// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "remoting/host/desktop_session_agent.h"

#include "base/file_util.h"
#include "base/logging.h"
#include "base/memory/shared_memory.h"
#include "ipc/ipc_channel_proxy.h"
#include "ipc/ipc_message.h"
#include "ipc/ipc_message_macros.h"
#include "remoting/base/auto_thread_task_runner.h"
#include "remoting/base/constants.h"
#include "remoting/host/audio_capturer.h"
#include "remoting/host/chromoting_messages.h"
#include "remoting/host/desktop_environment.h"
#include "remoting/host/input_injector.h"
#include "remoting/host/ipc_util.h"
#include "remoting/host/remote_input_filter.h"
#include "remoting/host/screen_controls.h"
#include "remoting/host/screen_resolution.h"
#include "remoting/proto/audio.pb.h"
#include "remoting/proto/control.pb.h"
#include "remoting/proto/event.pb.h"
#include "remoting/protocol/clipboard_stub.h"
#include "remoting/protocol/input_event_tracker.h"
#include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h"
#include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
#include "third_party/webrtc/modules/desktop_capture/shared_memory.h"

namespace remoting {

namespace {

// Routes local clipboard events though the IPC channel to the network process.
class DesktopSesssionClipboardStub : public protocol::ClipboardStub {
 public:
  explicit DesktopSesssionClipboardStub(
      scoped_refptr<DesktopSessionAgent> desktop_session_agent);
  virtual ~DesktopSesssionClipboardStub();

  // protocol::ClipboardStub implementation.
  virtual void InjectClipboardEvent(
      const protocol::ClipboardEvent& event) OVERRIDE;

 private:
  scoped_refptr<DesktopSessionAgent> desktop_session_agent_;

  DISALLOW_COPY_AND_ASSIGN(DesktopSesssionClipboardStub);
};

DesktopSesssionClipboardStub::DesktopSesssionClipboardStub(
    scoped_refptr<DesktopSessionAgent> desktop_session_agent)
    : desktop_session_agent_(desktop_session_agent) {
}

DesktopSesssionClipboardStub::~DesktopSesssionClipboardStub() {
}

void DesktopSesssionClipboardStub::InjectClipboardEvent(
    const protocol::ClipboardEvent& event) {
  desktop_session_agent_->InjectClipboardEvent(event);
}

}  // namespace

// webrtc::SharedMemory implementation that notifies creating
// DesktopSessionAgent when it's deleted.
class DesktopSessionAgent::SharedBuffer : public webrtc::SharedMemory {
 public:
  static scoped_ptr<SharedBuffer> Create(DesktopSessionAgent* agent,
                                         size_t size,
                                         int id) {
    scoped_ptr<base::SharedMemory> memory(new base::SharedMemory());
    if (!memory->CreateAndMapAnonymous(size))
      return scoped_ptr<SharedBuffer>();
    return scoped_ptr<SharedBuffer>(
        new SharedBuffer(agent, memory.Pass(), size, id));
  }

  virtual ~SharedBuffer() {
    agent_->OnSharedBufferDeleted(id());
  }

 private:
  SharedBuffer(DesktopSessionAgent* agent,
               scoped_ptr<base::SharedMemory> memory,
               size_t size,
               int id)
      : SharedMemory(memory->memory(), size,
#if defined(OS_WIN)
                     memory->handle(),
#else
                     memory->handle().fd,
#endif
                     id),
        agent_(agent),
        shared_memory_(memory.Pass()) {
  }

  DesktopSessionAgent* agent_;
  scoped_ptr<base::SharedMemory> shared_memory_;

  DISALLOW_COPY_AND_ASSIGN(SharedBuffer);
};

