Projekt_Sztuczna_Inteligencja/searching_algorithms/bfs.py

from __future__ import annotations
from typing import List, Set

from project_constants import Direction, Action

# temporary goal for testing
GOAL = (9, 9)


class State:
    def __init__(self, row, column, direction: Direction):
        self.row = row
        self.column = column
        self.direction = direction


class Node:
    def __init__(self, state: State, parent: Node = None, action: Action = None):
        self.state = state
        self.parent = parent
        self.action = action


def goal_test(state: State):
    if (state.row, state.column) == GOAL:
        return True
    return False


# TODO: depends od Agent Class (rotate/go implementation)
def get_successors(state: State):
    successors = list()

    # state_left = get Agent State after rotate_left()
    # successors.add("rotate_left", state_left)

    # state_right = get Agent State after rotate_right()
    # successors.add("rotate_right", state_right)

    # target = get Agent position after go()
    # if is_valid_move(target):
    # state_go = Agent State after go()
    # successors.add("go", state_go)

    return successors


def graphsearch(fringe: List[Node], explored: Set[Node], initial_state: State):

    fringe.append(Node(initial_state))

    while True:
        # fringe empty -> solution not found
        if not len(fringe):
            return False

        element = fringe.pop(0)

        # solution found, prepare and return actions sequence
        if goal_test(element.state):
            actions_sequence = list()
            parent = element.parent

            while parent is not None:
                # root's action will be None, don't add it
                if parent.action is not None:
                    actions_sequence.append(parent.action)
                parent = parent.parent

            return actions_sequence.reverse()

        explored.add(element)

        for successor in get_successors(element.state):
            # either me or the pseudocode is dumb
            # somebody has to verify it
            fringe_states = [el.state for el in fringe]
            explored_states = [el.state for el in explored]

            if successor.state not in fringe_states and \
                    successor.state not in explored_states:

                new_node = Node(state=successor.state,
                                parent=element,
                                action=successor.action)
                fringe.append(new_node)