/** @file
 *
 *  A brief file description
 *
 *  @section license License
 *
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#include "QUICApplication.h"
#include "QUICStream.h"

static constexpr char tag_stream_io[] = "quic_stream_io";
static constexpr char tag_app[]       = "quic_app";

#define QUICStreamIODebug(fmt, ...)                                                                                           \
  Debug(tag_stream_io, "[%s] [%" PRIu64 "] " fmt, this->_stream_vc->connection_info()->cids().data(), this->_stream_vc->id(), \
        ##__VA_ARGS__)

//
// QUICStreamIO
//
QUICStreamIO::QUICStreamIO(QUICApplication *app, QUICStreamVConnection *stream_vc) : _stream_vc(stream_vc)
{
  this->_read_buffer  = new_MIOBuffer(BUFFER_SIZE_INDEX_8K);
  this->_write_buffer = new_MIOBuffer(BUFFER_SIZE_INDEX_8K);

  this->_read_buffer_reader  = this->_read_buffer->alloc_reader();
  this->_write_buffer_reader = this->_write_buffer->alloc_reader();

  switch (stream_vc->direction()) {
  case QUICStreamDirection::BIDIRECTIONAL:
    this->_read_vio  = stream_vc->do_io_read(app, INT64_MAX, this->_read_buffer);
    this->_write_vio = stream_vc->do_io_write(app, INT64_MAX, this->_write_buffer_reader);
    break;
  case QUICStreamDirection::SEND:
    this->_write_vio = stream_vc->do_io_write(app, INT64_MAX, this->_write_buffer_reader);
    break;
  case QUICStreamDirection::RECEIVE:
    this->_read_vio = stream_vc->do_io_read(app, INT64_MAX, this->_read_buffer);
    break;
  default:
    ink_assert(false);
    break;
  }
}

QUICStreamIO::~QUICStreamIO()
{
  // All readers will be deallocated
  free_MIOBuffer(this->_read_buffer);
  free_MIOBuffer(this->_write_buffer);
};

uint32_t
QUICStreamIO::stream_id() const
{
  return this->_stream_vc->id();
}

bool
QUICStreamIO::is_bidirectional() const
{
  return this->_stream_vc->is_bidirectional();
}

int64_t
QUICStreamIO::read(uint8_t *buf, int64_t len)
{
  if (is_debug_tag_set(tag_stream_io)) {
    if (this->_read_vio->nbytes == INT64_MAX) {
      QUICStreamIODebug("nbytes=- ndone=%" PRId64 " read_avail=%" PRId64 " read_len=%" PRId64, this->_read_vio->ndone,
                        this->_read_buffer_reader->read_avail(), len);
    } else {
      QUICStreamIODebug("nbytes=%" PRId64 " ndone=%" PRId64 " read_avail=%" PRId64 " read_len=%" PRId64, this->_read_vio->nbytes,
                        this->_read_vio->ndone, this->_read_buffer_reader->read_avail(), len);
    }
  }

  int64_t nread = this->_read_buffer_reader->read(buf, len);
  if (nread > 0) {
    this->_read_vio->ndone += nread;
  }

  this->_stream_vc->on_read();

  return nread;
}

int64_t
QUICStreamIO::peek(uint8_t *buf, int64_t len)
{
  return this->_read_buffer_reader->memcpy(buf, len) - reinterpret_cast<char *>(buf);
}

void
QUICStreamIO::consume(int64_t len)
{
  this->_read_buffer_reader->consume(len);
  this->_stream_vc->on_read();
}

bool
QUICStreamIO::is_read_done() const
{
  return this->_read_vio->ntodo() == 0;
}

int64_t
QUICStreamIO::write(const uint8_t *buf, int64_t len)
{
  SCOPED_MUTEX_LOCK(lock, this->_write_vio->mutex, this_ethread());

  int64_t nwritten = this->_write_buffer->write(buf, len);
  if (nwritten > 0) {
    this->_nwritten += nwritten;
  }

