/**

 * Relational pipes

 * Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 3 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

#pragma once

#include <memory>

#include <atomic>

#include <cstdlib>

#include <cstring>

#include <sstream>

#include <sys/mman.h>

#include <unistd.h>

#include <pthread.h>

#include <functional>

#include <iomanip>

#include <jack/jack.h>

#include <jack/midiport.h>

#include <jack/ringbuffer.h>

#include <relpipe/common/type/typedefs.h>

#include <relpipe/writer/RelationalWriter.h>

#include <relpipe/writer/RelpipeWriterException.h>

#include <relpipe/writer/AttributeMetadata.h>

#include <relpipe/writer/Factory.h>

#include <relpipe/writer/TypeId.h>

#include <relpipe/cli/CLI.h>

#include "Configuration.h"

#include "JackException.h"

namespace relpipe {

namespace in {

namespace jack {

int enqueueMessage(jack_nframes_t frames, void* arg);

class JackCommand {

private:

	Configuration& configuration;

	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // TODO: local system encoding

	std::atomic<bool> continueProcessing{true};

	/**

	 * Is passed through the ring buffer

	 * from the the jack-writing thread (callback) to the relpipe-writing thread.

	 */

	struct MidiMessage {

		uint8_t buffer[4096] = {0};

		uint32_t size;

		uint32_t time;

	};

	/**

	 * JACK callbacks (called from the real-time thread)

	 */

	class RealTimeContext {

	public:

		jack_client_t* jackClient = nullptr;

		jack_port_t* jackPort = nullptr;

		jack_ringbuffer_t* ringBuffer = nullptr;

		pthread_mutex_t processingLock = PTHREAD_MUTEX_INITIALIZER;

		pthread_cond_t processingDone = PTHREAD_COND_INITIALIZER;

		const int RING_BUFFER_SIZE = 100;

		int processCallback(jack_nframes_t frames) {

			void* buffer = jack_port_get_buffer(jackPort, frames);

			if (buffer == nullptr) throw JackException(L"Unable to get port buffer."); // TODO: exception in RT callback?

			for (jack_nframes_t i = 0, eventCount = jack_midi_get_event_count(buffer); i < eventCount; i++) {

				jack_midi_event_t event;

				int noData = jack_midi_event_get(&event, buffer, i);

				if (noData) continue;

				if (event.size > sizeof (MidiMessage::buffer)) {

					// TODO: should not printf in RT callback:

					fwprintf(stderr, L"Error: MIDI message was too large → skipping event. Maximum allowed size: %lu bytes.\n", sizeof (MidiMessage::buffer));

				} else if (jack_ringbuffer_write_space(ringBuffer) >= sizeof (MidiMessage)) {

					MidiMessage m;

					m.time = event.time;

					m.size = event.size;

					memcpy(m.buffer, event.buffer, event.size);

					jack_ringbuffer_write(ringBuffer, (const char *) &m, sizeof (MidiMessage));

				} else {

					// TODO: should not printf in RT callback:

					fwprintf(stderr, L"Error: ring buffer is full → skipping event.\n");

				}

			}

			// TODO: just count skipped events and bytes and report them in next successful message instead of printing to STDERR

			if (pthread_mutex_trylock(&processingLock) == 0) {

				pthread_cond_signal(&processingDone);

				pthread_mutex_unlock(&processingLock);

			}

			return 0;

		}

		static int processCallback(jack_nframes_t frames, void* instance) {

			return static_cast<RealTimeContext*> (instance)->processCallback(frames);

		}

	} realTimeContext;

	static void writeRecord(std::shared_ptr<relpipe::writer::RelationalWriter> writer,

			relpipe::common::type::StringX eventType, relpipe::common::type::Integer channel,

			relpipe::common::type::Boolean noteOn, relpipe::common::type::Integer pitch, relpipe::common::type::Integer velocity,

			relpipe::common::type::Integer controllerId, relpipe::common::type::Integer value,

			relpipe::common::type::StringX raw) {

		writer->writeAttribute(eventType);

		writer->writeAttribute(&channel, typeid (channel));

		writer->writeAttribute(&noteOn, typeid (noteOn));

		writer->writeAttribute(&pitch, typeid (pitch));

		writer->writeAttribute(&velocity, typeid (velocity));

		writer->writeAttribute(&controllerId, typeid (controllerId));

		writer->writeAttribute(&value, typeid (value));

		writer->writeAttribute(&raw, typeid (raw));

	}

	void processMessage(std::shared_ptr<relpipe::writer::RelationalWriter> writer, MidiMessage* event) {

		if (event->size == 0) {

			return;

		} else {

			uint8_t type = event->buffer[0] & 0xF0;

			uint8_t channel = event->buffer[0] & 0x0F;

