#!/usr/bin/env python3
#
#    A simple convertor of the GSMA Mobile Threat Intelligence Framework (MoTIF) Principles to a MISP Galaxy datastructure.
#    https://www.gsma.com/security/resources/fs-57-mobile-threat-intelligence-framework-motif-principles/
#    Copyright (c) 2024 MISP Project
#    Copyright (c) 2024 Christophe Vandeplas
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Affero General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU Affero General Public License for more details.
#
#    You should have received a copy of the GNU Affero General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.


import pdfplumber
import requests
import json
import tempfile
import os
import uuid


pdf_url = 'https://www.gsma.com/solutions-and-impact/technologies/security/wp-content/uploads/2024/04/FS.57-MoTIF-Principles-v1.0.pdf'
uuid_seed = '5022ff98-cf0d-45d2-89b5-5c63104197cc'


def sub_table_to_list(table: list) -> list:
    if len(table) == 0:
        return []
    try:
        result = []
        # FIXME use header row to know column names
        for row in table:
            result.append({
                'ID': row[2].replace('\n', ''),
                'Name': row[4]. replace('\n', ' ').strip(),
                'Description': row[5]
            })
        return result
    except IndexError:
        return []


def table_to_technique(table: list) -> dict:
    '''
    Convert a table to a technique dictionary
    '''
    result = {}
    row_index = 0
    while row_index < len(table):
        row = table[row_index]

        # row[1] is None : sub-table in table
        field = cleanup_field(row[0])
        try:
            if result['ID'] == 'MOT1036.301':
                pass
        except KeyError:
            pass
        if field == 'Procedure Examples':
            # extract sub-table in the next rows
            sub_table = []
            try:
                while table[row_index + 1][0] is None:
                    sub_table.append(table[row_index + 1])
                    row_index += 1
            except IndexError:  # just the end of the page, will be handled in the next page
                pass
            value = sub_table_to_list(sub_table)
        elif field == 'Analogous technique in other frameworks':
            # column index is not always the same... so figure out the first non-empty cell
            i = 1
            value = ''
            while i < len(row):
                try:
                    if row[i] is not None:
                        value = row[i]
                        break
                except IndexError:
                    pass
                i += 1
        elif not field:
            # annoyingly a sub-table might have been parsed differently from previous page. So bad luck. There's not much we can do about it except even worse code than we have here.
            row_index += 1
            continue
        else:
            value = row[1].replace('\n', ' ').strip()

        result[field] = value

        row_index += 1

    return result


def cleanup_field(field: str) -> str:
    '''
    Cleanup a field name
    '''
    try:
        return field.strip().replace(':', '').replace('\n', ' ').replace('- ', '-').strip()
    except AttributeError:
        return ''


def is_end_of_table(table: list) -> bool:
    '''
    Check if this is the end of the table, by checking the last row in the table.
    '''
    try:
        # Techniques
        if table['ID'].startswith('MOT') and 'Analogous technique in other frameworks' in table:
            return True
        # Mitigations
        if table['ID'].startswith('MOS') and 'References' in table:
            return True

    except KeyError:
        pass
    return False


def parse_pdf(pdf_file_name: str) -> dict:
    table_settings = {
        "vertical_strategy": "lines",
        "horizontal_strategy": "lines",
        # "explicit_vertical_lines": [],
        # "explicit_horizontal_lines": [],
        # "snap_tolerance": 6,
        "snap_x_tolerance": 6,   # pg49: must be 6
        "snap_y_tolerance": 3,   # max 14
        # "join_tolerance": 3,
        # "join_x_tolerance": 3,
        # "join_y_tolerance": 3,
        # "edge_min_length": 3,
        # "min_words_vertical": 3,
        # "min_words_horizontal": 1,
        # "intersection_tolerance": 3,
        # "intersection_x_tolerance": 3,
        # "intersection_y_tolerance": 3,
        # "text_tolerance": 3,
        # "text_x_tolerance": 3,
        # "text_y_tolerance": 3,
    }
    entries = {}

    with pdfplumber.open(pdf_file_name) as pdfp:

        page_index = 0
        title_seen = False
        curr_table = None

        while page_index < len(pdfp.pages):
            page = pdfp.pages[page_index]
            # skip to section 4.1 Techniques and Sub-techniques Definition
            if not title_seen:
                page_text = page.extract_text()
                if '4.1 Techniques and Sub-techniques Definition' not in page_text or 'Table of Contents' in page_text:
                    # print(f"Skipping page {page_index}")
                    page_index += 1
                    continue
                title_seen = True

