/*
    Copyright © 2015 Gluzskiy Alexandr (sss)

    This file is part of Unknown Download Manager (UDM).

    UDM 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 2 of the License, or
    (at your option) any later version.

    UDM 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 UDM.  If not, see <http://www.gnu.org/licenses/>.

*/


#include "client_session.h"
#include <boost/bind.hpp>
#include <boost/log/trivial.hpp>
#include <openssl/sha.h>

std::shared_ptr<char*> pack_data(const std::string &buf, int *size_)
{
    BOOST_LOG_TRIVIAL(debug)<<__FILE__<<":"<<__LINE__<<"\t"<<__func__;
    std::shared_ptr<char*> ptr = std::make_shared<char*>(new char[buf.length() + 4]);
    int32_t size = buf.length();
    *size_ = size + 4;
    (*ptr)[3] = size & 0xff;
    (*ptr)[2] = (size>>8) & 0xff;
    (*ptr)[1] = (size>>16) & 0xff;
    (*ptr)[0] = (size>>24) & 0xff;
    char *fck = (*ptr)+4;
    memcpy(fck, buf.data(), buf.length());
    return ptr;
}

std::shared_ptr<char*> pack_msg(client_msg *msg, int *size_)
{
    BOOST_LOG_TRIVIAL(debug)<<__FILE__<<":"<<__LINE__<<"\t"<<__func__;
    BOOST_LOG_TRIVIAL(trace)<<"packing message:\n"<<msg->DebugString();
    std::string msg_buf;
    msg->SerializeToString(&msg_buf);
    return pack_data(msg_buf, size_);
}


class socket_wraper
{
public:
    socket_wraper(boost::asio::ssl::stream<boost::asio::ip::tcp::socket> *s) : is_ssl(true)
    {
        socket_ssl_ = s;
    }

    socket_wraper(tcp::socket *s) : is_ssl(false)
    {
        socket_ = s;
    }

    void operator=(boost::asio::ssl::stream<boost::asio::ip::tcp::socket> *s)
    {
        socket_ssl_ = s;
        is_ssl = true;
    }
    void operator=(tcp::socket *s)
    {
        socket_ = s;
        is_ssl = false;
    }

    boost::asio::ip::tcp::socket& get_socket()
    {
        return *socket_;
    }

    boost::asio::ssl::stream<boost::asio::ip::tcp::socket>& get_ssl_socket()
    {
        return *socket_ssl_;
    }
    template<typename MutableBufferSequence> std::size_t read_some(const MutableBufferSequence & buffers)
    {
        if(is_ssl)
            return socket_ssl_->read_some(buffers);
        else
            return socket_->read_some(buffers);
    }
    template<typename MutableBufferSequence> std::size_t read_some(const MutableBufferSequence & buffers, boost::system::error_code & ec)
    {
        if(is_ssl)
            return socket_ssl_->read_some(buffers, ec);
        else
            return socket_->read_some(buffers, ec);
    }

    template<typename MutableBufferSequence, typename ReadHandler>  void async_read_some(const MutableBufferSequence & buffers, ReadHandler handler)
    {
        if(is_ssl)
            socket_ssl_->async_read_some(buffers, handler);
        else
            socket_->async_read_some(buffers, handler);
    }

    template<typename ConstBufferSequence, typename WriteHandler> void async_write_some(const ConstBufferSequence & buffers, WriteHandler handler)
    {
        if(is_ssl)
            socket_ssl_->async_write_some(buffers, handler);
        else
            socket_->async_write_some(buffers, handler);
    }
    ~socket_wraper()
    {
        if(is_ssl)
            delete socket_ssl_;
        else
            delete socket_;
    }
private:
    bool is_ssl;
    tcp::socket *socket_;
    boost::asio::ssl::stream<boost::asio::ip::tcp::socket> *socket_ssl_;

};


client_session::client_session(QObject *parent, boost::asio::io_service *io_service) : QObject(parent), io_service_(*io_service)
{
}


/*tcp::socket& client_session::socket()
{
    return *socket_;
} */

void client_session::client_connect(QString host, QString password, int port)
{
    //TODO: settings for connection timeout
    this->pasword = password;
    if(!password.isEmpty())
    {
        unsigned char hash[64];
        SHA512((unsigned char*)password.toUtf8().data(), password.length(), hash);
        password_sha512 = (char*)hash;
    }


    char port_buf[6];
    snprintf(port_buf, 5, "%d", port);
    boost::asio::ip::tcp::resolver r(io_service_);
    boost::asio::ip::tcp::resolver::query query(host.toUtf8().data(), port_buf);
    boost::asio::ip::tcp::resolver::iterator it = r.resolve(query);

    socket_ = new socket_wraper(new tcp::socket(io_service_));

    boost::asio::async_connect(socket_->get_socket(), it, boost::bind(&client_session::handle_connect, this, boost::asio::placeholders::error));
//    socket_.async_connect(ep, boost::bind(&client_session::handle_connect, this, boost::asio::placeholders::error));
    io_service_.run();
}

