#!/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
parser = argparse.ArgumentParser(prog='stegano-lsb-set')
subparsers = parser.add_subparsers(help='sub-command help', dest='command')


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)


# 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__))
