/**
 * 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 <regex>

#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};

	int maxJackPortConnections = 0;

	/**
	 * 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();
	}

	void listPorts(std::shared_ptr<relpipe::writer::RelationalWriter> writer) {
		using namespace relpipe::writer;
		vector<AttributeMetadata> metadata;

		metadata.push_back({L"name", TypeId::STRING});
		metadata.push_back({L"input", TypeId::BOOLEAN});
		metadata.push_back({L"output", TypeId::BOOLEAN});
		metadata.push_back({L"physical", TypeId::BOOLEAN});
		metadata.push_back({L"terminal", TypeId::BOOLEAN});
		metadata.push_back({L"mine", TypeId::BOOLEAN});
		metadata.push_back({L"midi", TypeId::BOOLEAN});
		metadata.push_back({L"type", TypeId::STRING});
		writer->startRelation(L"port", metadata, true);

		const char** portNames = jack_get_ports(realTimeContext.jackClient, nullptr, nullptr, 0);

		std::regex midiTypePattern(".*midi$");

		for (const char** portName = portNames; *portName; portName++) {
			jack_port_t* port = jack_port_by_name(realTimeContext.jackClient, *portName);

			const char* portType = jack_port_type(port);
			int portFlags = jack_port_flags(port);

			bool isInput = portFlags & JackPortFlags::JackPortIsInput;
			bool isOuputput = portFlags & JackPortFlags::JackPortIsOutput;
			bool isPhysical = portFlags & JackPortFlags::JackPortIsPhysical;
			bool isTerminal = portFlags & JackPortFlags::JackPortIsTerminal;
			bool isMine = jack_port_is_mine(realTimeContext.jackClient, port);
			bool isMidi = std::regex_search(portType, midiTypePattern);

			writer->writeAttribute(convertor.from_bytes(*portName));
			writer->writeAttribute(&isInput, typeid (isInput));
			writer->writeAttribute(&isOuputput, typeid (isOuputput));
			writer->writeAttribute(&isPhysical, typeid (isPhysical));
			writer->writeAttribute(&isTerminal, typeid (isTerminal));
			writer->writeAttribute(&isMine, typeid (isMine));
			writer->writeAttribute(&isMidi, typeid (isMidi));
			writer->writeAttribute(convertor.from_bytes(portType));
		}

		jack_free(portNames);
	}

	void listConnections(std::shared_ptr<relpipe::writer::RelationalWriter> writer) {
		using namespace relpipe::writer;
		vector<AttributeMetadata> metadata;

		metadata.push_back({L"event", TypeId::STRING});
		metadata.push_back({L"source_port", TypeId::STRING});
		metadata.push_back({L"destination_port", TypeId::STRING});
		writer->startRelation(L"connection", metadata, true);

		const relpipe::common::type::StringX event = L"connect";

		const char** sourcePortNames = jack_get_ports(realTimeContext.jackClient, nullptr, nullptr, JackPortFlags::JackPortIsOutput);

		for (const char** sourcePortName = sourcePortNames; *sourcePortName; sourcePortName++) {
			jack_port_t* sourcePort = jack_port_by_name(realTimeContext.jackClient, *sourcePortName);

			const char** destinationPortNames = jack_port_get_all_connections(realTimeContext.jackClient, sourcePort);

			for (const char** destinationPortName = destinationPortNames; destinationPortNames && *destinationPortName; destinationPortName++) {
				writer->writeAttribute(event);
				writer->writeAttribute(convertor.from_bytes(*sourcePortName));
				writer->writeAttribute(convertor.from_bytes(*destinationPortName));
			}

			jack_free(destinationPortNames);
		}

		jack_free(sourcePortNames);
	}

	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.client);
		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, convertor.to_bytes(configuration.port).c_str(), 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.");


		// Connect to configured destination ports:
		const char* jackPortName = jack_port_name(realTimeContext.jackPort);
		for (auto sourcePort : configuration.connectTo) {
			int error = jack_connect(realTimeContext.jackClient, convertor.to_bytes(sourcePort).c_str(), jackPortName);
			if (error) failInConstructor(L"Connection to the JACK port failed: " + sourcePort);
		}

	}

	void processJackStream(std::shared_ptr<relpipe::writer::RelationalWriter> writer, std::function<void() > relationalWriterFlush) {
		// Relation headers:
		using namespace relpipe::writer;
		vector<AttributeMetadata> metadata;

		if (configuration.listPorts) listPorts(writer);
		if (configuration.listConnections) listConnections(writer);
		if (!configuration.listMidiMessages) return;

		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();

			// Once the Configuration::requiredJackConnections count was reached, we will disconnect if the count drops under this level.
			if (configuration.requiredConnections) {
				int currentConnectionCount = jack_port_connected(realTimeContext.jackPort);
				if (currentConnectionCount > maxJackPortConnections) maxJackPortConnections = currentConnectionCount;
				else if (maxJackPortConnections >= configuration.requiredConnections && currentConnectionCount < configuration.requiredConnections) break;
			}
		}
	}

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

	virtual ~JackCommand() {
		finalize();
	}

};

}
}
}