v0.4.16: fix v0.4.15 reviewer-flagged regressions

1. VideoPlayerConfig.save() now persists max_cache_mb. Previously the
   auto-augment path in load() called save(), but save() didn't emit the
   key — so the rewrite kept losing it. Now updated comment + property.

2. /videoCache clear sends a new ClearCachePayload (no body) that wipes
   the entire client video_player_cache/ directory. Previously it only
   broadcast a DeleteCachePayload per *registered* URL, so leftover files
   from legacy preload_urls or prior sessions were never cleaned; now
   we always send clearAll regardless of whether the named index was
   non-empty.

3. Downloads are now serialized through a single-thread executor instead
   of `new Thread(...).start()`. With parallel downloads, every worker
   was snapshotting cacheDirSize() before any .part was renamed to its
   final name, so 50 simultaneous joins could collectively bust the
   max_cache_mb cap. With one in-flight at a time, each download's
   directory scan reflects every preceding completion.

Network: new S2C ClearCachePayload(unit codec), registered in
VideoPlayerNetwork + ClientNetworking. VideoCache.clearAll() iterates
the dir, deletes regular files, resets READY/IN_FLIGHT, reports
deleted/failed counts in chat + log. /videoCache clear command always
broadcasts to all clients now.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

gradle.properties

@@ -5,7 +5,7 @@ org.gradle.configuration-cache=false
 
 # Mod
 mod_id=video_player
-mod_version=0.4.15
+mod_version=0.4.16
 maven_group=com.ejclaw.videoplayer
 archives_base_name=video_player
 

src/main/java/com/ejclaw/videoplayer/VideoPlayerConfig.java

@@ -299,10 +299,12 @@ public final class VideoPlayerConfig {
             JsonObject root = new JsonObject();
             root.addProperty("_comment",
                 "max_preload_mb: per-video download cap (each client). "
+                    + "max_cache_mb: total cache directory cap (each client). "
                     + "render_distance_blocks: max distance at which a video anchor still renders. "
                     + "preload_urls: legacy un-named auto-preload list. "
                     + "cache_entries: managed by /videoCache add|list|remove.");
             root.addProperty("max_preload_mb", maxPreloadMb);
+            root.addProperty("max_cache_mb", maxCacheMb);
             root.addProperty("render_distance_blocks", renderDistanceBlocks);
             JsonArray legacyArr = new JsonArray();
             for (String u : preloadUrls) legacyArr.add(u);

src/main/java/com/ejclaw/videoplayer/client/net/ClientNetworking.java

@@ -6,6 +6,7 @@ import com.ejclaw.videoplayer.client.gui.VideoConfigScreen;
 import com.ejclaw.videoplayer.client.playback.VideoCache;
 import com.ejclaw.videoplayer.client.playback.VideoPlayback;
 import com.ejclaw.videoplayer.net.CachePolicyPayload;
+import com.ejclaw.videoplayer.net.ClearCachePayload;
 import com.ejclaw.videoplayer.net.DeleteCachePayload;
 import com.ejclaw.videoplayer.net.OpenScreenPayload;
 import com.ejclaw.videoplayer.net.PreloadPayload;
@@ -57,5 +58,10 @@ public final class ClientNetworking {
         ClientPlayNetworking.registerGlobalReceiver(DeleteCachePayload.TYPE, (payload, context) -> {
             VideoCache.purge(payload.url());
         });
+
+        // /videoCache clear — wipe the entire client cache directory.
+        ClientPlayNetworking.registerGlobalReceiver(ClearCachePayload.TYPE, (payload, context) -> {
+            VideoCache.clearAll();
+        });
     }
 }

src/main/java/com/ejclaw/videoplayer/client/playback/VideoCache.java

@@ -20,6 +20,8 @@ import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 
 /**
  * Client-side disk cache for preloaded HTTP video URLs. Driven by the {@code /videopreload}
@@ -38,9 +40,23 @@ public final class VideoCache {
 