			// TODO: write timestamp, message number

			if ((type == 0x90 || type == 0x80) && event->size == 3) {

				writeRecord(writer, L"note", channel, type == 0x90, event->buffer[1], event->buffer[2], 0, 0, toHex(event));

			} else if (type == 0xB0 && event->size == 3) {

				writeRecord(writer, L"control", channel, false, 0, 0, event->buffer[1], event->buffer[2], toHex(event));

			} else if (event->buffer[0] == 0xF0) {

				writeRecord(writer, L"sysex", channel, false, 0, 0, 0, 0, toHex(event));

			} else {

				writeRecord(writer, L"unknown", channel, false, 0, 0, 0, 0, toHex(event));

			}

		}

	}

	relpipe::common::type::StringX toHex(MidiMessage* event) {

		std::wstringstream result;

		result << std::hex << std::setfill(L'0');

		for (size_t i = 0; i < event->size && i < sizeof (event->buffer); i++) {

			if (i > 0) result << L' ';

			result << std::setw(2) << event->buffer[i];

			// result << ("0123456789abcdef"[event->buffer[i] >> 4]);

			// result << ("0123456789abcdef"[event->buffer[i] & 0xf]);

		}

		return result.str();

	}

	static void jackErrorCallback(const char * message) {

		std::wstring_convert < std::codecvt_utf8<wchar_t>> convertor; // TODO: local system encoding

		std::wcerr << L"JACK: " << convertor.from_bytes(message) << std::endl;

	}

	void finalize() {

		// Close JACK connection:

		jack_deactivate(realTimeContext.jackClient);

		jack_client_close(realTimeContext.jackClient);

		jack_ringbuffer_free(realTimeContext.ringBuffer);

		pthread_mutex_unlock(&realTimeContext.processingLock);

	}

	void failInConstructor(const relpipe::common::type::StringX& errorMessage) {

		finalize();

		throw JackException(errorMessage);

	}

	/**

	 * Wait for the signal that is emitted at the end of the real-time processCallback() cycle.

	 */

	void waitForRTCycle() {

		pthread_cond_wait(&realTimeContext.processingDone, &realTimeContext.processingLock);

	}

public:

	JackCommand(Configuration& configuration) : configuration(configuration) {

		pthread_mutex_lock(&realTimeContext.processingLock);

		// Initialize JACK connection:

		std::string clientName = convertor.to_bytes(configuration.jackClientName);

		realTimeContext.jackClient = jack_client_open(clientName.c_str(), JackNullOption, nullptr);

		if (realTimeContext.jackClient == nullptr) failInConstructor(L"Could not create JACK client.");

		realTimeContext.ringBuffer = jack_ringbuffer_create(realTimeContext.RING_BUFFER_SIZE * sizeof (MidiMessage));

		jack_set_process_callback(realTimeContext.jackClient, RealTimeContext::processCallback, &realTimeContext);

		// TODO: report also other events (connections etc.)

		jack_set_error_function(jackErrorCallback);

		jack_set_info_function(jackErrorCallback);

		realTimeContext.jackPort = jack_port_register(realTimeContext.jackClient, "input", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);

		if (realTimeContext.jackPort == nullptr) failInConstructor(L"Could not register the JACK port.");

		if (mlockall(MCL_CURRENT | MCL_FUTURE)) fwprintf(stderr, L"Warning: Can not lock memory.\n");

		int jackError = jack_activate(realTimeContext.jackClient);

		if (jackError) failInConstructor(L"Could not activate the JACK client.");

	}

	void processJackStream(std::shared_ptr<relpipe::writer::RelationalWriter> writer, std::function<void() > relationalWriterFlush) {

		// Relation headers:

		using namespace relpipe::writer;

		vector<AttributeMetadata> metadata;

		metadata.push_back({L"event", TypeId::STRING});

		metadata.push_back({L"channel", TypeId::INTEGER});

		metadata.push_back({L"note_on", TypeId::BOOLEAN});

		metadata.push_back({L"note_pitch", TypeId::INTEGER});

		metadata.push_back({L"note_velocity", TypeId::INTEGER});

		metadata.push_back({L"controller_id", TypeId::INTEGER});

		metadata.push_back({L"controller_value", TypeId::INTEGER});

		metadata.push_back({L"raw", TypeId::STRING});

		writer->startRelation(L"midi", metadata, true);

		relationalWriterFlush();

		// Process messages from the ring buffer queue:

		while (continueProcessing) {

			while (jack_ringbuffer_read_space(realTimeContext.ringBuffer) >= sizeof (MidiMessage)) {

				MidiMessage m;

				jack_ringbuffer_read(realTimeContext.ringBuffer, (char*) &m, sizeof (MidiMessage));

				processMessage(writer, &m);

				relationalWriterFlush();

			}

			waitForRTCycle();

		}

	}

	void finish(int sig) {

		continueProcessing = false;

	}

	virtual ~JackCommand() {

		finalize();

	}

};

}

}

}