#!/usr/bin/env python3
#
# 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 io
import re
import getopt
from zipfile import ZipFile
import cchardet as chardet
from ExtensionCrawler.js_mincer import mince_js, JsBlockType

# 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-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("    -r regexp select only comments/code/strings where regexp matches")

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."""
    comment = True
    strings = False
    group = False
    program = False
    regexp = None
    filename = None
    path = None

    try:
        opts, args = getopt.getopt(argv, "hcsnvr:",["--regesp"])
    except getopt.GetoptError:
        helpmsg()
        sys.exit(2)
    for opt, arg in opts:
        if opt == '-h':
            helpmsg()
            sys.exit()
        elif opt == '-n':
            comment = False
        elif opt == '-s':
            strings = True
        elif opt == '-g':
            group = True
        elif opt == '-c':
            program = True
        elif opt in ('-r', "--regexp"):
            regexp = 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()
                encoding =  chardet.detect(data)['encoding']
                data = None
            with crxobj.open(path) as js_file:
                with io.TextIOWrapper(js_file, encoding) as js_text_file_obj:
                    for block in mince_js(js_text_file_obj, single_line_comments_block=group):
                         print_block(comment, program, strings, regexp, block)
    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()
                    encoding =  chardet.detect(data)['encoding']
                    data = None
                with crxobj.open(jsfile) as js_file_obj:
                    with io.TextIOWrapper(js_file_obj, encoding) as js_text_file_obj:
                        for block in mince_js(js_text_file_obj, single_line_comments_block=group):
                            print_block(comment, program, strings, regexp, block)
    else:
        for block in mince_js(filename, single_line_comments_block=group):
            print_block(comment, program, strings, regexp, block)
            
if __name__ == "__main__":
    main(sys.argv[1:])