refactor: add comments

app/src/main/java/io/github/kirasok/alarmix/domain/repository/AlarmScheduler.kt

@@ -2,6 +2,7 @@ package io.github.kirasok.alarmix.domain.repository
 
 import io.github.kirasok.alarmix.domain.model.Alarm
 
+// AlarmScheduler interface allows us to schedule alarms within domain layer by providing context with DI
 interface AlarmScheduler {
 
   fun schedule(alarm: Alarm)

app/src/main/java/io/github/kirasok/alarmix/domain/use_case/AlarmUseCases.kt

@@ -11,7 +11,7 @@ data class AlarmUseCases(
   val getAlarmById: GetAlarmById,
   val insertAlarm: InsertAlarm,
   val deleteAlarm: DeleteAlarm,
-  // We don't need ValidateAlarm because it's used in insertAlarm, not in presentation layer
+  // We don't need ValidateAlarm there because it's used in insertAlarm, not in presentation layer
 )
 
 class GetAlarms(private val repository: AlarmRepository) {

app/src/main/java/io/github/kirasok/alarmix/presentation/editor/EditorScreen.kt

@@ -51,7 +51,7 @@ fun EditorScreen(navController: NavController, viewModel: EditorViewModel = hilt
       horizontalAlignment = Alignment.CenterHorizontally,
       verticalArrangement = Arrangement.Center
     ) {
-      val initialHour = 7
+      val initialHour = 7 // TODO: set initial hour and minute by checking viewModel.time because we could be editing alarm instead of creating new one; use time difference between .now() and time when alarm would be fired for initial hour and minute in case of editing alarm
       val initialMinute = 30
       val timePickerState = rememberTimePickerState(initialHour, initialMinute)
 

app/src/main/java/io/github/kirasok/alarmix/presentation/receiver/AlarmReceiver.kt

@@ -11,10 +11,11 @@ class AlarmReceiver : BroadcastReceiver() {
     val serviceIntent =
       Intent(context, AlarmService::class.java).putExtra(INTENT_EXTRA_ALARM_ID, id)
     // We need to use foreground service because we can't start activity from broadcast receiver
+    // Instead, the best practice is to show user notification with foreground service
     context.startForegroundService(serviceIntent)
   }
 
   companion object {
-    const val INTENT_EXTRA_ALARM_ID = "intent_extra_alarm_id"
+    const val INTENT_EXTRA_ALARM_ID = "intent_extra_alarm_id" // value for passing alarm id within intent
   }
 }

app/src/main/java/io/github/kirasok/alarmix/presentation/receiver/AlarmService.kt

@@ -35,14 +35,15 @@ import javax.inject.Inject
 @AndroidEntryPoint
 class AlarmService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnErrorListener {
 
-  private val context = this
+  private val context = this // Used within mediaPlayer.apply{} to access context
   private lateinit var vibrator: VibratorManager
   private lateinit var mediaPlayer: MediaPlayer
   private lateinit var alarm: Alarm
 
   @Inject
   lateinit var useCases: AlarmUseCases
 
+  // Receiver that triggers when user presses button in notification
   private val alarmActionReceiver = object : BroadcastReceiver() {
     override fun onReceive(context: Context, intent: Intent) {
       when (intent.getStringExtra(ALARM_ACTION_KEY)?.let { AlarmAction.valueOf(it) }) {
@@ -74,7 +75,7 @@ class AlarmService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
       ?: throw IllegalStateException("Alarm id can't be null")
     // val alarm = runBlocking { useCases.getAlarmById(id) } TODO: fix getting alarm
     //   ?: throw InvalidAlarmException("Alarm can't be null")
-    this.alarm = Alarm(id, ZonedDateTime.now())
+    this.alarm = Alarm(id, ZonedDateTime.now()) // TODO: remove this when alarm is fixed
     Log.d(null, "Got $alarm; timestamp: ${alarm.timestamp}; id: ${alarm.id}")
 
     mediaPlayer = MediaPlayer()
@@ -94,14 +95,14 @@ class AlarmService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
   private fun initMediaPlayer() = mediaPlayer.apply {
     setOnPreparedListener(this@AlarmService)
     setOnErrorListener(this@AlarmService)
-    isLooping = true
+    isLooping = true // repeats sound infinitely
     setDataSource(
-      context, RingtoneManager.getActualDefaultRingtoneUri(context, RingtoneManager.TYPE_ALARM)
+      context, RingtoneManager.getActualDefaultRingtoneUri(context, RingtoneManager.TYPE_ALARM) // Only getActualDefaultRingtoneUri doesn't throw SecurityException for not having READ_PRIVILEGED_PHONE_STATE
     )
     setAudioAttributes(AudioAttributes.Builder().apply {
       setUsage(AudioAttributes.USAGE_ALARM)
       setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
-    }.build())
+    }.build()) // sets attribute that the sound is an alarm
     prepare()
   }
 
@@ -117,6 +118,8 @@ class AlarmService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
 
   override fun onPrepared(mp: MediaPlayer?) {
     mp?.start()
+
+    // Handles vibrations
     val combinedVibration = CombinedVibration.createParallel(
       VibrationEffect.createWaveform(
         longArrayOf(
@@ -141,6 +144,7 @@ class AlarmService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
   }
 
   private fun createNotification(): Notification {
+    // Starts activity on click on notification
     val pendingIntent = PendingIntent.getActivity(
       this, alarm.id, Intent(this, MainActivity::class.java).apply {
         addFlags(
@@ -170,7 +174,7 @@ class AlarmService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
       setOngoing(true) // User can't dismiss notification
       setPriority(NotificationCompat.PRIORITY_MAX)
       setCategory(NotificationCompat.CATEGORY_ALARM)
-      foregroundServiceBehavior = FOREGROUND_SERVICE_IMMEDIATE
+      foregroundServiceBehavior = FOREGROUND_SERVICE_IMMEDIATE // Shows notification in foreground
       setFullScreenIntent(pendingIntent, true)
       addAction(dismissAction)
       addAction(snoozeAction)