/****************************************************************************
 Copyright (c) 2014 Chukong Technologies Inc.
 
 http://www.cocos2d-x.org
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ****************************************************************************/

#define LOG_TAG "AudioEngine-inl.mm"

#include "platform/CCPlatformConfig.h"
#if CC_TARGET_PLATFORM == CC_PLATFORM_IOS || CC_TARGET_PLATFORM == CC_PLATFORM_MAC

#include "audio/apple/AudioEngine-inl.h"

#import <OpenAL/alc.h>
#import <AVFoundation/AVFoundation.h>

#include "audio/include/AudioEngine.h"
#include "platform/CCFileUtils.h"
#include "base/CCDirector.h"
#include "base/CCScheduler.h"
#include "base/ccUtils.h"

using namespace cocos2d;
using namespace cocos2d::experimental;

static ALCdevice *s_ALDevice = nullptr;
static ALCcontext *s_ALContext = nullptr;

#if CC_TARGET_PLATFORM == CC_PLATFORM_IOS
@interface AudioEngineSessionHandler : NSObject
{
}

-(id) init;
-(void)handleInterruption:(NSNotification*)notification;

@end

@implementation AudioEngineSessionHandler

// only enable it on iOS. Disable it on tvOS
#if !defined(CC_TARGET_OS_TVOS)
void AudioEngineInterruptionListenerCallback(void* user_data, UInt32 interruption_state)
{
    if (kAudioSessionBeginInterruption == interruption_state)
    {
      alcMakeContextCurrent(nullptr);
    }
    else if (kAudioSessionEndInterruption == interruption_state)
    {
      OSStatus result = AudioSessionSetActive(true);
      if (result) NSLog(@"Error setting audio session active! %d\n", result);

      alcMakeContextCurrent(s_ALContext);
    }
}
#endif

-(id) init
{
    if (self = [super init])
    {
      if ([[[UIDevice currentDevice] systemVersion] intValue] > 5) {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterruption:) name:AVAudioSessionInterruptionNotification object:[AVAudioSession sharedInstance]];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterruption:) name:UIApplicationDidBecomeActiveNotification object:nil];
      }
    // only enable it on iOS. Disable it on tvOS
    // AudioSessionInitialize removed from tvOS
#if !defined(CC_TARGET_OS_TVOS)
      else {
        AudioSessionInitialize(NULL, NULL, AudioEngineInterruptionListenerCallback, self);
      }
#endif
    }
    return self;
}

-(void)handleInterruption:(NSNotification*)notification
{
    static bool resumeOnBecomingActive = false;
    
    if ([notification.name isEqualToString:AVAudioSessionInterruptionNotification]) {
        NSInteger reason = [[[notification userInfo] objectForKey:AVAudioSessionInterruptionTypeKey] integerValue];
        if (reason == AVAudioSessionInterruptionTypeBegan) {
            alcMakeContextCurrent(NULL);
        }
        
        if (reason == AVAudioSessionInterruptionTypeEnded) {
            if ([UIApplication sharedApplication].applicationState == UIApplicationStateActive) {
                NSError *error = nil;
                [[AVAudioSession sharedInstance] setActive:YES error:&error];
                alcMakeContextCurrent(s_ALContext);
            } else {
                resumeOnBecomingActive = true;
            }
        }
    }
    
    if ([notification.name isEqualToString:UIApplicationDidBecomeActiveNotification] && resumeOnBecomingActive) {
        resumeOnBecomingActive = false;
        NSError *error = nil;
        BOOL success = [[AVAudioSession sharedInstance]
                        setCategory: AVAudioSessionCategoryAmbient
                        error: &error];
        if (!success) {
            ALOGE("Fail to set audio session.");
            return;
        }
        [[AVAudioSession sharedInstance] setActive:YES error:&error];
        alcMakeContextCurrent(s_ALContext);
    }
}

-(void) dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:AVAudioSessionInterruptionNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidBecomeActiveNotification object:nil];
    
    [super dealloc];
}
@end

static id s_AudioEngineSessionHandler = nullptr;
#endif

AudioEngineImpl::AudioEngineImpl()
: _lazyInitLoop(true)
, _currentAudioID(0)
{
    
}

AudioEngineImpl::~AudioEngineImpl()
{
    if (s_ALContext) {
        alDeleteSources(MAX_AUDIOINSTANCES, _alSources);
        
        _audioCaches.clear();
        
        alcMakeContextCurrent(nullptr);
        alcDestroyContext(s_ALContext);
    }
    if (s_ALDevice) {
        alcCloseDevice(s_ALDevice);
    }

