Test: complete send chat message without signature

libmc-common/src/commonMain/kotlin/cn/rtast/libmc/primitives/BitSet.kt

@@ -33,3 +33,32 @@ public fun BitSet.getBit(bitIndex: Int): Boolean {
     val bitOffset = bitIndex and 63
     return (this[longIndex] and (1L shl bitOffset)) != 0L
 }
+
+public class FixedBitSet20(initialBits: Int = 0) {
+    private var bits: Int = initialBits and 0xFFFFF
+
+    public operator fun get(index: Int): Boolean {
+        require(index in 0..19) { "Index out of range [0, 19]" }
+        return (bits and (1 shl index)) != 0
+    }
+
+    public operator fun set(index: Int, value: Boolean) {
+        require(index in 0..19) { "Index out of range [0, 19]" }
+        bits = if (value) {
+            bits or (1 shl index)
+        } else {
+            bits and (1 shl index).inv()
+        }
+    }
+
+    public fun toByteArray(): ByteArray {
+        val result = ByteArray(3)
+        result[0] = (bits and 0xFF).toByte()
+        result[1] = ((bits shr 8) and 0xFF).toByte()
+        result[2] = ((bits shr 16) and 0x0F).toByte()
+        return result
+    }
+}
+
+public fun createFixedBitSet20(initialBits: Int = 0): FixedBitSet20 =
+    FixedBitSet20(initialBits)

libmc-protocol/src/commonMain/kotlin/cn/rtast/libmc/protocol/packet/play/clientbound/ClientboundEntityEffectPacket.kt

@@ -13,7 +13,7 @@ import cn.rtast.libmc.packet.MinecraftPacket
 import cn.rtast.libmc.primitives.readVarInt
 import cn.rtast.libmc.protocol.protocol.game.effect.EntityEffectFlags
 import cn.rtast.libmc.protocol.protocol.game.effect.readEntityEffectFlags
-import cn.rtast.libmc.protocol.tick.ticks
+import cn.rtast.libmc.protocol.util.ticks
 import kotlin.time.Duration
 
 public data class ClientboundEntityEffectPacket(

libmc-protocol/src/commonMain/kotlin/cn/rtast/libmc/protocol/packet/play/clientbound/ClientboundPlayerEndCombatPacket.kt

@@ -11,7 +11,7 @@ import cn.rtast.libmc.stream.BytesBuffer
 import cn.rtast.libmc.packet.PacketCodec
 import cn.rtast.libmc.packet.MinecraftPacket
 import cn.rtast.libmc.primitives.readVarInt
-import cn.rtast.libmc.protocol.tick.ticks
+import cn.rtast.libmc.protocol.util.ticks
 import kotlin.time.Duration
 
 public data class ClientboundPlayerEndCombatPacket(val duration: Duration) : MinecraftPacket {

