/**
 * 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 <cstdlib>
#include <cstring>
#include <memory>
#include <unistd.h>
#include <pthread.h>
#include <sys/mman.h>
#include <atomic>
#include <functional>

#include <jack/jack.h>
#include <jack/midiport.h>
#include <jack/ringbuffer.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 "JackException.h"

using namespace relpipe::writer;

namespace relpipe {
namespace in {
namespace jack {

int enqueueMessage(jack_nframes_t frames, void* arg);

class JackCommand {
private:
	jack_port_t* jackPort = nullptr;
	jack_ringbuffer_t* ringBuffer = nullptr;
	pthread_mutex_t messageThreadLock = PTHREAD_MUTEX_INITIALIZER;
	pthread_cond_t dataReady = PTHREAD_COND_INITIALIZER;

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

	const int RING_BUFFER_SIZE = 100;

	struct MidiMessage {
		uint8_t buffer[4096];
		uint32_t size;
		uint32_t time;
	};

public:

	int enqueueMessage(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(&messageThreadLock) == 0) {
			pthread_cond_signal(&dataReady);
			pthread_mutex_unlock(&messageThreadLock);
		}

		return 0;
	}

private:

	static void writeRecord(std::shared_ptr<RelationalWriter> writer,
			string_t eventType, integer_t channel,
			boolean_t noteOn, integer_t pitch, integer_t velocity,
			integer_t controllerId, integer_t value) {
		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));
	}

	void processMessage(std::shared_ptr<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
			// TODO: write raw buffer in hex

			if ((type == 0x90 || type == 0x80) && event->size == 3) {
				writeRecord(writer, L"note", channel, type == 0x90, event->buffer[1], event->buffer[2], 0, 0);
			} else if (type == 0xB0 && event->size == 3) {
				writeRecord(writer, L"control", channel, false, 0, 0, event->buffer[1], event->buffer[2]);
			} else {
				writeRecord(writer, L"unknown", channel, false, 0, 0, 0, 0);
			}
		}
	}

public:

	void finish(int sig) {
		continueProcessing = false;
	}

	void processJackStream(std::shared_ptr<writer::RelationalWriter> writer, std::function<void() > relationalWriterFlush) {
		// Relation headers:
		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});
		writer->startRelation(L"midi", metadata, true);
		relationalWriterFlush();

		// Initialize JACK connection:
		std::string clientName = "relpipe-in-jack";
		jack_client_t* client = jack_client_open(clientName.c_str(), JackNullOption, nullptr);
		if (client == nullptr) throw JackException(L"Could not create JACK client.");

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

		jack_set_process_callback(client, relpipe::in::jack::enqueueMessage, this);
		// TODO: report also other events (connections etc.)

		jackPort = jack_port_register(client, "input", JACK_DEFAULT_MIDI_TYPE, JackPortIsInput, 0);
		if (jackPort == nullptr) throw JackException(L"Could not register port.");

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

		int jackError = jack_activate(client);
		if (jackError) throw JackException(L"Could not activate client.");

		// Process messages from the ring buffer queue:
		pthread_mutex_lock(&messageThreadLock);
		while (continueProcessing) {
			const size_t queuedMessages = jack_ringbuffer_read_space(ringBuffer) / sizeof (MidiMessage);
			for (size_t i = 0; i < queuedMessages; ++i) {
				MidiMessage m;
				jack_ringbuffer_read(ringBuffer, (char*) &m, sizeof (MidiMessage));
				processMessage(writer, &m);
				relationalWriterFlush();
			}
			pthread_cond_wait(&dataReady, &messageThreadLock);
		}
		pthread_mutex_unlock(&messageThreadLock);

		// Close JACK connection:
		jack_deactivate(client);
		jack_client_close(client);
		jack_ringbuffer_free(ringBuffer);
	}

};

int enqueueMessage(jack_nframes_t frames, void* arg) {
	JackCommand* instance = (JackCommand*) arg;
	return instance->enqueueMessage(frames);
}

}
}
}