/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "base/basictypes.h"

#include "BluetoothA2dpManager.h"

#include "BluetoothCommon.h"
#include "BluetoothService.h"
#include "BluetoothSocket.h"
#include "BluetoothUtils.h"

#include "mozilla/dom/bluetooth/BluetoothTypes.h"
#include "mozilla/Services.h"
#include "mozilla/StaticPtr.h"
#include "nsIObserverService.h"
#include "MainThreadUtils.h"


using namespace mozilla;
USING_BLUETOOTH_NAMESPACE

namespace {
  StaticRefPtr<BluetoothA2dpManager> sBluetoothA2dpManager;
  bool sInShutdown = false;
} // namespace

NS_IMETHODIMP
BluetoothA2dpManager::Observe(nsISupports* aSubject,
                              const char* aTopic,
                              const char16_t* aData)
{
  MOZ_ASSERT(sBluetoothA2dpManager);

  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
    HandleShutdown();
    return NS_OK;
  }

  MOZ_ASSERT(false, "BluetoothA2dpManager got unexpected topic!");
  return NS_ERROR_UNEXPECTED;
}

BluetoothA2dpManager::BluetoothA2dpManager()
{
  Reset();
}

void
BluetoothA2dpManager::Reset()
{
  mA2dpConnected = false;
  mSinkState = SinkState::SINK_DISCONNECTED;
  mController = nullptr;
}

bool
BluetoothA2dpManager::Init()
{
  MOZ_ASSERT(NS_IsMainThread());

  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  NS_ENSURE_TRUE(obs, false);
  if (NS_FAILED(obs->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false))) {
    BT_WARNING("Failed to add shutdown observer!");
    return false;
  }

  return true;
}

BluetoothA2dpManager::~BluetoothA2dpManager()
{
  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  NS_ENSURE_TRUE_VOID(obs);
  if (NS_FAILED(obs->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID))) {
    BT_WARNING("Failed to remove shutdown observer!");
  }
}

static BluetoothA2dpManager::SinkState
StatusStringToSinkState(const nsAString& aStatus)
{
  BluetoothA2dpManager::SinkState state =
    BluetoothA2dpManager::SinkState::SINK_UNKNOWN;
  if (aStatus.EqualsLiteral("disconnected")) {
    state = BluetoothA2dpManager::SinkState::SINK_DISCONNECTED;
  } else if (aStatus.EqualsLiteral("connecting")) {
    state = BluetoothA2dpManager::SinkState::SINK_CONNECTING;
  } else if (aStatus.EqualsLiteral("connected")) {
    state = BluetoothA2dpManager::SinkState::SINK_CONNECTED;
  } else if (aStatus.EqualsLiteral("playing")) {
    state = BluetoothA2dpManager::SinkState::SINK_PLAYING;
  } else {
    BT_WARNING("Unknown sink state");
  }
  return state;
}

//static
BluetoothA2dpManager*
BluetoothA2dpManager::Get()
{
  MOZ_ASSERT(NS_IsMainThread());

  // If sBluetoothA2dpManager already exists, exit early
  if (sBluetoothA2dpManager) {
    return sBluetoothA2dpManager;
  }

  // If we're in shutdown, don't create a new instance
  NS_ENSURE_FALSE(sInShutdown, nullptr);

  // Create a new instance, register, and return
  BluetoothA2dpManager* manager = new BluetoothA2dpManager();
  NS_ENSURE_TRUE(manager->Init(), nullptr);

  sBluetoothA2dpManager = manager;
  return sBluetoothA2dpManager;
}

void
BluetoothA2dpManager::HandleShutdown()
{
  MOZ_ASSERT(NS_IsMainThread());
  sInShutdown = true;
  Disconnect(nullptr);
  sBluetoothA2dpManager = nullptr;
}

void
BluetoothA2dpManager::Connect(const BluetoothAddress& aDeviceAddress,
                              BluetoothProfileController* aController)
{
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!aDeviceAddress.IsCleared());
  MOZ_ASSERT(aController && !mController);

