#include "annealing.h"



double cooling_temperature=0.9999;
double initial_temperature=1000.0;
double minimal_temperature=0.0001;
unsigned int iterations=100;
double current_temperature;


double current_length;
double best_length;
int* current_path;
int* best_path;

int get_iterations() { return iterations; }
double get_minimal_temperature() { return minimal_temperature; }
double get_initial_temperature() { return initial_temperature; }
double get_cooling_temperature() { return cooling_temperature; }

void random_swap(int numberOfCities)
{
	int a = std::rand() % numberOfCities;
	int b = std::rand() % numberOfCities;
	while (a == b) b = std::rand() % numberOfCities;

	current_path = best_path;
	int temporary = current_path[a];
	current_path[a] = current_path[b];
	current_path[b] = temporary;
}

double path_length(int** matrix,int* path, int numberOfCities)
{
  int len=0;
	int vertex1, vertex2;
	for(int i = 0; i<numberOfCities-1;i++)
	{
			vertex1 = path[i];
			vertex2 = path[i+1];
			len+=matrix[vertex1][vertex2];
	}
	len+=matrix[vertex2][path[0]];

	return len;
}

double probability()
{
	double power = -((current_length - best_length) / current_temperature);
	return pow(M_E, power);
}

void annealing(int** matrix,int numberOfCities)
{
  	current_temperature = initial_temperature;
    current_path = new int[numberOfCities];
    best_path = new int[numberOfCities];


  	for (unsigned int i = 0; i <numberOfCities; i++)
  		current_path[i] = i;
    current_length = path_length(matrix,current_path, numberOfCities);

    for (size_t i = 0; i < numberOfCities; i++)
      best_path[i] = current_path[i];
    best_length = current_length;

  	srand((unsigned int)time(NULL));



	while (current_temperature > minimal_temperature)
	{
		for (int j = 0; j < iterations; j++)
		{
			random_swap(numberOfCities);
			current_length = path_length(matrix,current_path,numberOfCities);

			if (current_length < best_length || ((double)rand() / (double)RAND_MAX) < probability())
			{
        best_path = current_path;
        best_length = current_length;

        // for (unsigned int i = 0; i < numberOfCities; i++)
        //   cout << " " << best_path[i];
        // cout << " " << best_path[0] << " | " << best_length << endl;

      }
		}
		current_temperature *= cooling_temperature;
	}

  for (unsigned int i = 0; i < numberOfCities; i++)
    cout << " " << best_path[i];
  cout << " " << best_path[0] << " | " << best_length << endl;

}