import random


def sort_edges(edges, edge):
    if edge[0] > edge[1]:
        temp = edge[0]
        edge[0] = edge[1]
        edge[1] = temp
    index = 0
    for i in edges:
        if edge[0] < i[0]:
            break
        elif edge[0] == i[0] and edge[1] < i[1]:
            break
        else:
            index += 1
    edges.insert(index, edge)


def generate_tree_from_prufer_code(code):
    L1 = code[:]
    L2 = []
    edges = []
    nodes = set()
    for i in range(len(code)+2):
        L2.append(i+1)
        nodes.add(i+1)
    for k in range(len(L1)):
        current_node = L2[0]
        counter = 1
        while L1.count(current_node) > 0:
            current_node = L2[counter]
            counter += 1
        sort_edges(edges, [code[k], current_node])
        L1.remove(code[k])
        L2.remove(current_node)
    sort_edges(edges, [L2[0], L2[1]])
    return edges


def generate_prufers_code(n: int):
    code = []
    for i in range(n-2):
        code.append(random.randint(1, n))
    return code


def generate_random_graph(n: int, log=False):
    code = generate_prufers_code(n)
    edges = generate_tree_from_prufer_code(code)
    number_of_edges_to_add = random.randint(n//4, int(n/3))
    if log:
        print("number of edges to add:", number_of_edges_to_add)
    counter = 0
    while counter < number_of_edges_to_add:
        node1 = random.randint(1, n)
        node2 = random.randint(1, n)
        while node1 == node2:
            node2 = random.randint(1, n)
        if node1 < node2:
            if [node1, node2] not in edges:
                edges.append([node1, node2])
                counter += 1
        else:
            if [node2, node1] not in edges:
                edges.append([node2, node1])
                counter += 1
    return edges


def write_graph_to_file(graph, filename, path="graphs/"):
    with open(path + filename, 'w') as file:
        for edge in graph:
            weight = random.randint(1, 100)
            file.write(str(edge[0]) + " " + str(edge[1]) + " " + str(weight) + "\n")
            file.write(str(edge[1]) + " " + str(edge[0]) + " " + str(weight) + "\n")


def read_graph_from_file(filename, path="graphs/"):
    N = set()
    A = {}
    A_b = {}
    w = {}
    with open(path + filename, 'r') as file:
        line = file.readline()
        while line != '':
            split = line.strip('\n').split(" ")

            first_node = int(split[0])
            second_node = int(split[1])

            N.add(first_node)
            N.add(second_node)

            if first_node not in A.keys():
                A[first_node] = [second_node]
            else:
                A[first_node].append(second_node)

            if second_node not in A_b.keys():
                A_b[second_node] = [first_node]
            else:
                A_b[second_node].append(first_node)

            w[(first_node, second_node)] = int(split[2])

            line = file.readline()
    return N, A, A_b, w


if __name__ == '__main__':
    for i in range(1, 11):
        n = random.randint(3000, 6000)
        print("generating graph:", i, "of", 10, "with", n, "nodes")
        g = generate_random_graph(n, log=True)
        f = "graph" + str(i)
        write_graph_to_file(g, f)