// 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 "media/audio/audio_manager.h"

#include <stdint.h>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/command_line.h"
#include "base/debug/alias.h"
#include "base/debug/crash_logging.h"
#include "base/debug/dump_without_crashing.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/message_loop/message_loop.h"
#include "base/metrics/histogram_macros.h"
#include "base/power_monitor/power_monitor.h"
#include "base/strings/stringprintf.h"
#include "build/build_config.h"
#include "media/audio/audio_manager_factory.h"
#include "media/audio/fake_audio_log_factory.h"
#include "media/base/media_resources.h"
#include "media/base/media_switches.h"

#if defined(OS_WIN)
#include "base/win/scoped_com_initializer.h"
#include "media/audio/win/core_audio_util_win.h"
#endif

namespace media {
namespace {

// The singleton instance of AudioManager. This is set when Create() is called.
AudioManager* g_last_created = nullptr;

// The singleton instance of AudioManagerFactory. This is only set if
// SetFactory() is called. If it is set when Create() is called, its
// CreateInstance() function is used to set |g_last_created|. Otherwise, the
// linked implementation of media::CreateAudioManager is used to set
// |g_last_created|.
AudioManagerFactory* g_audio_manager_factory = nullptr;

// Maximum number of failed pings to the audio thread allowed. A UMA will be
// recorded once this count is reached; if enabled, a non-crash dump will be
// captured as well. We require at least three failed pings before recording to
// ensure unobservable power events aren't mistakenly caught (e.g., the system
// suspends before a OnSuspend() event can be fired).
const int kMaxFailedPingsCount = 3;

// Helper class for managing global AudioManager data and hang monitor. If the
// audio thread is hung for > |kMaxFailedPingsCount| * |max_hung_task_time_|, we
// want to record a UMA and optionally a non-crash dump to find offenders in the
// field.
class AudioManagerHelper : public base::PowerObserver {
 public:
  // These values are histogrammed over time; do not change their ordinal
  // values.
  enum ThreadStatus {
    THREAD_NONE = 0,
    THREAD_STARTED,
    THREAD_HUNG,
    THREAD_RECOVERED,
    THREAD_MAX = THREAD_RECOVERED
  };

  AudioManagerHelper() {}
  ~AudioManagerHelper() override {}

  void HistogramThreadStatus(ThreadStatus status) {
    audio_thread_status_ = status;
    UMA_HISTOGRAM_ENUMERATION("Media.AudioThreadStatus", audio_thread_status_,
                              THREAD_MAX + 1);
  }

  void StartHangTimer(
      const scoped_refptr<base::SingleThreadTaskRunner>& monitor_task_runner) {
    CHECK(!monitor_task_runner_);
    monitor_task_runner_ = monitor_task_runner;
    base::PowerMonitor::Get()->AddObserver(this);
    failed_pings_ = 0;
    io_task_running_ = audio_task_running_ = true;
    UpdateLastAudioThreadTimeTick();
    RecordAudioThreadStatus();
  }

  // Disable hang detection when the system goes into the suspend state.
  void OnSuspend() override {
    base::AutoLock lock(hang_lock_);
    hang_detection_enabled_ = false;
    failed_pings_ = successful_pings_ = 0;
  }

  // Reenable hang detection once the system comes out of the suspend state.
  void OnResume() override {
    base::AutoLock lock(hang_lock_);
    hang_detection_enabled_ = true;
    last_audio_thread_timer_tick_ = base::TimeTicks::Now();
    failed_pings_ = successful_pings_ = 0;

    // If either of the tasks were stopped during suspend, start them now.
    if (!audio_task_running_) {
      audio_task_running_ = true;

      base::AutoUnlock unlock(hang_lock_);
      UpdateLastAudioThreadTimeTick();
    }

    if (!io_task_running_) {
      io_task_running_ = true;

      base::AutoUnlock unlock(hang_lock_);
      RecordAudioThreadStatus();
    }
  }

  // Runs on |monitor_task_runner| typically, but may be started on any thread.
  void RecordAudioThreadStatus() {
    {
      base::AutoLock lock(hang_lock_);

