from random import choice

class RandomWalk():
    """ a class to generate random walks """
    def __init__(self, num_points=5000):
        """ initializes attributes of a walk """
        self.num_points = num_points

        """ all walks start at (0,0) """
        self.x_values = [0]
        self.y_values =[0]

    def fill_walk(self):
        """ calculate all the points in the walk """
        # keep taking steps until the walk reaches the desired length
        while len(self.x_values) < self.num_points:
            # decide which direction to go and how far to go in that direction 
            x_direction = choice([1, -1])
            x_distance = choice([0, 1, 2, 3, 4])
            x_step = x_direction * x_distance

            y_direction = choice([1, -1])
            y_distance = choice([0, 1, 2, 3, 4])
            y_step = y_direction * y_distance

            # rejects moves that go nowhere 
            if x_step == 0 and y_step == 0:
                continue
            
            # calculate the next x and y values
            next_x = self.x_values[-1] + x_step
            next_y = self.y_values[-1] + y_step

            self.x_values.append(next_x)
            self.y_values.append(next_y)