DesktopSessionAgent::Delegate::~Delegate() {
}

DesktopSessionAgent::DesktopSessionAgent(
    scoped_refptr<AutoThreadTaskRunner> audio_capture_task_runner,
    scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
    scoped_refptr<AutoThreadTaskRunner> input_task_runner,
    scoped_refptr<AutoThreadTaskRunner> io_task_runner,
    scoped_refptr<AutoThreadTaskRunner> video_capture_task_runner)
    : audio_capture_task_runner_(audio_capture_task_runner),
      caller_task_runner_(caller_task_runner),
      input_task_runner_(input_task_runner),
      io_task_runner_(io_task_runner),
      video_capture_task_runner_(video_capture_task_runner),
      control_factory_(this),
      desktop_pipe_(IPC::InvalidPlatformFileForTransit()),
      next_shared_buffer_id_(1),
      shared_buffers_(0),
      started_(false) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());
}

bool DesktopSessionAgent::OnMessageReceived(const IPC::Message& message) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  bool handled = true;
  if (started_) {
    IPC_BEGIN_MESSAGE_MAP(DesktopSessionAgent, message)
      IPC_MESSAGE_HANDLER(ChromotingNetworkDesktopMsg_CaptureFrame,
                          OnCaptureFrame)
      IPC_MESSAGE_HANDLER(ChromotingNetworkDesktopMsg_InjectClipboardEvent,
                          OnInjectClipboardEvent)
      IPC_MESSAGE_HANDLER(ChromotingNetworkDesktopMsg_InjectKeyEvent,
                          OnInjectKeyEvent)
      IPC_MESSAGE_HANDLER(ChromotingNetworkDesktopMsg_InjectMouseEvent,
                          OnInjectMouseEvent)
      IPC_MESSAGE_HANDLER(ChromotingNetworkDesktopMsg_SetScreenResolution,
                          SetScreenResolution)
      IPC_MESSAGE_UNHANDLED(handled = false)
    IPC_END_MESSAGE_MAP()
  } else {
    IPC_BEGIN_MESSAGE_MAP(DesktopSessionAgent, message)
      IPC_MESSAGE_HANDLER(ChromotingNetworkDesktopMsg_StartSessionAgent,
                          OnStartSessionAgent)
      IPC_MESSAGE_UNHANDLED(handled = false)
    IPC_END_MESSAGE_MAP()
  }

  CHECK(handled) << "Received unexpected IPC type: " << message.type();
  return handled;
}

void DesktopSessionAgent::OnChannelConnected(int32 peer_pid) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  VLOG(1) << "IPC: desktop <- network (" << peer_pid << ")";

  CloseDesktopPipeHandle();
}

void DesktopSessionAgent::OnChannelError() {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  // Make sure the channel is closed.
  network_channel_.reset();
  CloseDesktopPipeHandle();

  // Notify the caller that the channel has been disconnected.
  if (delegate_.get())
    delegate_->OnNetworkProcessDisconnected();
}

webrtc::SharedMemory* DesktopSessionAgent::CreateSharedMemory(size_t size) {
  DCHECK(video_capture_task_runner_->BelongsToCurrentThread());

  scoped_ptr<SharedBuffer> buffer =
      SharedBuffer::Create(this, size, next_shared_buffer_id_);
  if (buffer) {
    shared_buffers_++;

    // |next_shared_buffer_id_| starts from 1 and incrementing it by 2 makes
    // sure it is always odd and therefore zero is never used as a valid buffer
    // ID.
    //
    // It is very unlikely (though theoretically possible) to allocate the same
    // ID for two different buffers due to integer overflow. It should take
    // about a year of allocating 100 new buffers every second. Practically
    // speaking it never happens.
    next_shared_buffer_id_ += 2;

    IPC::PlatformFileForTransit handle;
#if defined(OS_WIN)
    handle = buffer->handle();
#else
    handle = base::FileDescriptor(buffer->handle(), false);
#endif
    SendToNetwork(new ChromotingDesktopNetworkMsg_CreateSharedBuffer(
        buffer->id(), handle, buffer->size()));
  }

  return buffer.release();
}

DesktopSessionAgent::~DesktopSessionAgent() {
  DCHECK(!audio_capturer_);
  DCHECK(!desktop_environment_);
  DCHECK(!network_channel_);
  DCHECK(!screen_controls_);
  DCHECK(!video_capturer_);

