franta-hg@2: /**
franta-hg@2:  * DJM-Fix
franta-hg@16:  * Copyright © 2025 František Kučera (Frantovo.cz, GlobalCode.info)
franta-hg@2:  *
franta-hg@2:  * This program is free software: you can redistribute it and/or modify
franta-hg@2:  * it under the terms of the GNU General Public License as published by
franta-hg@2:  * the Free Software Foundation, version 3 of the License.
franta-hg@2:  *
franta-hg@2:  * This program is distributed in the hope that it will be useful,
franta-hg@2:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
franta-hg@2:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
franta-hg@2:  * GNU General Public License for more details.
franta-hg@2:  *
franta-hg@2:  * You should have received a copy of the GNU General Public License
franta-hg@2:  * along with this program. If not, see <http://www.gnu.org/licenses/>.
franta-hg@2:  */
franta-hg@2: #include <iostream>
franta-hg@13: #include <iomanip>
franta-hg@12: #include <sstream>
franta-hg@5: #include <stdexcept>
franta-hg@5: #include <thread>
franta-hg@9: #include <mutex>
franta-hg@5: #include <atomic>
franta-hg@11: #include <regex>
franta-hg@2: 
franta-hg@3: #include <alsa/asoundlib.h>
franta-hg@3: 
franta-hg@2: #include "AlsaBridge.h"
franta-hg@12: #include "Logger.h"
franta-hg@2: 
franta-hg@2: namespace djmfix {
franta-hg@2: namespace alsa {
franta-hg@2: 
franta-hg@12: using L = djmfix::logging::Level;
franta-hg@12: 
franta-hg@2: class AlsaBridgeImpl : public AlsaBridge, private djmfix::MidiSender {
franta-hg@2: private:
franta-hg@2: 	djmfix::DJMFix* djmFix;
franta-hg@12: 	djmfix::logging::Logger* logger;
franta-hg@5: 	snd_rawmidi_t* input;
franta-hg@5: 	snd_rawmidi_t* output;
franta-hg@5: 	std::thread receivingThread;
franta-hg@9: 	std::recursive_mutex midiMutex;
franta-hg@5: 	std::atomic<bool> stopped{false};
franta-hg@5: 
franta-hg@18: 	struct FoundDevice {
franta-hg@18: 		std::string id;
franta-hg@18: 		std::string name;
franta-hg@18: 	};
franta-hg@11: 
franta-hg@18: 	FoundDevice findDeviceName(std::regex cardNamePattern) {
franta-hg@11: 		std::vector<int> cardNumbers;
franta-hg@18: 		std::vector<std::string> cardNames;
franta-hg@11: 
franta-hg@12: 		logger->log(L::INFO, "Looking for available cards:");
franta-hg@11: 
franta-hg@11: 		for (int card = -1; snd_card_next(&card) == 0 && card >= 0;) {
franta-hg@11: 			char* longName = nullptr;
franta-hg@11: 			snd_card_get_longname(card, &longName);
franta-hg@12: 
franta-hg@12: 			std::stringstream logMessage;
franta-hg@12: 			logMessage << " - card: #" << card << ": '" << longName << "'";
franta-hg@12: 
franta-hg@11: 			if (std::regex_match(longName, cardNamePattern)) {
franta-hg@11: 				cardNumbers.push_back(card);
franta-hg@18: 				cardNames.push_back(longName);
franta-hg@12: 				logMessage << " [matches]";
franta-hg@11: 			}
franta-hg@12: 
franta-hg@12: 			logger->log(L::INFO, logMessage.str());
franta-hg@12: 
franta-hg@11: 			free(longName);
franta-hg@11: 		}
franta-hg@11: 
franta-hg@11: 		if (cardNumbers.size() == 1) {
franta-hg@16: 			const auto n = std::to_string(cardNumbers[0]);
franta-hg@16: 			logger->log(L::INFO, "Going to fix card #" + n);
franta-hg@18: 			return {"hw:" + n, cardNames[0]};
franta-hg@11: 		} else if (cardNumbers.empty()) {
franta-hg@16: 			throw std::invalid_argument(
franta-hg@16: 					"No card with matching name found. Is the card connected? "
franta-hg@16: 					"Maybe try to provide different name pattern.");
franta-hg@11: 		} else {
franta-hg@16: 			throw std::invalid_argument(
franta-hg@16: 					"Multiple cards with matching name found. "
franta-hg@16: 					"Please provide a name pattern that matches only one card");
franta-hg@11: 		}
franta-hg@11: 	}
franta-hg@11: 
franta-hg@13: 	std::string toString(const MidiMessage& midiMessage) {
franta-hg@13: 		std::stringstream result;
franta-hg@16: 		for (uint8_t b : midiMessage)
franta-hg@16: 			result << std::hex << std::setw(2) << std::setfill('0') << (int) b;
franta-hg@13: 		return result.str();
franta-hg@13: 	}
franta-hg@13: 
franta-hg@5: 	void run() {
franta-hg@18: 		MidiMessage msg;
franta-hg@5: 		while (!stopped) {
franta-hg@9: 			{
franta-hg@9: 				std::lock_guard<std::recursive_mutex> lock(midiMutex);
franta-hg@9: 				// TODO: poll
franta-hg@16: 				uint8_t buf[256];
franta-hg@16: 				ssize_t length = snd_rawmidi_read(input, buf, sizeof (buf));
franta-hg@16: 				if (length > 0 && length <= sizeof (buf)) {
franta-hg@18: 					// Parse MIDI messages and ignore/skip unwanted data.
