/*
  dmxwidget.cpp

  Copyright (c) 2023 Kevin Matz (kevin.matz@gmail.com)

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
#include "dmxwidget.h"
#include <QDebug>

DmxWidget::DmxWidget(QObject *parent)
    : QObject{parent}
    , port_(new QSerialPort(this))
{
  connect(this, &DmxWidget::serialDataRead, this, &DmxWidget::parseMessageBuffer);
  connect(port_, &QSerialPort::errorOccurred, this, &DmxWidget::serialErrorOccured);
  connect(port_, &QSerialPort::readyRead, this, [this]() {
      message_rx_buffer_.append(port_->readAll());
      emit serialDataRead();
  });
}


DmxWidget::~DmxWidget()
{
  DmxWidget::close();
}


void DmxWidget::open()
{
  auto wait_for = [this](bool &reply) {
    reply = false;                          // reset the reply state variale
    for (int i = 0; i < 10; i++) {          // serial reply may not be first in the read buffer
      port_->waitForReadyRead(100);         // wait for the port read buffer to have content
      if (reply)
        break;                              // break the loop if a reply was received
    }
    return reply;
  };

  if (!port_->open(QIODeviceBase::ReadWrite))   // open the port
    return;
  ENTTEC::Widget::open();                   // open the base class widget

  getSerialNumber();                        // request a serial number
  getParameters(0);                         // get the metadata while we're here
  if (wait_for(reply_serial))               // widget is found if a serial number reply is received
  {
    setModeBridge();                        // widget defaults to bridge, so sync our state
    emit connectedChanged(isConnected());
  }
  else
    close();
}


void DmxWidget::close()
{
  port_->close();
  ENTTEC::Widget::close();
  emit connectedChanged(isConnected());
}


/**
 * @brief DmxWidget::parseMessageBuffer
 */
void DmxWidget::parseMessageBuffer()
{
  OperatingMode other_side = USBunknown;
  switch (usb_mode) {
  case ENTTEC::Widget::USBdevice:
      other_side = USBhost;
      break;
  case ENTTEC::Widget::USBhost:
      other_side = USBdevice;
      break;
  default:
      break;
  }
  uint16_t length;
  const int fixed_length = 5;               // start + label + 2xlength + end
  auto fast_forward = [this](int offset = 0) {
    if (message_rx_buffer_.isEmpty())
      return false;
    if (offset == 0)
      offset = message_rx_buffer_.indexOf(ENTTEC::Pro::START_DELIMITER);
    if (offset < 0)
      message_rx_buffer_.clear();              // start delimiter not found
    else if (offset > 0)
      message_rx_buffer_.remove(0, offset);    // delimiter now at start of buffer
    return (message_rx_buffer_.size() >= fixed_length
            && (uint8_t)message_rx_buffer_[0] == ENTTEC::Pro::START_DELIMITER);
  };

  while(fast_forward())
  {
    // read and check the data length
    length = message_rx_buffer_[2] | message_rx_buffer_[3] << 8;
    if (message_rx_buffer_.size() < length + fixed_length)
      return;                               // message in buffer is incomplete
    // look for the end delimeter
    if ((uint8_t)message_rx_buffer_[length + fixed_length - 1] != ENTTEC::Pro::END_DELIMITER) {
      fast_forward(length + fixed_length - 1); // discard corrupted bytes
      continue;
    }
    // make a new message data
    auto msg = MessageDataFactory((MESSAGE_LABEL)message_rx_buffer_[1], other_side);
    // fill it with data
    std::shared_ptr<bufferstream> stream(new bufferstream(
        reinterpret_cast<uint8_t*>(message_rx_buffer_.data()+fixed_length-1),
                                                          length, bufferstream::LittleEndian));
    msg->iStream(stream);
    // ship it
    routeRxMessage(msg);
    // discard processed bytes
    fast_forward(length + fixed_length);
  }
}


void DmxWidget::sendMessage(std::shared_ptr<ENTTEC::Pro::MessageData> msg) const
{
  uint16_t length = msg->streamSize();
  const int fixed_length = 5;

  char buffer[length + fixed_length];
  std::shared_ptr<bufferstream> stream(new bufferstream(reinterpret_cast<uint8_t*>(buffer),
                                                        sizeof(buffer),
                                                        bufferstream::LittleEndian));
  *stream << ENTTEC::Pro::START_DELIMITER;
  *stream << msg->label;
  *stream << length;
  msg->oStream(stream);
  *stream << ENTTEC::Pro::END_DELIMITER;

  port_->write(buffer, sizeof(buffer));
}


/**
 * @brief DmxWidget::serialErrorOccured
 * @param error
 */
void DmxWidget::serialErrorOccured(QSerialPort::SerialPortError error)
{
  switch (error) {
  case QSerialPort::WriteError:
  case QSerialPort::ReadError:
  case QSerialPort::ResourceError:
  case QSerialPort::TimeoutError:
    close();
    break;
  default:
    break;
  }
}


/**
 * @brief DmxWidget::availableWidgets
 * @return
 */
QList<std::shared_ptr<DmxWidget>> DmxWidget::availableWidgets()
{
  QList<std::shared_ptr<DmxWidget>> wdgts;
  // evaluate all system serial ports
  const auto ports = QSerialPortInfo::availablePorts();
  for (const QSerialPortInfo &port : ports) {
    // try to open a widget on each port
    auto widget = std::make_shared<DmxWidget>();
    widget->setPort(port);
    widget->open();
    if (widget->isConnected())
      wdgts.push_back(widget);              // add valid widgets to the list
    else
      widget->close();
  }
  return wdgts;
}