  CloseDesktopPipeHandle();
}

const std::string& DesktopSessionAgent::client_jid() const {
  return client_jid_;
}

void DesktopSessionAgent::DisconnectSession() {
  SendToNetwork(new ChromotingDesktopNetworkMsg_DisconnectSession());
}

void DesktopSessionAgent::OnLocalMouseMoved(
    const webrtc::DesktopVector& new_pos) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  remote_input_filter_->LocalMouseMoved(new_pos);
}

void DesktopSessionAgent::SetDisableInputs(bool disable_inputs) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  // Do not expect this method to be called because it is only used by It2Me.
  NOTREACHED();
}

void DesktopSessionAgent::OnStartSessionAgent(
    const std::string& authenticated_jid,
    const ScreenResolution& resolution,
    bool virtual_terminal) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());
  DCHECK(!started_);
  DCHECK(!audio_capturer_);
  DCHECK(!desktop_environment_);
  DCHECK(!input_injector_);
  DCHECK(!screen_controls_);
  DCHECK(!video_capturer_);

  started_ = true;
  client_jid_ = authenticated_jid;

  // Enable the curtain mode.
  delegate_->desktop_environment_factory().SetEnableCurtaining(
      virtual_terminal);

  // Create a desktop environment for the new session.
  desktop_environment_ = delegate_->desktop_environment_factory().Create(
      control_factory_.GetWeakPtr());

  // Create the session controller and set the initial screen resolution.
  screen_controls_ = desktop_environment_->CreateScreenControls();
  SetScreenResolution(resolution);

  // Create the input injector.
  input_injector_ = desktop_environment_->CreateInputInjector();

  // Hook up the input filter.
  input_tracker_.reset(new protocol::InputEventTracker(input_injector_.get()));
  remote_input_filter_.reset(new RemoteInputFilter(input_tracker_.get()));

#if defined(OS_WIN)
  // LocalInputMonitorWin filters out an echo of the injected input before it
  // reaches |remote_input_filter_|.
  remote_input_filter_->SetExpectLocalEcho(false);
#endif  // defined(OS_WIN)

  // Start the input injector.
  scoped_ptr<protocol::ClipboardStub> clipboard_stub(
      new DesktopSesssionClipboardStub(this));
  input_injector_->Start(clipboard_stub.Pass());

  // Start the audio capturer.
  if (delegate_->desktop_environment_factory().SupportsAudioCapture()) {
    audio_capturer_ = desktop_environment_->CreateAudioCapturer();
    audio_capture_task_runner_->PostTask(
        FROM_HERE, base::Bind(&DesktopSessionAgent::StartAudioCapturer, this));
  }

  // Start the video capturer.
  video_capturer_ = desktop_environment_->CreateVideoCapturer();
  video_capture_task_runner_->PostTask(
      FROM_HERE, base::Bind(&DesktopSessionAgent::StartVideoCapturer, this));
}

void DesktopSessionAgent::OnCaptureCompleted(webrtc::DesktopFrame* frame) {
  DCHECK(video_capture_task_runner_->BelongsToCurrentThread());

  last_frame_.reset(frame);

  current_size_ = frame->size();

  // Serialize webrtc::DesktopFrame.
  SerializedDesktopFrame serialized_frame;
  serialized_frame.shared_buffer_id = frame->shared_memory()->id();
  serialized_frame.bytes_per_row = frame->stride();
  serialized_frame.dimensions = frame->size();
  serialized_frame.capture_time_ms = frame->capture_time_ms();
  serialized_frame.dpi = frame->dpi();
  for (webrtc::DesktopRegion::Iterator i(frame->updated_region());
       !i.IsAtEnd(); i.Advance()) {
    serialized_frame.dirty_region.push_back(i.rect());
  }

