/*
 *  Copyright (c) 2013 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 <errno.h>
#include <stdarg.h>
#include <stdio.h>

#include <memory>
#include <string>
#include <vector>

#include "webrtc/base/bind.h"
#include "webrtc/base/copyonwritebuffer.h"
#include "webrtc/base/criticalsection.h"
#include "webrtc/base/gunit.h"
#include "webrtc/base/helpers.h"
#include "webrtc/base/messagehandler.h"
#include "webrtc/base/messagequeue.h"
#include "webrtc/base/ssladapter.h"
#include "webrtc/base/thread.h"
#include "webrtc/media/base/mediachannel.h"
#include "webrtc/media/base/mediaconstants.h"
#include "webrtc/media/sctp/sctpdataengine.h"

enum {
  MSG_PACKET = 1,
};

// Fake NetworkInterface that sends/receives sctp packets.  The one in
// webrtc/media/base/fakenetworkinterface.h only works with rtp/rtcp.
class SctpFakeNetworkInterface : public cricket::MediaChannel::NetworkInterface,
                                 public rtc::MessageHandler {
 public:
  explicit SctpFakeNetworkInterface(rtc::Thread* thread)
    : thread_(thread),
      dest_(NULL) {
  }

  void SetDestination(cricket::DataMediaChannel* dest) { dest_ = dest; }

 protected:
  // Called to send raw packet down the wire (e.g. SCTP an packet).
  virtual bool SendPacket(rtc::CopyOnWriteBuffer* packet,
                          const rtc::PacketOptions& options) {
    LOG(LS_VERBOSE) << "SctpFakeNetworkInterface::SendPacket";

    rtc::CopyOnWriteBuffer* buffer = new rtc::CopyOnWriteBuffer(*packet);
    thread_->Post(this, MSG_PACKET, rtc::WrapMessageData(buffer));
    LOG(LS_VERBOSE) << "SctpFakeNetworkInterface::SendPacket, Posted message.";
    return true;
  }

  // Called when a raw packet has been recieved. This passes the data to the
  // code that will interpret the packet. e.g. to get the content payload from
  // an SCTP packet.
  virtual void OnMessage(rtc::Message* msg) {
    LOG(LS_VERBOSE) << "SctpFakeNetworkInterface::OnMessage";
    std::unique_ptr<rtc::CopyOnWriteBuffer> buffer(
        static_cast<rtc::TypedMessageData<rtc::CopyOnWriteBuffer*>*>(
            msg->pdata)->data());
    if (dest_) {
      dest_->OnPacketReceived(buffer.get(), rtc::PacketTime());
    }
    delete msg->pdata;
  }

  // Unsupported functions required to exist by NetworkInterface.
  // TODO(ldixon): Refactor parent NetworkInterface class so these are not
  // required. They are RTC specific and should be in an appropriate subclass.
  virtual bool SendRtcp(rtc::CopyOnWriteBuffer* packet,
                        const rtc::PacketOptions& options) {
    LOG(LS_WARNING) << "Unsupported: SctpFakeNetworkInterface::SendRtcp.";
    return false;
  }
  virtual int SetOption(SocketType type, rtc::Socket::Option opt,
                        int option) {
    LOG(LS_WARNING) << "Unsupported: SctpFakeNetworkInterface::SetOption.";
    return 0;
  }
  virtual void SetDefaultDSCPCode(rtc::DiffServCodePoint dscp) {
    LOG(LS_WARNING) << "Unsupported: SctpFakeNetworkInterface::SetOption.";
  }

 private:
  // Not owned by this class.
  rtc::Thread* thread_;
  cricket::DataMediaChannel* dest_;
};

