feat(PlayerHelper): automatically select max buffer duration

Automatically selects the 'best' max buffer duration based on the amount
of available memory. This improves the users experience as the player is
less likely to constantly load, whilst avoid having user to configure
the technical setting themselves (without any help/guidelines).

Author: FineFindus

app/src/main/java/com/github/libretube/helpers/PlayerHelper.kt

@@ -1,6 +1,7 @@
 package com.github.libretube.helpers
 
 import android.app.Activity
+import android.app.ActivityManager
 import android.content.Context
 import android.content.Intent
 import android.content.pm.ActivityInfo
@@ -512,7 +513,7 @@ object PlayerHelper {
      * Create a basic player, that is used for all types of playback situations inside the app
      */
     @OptIn(androidx.media3.common.util.UnstableApi::class)
-    fun createPlayer(context: Context, trackSelector: DefaultTrackSelector, ): ExoPlayer {
+    fun createPlayer(context: Context, trackSelector: DefaultTrackSelector): ExoPlayer {
         val dataSourceFactory = DefaultDataSource.Factory(context)
         val audioAttributes = AudioAttributes.Builder()
             .setUsage(C.USAGE_MEDIA)
@@ -532,22 +533,38 @@ object PlayerHelper {
             }
     }
 
+
+    /**
+     * Returns the recommended duration that should be buffer in milliseconds, based on the available memory.
+     */
+    private fun getRecommendedBufferMs(): Int {
+        val activityManager =
+            LibreTubeApp.instance.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
+        val memInfo = ActivityManager.MemoryInfo().also { memoryInfo ->
+            activityManager.getMemoryInfo(memoryInfo)
+        }
+        // device memory in MB
+        val availableMemory = memInfo.totalMem / (1024 * 1024)
+        return when {
+            availableMemory >= 8192 -> 1000 * 450
+            availableMemory >= 4096 -> 1000 * 300
+            availableMemory > 2048 -> 1000 * 60 * 2
+            else -> MINIMUM_BUFFER_DURATION
+        }
+    }
+
     /**
      * Get the load controls for the player (buffering, etc)
      */
     @OptIn(androidx.media3.common.util.UnstableApi::class)
-    fun getLoadControl(): LoadControl {
-        return DefaultLoadControl.Builder()
-            // cache the last three minutes
-            .setBackBuffer(1000 * 60 * 3, true)
-            .setBufferDurationsMs(
-                MINIMUM_BUFFER_DURATION,
-                max(bufferingGoal, MINIMUM_BUFFER_DURATION),
-                DefaultLoadControl.DEFAULT_BUFFER_FOR_PLAYBACK_MS,
-                DefaultLoadControl.DEFAULT_BUFFER_FOR_PLAYBACK_AFTER_REBUFFER_MS
-            )
-            .build()
-    }
+    fun getLoadControl(): LoadControl = DefaultLoadControl.Builder()
+        // cache the last three minutes
+        .setBackBuffer(1000 * 60 * 3, true).setBufferDurationsMs(
+            MINIMUM_BUFFER_DURATION,
+            getRecommendedBufferMs(),
+            DefaultLoadControl.DEFAULT_BUFFER_FOR_PLAYBACK_MS,
+            DefaultLoadControl.DEFAULT_BUFFER_FOR_PLAYBACK_AFTER_REBUFFER_MS
+        ).build()
 
     /**
      * Load playback parameters such as speed and skip silence