/**

 * DJM-Fix

 * 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 <iostream>

#include <stdexcept>

#include <thread>

#include <mutex>

#include <atomic>

#include <alsa/asoundlib.h>

#include "AlsaBridge.h"

namespace djmfix {

namespace alsa {

class AlsaBridgeImpl : public AlsaBridge, private djmfix::MidiSender {

private:

	djmfix::DJMFix* djmFix;

	snd_rawmidi_t* input;

	snd_rawmidi_t* output;

	std::thread receivingThread;

	std::recursive_mutex midiMutex;

	std::atomic<bool> stopped{false};

	void run() {

		while (!stopped) {

			{

				std::lock_guard<std::recursive_mutex> lock(midiMutex);

				// TODO: poll

				uint8_t buffer[256];

				ssize_t length = snd_rawmidi_read(input, buffer, sizeof (buffer));

				if (length > 0 && length <= sizeof (buffer)) {

					// TODO: multiple messages combined together?

					djmFix->receive(MidiMessage(buffer, buffer + length));

				}

			}

			std::this_thread::sleep_for(std::chrono::milliseconds(100));

		}

	}

public:

	AlsaBridgeImpl(djmfix::DJMFix* djmFix, const std::string& deviceName) : djmFix(djmFix) {

		if (djmFix == nullptr) throw std::invalid_argument("need a djmFix for AlsaBridge");

		int error = snd_rawmidi_open(&input, &output, deviceName.c_str(), SND_RAWMIDI_NONBLOCK);

		if (error) throw std::invalid_argument("unable to open ALSA device");

		djmFix->setMidiSender(this);

	}

	virtual ~AlsaBridgeImpl() {

		// TODO: do not use raw/exclusive access to the device

		snd_rawmidi_close(input);

		snd_rawmidi_close(output);

		std::cerr << "~AlsaBridgeImpl()" << std::endl; // TODO: do not mess STDIO

	}

	virtual void start() override {

		djmFix->start();

		receivingThread = std::thread(&AlsaBridgeImpl::run, this);

	}

	virtual void stop() override {

		stopped = true;

		receivingThread.join();

		djmFix->stop();

	}

	virtual void send(MidiMessage midiMessage) override {

		std::lock_guard<std::recursive_mutex> lock(midiMutex);

		ssize_t length = snd_rawmidi_write(output, midiMessage.data(), midiMessage.size());

		std::cerr << "AlsaBridgeImpl::send(): length = " << length << std::endl; // TODO: do not mess STDIO

	}

};

AlsaBridge* create(djmfix::DJMFix* djmFix, const std::string& deviceName) {

	return new AlsaBridgeImpl(djmFix, deviceName);

}

}

}