/**
 * \file
 * \author Egor Tensin <Egor.Tensin@gmail.com>
 * \date 2015
 * \copyright This file is licensed under the terms of the MIT License.
 *            See LICENSE.txt for details.
 */

#include "aes_file_common.hpp"

#include <aesni/all.h>

#include <aesnixx/all.hpp>

#include <boost/program_options.hpp>

#include <cstdlib>

#include <exception>
#include <fstream>
#include <iostream>
#include <string>
#include <utility>
#include <vector>

namespace
{
    std::ifstream::pos_type get_file_size(const std::string& path)
    {
        std::ifstream ifs;
        ifs.exceptions(std::ifstream::badbit | std::ifstream::failbit);
        ifs.open(path, std::ifstream::binary | std::ifstream::ate);
        return ifs.tellg();
    }

    std::vector<char> read_file(const std::string& path)
    {
        const auto size = static_cast<std::size_t>(get_file_size(path));

        std::ifstream ifs;
        ifs.exceptions(std::ifstream::badbit | std::ifstream::failbit);
        ifs.open(path, std::ifstream::binary);

        std::vector<char> src_buf;
        src_buf.reserve(size);
        src_buf.assign(std::istreambuf_iterator<char>(ifs),
                       std::istreambuf_iterator<char>());
        return src_buf;
    }

    void write_file(const std::string& path, const std::vector<char>& src)
    {
        std::ofstream ofs;
        ofs.exceptions(std::ofstream::badbit | std::ofstream::failbit);
        ofs.open(path, std::ofstream::binary);
        ofs.write(src.data(), src.size());
    }
}

int main(int argc, char** argv)
{
    try
    {
        CommandLineParser cmd_parser("aes_encrypt_file.exe");

        if (!cmd_parser.parse_options(argc, argv))
            return 0;

        auto args = cmd_parser.get_args();

        if (args.empty())
        {
            cmd_parser.print_usage();
            return 1;
        }

        AesNI_BoxAlgorithmParams algorithm_params;

        switch (cmd_parser.get_algorithm())
        {
            case AESNI_AES128:
                aesni::aes::from_string(algorithm_params.aes128_key, args.front());
                break;

            case AESNI_AES192:
                aesni::aes::from_string(algorithm_params.aes192_key, args.front());
                break;

            case AESNI_AES256:
                aesni::aes::from_string(algorithm_params.aes256_key, args.front());
                break;
        }

        args.pop_front();

        AesNI_BoxBlock iv;
        AesNI_BoxBlock* iv_ptr = nullptr;

        switch (cmd_parser.get_mode())
        {
            case AESNI_ECB:
                break;

            case AESNI_CBC:
            case AESNI_CFB:
            case AESNI_OFB:
            case AESNI_CTR:
                if (args.empty())
                {
                    cmd_parser.print_usage();
                    return 1;
                }
                aesni::aes::from_string(iv.aes_block, args.front());
                iv_ptr = &iv;
                args.pop_front();
                break;
        }

        if (args.size() != 2)
        {
            cmd_parser.print_usage();
            return 1;
        }

        const auto src_path = args[0];
        const auto dest_path = args[1];

        const auto src_buf = read_file(src_path);

        AesNI_Box box;

        aesni_box_init(
            &box,
            cmd_parser.get_algorithm(),
            &algorithm_params,
            cmd_parser.get_mode(),
            iv_ptr,
            aesni::ErrorDetailsThrowsInDestructor());

        std::size_t dest_size;

        aesni_box_decrypt_buffer(
            &box,
            src_buf.data(),
            src_buf.size(),
            nullptr,
            &dest_size,
            aesni::ErrorDetailsThrowsInDestructor());

        std::vector<char> dest_buf;
        dest_buf.resize(dest_size);

        aesni_box_decrypt_buffer(
            &box,
            src_buf.data(),
            src_buf.size(),
            dest_buf.data(),
            &dest_size,
            aesni::ErrorDetailsThrowsInDestructor());

        dest_buf.resize(dest_size);

        write_file(dest_path, dest_buf);

        return 0;
    }
    catch (const boost::program_options::error& e)
    {
        std::cerr << "Usage error: " << e.what() << "\n";
        return 1;
    }
    catch (const aesni::Error& e)
    {
        std::cerr << e;
        return 1;
    }
    catch (const std::exception& e)
    {
        std::cerr << e.what() << "\n";
        return 1;
    }
}