// This is essentially a buffer to hold recieved data. It stores only the last
// received data. Calling OnDataReceived twice overwrites old data with the
// newer one.
// TODO(ldixon): Implement constraints, and allow new data to be added to old
// instead of replacing it.
class SctpFakeDataReceiver : public sigslot::has_slots<> {
 public:
  SctpFakeDataReceiver() : received_(false) {}

  void Clear() {
    received_ = false;
    last_data_ = "";
    last_params_ = cricket::ReceiveDataParams();
  }

  virtual void OnDataReceived(const cricket::ReceiveDataParams& params,
                              const char* data, size_t length) {
    received_ = true;
    last_data_ = std::string(data, length);
    last_params_ = params;
  }

  bool received() const { return received_; }
  std::string last_data() const { return last_data_; }
  cricket::ReceiveDataParams last_params() const { return last_params_; }

 private:
  bool received_;
  std::string last_data_;
  cricket::ReceiveDataParams last_params_;
};

class SignalReadyToSendObserver : public sigslot::has_slots<> {
 public:
  SignalReadyToSendObserver() : signaled_(false), writable_(false) {}

  void OnSignaled(bool writable) {
    signaled_ = true;
    writable_ = writable;
  }

  bool IsSignaled(bool writable) {
    return signaled_ && (writable_ == writable);
  }

 private:
  bool signaled_;
  bool writable_;
};

class SignalChannelClosedObserver : public sigslot::has_slots<> {
 public:
  SignalChannelClosedObserver() {}
  void BindSelf(cricket::SctpDataMediaChannel* channel) {
    channel->SignalStreamClosedRemotely.connect(
        this, &SignalChannelClosedObserver::OnStreamClosed);
  }
  void OnStreamClosed(uint32_t stream) { streams_.push_back(stream); }

  int StreamCloseCount(uint32_t stream) {
    return std::count(streams_.begin(), streams_.end(), stream);
  }

  bool WasStreamClosed(uint32_t stream) {
    return std::find(streams_.begin(), streams_.end(), stream)
        != streams_.end();
  }

 private:
  std::vector<uint32_t> streams_;
};

class SignalChannelClosedReopener : public sigslot::has_slots<> {
 public:
  SignalChannelClosedReopener(cricket::SctpDataMediaChannel* channel,
                              cricket::SctpDataMediaChannel* peer)
      : channel_(channel), peer_(peer) {}

  void OnStreamClosed(int stream) {
    cricket::StreamParams p(cricket::StreamParams::CreateLegacy(stream));
    channel_->AddSendStream(p);
    channel_->AddRecvStream(p);
    peer_->AddSendStream(p);
    peer_->AddRecvStream(p);
    streams_.push_back(stream);
  }

  int StreamCloseCount(int stream) {
    return std::count(streams_.begin(), streams_.end(), stream);
  }

 private:
  cricket::SctpDataMediaChannel* channel_;
  cricket::SctpDataMediaChannel* peer_;
  std::vector<int> streams_;
};

// SCTP Data Engine testing framework.
class SctpDataMediaChannelTest : public testing::Test,
                                 public sigslot::has_slots<> {
 protected:
  // usrsctp uses the NSS random number generator on non-Android platforms,
  // so we need to initialize SSL.
  static void SetUpTestCase() {
  }

  virtual void SetUp() {
    engine_.reset(new cricket::SctpDataEngine());
  }

  void SetupConnectedChannels() {
    net1_.reset(new SctpFakeNetworkInterface(rtc::Thread::Current()));
    net2_.reset(new SctpFakeNetworkInterface(rtc::Thread::Current()));
    recv1_.reset(new SctpFakeDataReceiver());
    recv2_.reset(new SctpFakeDataReceiver());
    chan1_ready_to_send_count_ = 0;
    chan2_ready_to_send_count_ = 0;
    chan1_.reset(CreateChannel(net1_.get(), recv1_.get()));
    chan1_->set_debug_name("chan1/connector");
    chan1_->SignalReadyToSend.connect(
        this, &SctpDataMediaChannelTest::OnChan1ReadyToSend);
    chan2_.reset(CreateChannel(net2_.get(), recv2_.get()));
    chan2_->set_debug_name("chan2/listener");
    chan2_->SignalReadyToSend.connect(
        this, &SctpDataMediaChannelTest::OnChan2ReadyToSend);
    // Setup two connected channels ready to send and receive.
    net1_->SetDestination(chan2_.get());
    net2_->SetDestination(chan1_.get());

