#include "VoiceClient.h"
#include "../../audio/AudioOutput.h"
#include "../../audio/codec/Converter.h"
#include "../../audio/codec/OpusConverter.h"
#include "../../audio/AudioMerger.h"
#include "../../audio/js/AudioOutputStream.h"
#include "AudioEventLoop.h"
#include "../../logger.h"

using namespace std;
using namespace tc;
using namespace tc::audio::codec;
using namespace tc::connection;

extern tc::audio::AudioOutput* global_audio_output;

#define DEBUG_PREMATURE_PACKETS

#ifdef WIN32
    #define _field_(name, value) value
#else
    #define _field_(name, value) .name = value
#endif
const codec::condec_info codec::info[6] = {
	{
            _field_(supported, false),
            _field_(name, "speex_narrowband"),
            _field_(new_converter, nullptr)
	},
	{
            _field_(supported, false),
            _field_(name, "speex_wideband"),
            _field_(new_converter, nullptr)
	},
	{
            _field_(supported, false),
            _field_(name, "speex_ultra_wideband"),
            _field_(new_converter, nullptr)
	},
	{
            _field_(supported, false),
            _field_(name, "celt_mono"),
            _field_(new_converter, nullptr)
	},
	{
            _field_(supported, true),
            _field_(name, "opus_voice"),
            _field_(new_converter, [](string& error) -> shared_ptr<Converter> {
                auto result = make_shared<OpusConverter>(1, 48000, 960);
                if(!result->initialize(error, OPUS_APPLICATION_VOIP))
                    return nullptr;
                return dynamic_pointer_cast<Converter>(result);
            })
	},
	{
            _field_(supported, true),
            _field_(name, "opus_music"),
            _field_(new_converter, [](string& error) -> shared_ptr<Converter> {
                auto result = make_shared<OpusConverter>(2, 48000, 960);
                if(!result->initialize(error, OPUS_APPLICATION_AUDIO))
                    return nullptr;
                return dynamic_pointer_cast<Converter>(result);
            })
	}
};

void VoiceClientWrap::do_wrap(const v8::Local<v8::Object> &object) {
	this->Wrap(object);

	auto handle = this->_handle.lock();
	if(!handle) {
		Nan::ThrowError("weak handle");
		return;
	}
	Nan::Set(object, Nan::New<v8::String>("client_id").ToLocalChecked(), Nan::New<v8::Number>(handle->client_id()));
	handle->on_state_changed = [&]{ this->call_state_changed(); };

	this->call_state_changed = Nan::async_callback([&]{
		Nan::HandleScope scope;
		this->_call_state_changed();
	});
}

void VoiceClientWrap::_call_state_changed() {
	auto handle = this->_handle.lock();
	if(!handle) {
		log_warn(category::voice_connection, tr("State changed on invalid handle!"));
		return;
	}

	auto state = handle->state();
	auto call_playback_callback = state == VoiceClient::state::playing && !this->_currently_playing;
	auto call_stopped_callback = state == VoiceClient::state::stopped && this->_currently_playing;

	if(state == VoiceClient::state::stopped)
		this->_currently_playing = false;
	if(state == VoiceClient::state::playing)
		this->_currently_playing = true;

	if(call_playback_callback) {
		auto callback = Nan::Get(this->handle(), Nan::New<v8::String>("callback_playback").ToLocalChecked()).ToLocalChecked();
		if(callback->IsFunction())
			callback.As<v8::Function>()->Call(Nan::GetCurrentContext(), Nan::Undefined(), 0, nullptr);
	}
	if(call_stopped_callback) {
		auto callback = Nan::Get(this->handle(), Nan::New<v8::String>("callback_stopped").ToLocalChecked()).ToLocalChecked();
		if(callback->IsFunction())
			callback.As<v8::Function>()->Call(Nan::GetCurrentContext(), Nan::Undefined(), 0, nullptr);
	}

	auto callback = Nan::Get(this->handle(), Nan::New<v8::String>("callback_state_changed").ToLocalChecked()).ToLocalChecked();
	if(callback->IsFunction()) {
		v8::Local<v8::Value> argv[1] = {
			Nan::New<v8::Number>(state)
		};
		callback.As<v8::Function>()->Call(Nan::GetCurrentContext(), Nan::Undefined(), 1, argv);
	}
}

NAN_MODULE_INIT(VoiceClientWrap::Init) {
	auto klass = Nan::New<v8::FunctionTemplate>(VoiceClientWrap::NewInstance);
	klass->SetClassName(Nan::New("VoiceConnection").ToLocalChecked());
	klass->InstanceTemplate()->SetInternalFieldCount(1);

