Added plugin message response callbacks

src/main/kotlin/net/axay/kspigot/pluginmessages/BungeePluginMessageReceiver.kt

@@ -0,0 +1,49 @@
+package net.axay.kspigot.pluginmessages
+
+import net.axay.kspigot.runnables.taskRunLater
+import org.bukkit.entity.Player
+import org.bukkit.plugin.messaging.PluginMessageListener
+import java.io.ByteArrayInputStream
+import java.io.DataInputStream
+
+internal data class BungeePluginMessageResponseCallback(
+    val subChannel: String,
+    val player: Player,
+    val timeoutSeconds: Int,
+    val onResponse: (message: DataInputStream) -> Unit
+) {
+
+    init {
+
+        BungeePluginMessageReceiver.registered += this
+
+        taskRunLater(20L * timeoutSeconds) {
+            BungeePluginMessageReceiver.registered -= this
+        }
+
+    }
+
+}
+
+private object BungeePluginMessageReceiver : PluginMessageListener {
+
+    val registered = ArrayList<BungeePluginMessageResponseCallback>()
+
+    override fun onPluginMessageReceived(channel: String, player: Player, message: ByteArray) {
+
+        if (channel != "BungeeCord") return
+
+        val msgbytes = ByteArrayInputStream(message)
+        val msgin = DataInputStream(msgbytes)
+
+        val subChannel = msgin.readUTF()
+
+        val callback = registered.find { it.subChannel == subChannel && it.player == player }
+        if (callback != null) {
+            registered -= callback
+            callback.onResponse.invoke(msgin)
+        }
+
+    }
+
+}

src/main/kotlin/net/axay/kspigot/pluginmessages/PluginMessages.kt

@@ -4,6 +4,7 @@ import net.axay.kspigot.extensions.onlinePlayers
 import net.axay.kspigot.main.KSpigotMainInstance
 import org.bukkit.entity.Player
 import java.io.ByteArrayOutputStream
+import java.io.DataInputStream
 import java.io.DataOutputStream
 import java.io.IOException
 
@@ -16,11 +17,13 @@ import java.io.IOException
  */
 fun sendPluginMessageToBungeeCordRandomPlayer(
     subChannel: String,
-    content: List<String>? = null
+    content: List<String>? = null,
+    responseTimeout: Int = 20,
+    onResponse: ((message: DataInputStream) -> Unit)? = null
 ): Boolean {
     val randomPlayer = onlinePlayers.randomOrNull()
     return if (randomPlayer != null) {
-        sendPluginMessageToBungeeCord(randomPlayer, subChannel, content)
+        sendPluginMessageToBungeeCord(randomPlayer, subChannel, content, responseTimeout, onResponse)
         true
     } else false
 }
@@ -29,11 +32,18 @@ fun sendPluginMessageToBungeeCordRandomPlayer(
  * Sends a plugin message on the "BungeeCord" channel.
  * Specify your sub channel and if necessary add the
  * required content.
+ * @param player The player which should be used to send the message.
+ * @param subChannel The channel, where the message should be send. (Usually the channel defines the behaviour.)
+ * @param content The optional content of the message.
+ * @param responseTimeout The time in seconds after which the response counts as "not arrived".
+ * @param onResponse The optional reponse callback.
  */
 fun sendPluginMessageToBungeeCord(
     player: Player,
     subChannel: String,
-    content: List<String>? = null
+    content: List<String>? = null,
+    responseTimeout: Int = 20,
+    onResponse: ((message: DataInputStream) -> Unit)? = null
 ) {
 
     val msgbytes = ByteArrayOutputStream()
@@ -51,6 +61,9 @@ fun sendPluginMessageToBungeeCord(
         e.printStackTrace()
     }
 
+    if (onResponse != null)
+        BungeePluginMessageResponseCallback(subChannel, player, responseTimeout, onResponse)
+
     player.sendPluginMessage(KSpigotMainInstance, "BungeeCord", msgbytes.toByteArray())
 
 }