from problem_interface import *
from ville import *

class Problem_4(Problem_Interface) :
    """
    classe probleme n°4 : TSP
    """
    
    def __init__(self, villes):
        self.__size = len(villes)
        self.__villes = villes
        

        
    def create_individual(self):
        '''
        create a randomly generated indidivual for this problem

        :return: a randomly generated individual gfor this problem
        :rtype: an Individual object
        '''
        return Ville(self.__villes)

    def evaluate_fitness(self, individual):
        '''
        compute the fitness of individual for this problem

        :param individual: the individual to consider
        :type individual: an Individual object
        :return: the fitness of individual for this problem
        :rtype: an Individual object
        '''
        
        return individual.distance_totale()
        
       # return sum([1 if mot[letter]==cherche[letter] else 0 for letter in range(len(mot))])
    

    def sort_population(self, population):
        '''
        sort population from best fitted to worst fitted individuals.
        Depending on the problem, it can correspond to ascending or descending order with respect to the fitness function.

        side effect : population is modified by this method

        :param population: the list of individuals to sort
        :type population: list(Individual)        
        '''
        population.sort(key = lambda x: x.get_score())

    def best_individual(self, population):
        '''
        return the best fitted individual from population.
        Depending on the problem, it can correspond to the individual with the highest or the lowest fitness value.


        :param population: the list of individuals to sort
        :type population: list(Individual)
        :return: the best fitted individual of population
        :rtype: an Individual object
        '''
        self.sort_population(population)
        return population[len(population) -1 ]

    def tournament(self, first, second):
        '''
        perform a rounament between two individuals, the winner is the most fitted one, it is returned


        :param first: an individual
        :type first: an Indivdual object
        :param second: an individual
        :type second: an Individual object
        :return: the winner of the tournament
        :rtype: Individual object
        '''
        if first.get_score() < second.get_score():
            res = first
        else:
            res = second
        return res
        
        return first if first.get_score() < second.get_score() else second