#if CC_TARGET_PLATFORM == CC_PLATFORM_IOS
    [s_AudioEngineSessionHandler release];
#endif
}

bool AudioEngineImpl::init()
{
    bool ret = false;
    do{
#if CC_TARGET_PLATFORM == CC_PLATFORM_IOS
        s_AudioEngineSessionHandler = [[AudioEngineSessionHandler alloc] init];
#endif
        
        s_ALDevice = alcOpenDevice(nullptr);
        
        if (s_ALDevice) {
            s_ALContext = alcCreateContext(s_ALDevice, nullptr);
            alcMakeContextCurrent(s_ALContext);
            
            alGenSources(MAX_AUDIOINSTANCES, _alSources);
            auto alError = alGetError();
            if(alError != AL_NO_ERROR)
            {
                ALOGE("%s:generating sources failed! error = %x", __PRETTY_FUNCTION__, alError);
                break;
            }
            
            for (int i = 0; i < MAX_AUDIOINSTANCES; ++i) {
                _alSourceUsed[_alSources[i]] = false;
            }
            
            // fixed #16170: Random crash in alGenBuffers(AudioCache::readDataTask) at startup
            // Please note that, as we know the OpenAL operation is atomic (threadsafe),
            // 'alGenBuffers' may be invoked by different threads. But in current implementation of 'alGenBuffers',
            // When the first time it's invoked, application may crash!!!
            // Why? OpenAL is opensource by Apple and could be found at
            // http://opensource.apple.com/source/OpenAL/OpenAL-48.7/Source/OpenAL/oalImp.cpp .
            /*
             
            void InitializeBufferMap()
            {
                if (gOALBufferMap == NULL) // Position 1
                {
                    gOALBufferMap = new OALBufferMap ();  // Position 2
             
                    // Position Gap
             
                    gBufferMapLock = new CAGuard("OAL:BufferMapLock"); // Position 3
                    gDeadOALBufferMap = new OALBufferMap ();

                    OALBuffer   *newBuffer = new OALBuffer (AL_NONE);
                    gOALBufferMap->Add(AL_NONE, &newBuffer);
                }
            }

            AL_API ALvoid AL_APIENTRY alGenBuffers(ALsizei n, ALuint *bids)
            {
                ...

                try {
                    if (n < 0)
                    throw ((OSStatus) AL_INVALID_VALUE);

                    InitializeBufferMap();
                    if (gOALBufferMap == NULL)
                    throw ((OSStatus) AL_INVALID_OPERATION);

                    CAGuard::Locker locked(*gBufferMapLock);  // Position 4
                ...
                ...
            }
             
             */
            // 'gBufferMapLock' will be initialized in the 'InitializeBufferMap' function,
            // that's the problem. It means that 'InitializeBufferMap' may be invoked in different threads.
            // It will be very dangerous in multi-threads environment.
            // Imagine there're two threads (Thread A, Thread B), they call 'alGenBuffers' simultaneously.
            // While A goto 'Position Gap', 'gOALBufferMap' was assigned, then B goto 'Position 1' and find
            // that 'gOALBufferMap' isn't NULL, B just jump over 'InitialBufferMap' and goto 'Position 4'.
            // Meanwhile, A is still at 'Position Gap', B will crash at '*gBufferMapLock' since 'gBufferMapLock'
            // is still a null pointer. Oops, how could Apple implemented this method in this fucking way?
            
            // Workaround is do an unused invocation in the mainthread right after OpenAL is initialized successfully
            // as bellow.
            // ================ Workaround begin ================ //
            
            ALuint unusedAlBufferId = 0;
            alGenBuffers(1, &unusedAlBufferId);
            alDeleteBuffers(1, &unusedAlBufferId);
            
            // ================ Workaround end ================ //
            
            
            _scheduler = Director::getInstance()->getScheduler();
            ret = true;
            ALOGI("OpenAL was initialized successfully!");
        }
    }while (false);
    
    return ret;
}

AudioCache* AudioEngineImpl::preload(const std::string& filePath, std::function<void(bool)> callback)
{
    AudioCache* audioCache = nullptr;
    
    auto it = _audioCaches.find(filePath);
    if (it == _audioCaches.end()) {
        audioCache = &_audioCaches[filePath];
        audioCache->_fileFullPath = FileUtils::getInstance()->fullPathForFilename(filePath);
        unsigned int cacheId = audioCache->_id;
        auto isCacheDestroyed = audioCache->_isDestroyed;
        AudioEngine::addTask([audioCache, cacheId, isCacheDestroyed](){
            if (*isCacheDestroyed)
            {
                ALOGV("AudioCache (id=%u) was destroyed, no need to launch readDataTask.", cacheId);
                audioCache->setSkipReadDataTask(true);
                return;
            }
            audioCache->readDataTask(cacheId);
        });
    }
    else {
        audioCache = &it->second;
    }
    
