"""
This is an empty docstring.
"""

import numpy as np

class Force:

    def __init__(self, components):
        self.components = np.array(components, dtype='float64')

    def get_component(self, c_component):
        return self.components[c_component]

    def print(self):
        print('{}'.format(self.components))


class Constraint:

    def __init__(self, free):
        self.free = free

    def is_free(self, c_component):
        return self.free[c_component]

    def print(self):
        print('{}'.format(self.free))


class Node:

    def __init__(self, position):
        self.position = np.array(position, dtype='float64')
        self.displacement = np.array((3, 1), dtype='float64')
        self.constraint = Constraint()
        self.force = Force()
        self.dof_numbers = np.array((3, 1), dtype='float64')

    def get_position(self):
        return self.position

    def get_displacement(self):
        return self.displacement

    def set_displacement(self, new_displacement):
        self.displacement = new_displacement

    def set_constraint(self, new_constraint):
        self.constraint = new_constraint

    def get_constraint(self, c_component):
        return self.constraint

    def set_force(self, new_force):
        self.force = new_force

    def get_force(self):
        return self.force

    def enumerate_dofs(self, start):
        current_dof = start

        if not self.constraint:
            self.dof_numbers = [current_dof, current_dof+1, current_dof+2]

        else:
            for i in range(2):
                if not self.constraint.is_free(i):
                    self.dof_numbers[i] = -1
                else:
                    self.dof_numbers[i] = current_dof
                    current_dof = current_dof + 1

        return current_dof

    def get_dof_numbers(self):
        return self.dof_numbers

    def print(self):
        print('{}'.format(self.position))


class Element:
    """
    """

    def __init__(self, elastic_modulus, area, node_1, node_2):
        self.elastic_modulus = elastic_modulus
        self. area = area
        self.node_1 = node_1
        self.node_2 = node_2
        self.dof_numbers = np.array((6, 1), dtype='float64')

    def compute_stiffness_matrix(self):
        K = np.array((6,6), dtype='float64')
        diff = np.array((3,1), dtype='float64')
        component_1 = np.array((3,3), dtype='float64')
        component_2 = np.array((3,3), dtype='float64')

        diff = self.node_2.get_position() - self.node_1.get_position()
        component_1 =