  SendToNetwork(
      new ChromotingDesktopNetworkMsg_CaptureCompleted(serialized_frame));
}

void DesktopSessionAgent::OnCursorShapeChanged(
    webrtc::MouseCursorShape* cursor_shape) {
  DCHECK(video_capture_task_runner_->BelongsToCurrentThread());

  scoped_ptr<webrtc::MouseCursorShape> owned_cursor(cursor_shape);

  SendToNetwork(new ChromotingDesktopNetworkMsg_CursorShapeChanged(
      *cursor_shape));
}

void DesktopSessionAgent::InjectClipboardEvent(
    const protocol::ClipboardEvent& event) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  std::string serialized_event;
  if (!event.SerializeToString(&serialized_event)) {
    LOG(ERROR) << "Failed to serialize protocol::ClipboardEvent.";
    return;
  }

  SendToNetwork(
      new ChromotingDesktopNetworkMsg_InjectClipboardEvent(serialized_event));
}

void DesktopSessionAgent::ProcessAudioPacket(scoped_ptr<AudioPacket> packet) {
  DCHECK(audio_capture_task_runner_->BelongsToCurrentThread());

  std::string serialized_packet;
  if (!packet->SerializeToString(&serialized_packet)) {
    LOG(ERROR) << "Failed to serialize AudioPacket.";
    return;
  }

  SendToNetwork(new ChromotingDesktopNetworkMsg_AudioPacket(serialized_packet));
}

bool DesktopSessionAgent::Start(const base::WeakPtr<Delegate>& delegate,
                                IPC::PlatformFileForTransit* desktop_pipe_out) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());
  DCHECK(delegate_.get() == NULL);

  delegate_ = delegate;

  // Create an IPC channel to communicate with the network process.
  bool result = CreateConnectedIpcChannel(io_task_runner_,
                                          this,
                                          &desktop_pipe_,
                                          &network_channel_);
  *desktop_pipe_out = desktop_pipe_;
  return result;
}

void DesktopSessionAgent::Stop() {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  delegate_.reset();

  // Make sure the channel is closed.
  network_channel_.reset();

  if (started_) {
    started_ = false;

    // Ignore any further callbacks.
    control_factory_.InvalidateWeakPtrs();
    client_jid_.clear();

    remote_input_filter_.reset();

    // Ensure that any pressed keys or buttons are released.
    input_tracker_->ReleaseAll();
    input_tracker_.reset();

    desktop_environment_.reset();
    input_injector_.reset();
    screen_controls_.reset();

    // Stop the audio capturer.
    audio_capture_task_runner_->PostTask(
        FROM_HERE, base::Bind(&DesktopSessionAgent::StopAudioCapturer, this));

    // Stop the video capturer.
    video_capture_task_runner_->PostTask(
        FROM_HERE, base::Bind(&DesktopSessionAgent::StopVideoCapturer, this));
  }
}

void DesktopSessionAgent::OnCaptureFrame() {
  if (!video_capture_task_runner_->BelongsToCurrentThread()) {
    video_capture_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&DesktopSessionAgent::OnCaptureFrame, this));
    return;
  }

  // webrtc::ScreenCapturer supports a very few (currently 2) outstanding
  // capture requests. The requests are serialized on
  // |video_capture_task_runner()| task runner. If the client issues more
  // requests, pixel data in captured frames will likely be corrupted but
  // stability of webrtc::ScreenCapturer will not be affected.
  video_capturer_->Capture(webrtc::DesktopRegion());
}

void DesktopSessionAgent::OnInjectClipboardEvent(
    const std::string& serialized_event) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  protocol::ClipboardEvent event;
  if (!event.ParseFromString(serialized_event)) {
    LOG(ERROR) << "Failed to parse protocol::ClipboardEvent.";
    return;
  }

