Handle PubSub better with a queue and actually waiting

src/main/java/me/kavin/piped/Main.java

@@ -23,6 +23,8 @@ import org.schabi.newpipe.extractor.services.youtube.extractors.YoutubeStreamExt
 import rocks.kavin.reqwest4j.ReqwestUtils;
 
 import java.util.*;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
@@ -102,15 +104,39 @@ public class Main {
 
                     Collections.shuffle(channelIds);
 
-                    channelIds.stream()
+                    var queue = new ConcurrentLinkedQueue<>(channelIds);
-                            .parallel()
+
-                            .forEach(id -> Multithreading.runAsyncLimitedPubSub(() -> {
+                    System.out.println("PubSub: queue size - " + queue.size() + " channels");
+
+                    for (int i = 0; i < Runtime.getRuntime().availableProcessors(); i++) {
+                        new Thread(() -> {
+
+                            Object o = new Object();
+
+                            String channelId;
+                            while ((channelId = queue.poll()) != null) {
                                 try {
-                                    PubSubHelper.subscribePubSub(id);
+                                    CompletableFuture<?> future = PubSubHelper.subscribePubSub(channelId);
+
+                                    if (future == null)
+                                        continue;
+
+                                    future.whenComplete((resp, throwable) -> {
+                                        synchronized (o) {
+                                            o.notify();
+                                        }
+                                    });
+
+                                    synchronized (o) {
+                                        o.wait();
+                                    }
+
                                 } catch (Exception e) {
                                     ExceptionHandler.handle(e);
                                 }
-                            }));
+                            }
+                        }, "PubSub-" + i).start();
+                    }
 
                 } catch (Exception e) {
                     e.printStackTrace();

src/main/java/me/kavin/piped/utils/PubSubHelper.java

@@ -6,16 +6,21 @@ import okhttp3.FormBody;
 import okio.Buffer;
 import org.hibernate.StatelessSession;
 import rocks.kavin.reqwest4j.ReqwestUtils;
+import rocks.kavin.reqwest4j.Response;
 
+import javax.annotation.Nullable;
 import java.io.IOException;
 import java.util.Map;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 
 public class PubSubHelper {
-    public static void subscribePubSub(String channelId) throws IOException {
+
+    @Nullable
+    public static CompletableFuture<Response> subscribePubSub(String channelId) throws IOException {
 
         if (!ChannelHelpers.isValidId(channelId))
-            return;
+            return null;
 
         PubSub pubsub = DatabaseHelper.getPubSubFromId(channelId);
 
@@ -44,16 +49,21 @@ public class PubSubHelper {
             var buffer = new Buffer();
             formBuilder.build().writeTo(buffer);
 
-            ReqwestUtils.fetch(Constants.PUBSUB_HUB_URL, "POST", buffer.readByteArray(), Map.of())
+            var completableFuture = ReqwestUtils.fetch(Constants.PUBSUB_HUB_URL, "POST", buffer.readByteArray(), Map.of());
-                    .thenAccept(resp -> {
+
-                        if (resp.status() != 202)
+            completableFuture
+                    .whenComplete((resp, e) -> {
+                        if (e != null) {
+                            ExceptionHandler.handle((Exception) e);
+                            return;
+                        }
+                        if (resp != null && resp.status() != 202)
                             System.out.println("Failed to subscribe: " + resp.status() + "\n" + new String(resp.body()));
-                    })
-                    .exceptionally(e -> {
-                        ExceptionHandler.handle((Exception) e);
-                        return null;
                     });
+
+            return completableFuture;
         }
+        return null;
     }
 
     public static void updatePubSub(String channelId) {