// **************************************************************************
/** @class Connection

@brief Maintains an ansynchronous TCP/IP client connection

*/
// **************************************************************************
#include "ConnectionUSB.h"

#include <boost/bind.hpp>

using namespace std;

namespace ba    = boost::asio;
namespace bs    = boost::system;
namespace dummy = ba::placeholders;

using ba::serial_port_base;

//#define DEBUG_TX

    // -------- Abbreviations for starting async tasks ---------

int ConnectionUSB::Write(const Time &t, const string &txt, int qos)
{
    if (fLog)
        return fLog->Write(t, txt, qos);

    return MessageImp::Write(t, txt, qos);
}

void ConnectionUSB::AsyncRead(const ba::mutable_buffers_1 buffers, int type)
{
    ba::async_read(*this, buffers,
                   boost::bind(&ConnectionUSB::HandleReceivedData, this,
                               dummy::error, dummy::bytes_transferred, type));
}

void ConnectionUSB::AsyncWrite(const ba::const_buffers_1 &buffers)
{
    ba::async_write(*this, buffers,
                    boost::bind(&ConnectionUSB::HandleSentData, this,
                                dummy::error, dummy::bytes_transferred));
}

void ConnectionUSB::AsyncWait(ba::deadline_timer &timer, int millisec,
                           void (ConnectionUSB::*handler)(const bs::error_code&))
{
    // - The boost::asio::basic_deadline_timer::expires_from_now()
    //   function cancels any pending asynchronous waits, and returns
    //   the number of asynchronous waits that were cancelled. If it
    //   returns 0 then you were too late and the wait handler has
    //   already been executed, or will soon be executed. If it
    //   returns 1 then the wait handler was successfully cancelled.
    // - If a wait handler is cancelled, the bs::error_code passed to
    //   it contains the value bs::error::operation_aborted.
    timer.expires_from_now(boost::posix_time::milliseconds(millisec));

    timer.async_wait(boost::bind(handler, this, dummy::error));
}

// ------------------------ close --------------------------
// close from another thread
void ConnectionUSB::CloseImp(bool restart)
{
    if (IsConnected())
    {
        ostringstream str;
        str << "Connection closed to " << URL() << ".";
        Info(str);
    }

    // Close possible open connections
    bs::error_code ec;
    cancel(ec);
    if (!ec)
        Error("Cancel async requests on "+URL()+": "+ec.message());

    close(ec);
    if (!ec)
        Error("Closing "+URL()+": "+ec.message());

    // Reset the connection status
    fConnectionStatus = kDisconnected;

    // Stop deadline counters
    fInTimeout.cancel();
    fOutTimeout.cancel();

    // Empty output queue
    fOutQueue.clear();

    if (!restart || IsConnecting())
        return;

    // We need some timeout before reconnecting!
    // And we have to check if we are alreayd trying to connect
    // We shoudl wait until all operations in progress were canceled

    // Start trying to reconnect
    Connect();
}

void ConnectionUSB::PostClose(bool restart)
{
    get_io_service().post(boost::bind(&ConnectionUSB::CloseImp, this, restart));
}

// ------------------------ write --------------------------
void ConnectionUSB::HandleWriteTimeout(const bs::error_code &error)
{
    if (error==ba::error::basic_errors::operation_aborted)
        return;

    // 125: Operation canceled (bs::error_code(125, bs::system_category))
    if (error)
    {
        ostringstream str;
        str << "Write timeout of " << URL() << ": " << error.message() << " (" << error << ")";// << endl;
        Error(str);

        CloseImp();
        return;
    }

    if (!is_open())
    {
        // For example: Here we could schedule a new accept if we
        // would not want to allow two connections at the same time.
        return;
    }

    // Check whether the deadline has passed. We compare the deadline
    // against the current time since a new asynchronous operation
    // may have moved the deadline before this actor had a chance
    // to run.
    if (fOutTimeout.expires_at() > ba::deadline_timer::traits_type::now())
        return;

    Error("fOutTimeout has expired, writing data to "+URL());

    CloseImp();
}

void ConnectionUSB::HandleSentData(const bs::error_code& error, size_t n)
{
    if (error && error != ba::error::not_connected)
    {
        ostringstream str;
        str << "Writing to " << URL() << ": " << error.message() << " (" << error << ")";// << endl;
        Error(str);

