Let plugins intercept Events

Support for PlayerEvents already exists, but general event
support wasn't included in the original KotlinPluginScript.

game/src/main/kotlin/org/apollo/game/plugin/kotlin/KotlinPluginScript.kt

@@ -7,6 +7,7 @@ import org.apollo.game.message.impl.ButtonMessage
 import org.apollo.game.model.World
 import org.apollo.game.model.entity.Player
 import org.apollo.game.model.entity.setting.PrivilegeLevel
+import org.apollo.game.model.event.Event
 import org.apollo.game.model.event.EventListener
 import org.apollo.game.model.event.PlayerEvent
 import org.apollo.game.plugin.PluginContext
@@ -18,29 +19,34 @@ import kotlin.script.templates.ScriptTemplateDefinition
     scriptFilePattern = ".*\\.plugin\\.kts"
 )
 abstract class KotlinPluginScript(private var world: World, val context: PluginContext) {
-	var startListener: (World) -> Unit = { _ -> };
+    var startListener: (World) -> Unit = { _ -> }
-	var stopListener: (World) -> Unit = { _ -> };
+    var stopListener: (World) -> Unit = { _ -> }
 
     /**
-	 * Create a new [MessageHandler].
+     * Creates a [MessageHandler].
      */
-	fun <T : Message> on(type: () -> KClass<T>) = KotlinMessageHandler<T>(world, context, type.invoke())
+    fun <T : Message> on(type: () -> KClass<T>) = KotlinMessageHandler(world, context, type.invoke())
 
     /**
-	 * Create a new [EventListener] for a type of [PlayerEvent].
+     * Create an [EventListener] for a [PlayerEvent].
      */
     fun <T : PlayerEvent> on_player_event(type: () -> KClass<T>) = KotlinPlayerEventHandler(world, type.invoke())
 
     /**
-	 * Create a new [CommandHandler] for the given _command_ name, which only players with a [PrivelegeLevel]
+     * Create an [EventListener] for an [Event].
-	 * of _privileges_ and above can use.
+     */
+    fun <T : Event> on_event(type: () -> KClass<T>) = KotlinEventHandler(world, type.invoke())
+
+    /**
+     * Create a [CommandListener] for the given [command] name, which only players with a [PrivilegeLevel]
+     * of [privileges] and above can use.
      */
     fun on_command(command: String, privileges: PrivilegeLevel) = KotlinCommandHandler(world, command, privileges)
 
     /**
-	 * Create a new [ButtonMessage] [MessageHandler] for the given _button_ id.
+     * Create a [ButtonMessage] [MessageHandler] for the given [id].
      */
-	fun on_button(button: Int) = on { ButtonMessage::class }.where { widgetId == button }
+    fun on_button(id: Int) = on { ButtonMessage::class }.where { widgetId == id }
 
     fun start(callback: (World) -> Unit) {
         this.startListener = callback
@@ -57,13 +63,19 @@ abstract class KotlinPluginScript(private var world: World, val context: PluginC
     fun doStop(world: World) {
         this.stopListener.invoke(world)
     }
+
 }
 
+/**
+ * A proxy interface for any handler that operates on [Player]s.
+ */
 interface KotlinPlayerHandlerProxyTrait<S : Any> {
 
     var callback: S.(Player) -> Unit
     var predicate: S.() -> Boolean
 
+    fun register()
+
     fun where(predicate: S.() -> Boolean): KotlinPlayerHandlerProxyTrait<S> {
         this.predicate = predicate
         return this
@@ -74,15 +86,18 @@ interface KotlinPlayerHandlerProxyTrait<S : Any> {
         this.register()
     }
 
-	fun register()
 
     fun handleProxy(player: Player, subject: S) {
         if (subject.predicate()) {
             subject.callback(player)
         }
     }
+
 }
 
+/**
+ * A handler for [PlayerEvent]s.
+ */
 class KotlinPlayerEventHandler<T : PlayerEvent>(val world: World, val type: KClass<T>) :
     KotlinPlayerHandlerProxyTrait<T>, EventListener<T> {
 
@@ -94,6 +109,37 @@ class KotlinPlayerEventHandler<T : PlayerEvent>(val world: World, val type: KCla
 
 }
 
+/**
+ * A handler for [Event]s.
+ */
+class KotlinEventHandler<S : Event>(val world: World, val type: KClass<S>) : EventListener<S> {
+
+    private var callback: S.() -> Unit = {}
+    private var predicate: S.() -> Boolean = { true }
+
+    fun where(predicate: S.() -> Boolean): KotlinEventHandler<S> {
+        this.predicate = predicate
+        return this
+    }
+
+    fun then(callback: S.() -> Unit) {
+        this.callback = callback
+        this.register()
+    }
+
+    override fun handle(event: S) {
+        if (event.predicate()) {
+            event.callback()
+        }
+    }
+
+    fun register() = world.listenFor(type.java, this)
+
+}
+
+/**
+ * A handler for [Message]s.
+ */
 class KotlinMessageHandler<T : Message>(val world: World, val context: PluginContext, val type: KClass<T>) :
     KotlinPlayerHandlerProxyTrait<T>, MessageHandler<T>(world) {
 
@@ -105,6 +151,9 @@ class KotlinMessageHandler<T : Message>(val world: World, val context: PluginCon
 
 }
 
+/**
+ * A handler for [Command]s.
+ */
 class KotlinCommandHandler(val world: World, val command: String, privileges: PrivilegeLevel) :
     KotlinPlayerHandlerProxyTrait<Command>, CommandListener(privileges) {
 

game/src/main/kotlin/stub.kt

@@ -7,19 +7,19 @@
  */
 
 import org.apollo.game.command.Command
-import org.apollo.game.message.handler.MessageHandlerChainSet
 import org.apollo.game.message.impl.ButtonMessage
 import org.apollo.game.model.World
-import org.apollo.game.model.area.RegionRepository
-import org.apollo.game.model.entity.*
 import org.apollo.game.model.entity.setting.PrivilegeLevel
+import org.apollo.game.model.event.Event
 import org.apollo.game.model.event.PlayerEvent
-import org.apollo.game.plugin.kotlin.*
+import org.apollo.game.plugin.kotlin.KotlinEventHandler
+import org.apollo.game.plugin.kotlin.KotlinPlayerHandlerProxyTrait
 import org.apollo.net.message.Message
 import kotlin.reflect.KClass
 
 fun <T : Message> on(type: () -> KClass<T>): KotlinPlayerHandlerProxyTrait<T> = null!!
 fun <T : PlayerEvent> on_player_event(type: () -> KClass<T>): KotlinPlayerHandlerProxyTrait<T> = null!!
+fun <T : Event> on_event(type: () -> KClass<T>): KotlinEventHandler<T> = null!!
 fun on_command(command: String, privileges: PrivilegeLevel): KotlinPlayerHandlerProxyTrait<Command> = null!!
 fun on_button(button: Int): KotlinPlayerHandlerProxyTrait<ButtonMessage> = null!!