     /** url → local absolute path of the fully-downloaded cache file. */
     private static final Map<String, Path> READY = new ConcurrentHashMap<>();
-    /** urls whose download is currently in flight. */
+    /** urls whose download is currently queued or in flight. */
     private static final Set<String> IN_FLIGHT = ConcurrentHashMap.newKeySet();
 
+    /**
+     * Single-thread executor that serializes all downloads. Cap enforcement (the total
+     * cache size check) needs an authoritative view of the cache directory at the moment a
+     * download starts, so we run one download at a time — that way the directory scan in
+     * {@link #cacheDirSize} reflects every finished download up to this point. Parallel
+     * downloads were racing the cap by each reading the directory before any of them had
+     * renamed their .part to final.
+     */
+    private static final ExecutorService DOWNLOAD_POOL = Executors.newSingleThreadExecutor(r -> {
+        Thread t = new Thread(r, "video_player-preload");
+        t.setDaemon(true);
+        return t;
+    });
+
     /**
      * Hard ceiling on a single preload, in bytes. Default 2 GB sized to allow a single 4K
      * short clip; overridden per-session by {@link com.ejclaw.videoplayer.net.CachePolicyPayload}
@@ -103,6 +119,41 @@ public final class VideoCache {
         }
     }
 
+    /**
+     * Wipe the entire cache directory and drop both indexes. Sent in response to
+     * {@code /videoCache clear}. Best-effort per-file deletion; logs failures but doesn't
+     * abort on the first one. In-flight downloads aren't cancelled — they'll fail at the
+     * atomic-move step (target dir gone) and log a warning, which is fine.
+     */
+    public static void clearAll() {
+        int deleted = 0;
+        int failed  = 0;
+        try {
+            Path dir = cacheDir();
+            if (dir != null && Files.isDirectory(dir)) {
+                try (var stream = Files.newDirectoryStream(dir)) {
+                    for (Path p : stream) {
+                        try {
+                            if (Files.isRegularFile(p) && Files.deleteIfExists(p)) deleted++;
+                        } catch (Throwable t) {
+                            failed++;
+                            VideoPlayerMod.LOG.warn("[{}] clearAll: could not delete {}: {}",
+                                VideoPlayerMod.MOD_ID, p.getFileName(), t.toString());
+                        }
+                    }
+                }
+            }
+        } catch (Throwable t) {
+            VideoPlayerMod.LOG.warn("[{}] clearAll failed: {}",
+                VideoPlayerMod.MOD_ID, t.toString());
+        }
+        READY.clear();
+        IN_FLIGHT.clear();
+        VideoPlayerMod.LOG.info("[{}] clearAll: deleted={} failed={}",
+            VideoPlayerMod.MOD_ID, deleted, failed);
+        notifyChat("[videocache] 전체 캐시 삭제: " + deleted + "개 파일", ChatFormatting.YELLOW);
+    }
+
     /** Kick off a background download. No-op if already cached or in flight. */
     public static void preload(String url) {
         if (url == null || url.isEmpty()) return;
@@ -117,10 +168,8 @@ public final class VideoCache {
             notifyChat("[videopreload] 이미 다운로드 중: " + url, ChatFormatting.GRAY);
             return;
         }
-        notifyChat("[videopreload] 다운로드 시작: " + url, ChatFormatting.YELLOW);
-        Thread t = new Thread(() -> download(url), "video_player-preload");
-        t.setDaemon(true);
-        t.start();
+        notifyChat("[videopreload] 다운로드 대기열 추가: " + url, ChatFormatting.YELLOW);
+        DOWNLOAD_POOL.submit(() -> download(url));
     }
 
     /** Return the local cached file path for this URL, or {@code null} if not yet ready. */

src/main/java/com/ejclaw/videoplayer/command/VideoCacheCommand.java

@@ -1,6 +1,7 @@
 package com.ejclaw.videoplayer.command;
 
 import com.ejclaw.videoplayer.VideoPlayerConfig;
+import com.ejclaw.videoplayer.net.ClearCachePayload;
 import com.ejclaw.videoplayer.net.DeleteCachePayload;
 import com.ejclaw.videoplayer.net.PreloadPayload;
 import com.mojang.brigadier.CommandDispatcher;
@@ -127,26 +128,26 @@ public final class VideoCacheCommand {
 