  // InputStub implementations must verify events themselves, so we don't need
  // verification here. This matches HostEventDispatcher.
  input_injector_->InjectClipboardEvent(event);
}

void DesktopSessionAgent::OnInjectKeyEvent(
    const std::string& serialized_event) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  protocol::KeyEvent event;
  if (!event.ParseFromString(serialized_event)) {
    LOG(ERROR) << "Failed to parse protocol::KeyEvent.";
    return;
  }

  // InputStub implementations must verify events themselves, so we need only
  // basic verification here. This matches HostEventDispatcher.
  if (!event.has_usb_keycode() || !event.has_pressed()) {
    LOG(ERROR) << "Received invalid key event.";
    return;
  }

  remote_input_filter_->InjectKeyEvent(event);
}

void DesktopSessionAgent::OnInjectMouseEvent(
    const std::string& serialized_event) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  protocol::MouseEvent event;
  if (!event.ParseFromString(serialized_event)) {
    LOG(ERROR) << "Failed to parse protocol::MouseEvent.";
    return;
  }

  // InputStub implementations must verify events themselves, so we don't need
  // verification here. This matches HostEventDispatcher.
  remote_input_filter_->InjectMouseEvent(event);
}

void DesktopSessionAgent::SetScreenResolution(
    const ScreenResolution& resolution) {
  DCHECK(caller_task_runner_->BelongsToCurrentThread());

  if (screen_controls_ && resolution.IsEmpty())
    screen_controls_->SetScreenResolution(resolution);
}

void DesktopSessionAgent::SendToNetwork(IPC::Message* message) {
  if (!caller_task_runner_->BelongsToCurrentThread()) {
    caller_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&DesktopSessionAgent::SendToNetwork, this, message));
    return;
  }

  if (network_channel_) {
    network_channel_->Send(message);
  } else {
    delete message;
  }
}

void DesktopSessionAgent::StartAudioCapturer() {
  DCHECK(audio_capture_task_runner_->BelongsToCurrentThread());

  if (audio_capturer_) {
    audio_capturer_->Start(base::Bind(&DesktopSessionAgent::ProcessAudioPacket,
                                      this));
  }
}

void DesktopSessionAgent::StopAudioCapturer() {
  DCHECK(audio_capture_task_runner_->BelongsToCurrentThread());

  audio_capturer_.reset();
}

void DesktopSessionAgent::StartVideoCapturer() {
  DCHECK(video_capture_task_runner_->BelongsToCurrentThread());

  if (video_capturer_) {
    video_capturer_->SetMouseShapeObserver(this);
    video_capturer_->Start(this);
  }
}

void DesktopSessionAgent::StopVideoCapturer() {
  DCHECK(video_capture_task_runner_->BelongsToCurrentThread());

  video_capturer_.reset();
  last_frame_.reset();

  // Video capturer must delete all buffers.
  DCHECK_EQ(shared_buffers_, 0);
}

void DesktopSessionAgent::OnSharedBufferDeleted(int id) {
  DCHECK(video_capture_task_runner_->BelongsToCurrentThread());
  DCHECK(id != 0);

  shared_buffers_--;
  DCHECK_GE(shared_buffers_, 0);
  SendToNetwork(new ChromotingDesktopNetworkMsg_ReleaseSharedBuffer(id));
}

void DesktopSessionAgent::CloseDesktopPipeHandle() {
  if (!(desktop_pipe_ == IPC::InvalidPlatformFileForTransit())) {
#if defined(OS_WIN)
    base::ClosePlatformFile(desktop_pipe_);
#elif defined(OS_POSIX)
    base::ClosePlatformFile(desktop_pipe_.fd);
#else  // !defined(OS_POSIX)
#error Unsupported platform.
#endif  // !defined(OS_POSIX)

    desktop_pipe_ = IPC::InvalidPlatformFileForTransit();
  }
}

}  // namespace remoting