    LOG(LS_VERBOSE) << "Channel setup ----------------------------- ";
    AddStream(1);
    AddStream(2);

    LOG(LS_VERBOSE) << "Connect the channels -----------------------------";
    // chan1 wants to setup a data connection.
    chan1_->SetReceive(true);
    // chan1 will have sent chan2 a request to setup a data connection. After
    // chan2 accepts the offer, chan2 connects to chan1 with the following.
    chan2_->SetReceive(true);
    chan2_->SetSend(true);
    // Makes sure that network packets are delivered and simulates a
    // deterministic and realistic small timing delay between the SetSend calls.
    ProcessMessagesUntilIdle();

    // chan1 and chan2 are now connected so chan1 enables sending to complete
    // the creation of the connection.
    chan1_->SetSend(true);
  }

  virtual void TearDown() {
    channel1()->SetSend(false);
    channel2()->SetSend(false);

    // Process messages until idle to prevent a sent packet from being dropped
    // and causing memory leaks (not being deleted by the receiver).
    ProcessMessagesUntilIdle();
  }

  bool AddStream(int ssrc) {
    bool ret = true;
    cricket::StreamParams p(cricket::StreamParams::CreateLegacy(ssrc));
    ret = ret && chan1_->AddSendStream(p);
    ret = ret && chan1_->AddRecvStream(p);
    ret = ret && chan2_->AddSendStream(p);
    ret = ret && chan2_->AddRecvStream(p);
    return ret;
  }

  cricket::SctpDataMediaChannel* CreateChannel(
      SctpFakeNetworkInterface* net, SctpFakeDataReceiver* recv) {
    cricket::SctpDataMediaChannel* channel =
        static_cast<cricket::SctpDataMediaChannel*>(engine_->CreateChannel(
            cricket::DCT_SCTP));
    channel->SetInterface(net);
    // When data is received, pass it to the SctpFakeDataReceiver.
    channel->SignalDataReceived.connect(
        recv, &SctpFakeDataReceiver::OnDataReceived);
    return channel;
  }

  bool SendData(cricket::SctpDataMediaChannel* chan,
                uint32_t ssrc,
                const std::string& msg,
                cricket::SendDataResult* result) {
    cricket::SendDataParams params;
    params.ssrc = ssrc;

    return chan->SendData(params, rtc::CopyOnWriteBuffer(
        &msg[0], msg.length()), result);
  }

  bool ReceivedData(const SctpFakeDataReceiver* recv,
                    uint32_t ssrc,
                    const std::string& msg) {
    return (recv->received() &&
            recv->last_params().ssrc == ssrc &&
            recv->last_data() == msg);
  }

  bool ProcessMessagesUntilIdle() {
    rtc::Thread* thread = rtc::Thread::Current();
    while (!thread->empty()) {
      rtc::Message msg;
      if (thread->Get(&msg, rtc::Thread::kForever)) {
        thread->Dispatch(&msg);
      }
    }
    return !thread->IsQuitting();
  }

  cricket::SctpDataMediaChannel* channel1() { return chan1_.get(); }
  cricket::SctpDataMediaChannel* channel2() { return chan2_.get(); }
  SctpFakeDataReceiver* receiver1() { return recv1_.get(); }
  SctpFakeDataReceiver* receiver2() { return recv2_.get(); }

  int channel1_ready_to_send_count() { return chan1_ready_to_send_count_; }
  int channel2_ready_to_send_count() { return chan2_ready_to_send_count_; }
 private:
  std::unique_ptr<cricket::SctpDataEngine> engine_;
  std::unique_ptr<SctpFakeNetworkInterface> net1_;
  std::unique_ptr<SctpFakeNetworkInterface> net2_;
  std::unique_ptr<SctpFakeDataReceiver> recv1_;
  std::unique_ptr<SctpFakeDataReceiver> recv2_;
  std::unique_ptr<cricket::SctpDataMediaChannel> chan1_;
  std::unique_ptr<cricket::SctpDataMediaChannel> chan2_;