        CloseImp();
        return;
    }

    if (error == ba::error::not_connected)
    {
        ostringstream msg;
        msg << n << " bytes could not be sent to " << URL() << " due to missing connection.";
        Warn(msg);
    }
    else
    {
#ifdef DEBUG_TX
        ostringstream msg;
        msg << n << " bytes successfully sent to " << URL();
        Message(msg);
#endif
    }

    HandleTransmittedData(n);

    // This is "thread" safe because SendMessage and HandleSentMessage
    // are serialized in the EventQueue. Note: Do not call these
    // functions directly from any other place then Handlers, use
    // PostMessage instead
    fOutQueue.pop_front();

    if (fOutQueue.empty())
    {
        // Queue went empty, remove deadline
        fOutTimeout.cancel();
        return;
    }

    // AsyncWrite + Deadline
    AsyncWrite(ba::const_buffers_1(fOutQueue.front().data(), fOutQueue.front().size())/*, &ConnectionUSB::HandleSentData*/);
    AsyncWait(fOutTimeout, 5000, &ConnectionUSB::HandleWriteTimeout);
}

// It is important that when SendMessageImp is called, or to be more
// precise boost::bind is called, teh data is copied!
void ConnectionUSB::SendMessageImp(const vector<char> msg)
{
    /*
    if (!fConnectionEstablished)
    {
        UpdateWarn("SendMessageImp, but no connection to "+fAddress+":"+fPort+".");
        return;
    }*/

    const bool first_message_in_queue = fOutQueue.empty();

    // This is "thread" safe because SendMessage and HandleSentMessage
    // are serialized in the EventQueue. Note: Do not call these
    // functions directly from any other place then Handlers, use
    // PostMessage instead
    fOutQueue.push_back(msg);

    if (!first_message_in_queue)
        return;

    // AsyncWrite + Deadline
    AsyncWrite(ba::const_buffers_1(fOutQueue.front().data(), fOutQueue.front().size())/*, &ConnectionUSB::HandleSentData*/);
    AsyncWait(fOutTimeout, 5000, &ConnectionUSB::HandleWriteTimeout);
}

void ConnectionUSB::PostMessage(const void *ptr, size_t max)
{
    const vector<char> msg(reinterpret_cast<const char*>(ptr),
                           reinterpret_cast<const char*>(ptr)+max);

    get_io_service().post(boost::bind(&ConnectionUSB::SendMessageImp, this, msg));
}

void ConnectionUSB::PostMessage(const string &cmd, size_t max)
{
    if (max==size_t(-1))
        max = cmd.length()+1;

    vector <char>msg(max);

    copy(cmd.begin(), cmd.begin()+min(cmd.length()+1, max), msg.begin());

    PostMessage(msg);
}

void ConnectionUSB::Connect()
{
    fConnectionStatus = kConnecting;

    bs::error_code ec;
    open(URL(), ec);

    ostringstream msg;
    msg << "Connecting to " << URL() << "...";
    if (ec)
        msg << " " << ec.message() << " (" << ec << ")";
    else
        msg << "success.";

    if (ec)
    {
        Error(msg);
        fConnectionStatus = kDisconnected;
        return;
    }

    Info(msg);

    try
    {
        set_option(fBaudRate);
        set_option(fCharacterSize);
        set_option(fParity);
        set_option(fStopBits);
        set_option(fFlowControl);
    }
    catch (const bs::system_error &erc)
    {
        Error(string("Setting connection options: ")+erc.what());
        // CLOSE
        return;
    }

    fConnectionStatus = kConnected;

    ConnectionEstablished();
}

void ConnectionUSB::SetEndpoint(const string &addr)
{
    if (fConnectionStatus>=1)
        Warn("Connection or connection attempt in progress. New endpoint only valid for next connection.");

    fAddress = "/dev/"+addr;
}


ConnectionUSB::ConnectionUSB(ba::io_service& ioservice, ostream &out) :
MessageImp(out), ba::serial_port(ioservice), fLog(0),
fBaudRate(115200),
fCharacterSize(8), fParity(parity::none), fStopBits(stop_bits::one),
fFlowControl(flow_control::none),
fInTimeout(ioservice), fOutTimeout(ioservice), 
fConnectionStatus(kDisconnected)
{
}