      // Don't attempt to verify the tick time or post our task if the system is
      // in the process of suspending or resuming.
      if (!hang_detection_enabled_) {
        io_task_running_ = false;
        return;
      }

      DCHECK(io_task_running_);
      const base::TimeTicks now = base::TimeTicks::Now();
      const base::TimeDelta tick_delta = now - last_audio_thread_timer_tick_;
      if (tick_delta > max_hung_task_time_) {
        successful_pings_ = 0;
        if (++failed_pings_ >= kMaxFailedPingsCount &&
            audio_thread_status_ < THREAD_HUNG) {
          if (enable_crash_key_logging_)
            LogAudioDriverCrashKeys();
          HistogramThreadStatus(THREAD_HUNG);
        }
      } else {
        failed_pings_ = 0;
        ++successful_pings_;
        if (audio_thread_status_ == THREAD_NONE) {
          HistogramThreadStatus(THREAD_STARTED);
        } else if (audio_thread_status_ == THREAD_HUNG &&
                   successful_pings_ >= kMaxFailedPingsCount) {
          // Require just as many successful pings to recover from failure.
          HistogramThreadStatus(THREAD_RECOVERED);
        }
      }
    }

    // Don't hold the lock while posting the next task.
    monitor_task_runner_->PostDelayedTask(
        FROM_HERE, base::Bind(&AudioManagerHelper::RecordAudioThreadStatus,
                              base::Unretained(this)),
        max_hung_task_time_);
  }

  // Runs on the audio thread typically, but may be started on any thread.
  void UpdateLastAudioThreadTimeTick() {
    {
      base::AutoLock lock(hang_lock_);
      last_audio_thread_timer_tick_ = base::TimeTicks::Now();
      failed_pings_ = 0;

      // Don't post our task if the system is or will be suspended.
      if (!hang_detection_enabled_) {
        audio_task_running_ = false;
        return;
      }

      DCHECK(audio_task_running_);
    }

    // Don't hold the lock while posting the next task.
    g_last_created->GetTaskRunner()->PostDelayedTask(
        FROM_HERE,
        base::Bind(&AudioManagerHelper::UpdateLastAudioThreadTimeTick,
                   base::Unretained(this)),
        max_hung_task_time_ / 5);
  }

  AudioLogFactory* fake_log_factory() { return &fake_log_factory_; }

#if defined(OS_WIN)
  // This should be called before creating an AudioManager in tests to ensure
  // that the creating thread is COM initialized.
  void InitializeCOMForTesting() {
    com_initializer_for_testing_.reset(new base::win::ScopedCOMInitializer());
  }
#endif

#if defined(OS_LINUX)
  void set_app_name(const std::string& app_name) {
    app_name_ = app_name;
  }

  const std::string& app_name() const {
    return app_name_;
  }
#endif

  void enable_crash_key_logging() { enable_crash_key_logging_ = true; }

 private:
  void LogAudioDriverCrashKeys() {
    DCHECK(enable_crash_key_logging_);

#if defined(OS_WIN)
    std::string driver_name, driver_version;
    if (!CoreAudioUtil::GetDxDiagDetails(&driver_name, &driver_version))
      return;

    base::debug::ScopedCrashKey crash_key(
        "hung-audio-thread-details",
        base::StringPrintf("%s:%s", driver_name.c_str(),
                           driver_version.c_str()));

    // Please forward crash reports to http://crbug.com/422522
    base::debug::DumpWithoutCrashing();
#endif
  }

