//Chromosome.h
//
//This file declares a Chromosome class template for use in genetic algorithms
//


#ifndef CHROMOSOME_H
#define CHROMOSOME_H

//crossover types
//crossover may be single point, double point, or multiple point
enum {singlePoint, doublePoint, multiPoint};

//forward declaration
template <class geneType>
class Population;

template <class geneType>
class Chromosome {
  friend class Population<geneType>;
  public:
    Chromosome ();
    ~Chromosome ();

    //copy constructor
    Chromosome (const Chromosome &chrom);

    //initialization function creates a set of genes, and initializes them
    //with random values (the default is 0 or 1; instantiation of the class
    //for double values results in setting the genes to random values in the
    //-1, +1 range
    //numberGenes is the number of genes on each chromosome
    void initialize (int numberGenes);

    //equality operator
    bool operator== (const Chromosome &chrom);

    //assignment operator
    Chromosome& operator= (const Chromosome &chrom);

    //readers and writers
    //readGene returns the value of the gene with index geneNumber
    geneType readGene (int geneNumber);
    //writeGene writes the value "value" into gene "geneNumber"
    void writeGene (int geneNumber, geneType value);
    //readFitness returns the fitness value of the chromosome
    double readFitness ();
    //writeFitness sets the fitness of the chromosome to "value"
    void writeFitness (double value);

    //mutation function
    //default (integer values):  sets 0 to 1, 1 to 0
    //double genes:  adds a value in the (-1,1) range to to genes
    //"mutationProbability" is the probability of mutation of each gene;
    // the default value gives significant mutation
    //mutate returns the number of mutations
    int mutate (double mutationProbability = 0.01);

    //reproduction/crossover functions
    //the first function modifies both the calling and parameter chromosomes,
    //  producing two offspring from two parents, replacing the parents
    //crossoverType is singlePoint, doublePoint, or multiPoint
    void reproduce (Chromosome &chrom, int crossoverType);
    //the next function produces one offspring from two parents, without replacement
    Chromosome reproduceOneOffspring (const Chromosome &chrom, int crossoverType);

  protected:
    int size;  //number of genes
    double fitness;
    geneType *gene;

};

#endif