import simplejson as json
from sys import argv
from codecs import open


def read_all_nodes(file):
    with open(file, 'r', 'utf-8') as f:
        result = f.read()
        root = json.loads(result)
        return root["nodes"]


def write_nodes(nodes, current, deep, file):
    children = [n for n in nodes if n["parentid"] == current]
    if len(children) > 0:
        for child in children:
            file.write("\t" * deep)
            file.write(child["topic"])
            file.write("\n")
            write_nodes(nodes, child["id"], deep + 1, file)


if __name__ == "__main__":
    nodes = read_all_nodes(argv[1])
    root = [n for n in nodes if n["isroot"]][0]
    with open("output.txt", "w", "utf-8") as f:
        f.write(root["topic"])
        f.write("\n")
        write_nodes(nodes,root["id"],1,f)