type population struct {
    individuals    []individual
    maxIndividuals int
    maxFitness     int
    avgFitness     float64
}
type individual struct {
    entities   []int
    amount     int
    fitness    int
    generation int
}

func (p *population) ParentSelection() (individual, individual) {
    // Returns two random individuals which will be the parents
    length := len(p.individuals)
    mother := rand.Intn(length)
    father := rand.Intn(length)
    for {
        if mother == father {
            mother = rand.Intn(length)
        } else {
            break
        }
    }
    return p.TwoIndividual(mother, father)
}

func (p *population) RandomOnePointCrossover(x, y individual) (individual, individual) {
    randOnePoint := rand.Intn(len(x.entities))
    if debug {
        fmt.Println("RandomOnePointCrossover -", "Split at point:", randOnePoint)
        fmt.Println("RandomOnePointCrossover -", "Mother:", x)
        fmt.Println("RandomOnePointCrossover -", "Father:", y)
    }
    tempGene1 := make([]int, 0, len(x.entities))
    tempGene2 := make([]int, 0, len(y.entities))

    tempGene1 = append(tempGene1, x.entities[:randOnePoint]...)
    tempGene2 = append(tempGene2, y.entities[:randOnePoint]...)

    tempGene1 = append(tempGene1, y.entities[randOnePoint:]...)
    tempGene2 = append(tempGene2, x.entities[randOnePoint:]...)

    retGene1 := individual{tempGene1, len(tempGene1), fitness(tempGene1), 0}
    retGene2 := individual{tempGene2, len(tempGene2), fitness(tempGene2), 0}
    if debug {
        fmt.Println("RandomOnePointCrossover -", "Child1:", retGene1)
        fmt.Println("RandomOnePointCrossover -", "Child2:", retGene2)
    }
    return retGene1, retGene2
}

func (p *population) KillWeak() {
    // fmt.Println(p.individuals)
    sort.Sort(byFitness(p.individuals))
    p.individuals = append(p.individuals[len(p.individuals)-amountOfIndividuals:])
    // fmt.Println(p.individuals)
    p.RefreshAvgFitness()
}

type Config struct {
    entities int
    individuals int
    targetFitness int
    seed string
}