     private static int runClear(CommandContext<CommandSourceStack> ctx) {
         CommandSourceStack src = ctx.getSource();
+        // Drop server-side named entries (preload_urls is left alone — it's an admin-edited
+        // list, not something /videoCache manages).
         java.util.List<String> urls = VideoPlayerConfig.clearCacheEntries();
-        if (urls.isEmpty()) {
-            src.sendSuccess(() -> Component.literal("[videocache] 저장된 항목이 없습니다")
-                .withStyle(ChatFormatting.GRAY), false);
-            return 0;
-        }
+
+        // Always broadcast a full-cache wipe to every client, even if the named index was
+        // empty — leftover files from prior sessions, legacy preload_urls downloads, and
+        // any in-flight stragglers all get scrubbed in one shot.
         MinecraftServer server = src.getServer();
+        ClearCachePayload payload = new ClearCachePayload();
         int clients = 0;
         for (ServerPlayer p : PlayerLookup.all(server)) {
-            for (String url : urls) {
-                ServerPlayNetworking.send(p, new DeleteCachePayload(url));
-            }
+            ServerPlayNetworking.send(p, payload);
             clients++;
         }
         final int sentFinal = clients;
         final int countFinal = urls.size();
         src.sendSuccess(() -> Component.literal(
-            "[videocache] 전체 삭제: " + countFinal + "개 항목"
-                + "  (" + sentFinal + " 클라이언트에 cache_delete 전송)"), false);
-        return countFinal;
+            "[videocache] 전체 삭제: 등록 항목 " + countFinal + "개 제거"
+                + " + " + sentFinal + " 클라이언트 디스크 캐시 전체 wipe"), false);
+        return Math.max(countFinal, 1);
     }
 
     private static int runRemove(CommandContext<CommandSourceStack> ctx) throws CommandSyntaxException {

src/main/java/com/ejclaw/videoplayer/net/ClearCachePayload.java

@@ -0,0 +1,26 @@
+package com.ejclaw.videoplayer.net;
+
+import com.ejclaw.videoplayer.VideoPlayerMod;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.Identifier;
+
+/**
+ * S2C — tell every client to wipe its entire {@code video_player_cache} directory and reset
+ * the in-memory READY/IN_FLIGHT index. Sent by {@code /videoCache clear}. Carries no payload —
+ * the receiving client just nukes everything under the cache dir regardless of how the file
+ * got there (named entry, legacy preload_url, or leftover from a prior session).
+ */
+public record ClearCachePayload() implements CustomPacketPayload {
+    public static final CustomPacketPayload.Type<ClearCachePayload> TYPE =
+        new CustomPacketPayload.Type<>(Identifier.fromNamespaceAndPath(VideoPlayerMod.MOD_ID, "cache_clear"));
+
+    public static final StreamCodec<RegistryFriendlyByteBuf, ClearCachePayload> CODEC =
+        StreamCodec.unit(new ClearCachePayload());
+
+    @Override
+    public Type<? extends CustomPacketPayload> type() {
+        return TYPE;
+    }
+}

src/main/java/com/ejclaw/videoplayer/net/VideoPlayerNetwork.java

@@ -28,6 +28,7 @@ public final class VideoPlayerNetwork {
         PayloadTypeRegistry.clientboundPlay().register(PreloadPayload.TYPE, PreloadPayload.CODEC);
         PayloadTypeRegistry.clientboundPlay().register(CachePolicyPayload.TYPE, CachePolicyPayload.CODEC);
         PayloadTypeRegistry.clientboundPlay().register(DeleteCachePayload.TYPE, DeleteCachePayload.CODEC);
+        PayloadTypeRegistry.clientboundPlay().register(ClearCachePayload.TYPE, ClearCachePayload.CODEC);
         // C2S
         PayloadTypeRegistry.serverboundPlay().register(SaveConfigPayload.TYPE, SaveConfigPayload.CODEC);
         PayloadTypeRegistry.serverboundPlay().register(DeleteAnchorPayload.TYPE, DeleteAnchorPayload.CODEC);