  int chan1_ready_to_send_count_;
  int chan2_ready_to_send_count_;

  void OnChan1ReadyToSend(bool send) {
    if (send)
      ++chan1_ready_to_send_count_;
  }
  void OnChan2ReadyToSend(bool send) {
    if (send)
      ++chan2_ready_to_send_count_;
  }
};

// Verifies that SignalReadyToSend is fired.
TEST_F(SctpDataMediaChannelTest, SignalReadyToSend) {
  SetupConnectedChannels();

  SignalReadyToSendObserver signal_observer_1;
  SignalReadyToSendObserver signal_observer_2;

  channel1()->SignalReadyToSend.connect(&signal_observer_1,
                                        &SignalReadyToSendObserver::OnSignaled);
  channel2()->SignalReadyToSend.connect(&signal_observer_2,
                                        &SignalReadyToSendObserver::OnSignaled);

  cricket::SendDataResult result;
  ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
  ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);

  EXPECT_TRUE_WAIT(signal_observer_1.IsSignaled(true), 1000);
  EXPECT_TRUE_WAIT(signal_observer_2.IsSignaled(true), 1000);
}

TEST_F(SctpDataMediaChannelTest, SendData) {
  SetupConnectedChannels();

  cricket::SendDataResult result;
  LOG(LS_VERBOSE) << "chan1 sending: 'hello?' -----------------------------";
  ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
  LOG(LS_VERBOSE) << "recv2.received=" << receiver2()->received()
                  << ", recv2.last_params.ssrc="
                  << receiver2()->last_params().ssrc
                  << ", recv2.last_params.timestamp="
                  << receiver2()->last_params().ssrc
                  << ", recv2.last_params.seq_num="
                  << receiver2()->last_params().seq_num
                  << ", recv2.last_data=" << receiver2()->last_data();

  LOG(LS_VERBOSE) << "chan2 sending: 'hi chan1' -----------------------------";
  ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);
  LOG(LS_VERBOSE) << "recv1.received=" << receiver1()->received()
                  << ", recv1.last_params.ssrc="
                  << receiver1()->last_params().ssrc
                  << ", recv1.last_params.timestamp="
                  << receiver1()->last_params().ssrc
                  << ", recv1.last_params.seq_num="
                  << receiver1()->last_params().seq_num
                  << ", recv1.last_data=" << receiver1()->last_data();
}

// Sends a lot of large messages at once and verifies SDR_BLOCK is returned.
TEST_F(SctpDataMediaChannelTest, SendDataBlocked) {
  SetupConnectedChannels();

  cricket::SendDataResult result;
  cricket::SendDataParams params;
  params.ssrc = 1;

  std::vector<char> buffer(1024 * 64, 0);

  for (size_t i = 0; i < 100; ++i) {
    channel1()->SendData(
        params, rtc::CopyOnWriteBuffer(&buffer[0], buffer.size()), &result);
    if (result == cricket::SDR_BLOCK)
      break;
  }

  EXPECT_EQ(cricket::SDR_BLOCK, result);
}

TEST_F(SctpDataMediaChannelTest, ClosesRemoteStream) {
  SetupConnectedChannels();
  SignalChannelClosedObserver chan_1_sig_receiver, chan_2_sig_receiver;
  chan_1_sig_receiver.BindSelf(channel1());
  chan_2_sig_receiver.BindSelf(channel2());

  cricket::SendDataResult result;
  ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
  ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);

  // Close channel 1.  Channel 2 should notify us.
  channel1()->RemoveSendStream(1);
  EXPECT_TRUE_WAIT(chan_2_sig_receiver.WasStreamClosed(1), 1000);
}

