feat: pause looping videos after 5 automatic plays

Feed videos run under REPEAT_MODE_ONE and looped forever. AutoReplayLimiter
counts each MEDIA_ITEM_TRANSITION_REASON_REPEAT as one completed play and
pauses the player when the 5th play finishes, leaving the video on its first
frame with the play button showing. Pressing play (or the feed mutex resuming
a video scrolled back into view) grants a fresh 5-play allowance, and pooled
players reset the count when they switch to a different media item.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N9RXiM42yqznwTVjw8tLZv

amethyst/src/main/java/com/vitorpamplona/amethyst/service/playback/playerPool/ExoPlayerBuilder.kt

@@ -37,6 +37,7 @@ import com.vitorpamplona.amethyst.service.playback.diskCache.VideoCache
 import com.vitorpamplona.amethyst.service.playback.playerPool.aspectRatio.AspectRatioCacher
 import com.vitorpamplona.amethyst.service.playback.playerPool.positions.CurrentPlayPositionCacher
 import com.vitorpamplona.amethyst.service.playback.playerPool.positions.VideoViewedPositionCache
+import com.vitorpamplona.amethyst.service.playback.playerPool.repeat.AutoReplayLimiter
 import com.vitorpamplona.amethyst.service.playback.playerPool.wake.KeepVideosPlaying
 
 @OptIn(UnstableApi::class)
@@ -82,6 +83,7 @@ class ExoPlayerBuilder(
                 )
                 PcmTapRegistry.bind(currentMediaItem?.mediaId, sink)
                 addListener(AspectRatioCacher(MediaAspectRatioCache))
+                addListener(AutoReplayLimiter(pause = ::pause))
                 addListener(KeepVideosPlaying(this))
                 addListener(CurrentPlayPositionCacher(this, VideoViewedPositionCache))
             }

amethyst/src/main/java/com/vitorpamplona/amethyst/service/playback/playerPool/repeat/AutoReplayLimiter.kt

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.playback.playerPool.repeat
+
+import androidx.media3.common.MediaItem
+import androidx.media3.common.Player
+
+/**
+ * Caps how many times a video loops on its own under [Player.REPEAT_MODE_ONE].
+ *
+ * Feed videos are configured to repeat forever (keepPlaying → REPEAT_MODE_ONE in
+ * PlaybackService), which keeps decoders, network and the screen busy long after the
+ * user stopped watching. This listener lets a video play [maxAutoPlays] full times and
+ * then pauses it, so continuing requires an explicit press of the play button.
+ *
+ * Each loop under REPEAT_MODE_ONE surfaces as an [onMediaItemTransition] with
+ * [Player.MEDIA_ITEM_TRANSITION_REASON_REPEAT], marking one completed play. The
+ * transition has already seeked back to the start, so pausing there leaves the video
+ * on its first frame with the play button showing. Any resume — the user pressing
+ * play, or the feed mutex auto-playing when the video scrolls back to the center —
+ * grants a fresh allowance, and switching to a different media item resets it too.
+ */
+class AutoReplayLimiter(
+    val maxAutoPlays: Int = DEFAULT_MAX_AUTO_PLAYS,
+    val pause: () -> Unit,
+) : Player.Listener {
+    private var playsCompleted = 0
+
+    override fun onMediaItemTransition(
+        mediaItem: MediaItem?,
+        reason: Int,
+    ) {
+        if (reason == Player.MEDIA_ITEM_TRANSITION_REASON_REPEAT) {
+            playsCompleted++
+            if (playsCompleted >= maxAutoPlays) {
+                pause()
+            }
+        } else {
+            playsCompleted = 0
+        }
+    }
+
+    override fun onPlayWhenReadyChanged(
+        playWhenReady: Boolean,
+        reason: Int,
+    ) {
+        if (playWhenReady) {
+            playsCompleted = 0
+        }
+    }
+
+    companion object {
+        const val DEFAULT_MAX_AUTO_PLAYS = 5
+    }
+}

amethyst/src/test/java/com/vitorpamplona/amethyst/service/playback/playerPool/repeat/AutoReplayLimiterTest.kt

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.playback.playerPool.repeat
+
+import androidx.media3.common.Player
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class AutoReplayLimiterTest {
+    private var pauseCalls = 0
+    private val limiter = AutoReplayLimiter(maxAutoPlays = 5) { pauseCalls++ }
+
+    private fun startPlaying() = limiter.onPlayWhenReadyChanged(true, Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST)
+
+    private fun completeOnePlay() = limiter.onMediaItemTransition(null, Player.MEDIA_ITEM_TRANSITION_REASON_REPEAT)
+
+    private fun newMediaItem() = limiter.onMediaItemTransition(null, Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED)
+
+    @Test
+    fun pausesWhenTheFifthPlayCompletes() {
+        startPlaying()
+
+        // plays 1..4 complete: repeat transitions 1..4 start plays 2..5
+        repeat(4) { completeOnePlay() }
+        assertEquals(0, pauseCalls)
+
+        // play 5 completes: the 5th repeat transition would start play 6
+        completeOnePlay()
+        assertEquals(1, pauseCalls)
+    }
+
+    @Test
+    fun pressingPlayGrantsAFreshAllowance() {
+        startPlaying()
+        repeat(5) { completeOnePlay() }
+        assertEquals(1, pauseCalls)
+
+        // user presses play again
+        startPlaying()
+        repeat(4) { completeOnePlay() }
+        assertEquals(1, pauseCalls)
+
+        completeOnePlay()
+        assertEquals(2, pauseCalls)
+    }
+
+    @Test
+    fun switchingMediaItemsResetsTheCount() {
+        startPlaying()
+        repeat(4) { completeOnePlay() }
+
+        // the pooled player is handed a different video
+        newMediaItem()
+
+        repeat(4) { completeOnePlay() }
+        assertEquals(0, pauseCalls)
+
+        completeOnePlay()
+        assertEquals(1, pauseCalls)
+    }
+
+    @Test
+    fun pausingMidPlayDoesNotResetTheCount() {
+        startPlaying()
+        repeat(3) { completeOnePlay() }
+
+        // a pause alone (e.g. scrolled off screen) does not reset; only a resume does
+        limiter.onPlayWhenReadyChanged(false, Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST)
+
+        repeat(2) { completeOnePlay() }
+        assertEquals(1, pauseCalls)
+    }
+}