/******************************************************************************/
/**
	\Author 				Krzysztof Kwiatkowski
	\File					client.cpp
	\Description            The SSL client which connects to the server.cpp
                            and initiates renegotitaion after RENEG_INIT_LEN
                            chars exchanged with the server

*******************************************************************************/

#include "client.h"
#include <unistd.h>
#include "defs.h"
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <iostream>
#include <netinet/in.h>
#include <boost/thread/thread.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/locks.hpp>
#include <fcntl.h>
#include <openssl/err.h>

using namespace std;
using namespace boost;

SSL* SSLHandler = 0;
int CharsRead   = 0;

// with this you can block sender thread during renegotiation
mutex WriteReadMutex;

bool handle_error_code(int& len, SSL* SSLHandler, int code, const char* func)
{
    switch( SSL_get_error( SSLHandler, code ) )
    {
    case SSL_ERROR_NONE:
        len+=code;
        return false;
    case SSL_ERROR_ZERO_RETURN:
        cout << "CONNETION CLOSE ON WRITE" << endl;
        break;
    case SSL_ERROR_WANT_READ:
        cout << func << " WANT READ" << endl;
        return true;
        break;
    case SSL_ERROR_WANT_WRITE:
        cout << func << " WANT WRITE" << endl;
        return true;
        break;
    case SSL_ERROR_SYSCALL:
        cout << func << " ESYSCALL" << endl;
//        exit(1);
        break;
    case SSL_ERROR_SSL:
        cout << func << " ESSL" << endl;
        return true;
        exit(1);
        break;
    default:
        cout << func << " SOMETHING ELSE" << endl;
        return true;
        exit(1);

    }
    return true;
}



void Sender()
{
    while(1)
    {
        string buf(EXCHANGE_STRING);
        int len = 0;
        do
        {
            while( 1 )
            {
                lock_guard<mutex> lock(WriteReadMutex);
                cout << "SSL_write: start" << endl;
                int code = SSL_write(SSLHandler, buf.c_str()+len, buf.size()-len);
//                cout << "SSL_write: stop" << endl;
                handle_error_code(len, SSLHandler, code, "SSL_write");
            }

            // for debugging re-neg
            cout << "SSL STATE: " << SSL_state_string(SSLHandler) << endl;
        } while( len != static_cast<int>(buf.size()) );
        sleep(10);
    }
};

void Client::receive()
{
    char buf[MAX_PACKET_SIZE];

    // TODO: this way it takes 100% CPU, some signal would be usefull
    memset(buf,'\0',MAX_PACKET_SIZE);
    int len_rcv = 0;
    {
        bool flag = true;
        while( flag )
        {
            lock_guard<mutex> lock(WriteReadMutex);
//            cout << "SSL_read: start" << endl;
            len_rcv = SSL_read(SSLHandler, buf, MAX_PACKET_SIZE);
//            cout << "SSL_read: stop" << endl;
            flag = handle_error_code(len_rcv, SSLHandler, len_rcv, "SSL_read");
        }
    }

    if( len_rcv != 0 )
    {
        CharsRead += len_rcv;

        // dirty thing - if it has \n on the end - remove it
        if( buf[len_rcv-1] == '\n' )
            buf[len_rcv-1] = '\0';

        cout << "RCVD: " << buf << endl;
    }
    else
    {
        cout << "Closing connection " << _handler << endl;
        ::close(_handler);
    }
}


void Client::connect()
{
    lock_guard<mutex> lock(WriteReadMutex);

    struct sockaddr_in echoserver;
    _handler = socket(AF_INET, SOCK_STREAM, 0);
    memset(&echoserver, 0, sizeof(echoserver));
    echoserver.sin_family = AF_INET;
    echoserver.sin_addr.s_addr = inet_addr(IP);
    echoserver.sin_port = htons(PORT);

    /* Establish connection */
    if ( 0 > ::connect(_handler, (struct sockaddr *) &echoserver, sizeof(echoserver)) )
    {
        throw runtime_error("Can't connect to the server");
    }

    SSLHandler = SSL_new(_ctx);

    // if socket is blocking you can set this and forget about looking at SSL_get_error code on I/O calls
    // long mode = SSL_CTX_set_mode(_ctx, SSL_MODE_AUTO_RETRY);
    // if( ( mode & SSL_MODE_AUTO_RETRY) != SSL_MODE_AUTO_RETRY )
    // {
    //     throw runtime_error("SSL_MODE_AUTO_RETRY couldn't be set");
    // }

    SSL_set_fd(SSLHandler, _handler);

    if( SSL_connect(SSLHandler) <= 0)
    {
        cerr << "Can't setup SSL session" << endl;
        exit(1);
    }
//    bug reproduces even if call is blocking, so not need to uncommet this line
    int opts = fcntl(_handler,F_GETFL);
    opts = opts & ( ~O_NONBLOCK );
    fcntl(_handler, F_SETFL, opts);
}

void Client::start()
{
    // start sender thread first
    _sender  =new thread( Sender );

    struct timeval tv;

    // go to select loop
    while(1)
    {
        // wait timer for select
        tv.tv_sec  = 0;
        tv.tv_usec = 10;

        fd_set fd_read;

        FD_ZERO(&fd_read);
        FD_SET(_handler, &fd_read);
        select(_handler+1, &fd_read, NULL, NULL, (struct timeval *)&tv);
        if( FD_ISSET(_handler, &fd_read ) )
        {
            // this should be in other thread but... it works
#ifdef _RENEG_ON_
            if( CharsRead > RENEG_INIT_LEN )
            {
                CharsRead = 0;
                renegotiate();
            }
#endif
            receive();
        }
    }

}

void Client::renegotiate()
{
    lock_guard<mutex> lock_reads(WriteReadMutex);

    if( SSL_renegotiate_pending(SSLHandler) == false )
    {
        cout << "Starting SSL renegotiation on SSL"
             << "client (initiating by SSL client)" << endl;

        cout << "SSL State: " << SSL_state_string(SSLHandler) << endl;
        if(SSL_renegotiate(SSLHandler) <= 0){
            cerr << "SSL_renegotiate() failed. STATE: "
                 << SSL_state_string(SSLHandler) << endl;
            ERR_print_errors_fp(stderr);
            exit(1);
        }
    }

    // cout << "SSL State: " << SSL_state_string(SSLHandler) << endl;
    // if(SSL_do_handshake(SSLHandler) <= 0){
    //     cerr << "SSL_do_handshake() failed. STATE: "
    //          << SSL_state_string(SSLHandler) << endl;
    //     ERR_print_errors_fp(stderr);
    //     exit(1);
    // }
}

void Client::init()
{
    sslInit();
}

// --- MAIN --- //
int main()
{
    try
    {
        Client client;
        client.init();
        client.connect();
        client.start();
    }
    catch(std::runtime_error& e)
    {
        cerr << "ERROR " << e.what() << endl;
    }
    catch(...)
    {
        cerr << "Unknown exception" << endl;
    }
    return 0;
}