/*
 *  Copyright (c) 2017 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.
 */

#include "modules/rtp_rtcp/source/rtcp_transceiver.h"

#include <utility>

#include "absl/memory/memory.h"
#include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
#include "rtc_base/checks.h"
#include "rtc_base/event.h"
#include "rtc_base/timeutils.h"

namespace webrtc {

RtcpTransceiver::RtcpTransceiver(const RtcpTransceiverConfig& config)
    : task_queue_(config.task_queue),
      rtcp_transceiver_(absl::make_unique<RtcpTransceiverImpl>(config)),
      ptr_factory_(rtcp_transceiver_.get()),
      // Creating first weak ptr can be done on any thread, but is not
      // thread-safe, thus do it at construction. Creating second (e.g. making a
      // copy) is thread-safe.
      ptr_(ptr_factory_.GetWeakPtr()) {
  RTC_DCHECK(task_queue_);
}

RtcpTransceiver::~RtcpTransceiver() {
  if (task_queue_->IsCurrent())
    return;

  rtc::Event done(false, false);
  // TODO(danilchap): Merge cleanup into main closure when task queue does not
  // silently drop tasks.
  task_queue_->PostTask(rtc::NewClosure(
      [this] {
        // Destructor steps that has to run on the task_queue_.
        ptr_factory_.InvalidateWeakPtrs();
        rtcp_transceiver_.reset();
      },
      /*cleanup=*/[&done] { done.Set(); }));
  // Wait until destruction is complete to be sure weak pointers invalidated and
  // rtcp_transceiver destroyed on the queue while |this| still valid.
  done.Wait(rtc::Event::kForever);
  RTC_CHECK(!rtcp_transceiver_) << "Task queue is too busy to handle rtcp";
}

void RtcpTransceiver::AddMediaReceiverRtcpObserver(
    uint32_t remote_ssrc,
    MediaReceiverRtcpObserver* observer) {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  task_queue_->PostTask([ptr, remote_ssrc, observer] {
    if (ptr)
      ptr->AddMediaReceiverRtcpObserver(remote_ssrc, observer);
  });
}

void RtcpTransceiver::RemoveMediaReceiverRtcpObserver(
    uint32_t remote_ssrc,
    MediaReceiverRtcpObserver* observer,
    std::unique_ptr<rtc::QueuedTask> on_removed) {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  auto remove = [ptr, remote_ssrc, observer] {
    if (ptr)
      ptr->RemoveMediaReceiverRtcpObserver(remote_ssrc, observer);
  };
  task_queue_->PostTaskAndReply(std::move(remove), std::move(on_removed));
}

void RtcpTransceiver::SetReadyToSend(bool ready) {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  task_queue_->PostTask([ptr, ready] {
    if (ptr)
      ptr->SetReadyToSend(ready);
  });
}

void RtcpTransceiver::ReceivePacket(rtc::CopyOnWriteBuffer packet) {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  int64_t now_us = rtc::TimeMicros();
  task_queue_->PostTask([ptr, packet, now_us] {
    if (ptr)
      ptr->ReceivePacket(packet, now_us);
  });
}

void RtcpTransceiver::SendCompoundPacket() {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  task_queue_->PostTask([ptr] {
    if (ptr)
      ptr->SendCompoundPacket();
  });
}

void RtcpTransceiver::SetRemb(int64_t bitrate_bps,
                              std::vector<uint32_t> ssrcs) {
  // TODO(danilchap): Replace with lambda with move capture when available.
  struct SetRembClosure {
    void operator()() {
      if (ptr)
        ptr->SetRemb(bitrate_bps, std::move(ssrcs));
    }

    rtc::WeakPtr<RtcpTransceiverImpl> ptr;
    int64_t bitrate_bps;
    std::vector<uint32_t> ssrcs;
  };
  task_queue_->PostTask(SetRembClosure{ptr_, bitrate_bps, std::move(ssrcs)});
}

void RtcpTransceiver::UnsetRemb() {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  task_queue_->PostTask([ptr] {
    if (ptr)
      ptr->UnsetRemb();
  });
}

uint32_t RtcpTransceiver::SSRC() const {
  return rtcp_transceiver_->sender_ssrc();
}

bool RtcpTransceiver::SendFeedbackPacket(
    const rtcp::TransportFeedback& packet) {
  struct Closure {
    void operator()() {
      if (ptr)
        ptr->SendRawPacket(raw_packet);
    }
    rtc::WeakPtr<RtcpTransceiverImpl> ptr;
    rtc::Buffer raw_packet;
  };
  task_queue_->PostTask(Closure{ptr_, packet.Build()});
  return true;
}

void RtcpTransceiver::SendNack(uint32_t ssrc,
                               std::vector<uint16_t> sequence_numbers) {
  // TODO(danilchap): Replace with lambda with move capture when available.
  struct Closure {
    void operator()() {
      if (ptr)
        ptr->SendNack(ssrc, std::move(sequence_numbers));
    }

    rtc::WeakPtr<RtcpTransceiverImpl> ptr;
    uint32_t ssrc;
    std::vector<uint16_t> sequence_numbers;
  };
  task_queue_->PostTask(Closure{ptr_, ssrc, std::move(sequence_numbers)});
}

void RtcpTransceiver::SendPictureLossIndication(uint32_t ssrc) {
  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
  task_queue_->PostTask([ptr, ssrc] {
    if (ptr)
      ptr->SendPictureLossIndication(ssrc);
  });
}

void RtcpTransceiver::SendFullIntraRequest(std::vector<uint32_t> ssrcs) {
  // TODO(danilchap): Replace with lambda with move capture when available.
  struct Closure {
    void operator()() {
      if (ptr)
        ptr->SendFullIntraRequest(ssrcs);
    }

    rtc::WeakPtr<RtcpTransceiverImpl> ptr;
    std::vector<uint32_t> ssrcs;
  };
  task_queue_->PostTask(Closure{ptr_, std::move(ssrcs)});
}

}  // namespace webrtc