import java.util.Random;

public class Population {

    Point[] points;


    int population_size;
    int max = 10;
    int min = -10;
    int tournament_size = 5;

    int point_count = 0;

    public Population(int population_size) {
        points = new Point[population_size];
        for (int i = 0; i < population_size; i++) {
            points[i] = new Point();
        }


        this.population_size = population_size;


        randomizePopulation();
    }


    public void randomizePopulation() {
        for (int i = 0; i < population_size; i++) {
            points[i].x = min + Math.random() * (max - min);
            points[i].y = min + Math.random() * (max - min);
        }
    }

    public Population evolution() {
        //print(this,this.population_size);
        double[] results = new double[this.population_size];
        for (int i = 0; i < population_size; i++) {
            results[i] = GeneticAlgorithm.function.calculate(points[i].x, points[i].y);

        }

        Point best = getFittest();
        System.out.println("Najlepsza wartosc " + calculate_fittness(best));


        Population newpopulation = new Population(this.population_size);




        for (int j = 0; j < this.population_size; j++) {

            Point parent1 =  tournament(this);
            Point parent2 =  tournament(this);

            crossover(parent1, parent2, newpopulation);

            if (this.population_size == this.point_count) break;

        }

        this.point_count = 0;




        return newpopulation;
    }

    public void crossover(Point parent1 , Point parent2,Population newpopulation)
    {
        newpopulation.points[point_count].x=parent1.x;
        newpopulation.points[point_count].y=parent2.x;

        point_count+=1;

        newpopulation.points[point_count].x=parent1.y;
        newpopulation.points[point_count].y=parent2.y;

        point_count+=1;
    }

    public Point tournament(Population population)
    {
        Population tournament = new Population(this.tournament_size);

        for(int i = 0 ; i< this.tournament_size ; i++)
        {
            int index = (int) (Math.random() * this.population_size);
            tournament.points[i] = population.points[index];
        }


        Point parent = tournament.getFittest();


        return parent;
    }

    public Point getFittest()
    {
        double fittest = calculate_fittness(points[0]);
        Point x = this.points[0];
        for(int i=1;i<population_size;i++)
        {
           if(fittest> calculate_fittness(points[i]))
           {
               fittest=calculate_fittness(points[i]);
               x=this.points[i];
           }
        }

        return x;
    }


    public double calculate_fittness(Point p)
    {

        return GeneticAlgorithm.function.calculate(p.x,p.y);
    }

    public void print(Population population, int size)
    {
        for(int i=0;i<size;i++)
        {
            //System.out.println(population.points[i].x +" "+population.points[i].y);
        }
    }
}