/**

 * Relational pipes

 *

 * 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 <string>

#include <cstring>

#include <vector>

#include <iostream>

#include <sstream>

#include <locale>

#include <codecvt>

#include <sys/mman.h>

#include <signal.h>

#include <unistd.h>

#include <jack/jack.h>

#include <jack/midiport.h>

#include <jack/ringbuffer.h>

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

#include <relpipe/reader/TypeId.h>

#include <relpipe/reader/handlers/RelationalReaderStringHandler.h>

#include <relpipe/reader/handlers/AttributeMetadata.h>

#include "Configuration.h"

#include "JackException.h"

namespace relpipe {

namespace out {

namespace jack {

int dequeueMessages(jack_nframes_t frames, void* arg);

class JackHandler : public relpipe::reader::handlers::RelationalReaderStringHandler {

private:

	Configuration& configuration;

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

	jack_client_t* jackClient = nullptr;

	jack_port_t* jackPort = nullptr;

	jack_ringbuffer_t* ringBuffer = nullptr;

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

	const int RING_BUFFER_SIZE = 100;

	struct MidiMessage {

		uint8_t buffer[4096];

		uint32_t size;

		uint32_t time;

	};

	/**

	 */

public:

	JackHandler(Configuration& configuration) : configuration(configuration) {

		// Initialize JACK connection:

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

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

		if (jackClient == nullptr) throw JackException(L"Could not create JACK client.");

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

		jack_set_process_callback(jackClient, relpipe::out::jack::dequeueMessages, this);

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

		jackPort = jack_port_register(jackClient, "output", JACK_DEFAULT_MIDI_TYPE, JackPortIsOutput, 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(jackClient);

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

		// Wait for a port connection, because it does not make much sense to send MIDI events nowhere:

		while (jack_port_connected(jackPort) < configuration.requiredJackConnections) usleep(10000);

		// TODO: configurable auto-connection to another client/port

	}

	void startRelation(const relpipe::common::type::StringX name, std::vector<relpipe::reader::handlers::AttributeMetadata> attributes) override {

		// TODO: validate metadata and prepare attribute mappings (names and types are important, order does not matter)

	}

	void attribute(const relpipe::common::type::StringX& value) override {

		// TODO: append to current message + if this is last attribute, put whole message to the ring buffer

		// TODO: if (continueProcessing) {} ?

		// memcpy(currentMidiMessage.buffer, ….buffer, ….size);

		// currentMidiMessage.size = …;

		// currentMidiMessage.time = …;

		// TODO: correct timing?

		// TODO: real data

			} else {

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

			}

		}

	}

	void endOfPipe() {

		// TODO: send optional (configurable) MIDI events

		// Wait until the ring buffer is empty

		while (continueProcessing && jack_ringbuffer_read_space(ringBuffer)) usleep(1000);

		usleep(1000000);

		// TODO: better waiting (ringBuffer might be empty, but events have not been sent to JACK yet)

		// TODO: optionally mute all; probably enabled by default

	}

	int dequeueMessages(jack_nframes_t frames) {

		const size_t queuedMessages = jack_ringbuffer_read_space(ringBuffer) / sizeof (MidiMessage);

		void* jackPortBuffer = jack_port_get_buffer(jackPort, frames); // jack_port_get_buffer() must be called outside the loop, otherwise it will multiply the MIDI events

		jack_midi_clear_buffer(jackPortBuffer); // TODO: clean buffer?

		for (size_t i = 0; i < queuedMessages && i < frames; i++) {

			// TODO: correct timing?

			MidiMessage m;

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

			jack_midi_data_t* midiData = jack_midi_event_reserve(jackPortBuffer, m.time, m.size);

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

		}

		return 0;

	}

	void finish(int sig) {

		continueProcessing = false;

	}

	virtual ~JackHandler() {

		// Close JACK connection:

		jack_deactivate(jackClient);

		jack_client_close(jackClient);

		jack_ringbuffer_free(ringBuffer);

	}

};

int dequeueMessages(jack_nframes_t frames, void* arg) {

	JackHandler* instance = (JackHandler*) arg;

	return instance->dequeueMessages(frames);

}

}

}

}