import yaml
import sys

VAR_DELIM = ","
KEY_DELIM = ":"


def int_try_parse(value):
    try:
        return int(value)
    except ValueError:
        return value


def add_field(file_dict, key, value):
    fields = key.split(".")
    current = file_dict

    for idx, field, in enumerate(fields):
        if current.get(field) is None:
            if idx == len(fields) - 1:
                current[field] = int_try_parse(value)
            else:
                current[field] = {}
                current = current[field]
        else:
            current = current[field]
    return file_dict


def build_dict(list_of_keys):
    file_dict = {}
    pairs = list_of_keys.split(VAR_DELIM)
    for pair in pairs:
        [key, value] = pair.split(KEY_DELIM)
        file_dict = add_field(file_dict, key, value)

    return file_dict


def write_out_yaml_file(filename, to_yaml_dict):
    with open(filename, 'w') as outfile:
        yaml.dump(to_yaml_dict, outfile, default_flow_style=False)


def print_usage():
    usage = """
    NAME
        make_yaml.py - produces a yaml file from a list of key/value pairs

    SYNOPSIS
        make_yaml.py [filename] [key_value_list]

        The [key_value_list] is a list, delimited by {VAR_DELIM}, which specifies a yaml key at arbitrary depth
        and its value. The key/value are delimited by {KEY_DELIM}.

    EXAMPLE
        $ make_yaml.py out.yaml one:1,two:2,three.four.five:5,three.six:6,three.four.eight:8
        will produce a file called out.yaml with the contents:

        one: '1'
        three:
          four:
            eight: '8'
            five: '5'
          six: '6'
        two: '2'
    """

    print(usage)


def main(output_file, list_of_keys):
    to_yaml_dict = build_dict(list_of_keys)
    write_out_yaml_file(output_file, to_yaml_dict)


if __name__ == "__main__":
    if len(sys.argv) != 3:
        print_usage()
    else:
        _output_file = sys.argv[1]
        _list = sys.argv[2]

        main(_output_file, _list)