            # parse technique tables

            for table in page.extract_tables(table_settings=table_settings):
                if curr_table:   # merge tables if continuation
                    # if first row does not have a first column, then it's the continuation of the previous row
                    if table[0][0] == '' and table[0][1] != '':
                        curr_table[-1][1] += ' ' + table[0][1]  # add description of new row to previous row
                        table.pop(0)                            # remove the first new row of the table
                    # annoyingly a sub-table might have been parsed differently from previous page. So bad luck. There's not much we can do about it except even worse code than we have here.
                    # handle rest of merging case
                    table = curr_table + table
                    curr_table = None  # reset for clean start

                parsed_table = table_to_technique(table)
                if is_end_of_table(parsed_table):
                    # valid table
                    parsed_table['page'] = page_index + 1  # minor bug: we document the page where the table ends, not where it starts
                    entries[parsed_table['ID']] = parsed_table
                else:
                    # incomplete table, store in curr_table and continue next row
                    curr_table = table
            page_index += 1
    return entries


print(f"Downloading PDF: {pdf_url}")
r = requests.get(pdf_url, allow_redirects=True)
with tempfile.TemporaryFile() as tmp_f:
    tmp_f.write(r.content)
    print("Parsing PDF ... this takes time")
    items = parse_pdf(tmp_f)
    with open('items.json', 'w') as f:
        json.dump(items, f, indent=2, ensure_ascii=False)

print("Converting to MISP Galaxy ...")
# now convert and extract data to have something clean and usable
kill_chain_tactics = {
    'Techniques': [],
}

techniques = []
for item in items.values():
    if item['ID'].startswith('MOT'):
        kill_chain_root = 'Techniques'
    else:
        # TODO skip these MOS softwares for now
        continue

    if ',' in item['Tactic']:
        tactics = [t.strip().replace(' ', '-') for t in item['Tactic'].split(',')]
    else:
        tactics = [item['Tactic'].replace(' ', '-')]

    kill_chain = []
    for tactic in tactics:
        kill_chain_tactics[kill_chain_root].append(tactic)
        kill_chain.append(f"{kill_chain_root}:{tactic}")

    technique = {
        'value': item['Name'],
        'description': item['Description'],
        'uuid': str(uuid.uuid5(uuid.UUID(uuid_seed), item['ID'])),
        'meta': {
            'kill_chain': kill_chain,
            'refs': [
                f"page {item['page']} of {pdf_url}",
                item['References'],
                item['Analogous technique in other frameworks']
            ],
            'external_id': item['ID'],
        }
    }
    techniques.append(technique)
    # TODO relations + refs as subtechniques


# make entries unique
kill_chain_tactics['Techniques'] = list(set(kill_chain_tactics['Techniques']))


galaxy_fname = 'gsma-motif.json'
galaxy_type = "gsma-motif"
galaxy_name = "GSMA MoTIF"
galaxy_description = 'Mobile Threat Intelligence Framework (MoTIF) Principles. '
galaxy_source = 'https://www.gsma.com/solutions-and-impact/technologies/security/latest-news/establishing-motif-the-mobile-threat-intelligence-framework/'
json_galaxy = {
    'description': galaxy_description,
    'icon': "user-shield",
    'kill_chain_order': kill_chain_tactics,
    'name': galaxy_name,
    'namespace': "gsma",
    'type': galaxy_type,
    'uuid': "57cf3a17-e186-407a-b58b-d53887ce4950",
    'version': 1
}

json_cluster = {
    'authors': ["GSMA"],
    'category': 'attack-pattern',
    'name': galaxy_name,
    'description': galaxy_description,
    'source': galaxy_source,
    'type': galaxy_type,
    'uuid': "02cb3863-ecb2-4a93-a5ed-18bb6dfd5c89",
    'values': list(techniques),
    'version': 1
}


# save the Galaxy and Cluster file
# with open(os.path.join('..', 'galaxies', galaxy_fname), 'w') as f:
#     # sort_keys, even if it breaks the kill_chain_order , but jq_all_the_things requires sorted keys
#     json.dump(json_galaxy, f, indent=2, sort_keys=True, ensure_ascii=False)
#     f.write('\n')  # only needed for the beauty and to be compliant with jq_all_the_things

with open(os.path.join('..', 'clusters', galaxy_fname), 'w') as f:
    json.dump(json_cluster, f, indent=2, sort_keys=True, ensure_ascii=False)
    f.write('\n')  # only needed for the beauty and to be compliant with jq_all_the_things

print("All done, please don't forget to ./jq_all_the_things.sh, commit, and then ./validate_all.sh.")