franta-hg@18: 					// Needed for DJM-V10 that sends annoying amounts of 0xF8.
franta-hg@18: 					for (int i = 0; i < length; i++) {
franta-hg@18: 						uint8_t b = buf[i];
franta-hg@18: 						if (b == MIDI_CMD_COMMON_SYSEX) {
franta-hg@18: 							// start of MIDI SysEx message
franta-hg@18: 							msg.clear();
franta-hg@18: 							msg.push_back(b);
franta-hg@18: 						} else if (b == MIDI_CMD_COMMON_SYSEX_END) {
franta-hg@18: 							// end of MIDI SysEx message
franta-hg@18: 							msg.push_back(b);
franta-hg@18: 							djmFix->receive(msg);
franta-hg@18: 							msg.clear();
franta-hg@18: 						} else if (b == MIDI_CMD_COMMON_CLOCK) {
franta-hg@18: 							logger->log(L::FINEST, "timing clock ignored");
franta-hg@18: 						} else if (b == MIDI_CMD_COMMON_SENSING) {
franta-hg@18: 							logger->log(L::FINEST, "active sensing ignored");
franta-hg@18: 						} else if (b & 0x80) {
franta-hg@18: 							// unknown status, drop previous data
franta-hg@18: 							msg.clear();
franta-hg@18: 							logger->log(L::FINER, "unknown message ignored");
franta-hg@18: 						} else {
franta-hg@18: 							// message data
franta-hg@18: 							msg.push_back(b);
franta-hg@18: 						}
franta-hg@18: 					}
franta-hg@9: 				}
franta-hg@5: 			}
franta-hg@5: 			std::this_thread::sleep_for(std::chrono::milliseconds(100));
franta-hg@5: 		}
franta-hg@5: 	}
franta-hg@2: public:
franta-hg@2: 
franta-hg@16: 	AlsaBridgeImpl(
franta-hg@16: 			djmfix::DJMFix* djmFix,
franta-hg@16: 			const std::string& cardNamePattern,
franta-hg@16: 			djmfix::logging::Logger* logger)
franta-hg@16: 	: djmFix(djmFix), logger(logger ? logger : djmfix::logging::blackhole()) //
franta-hg@16: 	{
franta-hg@16: 		if (djmFix == nullptr)
franta-hg@16: 			throw std::invalid_argument("Need a djmFix for AlsaBridge.");
franta-hg@5: 
franta-hg@18: 		FoundDevice found = findDeviceName(std::regex(cardNamePattern));
franta-hg@11: 
franta-hg@16: 		int mode = SND_RAWMIDI_NONBLOCK;
franta-hg@18: 		int error = snd_rawmidi_open(&input, &output, found.id.c_str(), mode);
franta-hg@13: 		if (error) throw std::invalid_argument("Unable to open ALSA device.");
franta-hg@5: 
franta-hg@18: 		djmFix->setDeviceName(found.name);
franta-hg@2: 		djmFix->setMidiSender(this);
franta-hg@2: 	}
franta-hg@2: 
franta-hg@2: 	virtual ~AlsaBridgeImpl() {
franta-hg@12: 		// TODO: do not use raw/exclusive access to the MIDI device
franta-hg@5: 		snd_rawmidi_close(input);
franta-hg@5: 		snd_rawmidi_close(output);
franta-hg@13: 		logger->log(L::FINER, "~AlsaBridgeImpl()");
franta-hg@2: 	}
franta-hg@2: 
franta-hg@2: 	virtual void start() override {
franta-hg@2: 		djmFix->start();
franta-hg@5: 		receivingThread = std::thread(&AlsaBridgeImpl::run, this);
franta-hg@2: 	}
franta-hg@2: 
franta-hg@2: 	virtual void stop() override {
franta-hg@5: 		stopped = true;
franta-hg@5: 		receivingThread.join();
franta-hg@2: 		djmFix->stop();
franta-hg@2: 	}
franta-hg@2: 
franta-hg@16: 	virtual void send(MidiMessage msg) override {
franta-hg@9: 		std::lock_guard<std::recursive_mutex> lock(midiMutex);
franta-hg@16: 		ssize_t length = snd_rawmidi_write(output, msg.data(), msg.size());
franta-hg@16: 		logger->log(L::FINE, "Sent message:"
franta-hg@16: 				" length = " + std::to_string(length)
franta-hg@16: 				+ " data = " + toString(msg));
franta-hg@2: 	}
franta-hg@2: 
franta-hg@2: };
franta-hg@2: 
franta-hg@16: AlsaBridge* create(
franta-hg@16: 		djmfix::DJMFix* djmFix,
franta-hg@16: 		const std::string& deviceName,
franta-hg@16: 		djmfix::logging::Logger* logger) //
franta-hg@16: {
franta-hg@12: 	return new AlsaBridgeImpl(djmFix, deviceName, logger);
franta-hg@2: }
franta-hg@2: 
franta-hg@2: }
franta-hg@2: }