    if (audioCache && callback)
    {
        audioCache->addLoadCallback(callback);
    }
    return audioCache;
}

int AudioEngineImpl::play2d(const std::string &filePath ,bool loop ,float volume)
{
    if (s_ALDevice == nullptr) {
        return AudioEngine::INVALID_AUDIO_ID;
    }
    
    bool sourceFlag = false;
    ALuint alSource = 0;
    for (int i = 0; i < MAX_AUDIOINSTANCES; ++i) {
        alSource = _alSources[i];
        
        if ( !_alSourceUsed[alSource]) {
            sourceFlag = true;
            break;
        }
    }
    if(!sourceFlag){
        return AudioEngine::INVALID_AUDIO_ID;
    }
    
    auto player = new (std::nothrow) AudioPlayer;
    if (player == nullptr) {
        return AudioEngine::INVALID_AUDIO_ID;
    }
    
    player->_alSource = alSource;
    player->_loop = loop;
    player->_volume = volume;
    
    auto audioCache = preload(filePath, nullptr);
    if (audioCache == nullptr) {
        delete player;
        return AudioEngine::INVALID_AUDIO_ID;
    }
    
    player->setCache(audioCache);
    _threadMutex.lock();
    _audioPlayers[_currentAudioID] = player;
    _threadMutex.unlock();
    
    _alSourceUsed[alSource] = true;
    
    audioCache->addPlayCallback(std::bind(&AudioEngineImpl::_play2d,this,audioCache,_currentAudioID));
    
    if (_lazyInitLoop) {
        _lazyInitLoop = false;
        _scheduler->schedule(CC_SCHEDULE_SELECTOR(AudioEngineImpl::update), this, 0.05f, false);
    }
    
    return _currentAudioID++;
}

void AudioEngineImpl::_play2d(AudioCache *cache, int audioID)
{
    //Note: It may bn in sub thread or main thread :(
    if (!*cache->_isDestroyed && cache->_state == AudioCache::State::READY)
    {
        _threadMutex.lock();
        auto playerIt = _audioPlayers.find(audioID);
        if (playerIt != _audioPlayers.end() && playerIt->second->play2d()) {
            _scheduler->performFunctionInCocosThread([audioID](){
                
                if (AudioEngine::_audioIDInfoMap.find(audioID) != AudioEngine::_audioIDInfoMap.end()) {
                    AudioEngine::_audioIDInfoMap[audioID].state = AudioEngine::AudioState::PLAYING;
                }
            });
        }
        _threadMutex.unlock();
    }
    else
    {
        ALOGD("AudioEngineImpl::_play2d, cache was destroyed or not ready!");
        auto iter = _audioPlayers.find(audioID);
        if (iter != _audioPlayers.end())
        {
            iter->second->_removeByAudioEngine = true;
        }
    }
}

void AudioEngineImpl::setVolume(int audioID,float volume)
{
    auto player = _audioPlayers[audioID];
    player->_volume = volume;
    
    if (player->_ready) {
        alSourcef(_audioPlayers[audioID]->_alSource, AL_GAIN, volume);
        
        auto error = alGetError();
        if (error != AL_NO_ERROR) {
            ALOGE("%s: audio id = %d, error = %x", __PRETTY_FUNCTION__,audioID,error);
        }
    }
}

void AudioEngineImpl::setLoop(int audioID, bool loop)
{
    auto player = _audioPlayers[audioID];
    
    if (player->_ready) {
        if (player->_streamingSource) {
            player->setLoop(loop);
        } else {
            if (loop) {
                alSourcei(player->_alSource, AL_LOOPING, AL_TRUE);
            } else {
                alSourcei(player->_alSource, AL_LOOPING, AL_FALSE);
            }
            
            auto error = alGetError();
            if (error != AL_NO_ERROR) {
                ALOGE("%s: audio id = %d, error = %x", __PRETTY_FUNCTION__,audioID,error);
            }
        }
    }
    else {
        player->_loop = loop;
    }
}

bool AudioEngineImpl::pause(int audioID)
{
    bool ret = true;
    alSourcePause(_audioPlayers[audioID]->_alSource);
    
    auto error = alGetError();
    if (error != AL_NO_ERROR) {
        ret = false;
        ALOGE("%s: audio id = %d, error = %x", __PRETTY_FUNCTION__,audioID,error);
    }
    
    return ret;
}

bool AudioEngineImpl::resume(int audioID)
{
    bool ret = true;
    alSourcePlay(_audioPlayers[audioID]->_alSource);
    