  return len;
}

int64_t
QUICStreamIO::write(IOBufferReader *r, int64_t len)
{
  SCOPED_MUTEX_LOCK(lock, this->_write_vio->mutex, this_ethread());

  int64_t bytes_avail = this->_write_buffer->write_avail();

  if (bytes_avail > 0) {
    if (is_debug_tag_set(tag_stream_io)) {
      if (this->_write_vio->nbytes == INT64_MAX) {
        QUICStreamIODebug("nbytes=- ndone=%" PRId64 " write_avail=%" PRId64 " write_len=%" PRId64, this->_write_vio->ndone,
                          bytes_avail, len);
      } else {
        QUICStreamIODebug("nbytes=%" PRId64 " ndone=%" PRId64 " write_avail=%" PRId64 " write_len=%" PRId64,
                          this->_write_vio->nbytes, this->_write_vio->ndone, bytes_avail, len);
      }
    }

    int64_t bytes_len = std::min(bytes_avail, len);
    int64_t nwritten  = this->_write_buffer->write(r, bytes_len);

    if (nwritten > 0) {
      this->_nwritten += nwritten;
    }

    return nwritten;
  } else {
    return 0;
  }
}

// TODO: Similar to other "write" apis, but do not copy.
int64_t
QUICStreamIO::write(IOBufferBlock *b)
{
  ink_assert(!"not implemented yet");
  return 0;
}

void
QUICStreamIO::write_done()
{
  this->_write_vio->nbytes = this->_nwritten;
}

void
QUICStreamIO::read_reenable()
{
  return this->_read_vio->reenable();
}

void
QUICStreamIO::write_reenable()
{
  return this->_write_vio->reenable();
}

//
// QUICApplication
//
QUICApplication::QUICApplication(QUICConnection *qc) : Continuation(new_ProxyMutex())
{
  this->_qc = qc;
}

QUICApplication::~QUICApplication()
{
  for (auto const &kv : this->_stream_map) {
    delete kv.second;
  }
}

// @brief Bind stream and application
void
QUICApplication::set_stream(QUICStreamVConnection *stream_vc, QUICStreamIO *stream_io)
{
  if (stream_io == nullptr) {
    stream_io = new QUICStreamIO(this, stream_vc);
  }
  this->_stream_map.insert(std::make_pair(stream_vc->id(), stream_io));
}

// @brief Bind stream and application
void
QUICApplication::set_stream(QUICStreamIO *stream_io)
{
  this->_stream_map.insert(std::make_pair(stream_io->stream_id(), stream_io));
}

bool
QUICApplication::is_stream_set(QUICStreamVConnection *stream)
{
  auto result = this->_stream_map.find(stream->id());

  return result != this->_stream_map.end();
}

void
QUICApplication::reenable(QUICStreamVConnection *stream)
{
  QUICStreamIO *stream_io = this->_find_stream_io(stream->id());
  if (stream_io) {
    stream_io->read_reenable();
    stream_io->write_reenable();
  } else {
    Debug(tag_app, "[%s] Unknown Stream id=%" PRIx64, this->_qc->cids().data(), stream->id());
  }

  return;
}

void
QUICApplication::unset_stream(QUICStreamVConnection *stream)
{
  QUICStreamIO *stream_io = this->_find_stream_io(stream->id());
  if (stream_io) {
    this->_stream_map.erase(stream->id());
  }
}

QUICStreamIO *
QUICApplication::_find_stream_io(QUICStreamId id)
{
  auto result = this->_stream_map.find(id);

  if (result == this->_stream_map.end()) {
    return nullptr;
  } else {
    return result->second;
  }
}

QUICStreamIO *
QUICApplication::_find_stream_io(VIO *vio)
{
  if (vio == nullptr) {
    return nullptr;
  }

  QUICStream *stream = dynamic_cast<QUICStream *>(vio->vc_server);
  if (stream == nullptr) {
    return nullptr;
  }

  return this->_find_stream_io(stream->id());
}