#!/usr/bin/env python3

# Sample code from http://www.redblobgames.com/pathfinding/tower-defense/implementation.html

# Here's a sample graph node class:

class Node:
    def __init__(self, name):
        self.reached = False
        self.name = name
        self._neighbors = []

    def neighbors(self):
        return self._neighbors

    def __repr__(self):
        return "%s" % self.name

# and a sample graph:

A = Node("A")
B = Node("B")
C = Node("C")
D = Node("D")
E = Node("E")
A._neighbors = [B]
B._neighbors = [A, C]
C._neighbors = [D]
D._neighbors = [E]
E._neighbors = []

ALL_NODES = [A, B, C, D, E]


# Here's Breadth First Search from the article:
# modified to reset "reached" before running

from queue import Queue


def search_from(start, callback):
    open = Queue()
    open.put(start)
    for node in ALL_NODES:
        node.reached = False
    start.reached = True

    while not open.empty():
        current = open.get()
        callback(current)
        for next in current.neighbors():
            if not next.reached:
                next.reached = True
                open.put(next)

results = []
search_from(A, results.append)
print("First search from A: ", results)

results = []
search_from(A, results.append)
print("Second search from A: ", results)