	Nan::SetPrototypeMethod(klass, "get_state", VoiceClientWrap::_get_state);
	Nan::SetPrototypeMethod(klass, "get_volume", VoiceClientWrap::_get_volume);
	Nan::SetPrototypeMethod(klass, "set_volume", VoiceClientWrap::_set_volume);
	Nan::SetPrototypeMethod(klass, "abort_replay", VoiceClientWrap::_abort_replay);
	Nan::SetPrototypeMethod(klass, "get_stream", VoiceClientWrap::_get_stream);

	constructor().Reset(Nan::GetFunction(klass).ToLocalChecked());
}

NAN_METHOD(VoiceClientWrap::NewInstance) {
	if(!info.IsConstructCall())
		Nan::ThrowError("invalid invoke!");
}

NAN_METHOD(VoiceClientWrap::_get_volume) {
	auto client = ObjectWrap::Unwrap<VoiceClientWrap>(info.Holder());

	auto handle = client->_handle.lock();
	if(!handle) {
		Nan::ThrowError("weak handle");
		return;
	}

	info.GetReturnValue().Set(handle->get_volume());
}

NAN_METHOD(VoiceClientWrap::_set_volume) {
	auto client = ObjectWrap::Unwrap<VoiceClientWrap>(info.Holder());

	auto handle = client->_handle.lock();
	if(!handle) {
		Nan::ThrowError("weak handle");
		return;
	}

	if(info.Length() != 1 || !info[0]->IsNumber()) {
		Nan::ThrowError("Invalid arguments");
		return;
	}

	handle->set_volume(info[0]->NumberValue(Nan::GetCurrentContext()).FromMaybe(0));
}
NAN_METHOD(VoiceClientWrap::_abort_replay) {
	auto client = ObjectWrap::Unwrap<VoiceClientWrap>(info.Holder());

	auto handle = client->_handle.lock();
	if(!handle) {
		Nan::ThrowError("weak handle");
		return;
	}

	handle->cancel_replay();
}

NAN_METHOD(VoiceClientWrap::_get_state) {
	auto client = ObjectWrap::Unwrap<VoiceClientWrap>(info.Holder());

	auto handle = client->_handle.lock();
	if(!handle) {
		Nan::ThrowError("weak handle");
		return;
	}

	info.GetReturnValue().Set(handle->state());
}


NAN_METHOD(VoiceClientWrap::_get_stream) {
	auto client = ObjectWrap::Unwrap<VoiceClientWrap>(info.Holder());

	auto handle = client->_handle.lock();
	if(!handle) {
		Nan::ThrowError("weak handle");
		return;
	}

	auto wrapper = new audio::AudioOutputStreamWrapper(handle->output_stream(), false);
	auto object = Nan::NewInstance(Nan::New(audio::AudioOutputStreamWrapper::constructor()), 0, nullptr).ToLocalChecked();
	wrapper->do_wrap(object);
	info.GetReturnValue().Set(object);
}

VoiceClientWrap::VoiceClientWrap(const std::shared_ptr<VoiceClient>& client) : _handle(client) { }

VoiceClientWrap::~VoiceClientWrap() {}

VoiceClient::VoiceClient(const std::shared_ptr<VoiceConnection>&, uint16_t client_id) : _client_id(client_id) {
	this->output_source = global_audio_output->create_source();
	this->output_source->overflow_strategy = audio::overflow_strategy::ignore;
	this->output_source->max_latency = (size_t) ceil(this->output_source->sample_rate * 1);
	this->output_source->min_buffer = (size_t) ceil(this->output_source->sample_rate * 0.04);

	this->output_source->on_underflow = [&]{
		if(this->_state == state::stopping)
			this->set_state(state::stopped);
		else if(this->_state != state::stopped) {
			if(this->_last_received_packet + chrono::seconds(1) < chrono::system_clock::now()) {
				this->set_state(state::stopped);
				log_warn(category::audio, tr("Client {} has a audio buffer underflow and not received any data for one second. Stopping replay."), this->_client_id);
			} else {
				if(this->_state != state::buffering) {
					log_warn(category::audio, tr("Client {} has a audio buffer underflow. Buffer again and try to replay prematured packets."), this->_client_id);
					this->set_state(state::buffering);
				}

				play_premature_packets = true; /* try to replay any premature packets because we assume that the other packets got lost */
				audio::decode_event_loop->schedule(static_pointer_cast<event::EventEntry>(this->ref()));
			}
		}

		return false;
	};
	this->output_source->on_overflow = [&](size_t count){
		log_warn(category::audio, tr("Client {} has a audio buffer overflow of {}."), this->_client_id, count);
	};
}

