def heuristic_cost(start, goal, graph):
    return 0


def a_star_algorithm(graph, point_set, start, goal, h=heuristic_cost):
    for edge in graph.keys():
        point_set[edge[0]].append(edge[1])
        point_set[edge[1]].append(edge[0])
    open_set = set()
    open_set.add(start)
    came_from = {}
    g_score = {k: float('inf') for k in point_set.keys()}
    g_score[start] = 0
    f_score = {k: float('inf') for k in point_set.keys()}
    f_score[start] = h(start, goal, graph)
    while len(open_set) > 0:
        current = list(open_set)[0]
        for k in open_set:
            if f_score[k] < f_score[current]:
                current = k
        if current == goal:
            return came_from, current
        open_set.remove(current)
        for neighbor in point_set[current]:
            tentative_g_score = g_score[current]
            if current > neighbor:
                tentative_g_score += graph[(current, neighbor)]
            else:
                tentative_g_score += graph[(neighbor, current)]
            if tentative_g_score < g_score[neighbor]:
                came_from[neighbor] = current
                g_score[neighbor] = tentative_g_score
                f_score[neighbor] = g_score[neighbor] + h(neighbor, goal, graph)
                if neighbor not in open_set:
                    open_set.add(neighbor)


if __name__ == "__main__":
    g = {
        (2, 1): 3,
        (3, 2): 2,
        (5, 3): 1,
        (9, 5): 5,
        (10, 9): 4,
        (9, 4): 3,
        (4, 1): 4,
        (7, 1): 6,
        (3, 1): 4,
        (6, 2): 3,
        (8, 6): 8,
        (8, 3): 2
    }

    v = dict()
    for i in g.keys():
        v[i[0]] = []
        v[i[1]] = []

    print(a_star_algorithm(g, v, 7, 10, heuristic_cost))