    auto error = alGetError();
    if (error != AL_NO_ERROR) {
        ret = false;
        ALOGE("%s: audio id = %d, error = %x", __PRETTY_FUNCTION__,audioID,error);
    }
    
    return ret;
}

void AudioEngineImpl::stop(int audioID)
{
    auto player = _audioPlayers[audioID];
    player->destroy();
    //Note: Don't set the flag to false here, it should be set in 'update' function.
    // Otherwise, the state got from alSourceState may be wrong
//    _alSourceUsed[player->_alSource] = false;
}

void AudioEngineImpl::stopAll()
{
    for(auto&& player : _audioPlayers)
    {
        player.second->destroy();
    }
    //Note: Don't set the flag to false here, it should be set in 'update' function.
    // Otherwise, the state got from alSourceState may be wrong
//    for(int index = 0; index < MAX_AUDIOINSTANCES; ++index)
//    {
//        _alSourceUsed[_alSources[index]] = false;
//    }
}

float AudioEngineImpl::getDuration(int audioID)
{
    auto player = _audioPlayers[audioID];
    if(player->_ready){
        return player->_audioCache->_duration;
    } else {
        return AudioEngine::TIME_UNKNOWN;
    }
}

float AudioEngineImpl::getCurrentTime(int audioID)
{
    float ret = 0.0f;
    auto player = _audioPlayers[audioID];
    if(player->_ready){
        if (player->_streamingSource) {
            ret = player->getTime();
        } else {
            alGetSourcef(player->_alSource, AL_SEC_OFFSET, &ret);
            
            auto error = alGetError();
            if (error != AL_NO_ERROR) {
                ALOGE("%s, audio id:%d,error code:%x", __PRETTY_FUNCTION__,audioID,error);
            }
        }
    }
    
    return ret;
}

bool AudioEngineImpl::setCurrentTime(int audioID, float time)
{
    bool ret = false;
    auto player = _audioPlayers[audioID];
    
    do {
        if (!player->_ready) {
            break;
        }
        
        if (player->_streamingSource) {
            ret = player->setTime(time);
            break;
        }
        else {
            if (player->_audioCache->_bytesOfRead != player->_audioCache->_dataSize &&
                (time * player->_audioCache->_sampleRate * player->_audioCache->_bytesPerFrame) > player->_audioCache->_bytesOfRead) {
                ALOGE("%s: audio id = %d", __PRETTY_FUNCTION__,audioID);
                break;
            }
            
            alSourcef(player->_alSource, AL_SEC_OFFSET, time);
            
            auto error = alGetError();
            if (error != AL_NO_ERROR) {
                ALOGE("%s: audio id = %d, error = %x", __PRETTY_FUNCTION__,audioID,error);
            }
            ret = true;
        }
    } while (0);
    
    return ret;
}

void AudioEngineImpl::setFinishCallback(int audioID, const std::function<void (int, const std::string &)> &callback)
{
    _audioPlayers[audioID]->_finishCallbak = callback;
}

void AudioEngineImpl::update(float dt)
{
    ALint sourceState;
    int audioID;
    AudioPlayer* player;
    
//    ALOGV("AudioPlayer count: %d", (int)_audioPlayers.size());
    
    for (auto it = _audioPlayers.begin(); it != _audioPlayers.end(); ) {
        audioID = it->first;
        player = it->second;
        alGetSourcei(player->_alSource, AL_SOURCE_STATE, &sourceState);
        
        if (player->_removeByAudioEngine)
        {
            _alSourceUsed[player->_alSource] = false;
            
            AudioEngine::remove(audioID);
            _threadMutex.lock();
            it = _audioPlayers.erase(it);
            _threadMutex.unlock();
            delete player;
        }
        else if (player->_ready && sourceState == AL_STOPPED) {
            
            _alSourceUsed[player->_alSource] = false;
            if (player->_finishCallbak) {
                auto& audioInfo = AudioEngine::_audioIDInfoMap[audioID];
                player->_finishCallbak(audioID, *audioInfo.filePath); //FIXME: callback will delay 50ms
            }
            
            AudioEngine::remove(audioID);
            delete player;
            _threadMutex.lock();
            it = _audioPlayers.erase(it);
            _threadMutex.unlock();
        }
        else{
            ++it;
        }
    }
    
    if(_audioPlayers.empty()){
        _lazyInitLoop = true;
        _scheduler->unschedule(CC_SCHEDULE_SELECTOR(AudioEngineImpl::update), this);
    }
}

void AudioEngineImpl::uncache(const std::string &filePath)
{
    _audioCaches.erase(filePath);
}

void AudioEngineImpl::uncacheAll()
{
    _audioCaches.clear();
}

#endif