VoiceClient::~VoiceClient() {
	if(v8::Isolate::GetCurrent())
		this->finalize_js_object();
	else {
		assert(this->_js_handle.IsEmpty());
	}

	this->output_source->on_underflow = nullptr; /* to ensure */
	global_audio_output->delete_source(this->output_source);
}

void VoiceClient::initialize_js_object() {
	if(!this->_js_handle.IsEmpty())
		return;

	auto object_wrap = new VoiceClientWrap(this->ref());
	auto object = Nan::NewInstance(Nan::New(VoiceClientWrap::constructor()), 0, nullptr).ToLocalChecked();
	Nan::TryCatch tc;
	object_wrap->do_wrap(object);
	if(tc.HasCaught()) {
		tc.ReThrow();
		return;
	}

	this->_js_handle.Reset(Nan::GetCurrentContext()->GetIsolate(), object);
}

void VoiceClient::finalize_js_object() {
	this->_js_handle.Reset();
}

#define target_buffer_length 16384
void VoiceClient::process_packet(uint16_t packet_id, const pipes::buffer_view& buffer, codec::value codec, bool head) {
	if(this->_volume == 0)
		return;

	if(codec < 0 || codec > this->codec.size()) {
		log_warn(category::voice_connection, tr("Received voice packet from client {} with unknown codec ({})"), this->_client_id, codec);
		return;
	}

	auto encoded_buffer = make_unique<EncodedBuffer>();
	encoded_buffer->packet_id = packet_id;
	encoded_buffer->codec = codec;
	encoded_buffer->receive_timestamp = chrono::system_clock::now();
	encoded_buffer->buffer = buffer.own_buffer();
	encoded_buffer->head = head;

	this->_last_received_packet = encoded_buffer->receive_timestamp;
	{
		lock_guard lock(this->audio_decode_queue_lock);
		this->audio_decode_queue.push_back(move(encoded_buffer));
	}

	audio::decode_event_loop->schedule(static_pointer_cast<event::EventEntry>(this->ref()));
}

void VoiceClient::cancel_replay() {
	log_trace(category::voice_connection, tr("Cancel replay for client {}"), this->_client_id);
	this->output_source->clear();
	this->set_state(state::stopped);
}

void VoiceClient::event_execute(const std::chrono::system_clock::time_point &scheduled) {
	static auto max_time = chrono::milliseconds(10);

	bool reschedule = false;
	auto now = chrono::system_clock::now();
	while(true) {
		unique_lock buffer_lock(this->audio_decode_queue_lock);
		if(this->play_premature_packets) {
			this->play_premature_packets = false;

			for(auto& codec_data : this->codec) {
				if(!codec_data) continue;

				if(!codec_data->premature_packets.empty()) {
					size_t play_count = 0;
					while(!codec_data->premature_packets.empty()) {
						auto& packet = codec_data->premature_packets.front();

						//Test if we're able to replay stuff again
						if((uint16_t) (codec_data->last_packet_id + 1) < packet.packet_id && play_count > 0) //Only check for the order if we replayed one already
							break; //Nothing new

						this->output_source->enqueue_samples(packet.buffer);
						codec_data->last_packet_id = packet.packet_id;
						codec_data->premature_packets.pop_front();
						play_count++;
					}

#ifdef DEBUG_PREMATURE_PACKETS
					if(play_count > 0)
						log_debug(category::audio, tr("Replayed (buffer underflow) {} premature packets for client {}"), play_count, this->_client_id);
#endif
					break;
				}
			}
		}

		if(this->audio_decode_queue.empty())
			break;

		if(chrono::system_clock::now() - now > max_time) {
			reschedule = true;
			break;
		}

		auto entry = move(this->audio_decode_queue.front());
		this->audio_decode_queue.pop_front();
		buffer_lock.unlock();

		//TODO: Drop too old buffers!
		this->process_encoded_buffer(entry);
	}

	if(audio_decode_event_dropped.exchange(false) && !reschedule) {
		//Is not really a warning, it happens all the time and isn't really an issue
		//log_warn(category::voice_connection, tr("Dropped auto enqueue event execution for client {}. No reschedulling planned, hopefully we processed all buffers."), this->_client_id);
	}

	if(reschedule) {
		log_warn(category::voice_connection, tr("Audio data decode will take longer than {} us. Enqueueing for later"), chrono::duration_cast<chrono::microseconds>(max_time).count());
		audio::decode_event_loop->schedule(static_pointer_cast<event::EventEntry>(this->ref()));
	}
}

