/*
 * Copyright (c) 2015, Peter Thorson. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the WebSocket++ Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL PETER THORSON BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

 /**
  * NOTES
  *
  * This example uses a number of standard classes through the websocketpp::lib
  * namespace. This is to allow easy switching between Boost, the C++11 STL, and 
  * the standalone Asio library. Your program need not use these namespaces if
  * you do not need this sort of flexibility.
  */

#include <websocketpp/config/asio.hpp>

#include <websocketpp/server.hpp>

#include <iostream>

typedef websocketpp::server<websocketpp::config::asio_tls> server;

using websocketpp::lib::placeholders::_1;
using websocketpp::lib::placeholders::_2;
using websocketpp::lib::bind;

// pull out the type of messages sent by our config
typedef websocketpp::config::asio::message_type::ptr message_ptr;
typedef websocketpp::lib::shared_ptr<websocketpp::lib::asio::ssl::context> context_ptr;

void on_message(server* s, websocketpp::connection_hdl hdl, message_ptr msg) {
    std::cout << "on_message called with hdl: " << hdl.lock().get()
              << " and message: " << msg->get_payload()
              << std::endl;

    try {
        s->send(hdl, msg->get_payload(), msg->get_opcode());
    } catch (websocketpp::exception const & e) {
        std::cout << "Echo failed because: "
                  << "(" << e.what() << ")" << std::endl;
    }
}

void on_http(server* s, websocketpp::connection_hdl hdl) {
    server::connection_ptr con = s->get_con_from_hdl(hdl);
    
    con->set_body("Hello World!");
    con->set_status(websocketpp::http::status_code::ok);
}

std::string get_password() {
    return "test";
}

// See https://wiki.mozilla.org/Security/Server_Side_TLS for more details about
// the TLS modes. The code below demonstrates how to implement both the modern
enum tls_mode {
    MOZILLA_INTERMEDIATE = 1,
    MOZILLA_MODERN = 2
};

context_ptr on_tls_init(tls_mode mode, websocketpp::connection_hdl hdl) {
    namespace asio = websocketpp::lib::asio;

    std::cout << "on_tls_init called with hdl: " << hdl.lock().get() << std::endl;
    std::cout << "using TLS mode: " << (mode == MOZILLA_MODERN ? "Mozilla Modern" : "Mozilla Intermediate") << std::endl;

    context_ptr ctx = websocketpp::lib::make_shared<asio::ssl::context>(asio::ssl::context::sslv23);

    try {
        if (mode == MOZILLA_MODERN) {
            // Modern disables TLSv1
            ctx->set_options(asio::ssl::context::default_workarounds |
                             asio::ssl::context::no_sslv2 |
                             asio::ssl::context::no_sslv3 |
                             asio::ssl::context::no_tlsv1 |
                             asio::ssl::context::single_dh_use);
        } else {
            ctx->set_options(asio::ssl::context::default_workarounds |
                             asio::ssl::context::no_sslv2 |
                             asio::ssl::context::no_sslv3 |
                             asio::ssl::context::single_dh_use);
        }
        ctx->set_password_callback(bind(&get_password));
        ctx->use_certificate_chain_file("server.pem");
        ctx->use_private_key_file("server.pem", asio::ssl::context::pem);
        
        // Example method of generating this file:
        // `openssl dhparam -out dh.pem 2048`
        // Mozilla Intermediate suggests 1024 as the minimum size to use
        // Mozilla Modern suggests 2048 as the minimum size to use.
        ctx->use_tmp_dh_file("dh.pem");
        
        std::string ciphers;
        
        if (mode == MOZILLA_MODERN) {
            ciphers = "ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK";
        } else {
            ciphers = "ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA";
        }
        
        if (SSL_CTX_set_cipher_list(ctx->native_handle() , ciphers.c_str()) != 1) {
            std::cout << "Error setting cipher list" << std::endl;
        }
    } catch (std::exception& e) {
        std::cout << "Exception: " << e.what() << std::endl;
    }
    return ctx;
}

int main() {
    // Create a server endpoint
    server echo_server;

    // Initialize ASIO
    echo_server.init_asio();

    // Register our message handler
    echo_server.set_message_handler(bind(&on_message,&echo_server,::_1,::_2));
    echo_server.set_http_handler(bind(&on_http,&echo_server,::_1));
    echo_server.set_tls_init_handler(bind(&on_tls_init,MOZILLA_INTERMEDIATE,::_1));

    // Listen on port 9002
    echo_server.listen(9002);

    // Start the server accept loop
    echo_server.start_accept();

    // Start the ASIO io_service run loop
    echo_server.run();

}