TEST_F(SctpDataMediaChannelTest, ClosesTwoRemoteStreams) {
  SetupConnectedChannels();
  AddStream(3);
  SignalChannelClosedObserver chan_1_sig_receiver, chan_2_sig_receiver;
  chan_1_sig_receiver.BindSelf(channel1());
  chan_2_sig_receiver.BindSelf(channel2());

  cricket::SendDataResult result;
  ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
  ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);

  // Close two streams on one side.
  channel2()->RemoveSendStream(2);
  channel2()->RemoveSendStream(3);
  EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(2), 1000);
  EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(3), 1000);
}

TEST_F(SctpDataMediaChannelTest, ClosesStreamsOnBothSides) {
  SetupConnectedChannels();
  AddStream(3);
  AddStream(4);
  SignalChannelClosedObserver chan_1_sig_receiver, chan_2_sig_receiver;
  chan_1_sig_receiver.BindSelf(channel1());
  chan_2_sig_receiver.BindSelf(channel2());

  cricket::SendDataResult result;
  ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);
  ASSERT_TRUE(SendData(channel2(), 2, "hi chan1", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver1(), 2, "hi chan1"), 1000);

  // Close one stream on channel1(), while closing three streams on
  // channel2().  They will conflict (only one side can close anything at a
  // time, apparently).  Test the resolution of the conflict.
  channel1()->RemoveSendStream(1);

  channel2()->RemoveSendStream(2);
  channel2()->RemoveSendStream(3);
  channel2()->RemoveSendStream(4);
  EXPECT_TRUE_WAIT(chan_2_sig_receiver.WasStreamClosed(1), 1000);
  EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(2), 1000);
  EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(3), 1000);
  EXPECT_TRUE_WAIT(chan_1_sig_receiver.WasStreamClosed(4), 1000);
}

TEST_F(SctpDataMediaChannelTest, EngineSignalsRightChannel) {
  SetupConnectedChannels();
  EXPECT_TRUE_WAIT(channel1()->socket() != NULL, 1000);
  struct socket *sock = const_cast<struct socket*>(channel1()->socket());
  int prior_count = channel1_ready_to_send_count();
  cricket::SctpDataEngine::SendThresholdCallback(sock, 0);
  EXPECT_GT(channel1_ready_to_send_count(), prior_count);
}

TEST_F(SctpDataMediaChannelTest, RefusesHighNumberedChannels) {
  SetupConnectedChannels();
  EXPECT_TRUE(AddStream(1022));
  EXPECT_FALSE(AddStream(1023));
}

// Flaky on Linux and Windows. See webrtc:4453.
#if defined(WEBRTC_WIN) || defined(WEBRTC_LINUX)
#define MAYBE_ReusesAStream DISABLED_ReusesAStream
#else
#define MAYBE_ReusesAStream ReusesAStream
#endif
TEST_F(SctpDataMediaChannelTest, MAYBE_ReusesAStream) {
  // Shut down channel 1, then open it up again for reuse.
  SetupConnectedChannels();
  cricket::SendDataResult result;
  SignalChannelClosedObserver chan_2_sig_receiver;
  chan_2_sig_receiver.BindSelf(channel2());

  ASSERT_TRUE(SendData(channel1(), 1, "hello?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hello?"), 1000);

  channel1()->RemoveSendStream(1);
  EXPECT_TRUE_WAIT(chan_2_sig_receiver.WasStreamClosed(1), 1000);
  // Channel 1 is gone now.

  // Create a new channel 1.
  AddStream(1);
  ASSERT_TRUE(SendData(channel1(), 1, "hi?", &result));
  EXPECT_EQ(cricket::SDR_SUCCESS, result);
  EXPECT_TRUE_WAIT(ReceivedData(receiver2(), 1, "hi?"), 1000);
  channel1()->RemoveSendStream(1);
  EXPECT_TRUE_WAIT(chan_2_sig_receiver.StreamCloseCount(1) == 2, 1000);
}