From 43549dee0a8214c1bb02c874dcfd7ba37a8ef310 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Fri, 22 Nov 2024 12:02:08 -0500
Subject: ReliableUnicastSender

---
 src/main/java/derms/net/runicast/Retransmit.java | 57 ++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 src/main/java/derms/net/runicast/Retransmit.java

(limited to 'src/main/java/derms/net/runicast/Retransmit.java')

diff --git a/src/main/java/derms/net/runicast/Retransmit.java b/src/main/java/derms/net/runicast/Retransmit.java
new file mode 100644
index 0000000..affd00c
--- /dev/null
+++ b/src/main/java/derms/net/runicast/Retransmit.java
@@ -0,0 +1,57 @@
+package derms.net.runicast;
+
+import derms.net.ConcurrentDatagramSocket;
+import derms.net.MessagePayload;
+import derms.net.Packet;
+import derms.util.Wait;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.time.Duration;
+import java.util.Queue;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.logging.Logger;
+
+/** Retransmit unacknowledged messages. */
+class Retransmit<T extends MessagePayload> implements Runnable {
+    private static final Duration timeout = Duration.ofMillis(500);
+
+    private final AtomicLong unacked;
+    private final Queue<Message<T>> sent;
+    private final ConcurrentDatagramSocket sock;
+    private final Logger log;
+
+    Retransmit(AtomicLong unacked, Queue<Message<T>> sent, ConcurrentDatagramSocket sock) {
+        this.unacked = unacked;
+        this.sent = sent;
+        this.sock = sock;
+        this.log = Logger.getLogger(getClass().getName());
+    }
+
+    @Override
+    public void run() {
+        try {
+            for (;;) {
+                Wait.forDuration(timeout);
+
+                for (Message<T> msg : sent) {
+                    if (msg.seq >= unacked.get()) {
+                        retransmit(msg);
+                    }
+                }
+            }
+        } catch (InterruptedException e) {
+            log.info("Interrupted.");
+        }
+    }
+
+    private void retransmit(Message<T> msg) {
+        try {
+            DatagramPacket pkt = Packet.encode(msg, sock.getRemoteSocketAddress());
+            sock.send(pkt);
+            log.info("Retransmitted " + msg);
+        } catch (IOException e) {
+            log.warning("Failed to retransmit " + msg + ": " + e.getMessage());
+        }
+    }
+}
-- 
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