#!/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 getopt
import io
import re
import sys
import zlib
from io import StringIO
from zipfile import ZipFile
import collections

import cchardet as chardet
import jsbeautifier

from ExtensionCrawler.js_decomposer import init_file_info
from ExtensionCrawler.js_mincer import JsBlockType, mince_js

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

JsStringsConfig = collections.namedtuple('JsStringsConfig', [
    'comment', 'strings', 'group', 'program', 'beautify', 'regexp'
])


def jsstrings_data(path, data, config):
    file_info = init_file_info(path, data)

    if not file_info['dec_encoding'] is None:
        try:
            with zlib.decompressobj(zlib.MAX_WBITS | 16) as dec:
                dec_data = dec.decompress(data, 100 * file_info['size'])
            str_data = dec_data.decode(file_info['dec_encoding'])
            del dec_data
        except Exception:
            return [file_info]
    else:
        str_data = data.decode(file_info['encoding'])

    if config.beautify:
        str_data = jsbeautifier.beautify(str_data)

    with StringIO(str_data) as str_obj:
        for block in mince_js(
                str_obj, single_line_comments_block=config.group):
            print_block(config.comment, config.program, config.strings,
                        config.regexp, block)


def helpmsg():
    """Print help message."""
    print("crx-jsstrings [OPTION] [crx-file] js-file")
    print("    -h        print this help text")
    print("    -n        no comments")
    print("    -s        strings")
    print("    -g        group single line comments")
    print("    -c        program code")
    print("    -b        beautify JavaScript files before analyzing them")
    print(
        "    -r regexp select only comments/code/strings where regexp matches")
    print(
        "    -d date   use latest extension that was released not later than date (only for tar archives)"
    )


def print_block(comment, program, strings, regexp, block):
    """Print code/comment blocks."""
    rgx = None
    if regexp is not None:
        rgx = re.compile(regexp)
    if comment and block.is_comment():
        if regexp is None or rgx.match(block.content):
            print(block)
    elif block.is_code():
        if program:
            if regexp is None or rgx.match(block.content):
                print(block)
        if strings:
            for string in block.string_literals:
                if regexp is None or rgx.match(string):
                    print(string)


def main(argv):
    """Main function: JavaScript strings on steroids."""
    config = JsStringsConfig(
        comment=True,
        strings=False,
        group=False,
        program=False,
        beautify=False,
        regexp=None)

    filename = None
    path = None
    date = None

    try:
        opts, args = getopt.getopt(argv, "hbcd:snvr:",
                                   ["--regesp", "--date", "--beautify"])
    except getopt.GetoptError:
        helpmsg()
        sys.exit(2)
    for opt, arg in opts:
        if opt == '-h':
            helpmsg()
            sys.exit()
        elif opt == '-n':
            config = config._replace(comment=False)
        elif opt == '-s':
            config = config._replace(strings=True)
        elif opt == '-g':
            config = config._replace(group=True)
        elif opt == '-c':
            config = config._replace(program=True)
        elif opt in ('-b', "--beautify"):
            config = config._replace(beautify=True)
        elif opt in ('-r', "--regexp"):
            config = config._replace(regexp=arg)
        elif opt in ('-r', "--date"):
            date = arg
    if len(args) == 1:
        filename = args[0]
    elif len(args) == 2:
        filename = args[0]
        path = args[1]
    else:
        helpmsg()
        sys.exit()

    if filename.endswith('.crx') and path is not None:
        with ZipFile(filename) as crxobj:
            with crxobj.open(path) as js_file:
                data = js_file.read()
            jsstrings_data(path, data, config)
    elif filename.endswith('.crx') and path is None:
        with ZipFile(filename) as crxobj:
            js_files = list(
                filter(lambda x: x.filename.endswith(".js"),
                       crxobj.infolist()))
            for jsfile in js_files:
                with crxobj.open(jsfile) as js_file_obj:
                    data = js_file_obj.read()
                    path = js_file_obj.name
                jsstrings_data(path, data, config)
    elif filename.endswith('.tar') and path is not None:
        pass
    elif filename.endswith('.tar') and path is None:
        pass
    else:
        with open(filename, 'rb') as fileobj:
            data = fileobj.read()
        jsstrings_data(filename, data, config)


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