feat: Add Velocity protocol

4 files changed, 193 insertions, 0 deletions

diff --git a/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/permission/LunaticChatPermissionNode.kt b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/permission/LunaticChatPermissionNode.kt
index 9b6c3c6..72b7246 100644
--- a/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/permission/LunaticChatPermissionNode.kt
+++ b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/permission/LunaticChatPermissionNode.kt
@@ -47,6 +47,8 @@ sealed class LunaticChatPermissionNode(
 
     object ChatModeToggle : LunaticChatPermissionNode("lunaticchat.command.lc.chatmode.toggle")
 
+    object VelocityStatus : LunaticChatPermissionNode("lunaticchat.command.lcv.status")
+
     object Spy : LunaticChatPermissionNode("lunaticchat.spy")
 
     object NoticeUpdate : LunaticChatPermissionNode("lunaticchat.noticeupdate")
diff --git a/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/PluginMessage.kt b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/PluginMessage.kt
new file mode 100644
index 0000000..4f3a572
--- /dev/null
+++ b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/PluginMessage.kt
@@ -0,0 +1,58 @@
+package dev.m1sk9.lunaticChat.engine.protocol
+
+import kotlinx.serialization.Serializable
+
+/**
+ * Plugin message definitions for Paper-Velocity communication
+ */
+sealed interface PluginMessage {
+    /**
+     * Handshake message (Paper → Velocity)
+     *
+     * @property pluginVersion Plugin version (e.g., "0.7.0")
+     * @property protocolMajor Protocol major version
+     * @property protocolMinor Protocol minor version
+     * @property protocolPatch Protocol patch version
+     */
+    @Serializable
+    data class Handshake(
+        val pluginVersion: String,
+        val protocolMajor: Int,
+        val protocolMinor: Int,
+        val protocolPatch: Int,
+    ) : PluginMessage
+
+    /**
+     * Handshake response message (Velocity → Paper)
+     *
+     * @property compatible true if compatible
+     * @property velocityVersion Velocity plugin version
+     * @property error Error message (when incompatible)
+     */
+    @Serializable
+    data class HandshakeResponse(
+        val compatible: Boolean,
+        val velocityVersion: String,
+        val error: String? = null,
+    ) : PluginMessage
+
+    /**
+     * Status request message (Paper → Velocity)
+     */
+    @Serializable
+    data object StatusRequest : PluginMessage
+
+    /**
+     * Status response message (Velocity → Paper)
+     *
+     * @property velocityVersion Velocity plugin version
+     * @property protocolVersion Protocol version
+     * @property online true if connection is active
+     */
+    @Serializable
+    data class StatusResponse(
+        val velocityVersion: String,
+        val protocolVersion: String,
+        val online: Boolean,
+    ) : PluginMessage
+}
diff --git a/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/PluginMessageCodec.kt b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/PluginMessageCodec.kt
new file mode 100644
index 0000000..042a7dc
--- /dev/null
+++ b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/PluginMessageCodec.kt
@@ -0,0 +1,90 @@
+package dev.m1sk9.lunaticChat.engine.protocol
+
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.DataInputStream
+import java.io.DataOutputStream
+
+/**
+ * Plugin message encoding/decoding
+ *
+ * Format: [subChannel: UTF][messageJson: UTF]
+ */
+object PluginMessageCodec {
+    private val json = Json { ignoreUnknownKeys = true }
+
+    /**
+     * Sub-channel names
+     */
+    object SubChannel {
+        const val HANDSHAKE = "handshake"
+        const val HANDSHAKE_RESPONSE = "handshake_response"
+        const val STATUS_REQUEST = "status_request"
+        const val STATUS_RESPONSE = "status_response"
+    }
+
+    /**
+     * Encodes message
+     *
+     * @param message Message to encode
+     * @return Encoded byte array
+     */
+    fun encode(message: PluginMessage): ByteArray {
+        val out = ByteArrayOutputStream()
+        val dataOut = DataOutputStream(out)
+
+        val (subChannel, messageJson) =
+            when (message) {
+                is PluginMessage.Handshake -> {
+                    SubChannel.HANDSHAKE to json.encodeToString(message)
+                }
+                is PluginMessage.HandshakeResponse -> {
+                    SubChannel.HANDSHAKE_RESPONSE to json.encodeToString(message)
+                }
+                is PluginMessage.StatusRequest -> {
+                    SubChannel.STATUS_REQUEST to "{}"
+                }
+                is PluginMessage.StatusResponse -> {
+                    SubChannel.STATUS_RESPONSE to json.encodeToString(message)
+                }
+            }
+
+        dataOut.writeUTF(subChannel)
+        dataOut.writeUTF(messageJson)
+
+        return out.toByteArray()
+    }
+
+    /**
+     * Decodes message
+     *
+     * @param data Byte array to decode
+     * @return Decoded message
+     * @throws IllegalArgumentException Invalid message format
+     */
+    fun decode(data: ByteArray): PluginMessage {
+        val input = ByteArrayInputStream(data)
+        val dataIn = DataInputStream(input)
+
+        val subChannel = dataIn.readUTF()
+        val messageJson = dataIn.readUTF()
+
+        return when (subChannel) {
+            SubChannel.HANDSHAKE -> {
+                json.decodeFromString<PluginMessage.Handshake>(messageJson)
+            }
+            SubChannel.HANDSHAKE_RESPONSE -> {
+                json.decodeFromString<PluginMessage.HandshakeResponse>(messageJson)
+            }
+            SubChannel.STATUS_REQUEST -> {
+                PluginMessage.StatusRequest
+            }
+            SubChannel.STATUS_RESPONSE -> {
+                json.decodeFromString<PluginMessage.StatusResponse>(messageJson)
+            }
+            else -> throw IllegalArgumentException("Unknown sub-channel: $subChannel")
+        }
+    }
+}
diff --git a/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/ProtocolVersion.kt b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/ProtocolVersion.kt
new file mode 100644
index 0000000..a57d3a7
--- /dev/null
+++ b/engine/src/main/kotlin/dev/m1sk9/lunaticChat/engine/protocol/ProtocolVersion.kt
@@ -0,0 +1,43 @@
+package dev.m1sk9.lunaticChat.engine.protocol
+
+/**
+ * LunaticChat protocol version definition
+ *
+ * Manages version of communication protocol between Paper and Velocity.
+ * MAJOR.MINOR must match; differences in PATCH are compatible.
+ */
+object ProtocolVersion {
+    const val MAJOR = 1
+    const val MINOR = 0
+    const val PATCH = 0
+
+    val version: String = "$MAJOR.$MINOR.$PATCH"
+
+    /**
+     * Checks if specified protocol version is compatible
+     *
+     * @param major Major version
+     * @param minor Minor version
+     * @return true if MAJOR and MINOR match
+     */
+    fun isCompatible(
+        major: Int,
+        minor: Int,
+    ): Boolean = MAJOR == major && MINOR == minor
+
+    /**
+     * Checks compatibility from version string
+     *
+     * @param version Version string in "MAJOR.MINOR.PATCH" format
+     * @return true if compatible
+     */
+    fun isCompatible(version: String): Boolean {
+        val parts = version.split(".")
+        if (parts.size != 3) return false
+
+        val major = parts[0].toIntOrNull() ?: return false
+        val minor = parts[1].toIntOrNull() ?: return false
+
+        return isCompatible(major, minor)
+    }
+}