#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Stegano - Stegano is a pure Python steganography module.
# Copyright (C) 2010-2019 Cédric Bonhomme - https://www.cedricbonhomme.org
#
# For more information : https://github.com/cedricbonhomme/Stegano
#
# 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 <http://www.gnu.org/licenses/>

__author__ = "Cedric Bonhomme"
__version__ = "$Revision: 0.7 $"
__date__ = "$Date: 2016/03/18 $"
__revision__ = "$Date: 2019/06/04 $"
__license__ = "GPLv3"

import inspect
import crayons

try:
    from stegano import lsbset
    from stegano.lsbset import generators
except:
    print("Install stegano: pipx install Stegano")

from stegano import tools

import argparse



class ValidateGenerator(argparse.Action):
    def __call__(self, parser, args, values, option_string=None):
        valid_generators = [generator[0] for generator in inspect.getmembers(
            generators, inspect.isfunction)]
        # Verify that the generator is valid
        generator = values[0]
        if generator not in valid_generators:
            raise ValueError("Unknown generator: %s" % generator)
        # Set the generator_function arg of the parser
        setattr(args, self.dest, values)

def main():
    parser = argparse.ArgumentParser(prog='stegano-lsb-set')
    subparsers = parser.add_subparsers(help='sub-command help', dest='command')

    # Subparser: Hide
    parser_hide = subparsers.add_parser('hide', help='hide help')
    # Original image
    parser_hide.add_argument("-i", "--input", dest="input_image_file",
                             required=True, help="Input image file.")
    parser_hide.add_argument("-e", "--encoding", dest="encoding",
                             choices=tools.ENCODINGS.keys(), default='UTF-8',
                             help="Specify the encoding of the message to hide." +
                             " UTF-8 (default) or UTF-32LE.")

    # Generator
    parser_hide.add_argument("-g", "--generator", dest="generator_function",
                             action=ValidateGenerator,
                             nargs='*', required=True, help="Generator (with optional arguments)")
    parser_hide.add_argument("-s", "--shift", dest="shift",
                             default=0, help="Shift for the generator")

    group_secret = parser_hide.add_mutually_exclusive_group(required=True)
    # Non binary secret message to hide
    group_secret.add_argument("-m", dest="secret_message",
                              help="Your secret message to hide (non binary).")
    # Binary secret message to hide
    group_secret.add_argument("-f", dest="secret_file",
                              help="Your secret to hide (Text or any binary file).")

    # Image containing the secret
    parser_hide.add_argument("-o", "--output", dest="output_image_file",
                             required=True, help="Output image containing the secret.")


    # Subparser: Reveal
    parser_reveal = subparsers.add_parser('reveal', help='reveal help')
    parser_reveal.add_argument("-i", "--input", dest="input_image_file",
                               required=True, help="Input image file.")
    parser_reveal.add_argument("-e", "--encoding", dest="encoding",
                               choices=tools.ENCODINGS.keys(), default='UTF-8',
                               help="Specify the encoding of the message to reveal." +
                               " UTF-8 (default) or UTF-32LE.")
    parser_reveal.add_argument("-g", "--generator", dest="generator_function",
                               action=ValidateGenerator,
                               nargs='*', required=True, help="Generator (with optional arguments)")
    parser_reveal.add_argument("-s", "--shift", dest="shift",
                               default=0, help="Shift for the generator")
    parser_reveal.add_argument("-o", dest="secret_binary",
                               help="Output for the binary secret (Text or any binary file).")


    # Subparser: List generators
    parser_list_generators = subparsers.add_parser('list-generators',
                                                   help='list-generators help')

    arguments = parser.parse_args()

    if arguments.command != 'list-generators':
        try:
            arguments.generator_function[0]
        except AttributeError:
            print('You must specify the name of a generator.')
            parser.print_help()
            exit(1)

        try:
            if (arguments.generator_function[0] == "LFSR"):
                # Compute the size of the image for use by the LFSR generator if needed
                tmp = tools.open_image(arguments.input_image_file)
                size = tmp.width * tmp.height
                tmp.close()
                arguments.generator_function.append(size)
            if (len(arguments.generator_function) > 1):
                generator = getattr(generators, arguments.generator_function[0])(
                    *[int(e) for e in arguments.generator_function[1:]])
            else:
                generator = getattr(generators, arguments.generator_function[0])()

        except AttributeError as e:
            print("Unknown generator: {}".format(arguments.generator_function))
            exit(1)

    if arguments.command == 'hide':
        if arguments.secret_message != None:
            secret = arguments.secret_message
        elif arguments.secret_file != "":
            secret = tools.binary2base64(arguments.secret_file)

        img_encoded = lsbset.hide(arguments.input_image_file, secret, generator,
                                  int(arguments.shift))
        try:
            img_encoded.save(arguments.output_image_file)
        except Exception as e:
            # If hide() returns an error (Too long message).
            print(e)

    elif arguments.command == 'reveal':
        try:
            secret = lsbset.reveal(arguments.input_image_file, generator,
                                   int(arguments.shift))
        except IndexError:
            print("Impossible to detect message.")
            exit(0)
        if arguments.secret_binary != None:
            data = tools.base642binary(secret)
            with open(arguments.secret_binary, "w") as f:
                f.write(data)
        else:
            print(secret)

    elif arguments.command == 'list-generators':
        all_generators = inspect.getmembers(generators, inspect.isfunction)
        for generator in all_generators:
            print('Generator id:')
            print('    {}'.format(crayons.green(generator[0], bold=True)))
            print('Desciption:')
            print('    {}'.format(generator[1].__doc__))
