#!/usr/bin/env python3.5
#
# Copyright (C) 2017 The University of Sheffield, UK
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
"""Tool for extracting crx file from a tar archive."""

import sys
import getopt
import csv
from collections import OrderedDict
from zipfile import ZipFile
from tabulate import tabulate
from ExtensionCrawler.js_decomposer import decompose_js

# Script should run with python 3.4 or 3.5
assert sys.version_info >= (3, 4) and sys.version_info < (3, 6)


def helpmsg():
    """Print help message."""
    print("crx-jsinventory [OPTION] crx-file|js-file")
    print("    -h        print this help text")
    print("    -c=<FILE> cvs file (output)")
    print("    -v        verbose")
    print("    -s        silent")


def main(argv):
    """Main function of the extension crawler."""
    verbose = False
    silent = False
    filename = None
    csvfile = None
    try:
        opts, args = getopt.getopt(argv, "hvsc:", ["cvs="])
    except getopt.GetoptError:
        helpmsg()
        sys.exit(2)
    for opt, arg in opts:
        if opt == '-h':
            helpmsg()
            sys.exit()
        elif opt == '-v':
            verbose = True
        elif opt == '-s':
            silent = True
        elif opt in ('-c', "--cvs"):
            csvfile = arg

    if len(args) > 0:
        filename = args[0]
    else:
        helpmsg()
        sys.exit()

    fieldnames = [
        'jsFilename', 'path', 'size', 'md5', 'sha1', 'encoding', 'type',
        'detectionMethod', 'detectionMethodDetails', 'lib', 'version', 'evidenceText', 
        'evidenceStartPos', 'evidenceEndPos'
    ]

    brief_fieldnames = [
        'jsFilename', 'md5', 'type', 'detectionMethod',  'lib', 'version'
    ]

    if filename.endswith('.crx'):
        with ZipFile(filename) as crxobj:
            inventory = decompose_js(crxobj)
    else:
        inventory = decompose_js(filename)

    if not silent:
        if verbose:
            print_fieldnames = fieldnames
        else:
            print_fieldnames = brief_fieldnames

        print_inventory = []
        for item in inventory:
            tmp = {k: item[k] for k in print_fieldnames}
            if 'type' in tmp:
                tmp['type'] = tmp['type'].value
            if 'detectionMethod' in tmp:
                tmp['detectionMethod'] = tmp['detectionMethod'].value
            if 'md5' in tmp:
                tmp['md5'] = tmp['md5'].hex()
            if 'sha1' in tmp:
                tmp['sha1'] = tmp['sha1'].hex()
            
            print_inventory.append(
                OrderedDict(
                    sorted(
                        tmp.items(),
                        key=lambda t: print_fieldnames.index(t[0]))))
        print(tabulate(print_inventory, headers='keys'))

    if csvfile is not None:
        with open(csvfile, 'w') as csvobj:
            writer = csv.DictWriter(csvobj, fieldnames=fieldnames)
            writer.writeheader()
            writer.writerows(inventory)


if __name__ == "__main__":
    main(sys.argv[1:])