import math

class Model:

    def __init__(self):
        self.best_solution = []
        self.best_fitness = float("Inf")
        self.fitness_list = []

    def init(self, coords):
        self.coords = coords
        self.N = len(coords)
        self.nodes = [i for i in range(self.N)]

    def dist(self, node_0, node_1):
        """
        Euclidean distance between two nodes.
        """
        coord_0, coord_1 = self.coords[node_0], self.coords[node_1]
        return math.sqrt((coord_0[0] - coord_1[0]) ** 2 + (coord_0[1] - coord_1[1]) ** 2)

    def fitness(self, solution):
        """
        Total distance of the current solution path.
        """
        cur_fit = 0
        for i in range(self.N):
            cur_fit += self.dist(solution[i % self.N], solution[(i + 1) % self.N])
        return cur_fit

    def fit(self):
        raise NotImplementedError("Your fitting method not implemented yet")

    def log(self, message):
        print('[{name}] {msg}'.format(name=self.__class__.__name__, msg=message))