// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_SPEECH_TTS_MAC_H_
#define CONTENT_BROWSER_SPEECH_TTS_MAC_H_

#import <AVFAudio/AVFAudio.h>

#include <vector>

#include "base/functional/callback.h"
#include "base/gtest_prod_util.h"
#include "base/no_destructor.h"
#include "base/sequence_checker.h"
#include "base/task/task_traits.h"
#include "base/thread_annotations.h"
#include "base/threading/sequence_bound.h"
#include "content/browser/speech/tts_platform_impl.h"

namespace content {
FORWARD_DECLARE_TEST(TtsMacTest, CachedVoiceData);
}  // namespace content

class TtsPlatformImplMac;

class CONTENT_EXPORT TtsPlatformImplMacBackgroundWorker {
 public:
  TtsPlatformImplMacBackgroundWorker() = default;
  TtsPlatformImplMacBackgroundWorker(
      const TtsPlatformImplMacBackgroundWorker&) = delete;
  TtsPlatformImplMacBackgroundWorker& operator=(
      const TtsPlatformImplMacBackgroundWorker&) = delete;
  ~TtsPlatformImplMacBackgroundWorker() = default;

  AVSpeechSynthesisVoice* GetSystemDefaultVoice();
};

@interface ChromeTtsDelegate : NSObject <AVSpeechSynthesizerDelegate>

- (instancetype)initWithPlatformImplMac:(TtsPlatformImplMac*)ttsImplMac;

@end

class TtsPlatformImplMac : public content::TtsPlatformImpl {
 public:
  static constexpr int kInvalidUtteranceId = -1;

  ~TtsPlatformImplMac() override;

  TtsPlatformImplMac(const TtsPlatformImplMac&) = delete;
  TtsPlatformImplMac& operator=(const TtsPlatformImplMac&) = delete;

  bool PlatformImplSupported() override;
  bool PlatformImplInitialized() override;

  void Speak(int utterance_id,
             const std::string& utterance,
             const std::string& lang,
             const content::VoiceData& voice,
             const content::UtteranceContinuousParameters& params,
             base::OnceCallback<void(bool)> on_speak_finished) override;

  bool StopSpeaking() override;

  void Pause() override;

  void Resume() override;

  bool IsSpeaking() override;

  void GetVoices(std::vector<content::VoiceData>* out_voices) override;

  void RefreshVoices() override;

  // Called by ChromeTtsDelegate when we get a callback from the
  // native speech engine.
  void OnSpeechEvent(int utterance_id,
                     content::TtsEventType event_type,
                     int char_index,
                     int char_length,
                     const std::string& error_message);

  // Get the single instance of this class.
  CONTENT_EXPORT static TtsPlatformImplMac* GetInstance();

  CONTENT_EXPORT static base::SequenceBound<TtsPlatformImplMacBackgroundWorker>&
  GetBackgroundWorker();

 private:
  friend base::NoDestructor<TtsPlatformImplMac>;
  FRIEND_TEST_ALL_PREFIXES(content::TtsMacTest, CachedVoiceData);
  TtsPlatformImplMac();

  void ProcessSpeech(int utterance_id,
                     const std::string& lang,
                     const content::VoiceData& voice,
                     const content::UtteranceContinuousParameters& params,
                     base::OnceCallback<void(bool)> on_speak_finished,
                     const std::string& parsed_utterance);

  void UpdateSystemDefaultVoice();
  void OnGotDefaultVoice(AVSpeechSynthesisVoice* default_voice);
  const std::vector<content::VoiceData>& Voices();
  void OnApplicationWillBecomeActive();

  SEQUENCE_CHECKER(sequence_checker_);

  AVSpeechSynthesizer* __strong speech_synthesizer_;
  ChromeTtsDelegate* __strong delegate_;
  id __strong application_active_observer_ = nil;
  int utterance_id_ = kInvalidUtteranceId;
  std::string utterance_;
  int last_char_index_ = 0;
  bool paused_ = false;

  std::vector<content::VoiceData> voices_ GUARDED_BY_CONTEXT(sequence_checker_);
  AVSpeechSynthesisVoice* __strong default_voice_
      GUARDED_BY_CONTEXT(sequence_checker_) = nil;
  bool is_updating_default_voice_ GUARDED_BY_CONTEXT(sequence_checker_) = false;
  bool needs_reupdate_default_voice_ GUARDED_BY_CONTEXT(sequence_checker_) =
      false;
  bool received_voices_request_ GUARDED_BY_CONTEXT(sequence_checker_) = false;
};

#endif  // CONTENT_BROWSER_SPEECH_TTS_MAC_H_