  BluetoothService* bs = BluetoothService::Get();
  if (!bs || sInShutdown) {
    aController->NotifyCompletion(NS_LITERAL_STRING(ERR_NO_AVAILABLE_RESOURCE));
    return;
  }

  if (mA2dpConnected) {
    aController->NotifyCompletion(NS_LITERAL_STRING(ERR_ALREADY_CONNECTED));
    return;
  }

  mDeviceAddress = aDeviceAddress;
  mController = aController;

  nsAutoString deviceAddressStr;
  AddressToString(aDeviceAddress, deviceAddressStr);

  if (NS_FAILED(bs->SendSinkMessage(deviceAddressStr,
                                    NS_LITERAL_STRING("Connect")))) {
    aController->NotifyCompletion(NS_LITERAL_STRING(ERR_NO_AVAILABLE_RESOURCE));
    return;
  }
}

void
BluetoothA2dpManager::Disconnect(BluetoothProfileController* aController)
{
  BluetoothService* bs = BluetoothService::Get();
  if (!bs) {
    if (aController) {
      aController->NotifyCompletion(
        NS_LITERAL_STRING(ERR_NO_AVAILABLE_RESOURCE));
    }
    return;
  }

  if (!mA2dpConnected) {
    if (aController) {
      aController->NotifyCompletion(
        NS_LITERAL_STRING(ERR_ALREADY_DISCONNECTED));
    }
    return;
  }

  MOZ_ASSERT(!mDeviceAddress.IsCleared());
  MOZ_ASSERT(!mController);

  mController = aController;

  nsAutoString deviceAddressStr;
  AddressToString(mDeviceAddress, deviceAddressStr);

  if (NS_FAILED(bs->SendSinkMessage(deviceAddressStr,
                                    NS_LITERAL_STRING("Disconnect")))) {
    aController->NotifyCompletion(NS_LITERAL_STRING(ERR_NO_AVAILABLE_RESOURCE));
    return;
  }
}

void
BluetoothA2dpManager::OnConnect(const nsAString& aErrorStr)
{
  MOZ_ASSERT(NS_IsMainThread());

  /**
   * On the one hand, notify the controller that we've done for outbound
   * connections. On the other hand, we do nothing for inbound connections.
   */
  NS_ENSURE_TRUE_VOID(mController);

  RefPtr<BluetoothProfileController> controller = mController.forget();
  controller->NotifyCompletion(aErrorStr);
}

void
BluetoothA2dpManager::OnDisconnect(const nsAString& aErrorStr)
{
  MOZ_ASSERT(NS_IsMainThread());

  /**
   * On the one hand, notify the controller that we've done for outbound
   * connections. On the other hand, we do nothing for inbound connections.
   */
  NS_ENSURE_TRUE_VOID(mController);

  RefPtr<BluetoothProfileController> controller = mController.forget();
  controller->NotifyCompletion(aErrorStr);

  Reset();
}

/* HandleSinkPropertyChanged update sink state in A2dp
 *
 * Possible values: "disconnected", "connecting", "connected", "playing"
 *
 * 1. "disconnected" -> "connecting"
 *    Either an incoming or outgoing connection attempt ongoing
 * 2. "connecting" -> "disconnected"
 *    Connection attempt failed
 * 3. "connecting" -> "connected"
 *    Successfully connected
 * 4. "connected" -> "playing"
 *    Audio stream active
 * 5. "playing" -> "connected"
 *    Audio stream suspended
 * 6. "connected" -> "disconnected"
 *    "playing" -> "disconnected"
 *    Disconnected from local or the remote device
 */
void
BluetoothA2dpManager::HandleSinkPropertyChanged(const BluetoothSignal& aSignal)
{
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(aSignal.value().type() ==
             BluetoothValue::TArrayOfBluetoothNamedValue);

  const nsString& addressStr = aSignal.path();

  BluetoothAddress address;
  StringToAddress(addressStr, address);

  /**
   * Update sink property only if
   * - mDeviceAddress is empty (A2dp is disconnected), or
   * - this property change is from the connected sink.
   */
  NS_ENSURE_TRUE_VOID(mDeviceAddress.IsCleared() || mDeviceAddress == address);

  const InfallibleTArray<BluetoothNamedValue>& arr =
    aSignal.value().get_ArrayOfBluetoothNamedValue();
  MOZ_ASSERT(arr.Length() == 1);

