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

#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::cli;
using namespace relpipe::writer;
using namespace relpipe::in::jack;

static jack_port_t* jackPort = nullptr;
static jack_ringbuffer_t* ringBuffer = nullptr;
static pthread_mutex_t messageThreadLock = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t dataReady = PTHREAD_COND_INITIALIZER;

static bool continueProcessing = true;

const int RING_BUFFER_SIZE = 100;

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

int enqueueMessage(jack_nframes_t frames, void* arg) {
	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;
}

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));
}

static 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]);
		}
	}
}

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

void processJackStream(ostream &output) {
	// Relation headers:
	std::shared_ptr<RelationalWriter> writer(Factory::create(output));
	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);
	output.flush();

	// 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, enqueueMessage, nullptr);
	// 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.");

	signal(SIGHUP, finish);
	signal(SIGINT, finish);


	// 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);
			output.flush();
		}
		pthread_cond_wait(&dataReady, &messageThreadLock);
	}
	pthread_mutex_unlock(&messageThreadLock);

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

int main(int argc, char** argv) {
	setlocale(LC_ALL, "");
	CLI::untieStdIO();
	CLI cli(argc, argv);
	// TODO: options, CLI parsing, configurable attributes
	// TODO: separate handler class

	int resultCode = CLI::EXIT_CODE_UNEXPECTED_ERROR;

	try {
		processJackStream(cout);
		resultCode = CLI::EXIT_CODE_SUCCESS;
	} catch (JackException e) {
		fwprintf(stderr, L"Caught JACK exception: %ls\n", e.getMessge().c_str());
		fwprintf(stderr, L"Debug: Input stream: eof=%ls, lastRead=%d\n", (cin.eof() ? L"true" : L"false"), cin.gcount());
		resultCode = CLI::EXIT_CODE_UNEXPECTED_ERROR;
	} catch (RelpipeWriterException e) {
		fwprintf(stderr, L"Caught Writer exception: %ls\n", e.getMessge().c_str());
		fwprintf(stderr, L"Debug: Input stream: eof=%ls, lastRead=%d\n", (cin.eof() ? L"true" : L"false"), cin.gcount());
		resultCode = CLI::EXIT_CODE_DATA_ERROR;
	}

	return resultCode;
}