/*
 *  Copyright 2019 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef PC_SCTP_TRANSPORT_H_
#define PC_SCTP_TRANSPORT_H_

#include <cstddef>
#include <memory>
#include <optional>

#include "api/dtls_transport_interface.h"
#include "api/priority.h"
#include "api/rtc_error.h"
#include "api/scoped_refptr.h"
#include "api/sctp_transport_interface.h"
#include "api/sequence_checker.h"
#include "api/transport/data_channel_transport_interface.h"
#include "media/sctp/sctp_transport_internal.h"
#include "p2p/dtls/dtls_transport_internal.h"
#include "pc/dtls_transport.h"
#include "rtc_base/copy_on_write_buffer.h"
#include "rtc_base/ssl_stream_adapter.h"
#include "rtc_base/thread.h"
#include "rtc_base/thread_annotations.h"

namespace webrtc {

// This implementation wraps a webrtc::SctpTransport, and takes
// ownership of it.
// This object must be constructed and updated on the networking thread,
// the same thread as the one the webrtc::SctpTransportInternal object
// lives on.
class SctpTransport : public SctpTransportInterface,
                      public DataChannelTransportInterface {
 public:
  SctpTransport(std::unique_ptr<SctpTransportInternal> internal,
                scoped_refptr<DtlsTransport> dtls_transport);

  // SctpTransportInterface
  scoped_refptr<DtlsTransportInterface> dtls_transport() const override;
  SctpTransportInformation Information() const override;
  void RegisterObserver(SctpTransportObserverInterface* observer) override;
  void UnregisterObserver() override;

  // DataChannelTransportInterface
  RTCError OpenChannel(int channel_id, PriorityValue priority) override;
  RTCError SendData(int channel_id,
                    const SendDataParams& params,
                    const CopyOnWriteBuffer& buffer) override;
  RTCError CloseChannel(int channel_id) override;
  void SetDataSink(DataChannelSink* sink) override;
  bool IsReadyToSend() const override;
  size_t buffered_amount(int channel_id) const override;
  size_t buffered_amount_low_threshold(int channel_id) const override;
  void SetBufferedAmountLowThreshold(int channel_id, size_t bytes) override;
  std::optional<int> MaxChannels() override;
  std::optional<SSLRole> DtlsRole() override;

  // Internal functions
  void Clear();
  // Initialize the webrtc::SctpTransport. This must be called from
  // the signaling thread.
  bool Start(const SctpOptions& options);

  // TODO(https://bugs.webrtc.org/10629): Move functions that need
  // internal() to be functions on the SctpTransport interface,
  // and make the internal() function private.
  SctpTransportInternal* internal() {
    RTC_DCHECK_RUN_ON(owner_thread_);
    return internal_sctp_transport_.get();
  }

  const SctpTransportInternal* internal() const {
    RTC_DCHECK_RUN_ON(owner_thread_);
    return internal_sctp_transport_.get();
  }

 protected:
  ~SctpTransport() override;

 private:
  void UpdateInformation(SctpTransportState state);
  void OnInternalReadyToSendData();
  void OnAssociationChangeCommunicationUp();
  void OnInternalClosingProcedureStartedRemotely(int sid);
  void OnInternalClosingProcedureComplete(int sid);
  void OnDtlsStateChange(DtlsTransportInternal* transport,
                         DtlsTransportState state);

  // NOTE: `owner_thread_` is the thread that the SctpTransport object is
  // constructed on. In the context of PeerConnection, it's the network thread.
  Thread* const owner_thread_;
  SctpTransportInformation info_ RTC_GUARDED_BY(owner_thread_);
  std::unique_ptr<SctpTransportInternal> internal_sctp_transport_
      RTC_GUARDED_BY(owner_thread_);
  SctpTransportObserverInterface* observer_ RTC_GUARDED_BY(owner_thread_) =
      nullptr;
  scoped_refptr<DtlsTransport> dtls_transport_ RTC_GUARDED_BY(owner_thread_);
};

}  // namespace webrtc
#endif  // PC_SCTP_TRANSPORT_H_