feat: Add concatenate functionality

app/build.gradle

@@ -71,5 +71,7 @@ dependencies {
     annotationProcessor 'com.google.dagger:hilt-compiler:2.46.1'
     implementation "androidx.hilt:hilt-navigation-compose:1.0.0"
 
+    implementation 'com.arthenica:ffmpeg-kit-full:5.1'
+
     coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.0.3'
 }

app/src/main/java/app/myzel394/locationtest/AudioRecorder.kt

@@ -79,24 +79,19 @@ fun AudioRecorder() {
             Text(text = if (isRecording) "Stop" else "Start")
         }
         if (!isRecording && service != null)
-            LazyColumn() {
+            Button(
-                val items = service!!.getRecordingFilePaths().toList()
+                onClick = {
+                  val path = service!!.concatenateAudios()
 
-                items(items.size) {
+                    val player = MediaPlayer().apply {
-                    val path = items[it]
+                        setDataSource(path)
-
+                        prepare()
-                    Button(
-                        onClick = {
-                            val player = MediaPlayer().apply {
-                                setDataSource(path)
-                                prepare()
-                                start()
-                            }
-                        }
-                    ) {
-                        Text(text = "Play $it")
                     }
-                }
+
+                    player.start()
+                },
+            ) {
+                Text(text = "Convert")
             }
     }
 }

app/src/main/java/app/myzel394/locationtest/RecorderService.kt

@@ -9,8 +9,11 @@ import android.os.Build
 import android.os.Handler
 import android.os.IBinder
 import android.os.Looper
+import android.util.Log
 import androidx.compose.runtime.mutableStateOf
 import androidx.core.app.NotificationCompat
+import com.arthenica.ffmpegkit.FFmpegKit
+import com.arthenica.ffmpegkit.ReturnCode
 import kotlinx.coroutines.NonCancellable.start
 import java.io.File
 import java.time.LocalDateTime
@@ -19,7 +22,7 @@ import java.util.Date
 
 import java.util.UUID;
 
-const val INTERVAL_DURATION = 30000L
+const val INTERVAL_DURATION = 10000L
 
 class RecorderService: Service() {
     private val binder = LocalBinder()
@@ -74,6 +77,30 @@ class RecorderService: Service() {
         }
     }
 
+    fun concatenateAudios(): String {
+        val paths = getRecordingFilePaths().joinToString("|")
+        val outputFile = "$fileFolder/concatenated.${getFileExtensions()}"
+        val command = "-i \"concat:$paths\" -acodec copy $outputFile"
+
+        val session = FFmpegKit.execute(command)
+
+        if (!ReturnCode.isSuccess(session.returnCode)) {
+            Log.d(
+                "Audio Concatenation",
+                String.format(
+                    "Command failed with state %s and rc %s.%s",
+                    session.getState(),
+                    session.getReturnCode(),
+                    session.getFailStackTrace()
+                )
+            );
+
+            throw Exception("Failed to concatenate audios")
+        }
+
+        return outputFile
+    }
+
     private fun startNewRecording() {
         if (!isRecording) {
             return