val = v[0];

    #pragma omp parallel for reduction(min:min_val) reduction(max:max_val)
    for (size_t i = 0; i < v.size(); ++i) {
        if (v[i] < min_val) min_val = v[i];
        if (v[i] > max_val) max_val = v[i];
    }

    return make_tuple(min_val,max_val);
}


tuple<double, double, double> means_par(const vector<double>& v){
    size_t n = v.size();
    double sum = 0;
    double logsum = 0;
    double invsum = 0;

    #pragma omp parallel for shared(v,n) reduction(+:sum, logsum, invsum)
    for (size_t i = 0; i<n; ++i){
        sum += v[i];
        logsum += log(v[i]);
        invsum += 1.0/v[i];
    }

    double arith = sum / static_cast<double>(n);
    double geo = exp(1.0/static_cast<double>(n) * logsum);
    double harm = static_cast<double>(n) / invsum;
    return make_tuple(arith, geo, harm);
}

void fill_vector(istream& istr, vector<double>& v)
{
    double d=0;
    while ( istr >> d) v.push_back(d); // Einlesen
    if (!istr.eof())
    { // Fehlerbehandlung
        cout << " Error handling \n";
        if ( istr.bad() )  throw runtime_error("Schwerer Fehler in istr");
        if ( istr.fail() )   // Versuch des Aufraeumens
        {
            cout << " Failed in reading all data.\n";
            istr.clear();
        }
    }
    v.shrink_to_fit();                 // C++11
    return;
}


void read_vector_from_file(const string& file_name, vector<double>& v)
{
    ifstream fin(file_name);           // Oeffne das File im ASCII-Modus
    if( fin.is_open() )                // File gefunden:
    {
       v.clear();                      // Vektor leeren
       fill_vector(fin, v);
    }
    else                               // File nicht gefunden:
    {
        cout << "\nFile " << file_name << " has not been found.\n\n" ;
        assert( fin.is_open() && "File not found." );       // exeption handling for the poor programmer
    }

 return;
}

void write_vector_to_file(const string& file_name, const vector<double>& v)
{
    ofstream fout(file_name);          // Oeffne das File im ASCII-Modus
    if( fout.is_open() )
    {
       for (size_t k=0; k<v.size(); ++k)
       {
          fout << v.at(k) << endl;
       }
    }
    else
    {
        cout << "\nFile " << file_name << " has not been opened.\n\n" ;
        assert( fout.is_open() && "File not opened."  );         // exeption handling for the poor programmer
    }

 return;
}