/**
 * 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 <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::atomic<bool> stopped{false};

	void run() {
		while (!stopped) {
			// 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 {
		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);
}

}
}