#define MAX_LOST_PACKETS (6)
//Note: This function must be executed single threaded
void VoiceClient::process_encoded_buffer(const std::unique_ptr<EncodedBuffer> &buffer) {
	string error;

	auto& codec_data = this->codec[buffer->codec];

	if(!codec_data) {
		auto info = codec::get_info(buffer->codec);
		if(!info || !info->supported) {
			log_warn(category::voice_connection, tr("Received voice packet from client {}, but we dont support it ({})"), this->_client_id, buffer->codec);
			return;
		}

		auto instance = make_unique<AudioCodec>();
		instance->successfully_initialized = false;

		instance->last_packet_id = (uint16_t) (buffer->packet_id - 1); /* could be 0xFFFF */
		instance->converter = info->new_converter(error);
		if(!instance->converter) {
			codec_data = move(instance);

			log_warn(category::voice_connection, tr("Failed to initialize new codec {} for client {}: {}"), buffer->codec, this->_client_id, error);
			return;
		}

		instance->resampler = make_shared<audio::AudioResampler>(instance->converter->sample_rate(), this->output_source->sample_rate, instance->converter->channels());
		if(!instance->resampler->valid()) {
			codec_data = move(instance);

			log_warn(category::voice_connection, tr("Failed to initialize new codec resampler {} for client {}"), buffer->codec, this->_client_id);
			return;
		}
		instance->successfully_initialized = true;
		codec_data = move(instance);
	} else if(!codec_data->successfully_initialized) {
		return; /* already failed ignore that stuff */
	}

	uint16_t diff;
	bool premature = false;

	if(codec_data->last_packet_timestamp + chrono::seconds(1) < buffer->receive_timestamp || this->_state >= state::stopping) {
		diff = 0xFFFF;
	} else {
		if(codec_data->last_packet_id > buffer->packet_id) {
			auto local_index = (uint16_t) (codec_data->last_packet_id + MAX_LOST_PACKETS);
			if(local_index < buffer->packet_id)
				diff = 0xFF; /* we got in a new generation */
			else {
				log_warn(category::audio,
				         tr("Received voice packet for client {} with is older than the last we received (Current index: {}, Packet index: {}). Dropping packet."),
				         this->_client_id, buffer->packet_id, codec_data->last_packet_id
		        );
				return;
			}
		} else {
			diff = buffer->packet_id - codec_data->last_packet_id;
		}
	}

	const auto old_packet_id = codec_data->last_packet_id;
	codec_data->last_packet_timestamp = buffer->receive_timestamp;

	if(buffer->buffer.empty()) {
		/* lets playback the last samples and we're done */
		this->set_state(state::stopping);

		/* enqueue all premature packets (list should be already ordered!) */
		{
			unique_lock buffer_lock(this->audio_decode_queue_lock);
			for(const auto& packet : codec_data->premature_packets)
				this->output_source->enqueue_samples(packet.buffer);
			codec_data->premature_packets.clear();
		}

		log_trace(category::voice_connection, tr("Stopping replay for client {}. Empty buffer!"), this->_client_id);
		return;
	}

	if(diff == 0) {
		//Duplicated packets
		log_warn(category::audio, tr("Received voice packet with the same ID then the last one. Dropping packet."));
		return;
	} else
		diff--; /* because the diff is normally 1 (ofc) */

	if(diff <= MAX_LOST_PACKETS) {
		if(diff > 0) {
			/* lets first handle packet as "lost", even thou we're enqueueing it as premature */
			//auto status = codec_data->converter->decode_lost(error, diff);
			//if(status < 0)
			//	log_warn(category::voice_connection, tr("Failed to decode (skip) dropped packets. Return code {} => {}"), status, error);
			premature = !buffer->head && this->state() != state::stopped;

			log_debug(category::voice_connection,
					tr("Client {} dropped one or more audio packets. Old packet id: {}, New packet id: {}, Diff: {}. Head: {}. Flagging chunk as premature: {}"),
					this->_client_id, old_packet_id, buffer->packet_id, diff, buffer->head, premature);
		}
	} else {
		log_debug(category::voice_connection, tr("Client {} resetted decoder. Old packet id: {}, New packet id: {}, diff: {}"), this->_client_id, old_packet_id, buffer->packet_id, diff);
		codec_data->converter->reset_decoder();
		if(!codec_data->converter) {
			log_warn(category::voice_connection, tr("Failed to reset codec decoder {} for client {}: {}"), buffer->codec, this->_client_id, error);
			return;
		}
	}
	if(!premature)
		codec_data->last_packet_id = buffer->packet_id;

