Trashmaster/path_search_algorthms/a_star.py

from data_structures.heap import Heap
from path_search_algorthms import a_star_utils as utils


def get_cost(start_x: int, start_y: int, target_x: int, target_y: int, array):
    actions = search_path(start_x, start_y, utils.Rotation.NONE, target_x, target_y, array)
    if actions is None:
        return 1
    return len(actions)


def search_path(start_x: int, start_y: int, agent_rotation: utils.Rotation, target_x: int, target_y: int, array):
    start_node = utils.Node(start_x, start_y, agent_rotation)
    target_node = utils.Node(target_x, target_y, utils.Rotation.NONE)

    # heap version

    # nodes for check
    search_list = Heap()
    search_list.append(start_node, 0)

    # checked nodes
    searched_list: list[(int, int)] = []

    while (search_list.length() > 0):
        node: utils.Node = search_list.take_first()

        searched_list.append((node.x, node.y))

        # check for target node
        if ((node.x, node.y) == (target_x, target_y)):
            return trace_path(node)

        # neightbours processing
        neighbours = utils.get_neighbours(node, searched_list, array)
        for neighbour in neighbours:

            # calculate new g cost for neightbour (start -> node -> neightbour)
            new_neighbour_cost = node.g_cost + utils.get_neighbour_cost(node, neighbour)

            if (new_neighbour_cost < neighbour.g_cost or not search_list.contains(neighbour)):

                # replace cost and set parent node
                neighbour.g_cost = new_neighbour_cost
                neighbour.h_cost = utils.get_h_cost(neighbour, target_node)
                neighbour.parent = node

                # add to search
                if (not search_list.contains(neighbour)):
                    search_list.append(neighbour, neighbour.f_cost())


def trace_path(end_node: utils.Node):
    path = []
    node = end_node

    # set final rotation of end_node because we don't do it before
    node.rotation = utils.get_needed_rotation(node.parent, node)

    while (node.parent != False):
        if (node.parent == utils.Rotation.NONE):
            path += "forward"
        else:
            path += utils.get_move(node.parent, node)
        node = node.parent

    # delete move on initial tile
    path.pop()

    # we found path from end, so we need to reverse it (get_move reverse move words)
    path.reverse()

    # last forward to destination
    path.append("forward")

    return path