From d4de3a7b18f290ac34672ef0678cb1089a744adc Mon Sep 17 00:00:00 2001
From: Leandro Ferreira <leandro.daf@gmail.com>
Date: Sat, 26 Oct 2024 08:48:39 -0300
Subject: [PATCH] feat(cmd): add setup functions for logger, MIDI client, event
 channel, and listener management

Implement setup functions for initializing logging, configuring MIDI client, setting up event channels, hub, and listener management. Added MIDI event publishing.
---
 cmd/setup.go | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 cmd/setup.go

diff --git a/cmd/setup.go b/cmd/setup.go
new file mode 100644
index 0000000..7049511
--- /dev/null
+++ b/cmd/setup.go
@@ -0,0 +1,122 @@
+package cmd
+
+import (
+	"encoding/binary"
+	"fmt"
+	"math"
+	"time"
+
+	channelMIDI "github.com/leandrodaf/midi-client/internal/channel"
+	"github.com/leandrodaf/midi-client/internal/contracts/channel"
+	"github.com/leandrodaf/midi-client/internal/contracts/logger"
+	"github.com/leandrodaf/midi-client/internal/contracts/midi"
+	"github.com/leandrodaf/midi-client/internal/listeners"
+	"github.com/leandrodaf/midi-client/pkg/environment"
+	zaplogger "github.com/leandrodaf/midi-client/pkg/logger"
+	midiClient "github.com/leandrodaf/midi-client/pkg/midi"
+	"github.com/leandrodaf/midi-client/pkg/pubsub"
+)
+
+// SetupLogger initializes the logging system.
+func SetupLogger() (logger.Logger, error) {
+	return zaplogger.New(logger.Options{
+		Environment: environment.IsProduction(),
+	})
+}
+
+// SetupMIDIClient configures the MIDI client.
+func SetupMIDIClient(logger logger.Logger) (midi.ClientMIDI, error) {
+	return midiClient.NewMIDIClient(logger)
+}
+
+// SetupEventChannel creates the MIDI event channel.
+func SetupEventChannel(bufferSize int) channel.MIDIEventPublisher {
+	return channelMIDI.NewEventChannel(bufferSize)
+}
+
+// SetupHub configures and returns the Hub and topic names.
+func SetupHub() (*pubsub.Hub, string, string) {
+	hub := pubsub.NewHub()
+	topicName := "midi_events"
+	processedTopicName := "processed_events"
+	return hub, topicName, processedTopicName
+}
+
+// SetupListenerManager configures and returns the ListenerManager with registered listeners.
+func SetupListenerManager(
+	hub *pubsub.Hub,
+	topicName string,
+	processedTopicName string,
+	logger logger.Logger,
+	latencyInterval time.Duration,
+) *listeners.ListenerManager {
+	listenerManager := listeners.NewListenerManager(hub, topicName, logger)
+
+	// Create and register listeners, all publishing to the same output topic.
+	chordListener := &listeners.ChordDetectionListener{OutputTopic: processedTopicName, Hub: hub}
+	velocityListener := &listeners.VelocityAnalyzerListener{OutputTopic: processedTopicName, Hub: hub}
+	listenerManager.Register(chordListener)
+	listenerManager.Register(velocityListener)
+
+	go startLatencyTicker(logger, listenerManager, latencyInterval)
+
+	return listenerManager
+}
+
+// startLatencyTicker periodically calculates and logs the average latency.
+func startLatencyTicker(logger logger.Logger, listenerManager *listeners.ListenerManager, interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for range ticker.C {
+		latency := listenerManager.AverageLatency()
+		latencyRounded := math.Round(latency*1000) / 1000
+
+		logger.Info("Calculating average latency",
+			logger.Field().Float64("latency_average_ns", latencyRounded))
+	}
+}
+
+// SetupDevice selects and configures the MIDI device.
+func SetupDevice(adapter midi.ClientMIDI) (int, error) {
+	devices, err := adapter.ListDevices()
+	if err != nil {
+		return 0, err
+	}
+	fmt.Println("Available MIDI devices:")
+	for i, device := range devices {
+		fmt.Printf("[%d] %s\n", i, device)
+	}
+	var deviceID int
+	fmt.Print("Choose a MIDI device: ")
+	_, err = fmt.Scanf("%d", &deviceID)
+	if err != nil {
+		return 0, err
+	}
+	err = adapter.SelectDevice(deviceID)
+	if err != nil {
+		return deviceID, err
+	}
+	return deviceID, nil
+}
+
+// StartEventPublishing begins capturing and publishing MIDI events.
+func StartEventPublishing(eventChannel channel.MIDIEventPublisher, hub *pubsub.Hub, topicName string) {
+	go func() {
+		for event := range eventChannel.Events() {
+			// Capture the current time in nanoseconds
+			eventTimestamp := time.Now().UnixNano()
+
+			// Prepare the data buffer: 8 bytes for the timestamp and 3 bytes for the MIDI data
+			data := make([]byte, 8+3)
+			binary.BigEndian.PutUint64(data[:8], uint64(eventTimestamp))
+			data[8] = byte(event.Command)
+			data[9] = byte(event.Note)
+			data[10] = byte(event.Velocity)
+
+			// Create the event message and publish to the hub
+			msg := pubsub.Message{Data: data}
+			hub.Publish(topicName, msg)
+		}
+	}()
+}