libmc-protocol/src/commonMain/kotlin/cn/rtast/libmc/protocol/util/duration.kt

@@ -5,7 +5,7 @@
  */
 
 
-package cn.rtast.libmc.protocol.tick
+package cn.rtast.libmc.protocol.util
 
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.milliseconds

libmc-protocol/src/jvmTest/kotlin/test/ClientChatTracker.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/9/7
+ */
+
+
+package test
+
+import cn.rtast.libmc.primitives.FixedBitSet20
+import cn.rtast.libmc.primitives.createFixedBitSet20
+import cn.rtast.libmc.stream.BytesBuffer
+import kotlin.uuid.Uuid
+
+class ClientChatTracker {
+    private val lastSeenQueue = ArrayDeque<ByteArray>(20)
+    var pendingMessageCount: Int = 0
+        private set
+
+    fun onReceivePlayerChat(signature: ByteArray?) {
+        if (signature == null || signature.size != 256) return
+        if (lastSeenQueue.size >= 20) lastSeenQueue.removeFirst()
+        lastSeenQueue.addLast(signature)
+        pendingMessageCount++
+    }
+
+    fun prepareForOutgoingMessage(): ChatStateSnapshot {
+        val signatures = lastSeenQueue.toList()
+        val count = pendingMessageCount
+        pendingMessageCount = 0
+        return ChatStateSnapshot(signatures, count)
+    }
+}
+
+data class ChatStateSnapshot(val lastSeenSignatures: List<ByteArray>, val messageCount: Int)
+
+fun createAcknowledgedBitSet(lastSeenSignatures: List<ByteArray>): FixedBitSet20 {
+    val bitSet = createFixedBitSet20()
+    for (i in lastSeenSignatures.indices) {
+        if (i >= 20) break
+        bitSet[i] = true
+    }
+    return bitSet
+}
+
+object ChatPacketUtils {
+    fun computeByteArrayHashCode(bytes: ByteArray): Int {
+        var result = 1
+        for (element in bytes) result = 31 * result + element.toInt()
+        return result
+    }
+
+    fun computePacketChecksum(lastSeenSignatures: List<ByteArray>): Byte {
+        var combinedHash = 1
+        for (sig in lastSeenSignatures) {
+            val sigHash = computeByteArrayHashCode(sig)
+            combinedHash = 31 * combinedHash + sigHash
+        }
+        val resultByte = combinedHash.toByte()
+        return if (resultByte == 0.toByte()) 1.toByte() else resultByte
+    }
+}

libmc-protocol/src/jvmTest/kotlin/test/TestClientTestInJvm.kt

@@ -10,8 +10,8 @@ package test
 import cn.rtast.libmc.packet.ClientboundUnknownPacket
 import cn.rtast.libmc.protocol.client.createMinecraftClient
 import cn.rtast.libmc.protocol.crypto.DefaultProtocolContext
-import cn.rtast.libmc.protocol.packet.play.clientbound.ClientboundPlayerInfoUpdatePacket
+import cn.rtast.libmc.protocol.packet.play.clientbound.ClientboundPlayerChatMessagePacket
-import cn.rtast.libmc.protocol.packet.play.clientbound.ClientboundWaypointPacket
+import cn.rtast.libmc.protocol.packet.play.serverbound.ServerboundChatMessagePacket
 import cn.rtast.libmc.protocol.util.generateOfflineUuid
 import kotlinx.coroutines.launch
 import org.junit.Test
@@ -21,11 +21,14 @@ import java.security.KeyFactory
 import java.security.MessageDigest
 import java.security.spec.X509EncodedKeySpec
 import javax.crypto.Cipher
+import kotlin.random.Random
+import kotlin.time.Clock
 import kotlin.uuid.Uuid
 
 
 class TestClientTestInJvm {
     val accessToken = File("src/jvmTest/resources/accessToken.txt").readText()
+    private val chatTracker = ClientChatTracker()
 
     fun encrypt(publicKeyBytes: ByteArray, data: ByteArray): ByteArray {
         val keySpec = X509EncodedKeySpec(publicKeyBytes)
@@ -84,8 +87,25 @@ class TestClientTestInJvm {
 //            if (packet !is ClientboundWaypointPacket)
 //            println("$direction -> $packet")
 //        }
-//        cli.onPacket<ClientboundUnknownPacket> { println(it) }
+        cli.onPacket<ClientboundUnknownPacket> {
-        cli.onPacket<ClientboundPlayerInfoUpdatePacket> { println(it) }
+            println(it)
+            val snapshot = chatTracker.prepareForOutgoingMessage()
+            cli.networkChannel.sendPacket(
+                ServerboundChatMessagePacket(
+                    "114514", Clock.System.now().toEpochMilliseconds(),
+                    Random.nextLong(),
+                    null, snapshot.messageCount, createAcknowledgedBitSet(snapshot.lastSeenSignatures).toByteArray(),
+                    ChatPacketUtils.computePacketChecksum(snapshot.lastSeenSignatures)
+                )
+            )
+        }
+        cli.onPacket<ClientboundPlayerChatMessagePacket> {
+            chatTracker.onReceivePlayerChat(it.messageSignature)
+        }
+//        cli.onPacket<ClientboundServerDataPacket> { println(it) }
+//        cli.onPacket<ClientboundServerLinksPacket> { println(it) }
+//        cli.onPacket<ClientboundCodeOfConductPacket> { println(it) }
+//        cli.onPacket<ClientboundPlayerInfoUpdatePacket> { println(it) }
         cli.launch { cli.connect() }
         while (true) {
         }