#!/usr/bin/env python3
#
# update-tools-help.py - Update the command line help output in doc/wsug_src.
#
# Wireshark - Network traffic analyzer
# By Gerald Combs <gerald@wireshark.org>
# Copyright 1998 Gerald Combs
#
# SPDX-License-Identifier: GPL-2.0-or-later
'''Update tools help

For each file that matches doc/wsug_src/<command>-<flag>.txt, run
that command and flag. Update the file if the output differs.
'''

import argparse
import difflib
import glob
import os
import re
import subprocess
import sys

def main():
    parser = argparse.ArgumentParser(description='Update Wireshark tools help')
    parser.add_argument('-p', '--program-path', nargs=1, default=os.path.curdir, help='Path to Wireshark executables.')
    args = parser.parse_args()

    this_dir = os.path.dirname(__file__)
    wsug_src_dir = os.path.join(this_dir, '..', 'doc', 'wsug_src')

    tools_help_files = glob.glob(os.path.join(wsug_src_dir, '*-*.txt'))
    tools_help_files.sort()
    tool_pat = re.compile(r'(\w+)(-\w).txt')

    # If tshark is present, assume that our other executables are as well.
    program_path = args.program_path[0]
    if not os.path.isfile(os.path.join(program_path, 'tshark')):
        print('tshark not found at {}\n'.format(program_path))
        parser.print_usage()
        sys.exit(1)

    null_fd = open(os.devnull, 'w')

    for thf in tools_help_files:
        thf_base = os.path.basename(thf)
        m = tool_pat.match(thf_base)
        thf_command = os.path.join(program_path, m.group(1))
        thf_flag = m.group(2)

        if not os.path.isfile(thf_command):
            print('{} not found. Skipping.'.format(thf_command))
            continue

        with open(thf, 'r', encoding='UTF-8') as fd:
            cur_help = fd.read()

        try:
            new_help_data = subprocess.check_output((thf_command, thf_flag), stderr=null_fd)
        except subprocess.CalledProcessError as e:
            if thf_flag == '-h':
                raise e

        new_help = new_help_data.decode('UTF-8', 'replace')

        cur_lines = cur_help.splitlines()
        new_lines = new_help.splitlines()
        # Assume we have an extended version. Strip it.
        cur_lines[0] = re.split(r' \(v\d+\.\d+\.\d+', cur_lines[0])[0]
        new_lines[0] = re.split(r' \(v\d+\.\d+\.\d+', new_lines[0])[0]
        diff = list(difflib.unified_diff(cur_lines, new_lines))

        if (len(diff) > 0):
            print('Updating {} {}'.format(thf_command, thf_flag))
            with open(thf, 'w', encoding='UTF-8') as fd:
                fd.write(new_help)
        else:
            print('{} {} output unchanged.'.format(thf_command, thf_flag))

if __name__ == '__main__':
    main()