#!/usr/bin/env python3

# Copyright (C) 2019-2025 Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http:#mozilla.org/MPL/2.0/.

# Produce System Messages Manual
#
# This tool reads all the message files given on the command line.
# It pulls all the messages and description out, sorts them by
# message ID, and writes them out as a single (formatted) file.
#
# Invocation:
# The code is invoked using the command line:
#
# mes2doc.py [-o <output-file>] <files>
#
# If no output file is specified, output is written to stdout.
# The produced format is ReStructuredText.

import argparse
import os
import pathlib
import re
import sys


def parse_args():
    parser = argparse.ArgumentParser(description='Convert set of *.mes files to .rst documentation format')
    parser.add_argument('-o', '--output', help='Output file name (default to stdout).')
    parser.add_argument('files', help='Input .mes files.', nargs='?')

    args = parser.parse_args()
    return args


def read_input_files(files):
    messages = {}
    for f in files:
        if '/premium/' in f and not pathlib.Path(f).is_file():
            # Premium can be missing which is fine for daily development, and CI tasks.
            print(f'Ignoring non-existing file {f}')
            continue
        with open(f, encoding='utf-8') as fp:
            print(f'Processing {f}')
            msg_descr = None
            msg_id = None
            msg_text = None
            for line in fp.readlines():
                line = line.strip()

                if not line or line.startswith('#'):
                    pass

                elif line.startswith('//'):
                    pass

                elif line.startswith('$'):
                    pass

                elif line.startswith('%'):
                    # end previous message
                    if msg_id is not None:
                        section = msg_id.split('_')[0]
                        messages[msg_id] = (section, msg_id, msg_text, msg_descr)

                    # start next message
                    m = re.search(r'^%\s?([A-Z0-9_]+)\s+(.*)', line)
                    msg_id, msg_text = m.groups()
                    msg_descr = []

                else:
                    msg_descr.append(line)
            if msg_id is not None:
                section = msg_id.split('_')[0]
                messages[msg_id] = (section, msg_id, msg_text, msg_descr)

    return messages


def generate_rst(messages):
    rst = '..\n'
    rst += '    File generated by "doc/sphinx/mes2doc.py" or by "meson compile mes-doc". Do not edit by hand.\n\n'

    rst += '''.. _kea-messages:

###################
Kea Messages Manual
###################

Kea is an open source implementation of the Dynamic Host Configuration
Protocol (DHCP) servers, developed and maintained by Internet Systems
Consortium (ISC).

This is the reference guide for Kea version |release|.
Links to the most up-to-date version of this document (in PDF, HTML,
and plain text formats), along with other useful information about
Kea, can be found in ISC's `Knowledgebase <https://kea.readthedocs.io>`_.

Please note that in the messages below, the percent sign (``%``) followed by a number is
used to indicate a placeholder for data that is provided by the Kea code during its operation.


.. toctree::
   :numbered:
   :maxdepth: 5

'''

    prev_section = None
    for _, msg in sorted(messages.items()):
        section, msg_id, msg_text, msg_descr = msg

        if section != prev_section:
            prev_section = section
            rst += '*' * len(section) + '\n'
            rst += section + '\n'
            rst += '*' * len(section) + '\n'
            rst += '\n'

        rst += msg_id + '\n'
        rst += '=' * len(msg_id) + '\n'
        rst += '\n'

        rst += '.. code-block:: text\n'
        rst += '\n'
        rst += '    ' + msg_text + '\n'
        rst += '\n'

        rst += ''.join([line + '\n' for line in msg_descr])
        rst += '\n'

    rst += '''.. _kea-debug-messages:

*******************************
Kea Debug Messages By Log Level
*******************************

'''
    rst += '.. include:: debug-messages.rst'
    rst += '\n'

    return rst


def generate(in_files, out_file):
    messages = read_input_files(in_files)

    rst = generate_rst(messages)

    if out_file:
        with open(out_file, 'w', encoding='utf-8') as f:
            f.write(rst)
        print('Wrote generated RST content to: %s' % out_file)
    else:
        print(rst)


def main():
    args = parse_args()
    if args.files is None:
        parent_dir = os.path.dirname(os.path.realpath(os.path.abspath(sys.argv[0])))
        mes_files = sorted(pathlib.Path(f'{parent_dir}/../..').glob('**/*.mes'))
        # Convert from Path to str.
        mes_files = [str(i) for i in mes_files]
    else:
        mes_files = args.files
    generate(mes_files, args.output)


if __name__ == '__main__':
    main()