  /**
   * There are three properties:
   * - "State": a string
   * - "Connected": a boolean value
   * - "Playing": a boolean value
   *
   * Note that only "State" is handled in this function.
   */

  const nsString& name = arr[0].name();
  NS_ENSURE_TRUE_VOID(name.EqualsLiteral("State"));

  const BluetoothValue& value = arr[0].value();
  MOZ_ASSERT(value.type() == BluetoothValue::TnsString);
  SinkState newState = StatusStringToSinkState(value.get_nsString());
  NS_ENSURE_TRUE_VOID((newState != SinkState::SINK_UNKNOWN) &&
                      (newState != mSinkState));

  /**
   * Reject 'connected' state change if bluetooth is already disabled.
   * Sink state would be reset to 'disconnected' when bluetooth is disabled.
   *
   * See bug 984284 for more information about the edge case.
   */
  NS_ENSURE_FALSE_VOID(newState == SinkState::SINK_CONNECTED &&
                       mSinkState == SinkState::SINK_DISCONNECTED);

  SinkState prevState = mSinkState;
  mSinkState = newState;

  switch(mSinkState) {
    case SinkState::SINK_CONNECTING:
      // case 1: Either an incoming or outgoing connection attempt ongoing
      MOZ_ASSERT(prevState == SinkState::SINK_DISCONNECTED);
      break;
    case SinkState::SINK_PLAYING:
      // case 4: Audio stream active
      MOZ_ASSERT(prevState == SinkState::SINK_CONNECTED);
      break;
    case SinkState::SINK_CONNECTED:
      // case 5: Audio stream suspended
      if (prevState == SinkState::SINK_PLAYING) {
        break;
      }

      // case 3: Successfully connected
      MOZ_ASSERT(prevState == SinkState::SINK_CONNECTING);

      mA2dpConnected = true;
      mDeviceAddress = address;
      NotifyConnectionStatusChanged();

      OnConnect(EmptyString());
      break;
    case SinkState::SINK_DISCONNECTED:
      // case 2: Connection attempt failed
      if (prevState == SinkState::SINK_CONNECTING) {
        OnConnect(NS_LITERAL_STRING(ERR_CONNECTION_FAILED));
        break;
      }

      // case 6: Disconnected from the remote device
      MOZ_ASSERT(prevState == SinkState::SINK_CONNECTED ||
                 prevState == SinkState::SINK_PLAYING);

      mA2dpConnected = false;
      NotifyConnectionStatusChanged();
      mDeviceAddress.Clear();
      OnDisconnect(EmptyString());
      break;
    default:
      break;
  }
}

void
BluetoothA2dpManager::NotifyConnectionStatusChanged()
{
  MOZ_ASSERT(NS_IsMainThread());

  // Notify Gecko observers
  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  NS_ENSURE_TRUE_VOID(obs);

  nsAutoString deviceAddressStr;
  AddressToString(mDeviceAddress, deviceAddressStr);

  if (NS_FAILED(obs->NotifyObservers(this,
                                     BLUETOOTH_A2DP_STATUS_CHANGED_ID,
                                     deviceAddressStr.get()))) {
    BT_WARNING("Failed to notify bluetooth-a2dp-status-changed observsers!");
  }

  // Dispatch an event of status change
  DispatchStatusChangedEvent(
    NS_LITERAL_STRING(A2DP_STATUS_CHANGED_ID), deviceAddressStr, mA2dpConnected);
}

void
BluetoothA2dpManager::OnGetServiceChannel(const BluetoothAddress& aDeviceAddress,
                                          const BluetoothUuid& aServiceUuid,
                                          int aChannel)
{
}

void
BluetoothA2dpManager::OnUpdateSdpRecords(const BluetoothAddress& aDeviceAddress)
{
}

void
BluetoothA2dpManager::GetAddress(BluetoothAddress& aDeviceAddress)
{
  aDeviceAddress = mDeviceAddress;
}

bool
BluetoothA2dpManager::IsConnected()
{
  return mA2dpConnected;
}

NS_IMPL_ISUPPORTS(BluetoothA2dpManager, nsIObserver)