void client_session::client_connect_ssl(QString host, QString password, int port, QString ssl_ca, QString ssl_crt, QString ssl_key)
{
    ssl_enabled = true;
    this->pasword = password;
    boost::asio::ssl::context ctx(boost::asio::ssl::context::tlsv12_client);
    ctx.load_verify_file(ssl_ca.toUtf8().data());
    ctx.use_certificate_file(ssl_crt.toUtf8().data(), boost::asio::ssl::context::pem);
    ctx.use_private_key_file(ssl_key.toUtf8().data(), boost::asio::ssl::context::pem);
    auto socket_ssl_ = new boost::asio::ssl::stream<boost::asio::ip::tcp::socket>(io_service_, ctx);
    socket_ssl_->set_verify_mode(boost::asio::ssl::verify_peer);
    socket_ssl_->set_verify_callback(boost::bind(&client_session::verify_certificate, this, _1, _2 ));
    socket_ = new socket_wraper(socket_ssl_);

    char port_buf[6];
    snprintf(port_buf, 5, "%d", port);
    boost::asio::ip::tcp::resolver r(io_service_);
    boost::asio::ip::tcp::resolver::query query(host.toUtf8().data(), port_buf);
    boost::asio::ip::tcp::resolver::iterator it = r.resolve(query);

    boost::asio::async_connect(socket_->get_ssl_socket().lowest_layer(), it, boost::bind(&client_session::handle_connect, this, boost::asio::placeholders::error));
}

bool client_session::verify_certificate(bool preverified, boost::asio::ssl::verify_context& /*&ctx*/)
{
  // The verify callback can be used to check whether the certificate that is
  // being presented is valid for the peer. For example, RFC 2818 describes
  // the steps involved in doing this for HTTPS. Consult the OpenSSL
  // documentation for more details. Note that the callback is called once
  // for each certificate in the certificate chain, starting from the root
  // certificate authority.

  // In this example we will simply print the certificate's subject name.
/*  char subject_name[256];
  X509* cert = X509_STORE_CTX_get_current_cert(ctx.native_handle());
  X509_NAME_oneline(X509_get_subject_name(cert), subject_name, 256);
  std::cout << "Verifying " << subject_name << "\n"; */

  return preverified;
}


void client_session::handle_connect(const boost::system::error_code &e)
{
    BOOST_LOG_TRIVIAL(debug)<<__FILE__<<":"<<__LINE__<<"\t"<<typeid(this).name()<<"::"<<__func__;
    if(e)
    {
        //TODO: settings for reconnect count and timeout
        emit client_connected(false, QString::fromStdString(e.message()));
        BOOST_LOG_TRIVIAL(error)<<__FILE__<<":"<<__LINE__<<"\t"<<typeid(this).name()<<"::"<<__func__<<"\terror: "<<e.message();
        delete this; //suicide
    }
    else
    {
        emit client_connected(true, QString::fromStdString(e.message()));
        //listen for messages from server
        recv_data_ = new char[4];
        boost::asio::async_read(*socket_, boost::asio::buffer(recv_data_, 4), boost::bind(&client_session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
    }
}

void client_session::handle_read(const boost::system::error_code& error, size_t bytes_transferred)
{
    if (!error)
    {
        std::string s;
//        bool parsed = false;
        unsigned size =  ntohl(*(int32_t*)recv_data_);
        delete [] recv_data_;
        char *buf = new char[size];
        boost::system::error_code ec;
        boost::asio::read(*socket_, boost::asio::buffer(buf, size), ec);
        if(ec)
        {

        }
        //TODO: check for error
        s.append(buf, size);
        delete [] buf;
        if(size != s.length())
        {
            delete this;
            return;
        }
        //TODO:
        server_msg msg;
        if(msg.ParseFromString(s))
        {
            //parsed = true;
            emit server_message_received(msg); //at least one more copy ...., i hope messages will be always small
            //another way:
            //make signal work with pointer to server_msg
            //allocate msg via new server_msg and pass pointer to signal
            //check if someone connected to signal and delete message if noone
            //this will be limited to only one client connection because client will need to delete message manually
            recv_data_ = new char[4];
            boost::asio::async_read(*socket_, boost::asio::buffer(recv_data_, 4), boost::bind(&client_session::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
        }
//        if(!parsed)
        else
        {
            BOOST_LOG_TRIVIAL(error)<<"failed to parse client message";
            delete this; //close connection
            return;
        }
    }
    else
    {
        delete this;
    }
}

void client_session::send_message(client_msg &msg)
{
    int size = 0;
    std::shared_ptr<char*> ptr = pack_msg(&msg, &size);
    boost::asio::async_write(*socket_, boost::asio::buffer(*ptr, size), boost::bind(&client_session::handle_write, this, boost::asio::placeholders::error));
}

void client_session::handle_write(const boost::system::error_code& error)
{
    if(error)
    {
        //TODO: handle error
    }

}

client_session::~client_session()
{
    //TODO: correct thread termination, reimplement
    io_service_.stop();
    delete socket_;
    boost::asio::io_service *s = &io_service_;
    delete s;
    //emit terminate_thread();
}

/*boost::asio::io_service &client_session::io_service()
{
    return io_service_;
} */