	char target_buffer[target_buffer_length];
	if(target_buffer_length < codec_data->converter->expected_decoded_length(buffer->buffer.data_ptr(), buffer->buffer.length())) {
		log_warn(category::voice_connection, tr("Failed to decode audio data. Target buffer is smaller then expected bytes ({} < {})"), target_buffer_length, codec_data->converter->expected_decoded_length(buffer->buffer.data_ptr(), buffer->buffer.length()));
		return;
	}
	auto samples = codec_data->converter->decode(error, buffer->buffer.data_ptr(), buffer->buffer.length(), target_buffer);
	if(samples < 0) {
		log_warn(category::voice_connection, tr("Failed to decode audio data: {}"), error);
		return;
	}
	if(target_buffer_length < codec_data->resampler->estimated_output_size(samples) * codec_data->resampler->channels() * 4) {
		log_warn(category::voice_connection, tr("Failed to resample audio data. Target buffer is smaller then expected bytes ({} < {})"), target_buffer_length, (codec_data->resampler->estimated_output_size(samples) * codec_data->resampler->channels() * 4));
		return;
	}

	auto resampled_samples = codec_data->resampler->process(target_buffer, target_buffer, samples);
	if(resampled_samples <= 0) {
		log_warn(category::voice_connection, tr("Failed to resample audio data. Resampler resulted in  {}"), resampled_samples);
		return;
	}

	if(!audio::merge::merge_channels_interleaved(target_buffer, this->output_source->channel_count, target_buffer, codec_data->resampler->channels(), resampled_samples)) {
		log_warn(category::voice_connection, tr("Failed to merge channels to output stream channel count!"));
		return;
	}

	if(this->_volume != 1) {
		auto buf = (float*) target_buffer;
		auto count = this->output_source->channel_count * resampled_samples;
		while(count-- > 0)
			*(buf++) *= this->_volume;
	}

	if(premature) {
		auto audio_buffer = audio::SampleBuffer::allocate((uint8_t) this->output_source->channel_count, (uint16_t) resampled_samples);

		audio_buffer->sample_index = 0;
		memcpy(audio_buffer->sample_data, target_buffer, this->output_source->channel_count * resampled_samples * 4);

		{
			unique_lock buffer_lock(this->audio_decode_queue_lock);
			auto it = codec_data->premature_packets.begin();
			for(; it != codec_data->premature_packets.end(); it++) {
				if(it->packet_id > buffer->packet_id) {
					break; /* it is set to the right position */
				}
			}
			codec_data->premature_packets.insert(it, {
					buffer->packet_id,
					move(audio_buffer)
			});
			std::stable_sort(codec_data->premature_packets.begin(), codec_data->premature_packets.end(), [](const PrematureAudioPacket& a, const PrematureAudioPacket& b) {
				return a.packet_id < b.packet_id;
			});
		}
	} else {
		auto enqueued = this->output_source->enqueue_samples(target_buffer, resampled_samples);
		if(enqueued != resampled_samples)
			log_warn(category::voice_connection, tr("Failed to enqueue all samples for client {}. Enqueued {} of {}"), this->_client_id, enqueued, resampled_samples);
		this->set_state(state::playing);

		/* test if any premature got its original place */
		{
			unique_lock buffer_lock(this->audio_decode_queue_lock);

			size_t play_count = 0;
			while(!codec_data->premature_packets.empty()) {
				auto& packet = codec_data->premature_packets[0];

				//Test if we're able to replay stuff again
				if((uint16_t) (codec_data->last_packet_id + 1) < packet.packet_id)
					break; //Nothing new

				this->output_source->enqueue_samples(packet.buffer);
				codec_data->last_packet_id = packet.packet_id;
				codec_data->premature_packets.pop_front();
				play_count++;
			}
#ifdef DEBUG_PREMATURE_PACKETS
			if(play_count > 0)
				log_debug(category::audio, tr("Replayed (id match) {} premature packets for client {}"), play_count, this->_client_id);
#endif
		}
	}
}

void VoiceClient::event_execute_dropped(const std::chrono::system_clock::time_point &point) {
	if(audio_decode_event_dropped.exchange(true))
		//Is not really a warning, it happens all the time and isn't really an issue
		;//log_warn(category::voice_connection, tr("Dropped auto enqueue event execution two or more times in a row for client {}"), this->_client_id);
}