  FakeAudioLogFactory fake_log_factory_;

  const base::TimeDelta max_hung_task_time_ = base::TimeDelta::FromMinutes(1);
  scoped_refptr<base::SingleThreadTaskRunner> monitor_task_runner_;

  base::Lock hang_lock_;
  bool hang_detection_enabled_ = true;
  base::TimeTicks last_audio_thread_timer_tick_;
  uint32_t failed_pings_ = 0;
  bool io_task_running_ = false;
  bool audio_task_running_ = false;
  ThreadStatus audio_thread_status_ = THREAD_NONE;
  bool enable_crash_key_logging_ = false;
  uint32_t successful_pings_ = 0;

#if defined(OS_WIN)
  scoped_ptr<base::win::ScopedCOMInitializer> com_initializer_for_testing_;
#endif

#if defined(OS_LINUX)
  std::string app_name_;
#endif

  DISALLOW_COPY_AND_ASSIGN(AudioManagerHelper);
};

base::LazyInstance<AudioManagerHelper>::Leaky g_helper =
    LAZY_INSTANCE_INITIALIZER;

}  // namespace

// Forward declaration of the platform specific AudioManager factory function.
AudioManager* CreateAudioManager(AudioLogFactory* audio_log_factory);

AudioManager::AudioManager() {}

AudioManager::~AudioManager() {
  CHECK(!g_last_created || g_last_created == this);
  g_last_created = nullptr;
}

// static
void AudioManager::SetFactory(AudioManagerFactory* factory) {
  CHECK(factory);
  CHECK(!g_last_created);
  CHECK(!g_audio_manager_factory);
  g_audio_manager_factory = factory;
}

// static
void AudioManager::ResetFactoryForTesting() {
  if (g_audio_manager_factory) {
    delete g_audio_manager_factory;
    g_audio_manager_factory = nullptr;
  }
}

// static
AudioManager* AudioManager::Create(AudioLogFactory* audio_log_factory) {
  CHECK(!g_last_created);
  if (g_audio_manager_factory)
    g_last_created = g_audio_manager_factory->CreateInstance(audio_log_factory);
  else
    g_last_created = CreateAudioManager(audio_log_factory);

  return g_last_created;
}

// static
AudioManager* AudioManager::CreateWithHangTimer(
    AudioLogFactory* audio_log_factory,
    const scoped_refptr<base::SingleThreadTaskRunner>& monitor_task_runner) {
  AudioManager* manager = Create(audio_log_factory);

// On OSX the audio thread is the UI thread, for which a hang monitor is not
// necessary or recommended.
#if !defined(OS_MACOSX)
  g_helper.Pointer()->StartHangTimer(monitor_task_runner);
#endif

  return manager;
}

// static
AudioManager* AudioManager::CreateForTesting() {
#if defined(OS_WIN)
  g_helper.Pointer()->InitializeCOMForTesting();
#endif
  return Create(g_helper.Pointer()->fake_log_factory());
}

// static
void AudioManager::EnableCrashKeyLoggingForAudioThreadHangs() {
  CHECK(!g_last_created);
  g_helper.Pointer()->enable_crash_key_logging();
}

#if defined(OS_LINUX)
// static
void AudioManager::SetGlobalAppName(const std::string& app_name) {
  g_helper.Pointer()->set_app_name(app_name);
}

// static
const std::string& AudioManager::GetGlobalAppName() {
  return g_helper.Pointer()->app_name();
}
#endif

// static
AudioManager* AudioManager::Get() {
  return g_last_created;
}

// static
std::string AudioManager::GetDefaultDeviceName() {
#if !defined(OS_IOS)
  return GetLocalizedStringUTF8(DEFAULT_AUDIO_DEVICE_NAME);
#else
  NOTREACHED();
  return "";
#endif
}

// static
std::string AudioManager::GetCommunicationsDeviceName() {
#if defined(OS_WIN)
  return GetLocalizedStringUTF8(COMMUNICATIONS_AUDIO_DEVICE_NAME);
#else
  NOTREACHED();
  return "";
#endif
}

}  // namespace media