"""
Example Generate basic documeentation for arguments. :)
python generate_doc.py -md > doc.md
"""
import argparse

def add_md_help_argument(parser):
    """ md help parser """
    parser.add_argument('-md', action=MarkdownHelpAction,
                        help='print Markdown-formatted help text and exit.')


# MARKDOWN boilerplate

# Copyright 2016 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
class MarkdownHelpFormatter(argparse.HelpFormatter):
    """A really bare-bones argparse help formatter that generates valid markdown.
    This will generate something like:
    usage
    # **section heading**:
    ## **--argument-one**
    ```
    argument-one help text
    ```
    """

    def _format_usage(self, usage, actions, groups, prefix):
        return ""

    def format_help(self):
        print(self._prog)
        self._root_section.heading = '# Options: %s' % self._prog
        return super(MarkdownHelpFormatter, self).format_help()

    def start_section(self, heading):
        super(MarkdownHelpFormatter, self) \
            .start_section('### **%s**' % heading)

    def _format_action(self, action):
        if action.dest == "help" or action.dest == "md":
            return ""
        lines = []
        lines.append('* **-%s %s** ' % (action.dest,
                                        "[%s]" % action.default
                                        if action.default else "[]"))
        if action.help:
            help_text = self._expand_help(action)
            lines.extend(self._split_lines(help_text, 80))
        lines.extend(['', ''])
        return '\n'.join(lines)


class MarkdownHelpAction(argparse.Action):
    """ MD help action """

    def __init__(self, option_strings,
                 dest=argparse.SUPPRESS, default=argparse.SUPPRESS,
                 **kwargs):
        super(MarkdownHelpAction, self).__init__(
            option_strings=option_strings,
            dest=dest,
            default=default,
            nargs=0,
            **kwargs)

    def __call__(self, parser, namespace, values, option_string=None):
        parser.formatter_class = MarkdownHelpFormatter
        parser.print_help()
        parser.exit()

def model_opts(parser):
    """
    Example args
    """
    parser.add_argument('-rnn_size', type=int, default=500,
                        help='Size of LSTM hidden states')
    parser.add_argument('-emb_size', type=int, default=200,
                        help='Size of embedding layer')
    parser.add_argument('-rnn_type', type=str, default='LSTM',
                        choices=['LSTM', 'GRU'],
                        help="""The gate type to use in the RNNs""")

def main():
    parser = argparse.ArgumentParser(description='train.py')
    model_opts(parser)
    add_md_help_argument(parser)
    options = parser.parse_args()

if __name__ == '__main__':
    main()