Caching videos to reduce initialization delay.

app/src/main/java/com/vitorpamplona/amethyst/VideoCache.kt

@@ -0,0 +1,41 @@
+package com.vitorpamplona.amethyst
+
+import android.content.Context
+import com.google.android.exoplayer2.database.StandaloneDatabaseProvider
+import com.google.android.exoplayer2.upstream.DefaultHttpDataSource
+import com.google.android.exoplayer2.upstream.cache.CacheDataSource
+import com.google.android.exoplayer2.upstream.cache.LeastRecentlyUsedCacheEvictor
+import com.google.android.exoplayer2.upstream.cache.SimpleCache
+
+object VideoCache {
+
+  var exoPlayerCacheSize: Long = 90 * 1024 * 1024 // 90MB
+
+  var leastRecentlyUsedCacheEvictor = LeastRecentlyUsedCacheEvictor(exoPlayerCacheSize)
+
+  lateinit var exoDatabaseProvider: StandaloneDatabaseProvider
+  lateinit var simpleCache: SimpleCache
+
+  lateinit var cacheDataSourceFactory: CacheDataSource.Factory
+
+  fun get(context: Context): CacheDataSource.Factory {
+    if (!this::simpleCache.isInitialized) {
+      exoDatabaseProvider = StandaloneDatabaseProvider(context)
+
+      simpleCache = SimpleCache(
+        context.cacheDir,
+        leastRecentlyUsedCacheEvictor,
+        exoDatabaseProvider
+      )
+
+      cacheDataSourceFactory = CacheDataSource.Factory()
+        .setCache(simpleCache)
+        .setUpstreamDataSourceFactory(
+          DefaultHttpDataSource.Factory().setAllowCrossProtocolRedirects(true)
+        )
+        .setFlags(CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR)
+    }
+
+    return cacheDataSourceFactory
+  }
+}

app/src/main/java/com/vitorpamplona/amethyst/ui/components/VideoView.kt

@@ -13,8 +13,12 @@ import com.google.android.exoplayer2.C
 import com.google.android.exoplayer2.ExoPlayer
 import com.google.android.exoplayer2.MediaItem
 import com.google.android.exoplayer2.Player
+import com.google.android.exoplayer2.source.ProgressiveMediaSource
 import com.google.android.exoplayer2.ui.AspectRatioFrameLayout
 import com.google.android.exoplayer2.ui.StyledPlayerView
+import com.google.android.exoplayer2.upstream.DefaultHttpDataSource
+import com.google.android.exoplayer2.upstream.cache.CacheDataSource
+import com.vitorpamplona.amethyst.VideoCache
 
 @Composable
 fun VideoView(videoUri: String) {
@@ -28,17 +32,17 @@ fun VideoView(videoUri: String) {
   }
 
   DisposableEffect(exoPlayer) {
-    exoPlayer.setMediaItem(MediaItem.fromUri(videoUri))
+    exoPlayer.setMediaSource(
+      ProgressiveMediaSource.Factory(VideoCache.get(context.applicationContext)).createMediaSource(MediaItem.fromUri(videoUri))
+    )
     exoPlayer.prepare()
-
     onDispose {
       exoPlayer.release()
     }
   }
 
   AndroidView(
-    modifier = Modifier
-      .fillMaxWidth(),
+    modifier = Modifier.fillMaxWidth(),
     factory = {
       StyledPlayerView(context).apply {
         player = exoPlayer