diff -r 5b351628a377 -r 15d87fdd6e6c AlsaBridge.cpp
--- a/AlsaBridge.cpp	Mon Jan 04 13:38:08 2021 +0100
+++ b/AlsaBridge.cpp	Mon Jan 04 15:45:12 2021 +0100
@@ -15,6 +15,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 #include <iostream>
+#include <sstream>
 #include <stdexcept>
 #include <thread>
 #include <mutex>
@@ -24,13 +25,17 @@
 #include <alsa/asoundlib.h>
 
 #include "AlsaBridge.h"
+#include "Logger.h"
 
 namespace djmfix {
 namespace alsa {
 
+using L = djmfix::logging::Level;
+
 class AlsaBridgeImpl : public AlsaBridge, private djmfix::MidiSender {
 private:
 	djmfix::DJMFix* djmFix;
+	djmfix::logging::Logger* logger;
 	snd_rawmidi_t* input;
 	snd_rawmidi_t* output;
 	std::thread receivingThread;
@@ -41,22 +46,27 @@
 
 		std::vector<int> cardNumbers;
 
-		std::cerr << "Looking for available cards:" << std::endl; // TODO: do not mess STDIO
+		logger->log(L::INFO, "Looking for available cards:");
 
 		for (int card = -1; snd_card_next(&card) == 0 && card >= 0;) {
 			char* longName = nullptr;
 			snd_card_get_longname(card, &longName);
-			std::cerr << "card: #" << card << ": '" << longName << "'"; // TODO: do not mess STDIO
+
+			std::stringstream logMessage;
+			logMessage << " - card: #" << card << ": '" << longName << "'";
+
 			if (std::regex_match(longName, cardNamePattern)) {
 				cardNumbers.push_back(card);
-				std::cerr << " [matches]"; // TODO: do not mess STDIO
+				logMessage << " [matches]";
 			}
-			std::cerr << std::endl;
+
+			logger->log(L::INFO, logMessage.str());
+
 			free(longName);
 		}
 
 		if (cardNumbers.size() == 1) {
-			std::cerr << "Going to fix card #" << cardNumbers[0] << std::endl; // TODO: do not mess STDIO
+			logger->log(L::INFO, "Going to fix card #" + std::to_string(cardNumbers[0]));
 			return "hw:" + std::to_string(cardNumbers[0]);
 		} else if (cardNumbers.empty()) {
 			throw std::invalid_argument("No card with matching name found. Is the card connected? Maybe try to provide different name pattern.");
@@ -82,7 +92,7 @@
 	}
 public:
 
-	AlsaBridgeImpl(djmfix::DJMFix* djmFix, const std::string& cardNamePattern) : djmFix(djmFix) {
+	AlsaBridgeImpl(djmfix::DJMFix* djmFix, const std::string& cardNamePattern, djmfix::logging::Logger* logger) : djmFix(djmFix), logger(logger ? logger : djmfix::logging::blackhole()) {
 		if (djmFix == nullptr) throw std::invalid_argument("need a djmFix for AlsaBridge");
 
 		std::string deviceName = findDeviceName(std::regex(cardNamePattern));
@@ -95,10 +105,10 @@
 	}
 
 	virtual ~AlsaBridgeImpl() {
-		// TODO: do not use raw/exclusive access to the device
+		// TODO: do not use raw/exclusive access to the MIDI device
 		snd_rawmidi_close(input);
 		snd_rawmidi_close(output);
-		std::cerr << "~AlsaBridgeImpl()" << std::endl; // TODO: do not mess STDIO
+		logger->log(L::FINE, "~AlsaBridgeImpl()");
 	}
 
 	virtual void start() override {
@@ -115,13 +125,13 @@
 	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
+		logger->log(L::INFO, "AlsaBridgeImpl::send(): length = " + std::to_string(length));
 	}
 
 };
 
-AlsaBridge* create(djmfix::DJMFix* djmFix, const std::string& deviceName) {
-	return new AlsaBridgeImpl(djmFix, deviceName);
+AlsaBridge* create(djmfix::DJMFix* djmFix, const std::string& deviceName, djmfix::logging::Logger* logger) {
+	return new AlsaBridgeImpl(djmFix, deviceName, logger);
 }
 
 }