First draft of initial user flow

BauSystem/BauSystem_Main/build.gradle.kts

@@ -19,6 +19,7 @@
 
 plugins {
     steamwar.java
+    kotlin("jvm") version "2.4.0"
 }
 
 tasks.compileJava {
@@ -26,8 +27,6 @@ tasks.compileJava {
 }
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_21
-    targetCompatibility = JavaVersion.VERSION_21
 }
 
 dependencies {
@@ -46,4 +45,11 @@ dependencies {
 
     implementation(libs.luaj)
     implementation(files("$projectDir/../libs/YAPION-SNAPSHOT.jar"))
+    implementation(kotlin("stdlib-jdk8"))
 }
+repositories {
+    mavenCentral()
+}
+kotlin {
+    jvmToolchain(21)
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/CannonCore.kt

@@ -0,0 +1,30 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+import org.bukkit.Location
+
+class CannonCore(val location: Location) {
+
+    companion object Manager {
+        var activeCores:  Observable<List<CannonCore>> = Observable(ArrayList())
+    }
+}
+

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/CannonCoreCommand.kt

@@ -0,0 +1,36 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+import de.steamwar.bausystem.SWUtils
+import de.steamwar.command.SWCommand
+import de.steamwar.linkage.Linked
+import org.bukkit.entity.Player
+
+@Linked
+object CannonCoreCommand : SWCommand("cannoncore") {
+
+    @Register
+    fun giveCannonCoreWand(player: Player) {
+        val wandItem = CannonCoreWand.getWandItem()
+
+        SWUtils.giveItemToPlayer(player, wandItem)
+    }
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/CannonCoreEntity.kt

@@ -0,0 +1,46 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+import de.steamwar.entity.RBlockDisplay
+import de.steamwar.entity.REntityAction
+import de.steamwar.entity.REntityServer
+import de.steamwar.entity.RInteraction
+import org.bukkit.Location
+import org.bukkit.Material
+import org.bukkit.entity.Player
+
+class CannonCoreEntity: RBlockDisplay  {
+    val entityMaterial = Material.COMMAND_BLOCK
+
+    val hitbox: RInteraction
+
+    constructor(server: REntityServer, location: Location, onClick: (player: Player, clickAction: REntityAction) -> Unit) : super(server, location) {
+        setBlock(entityMaterial.createBlockData())
+
+        hitbox = RInteraction(server, location)
+        hitbox.setCallback(onClick)
+    }
+
+    override fun die() {
+        this.die()
+        hitbox.die()
+    }
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/CannonCoreWand.kt

@@ -0,0 +1,68 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+import de.steamwar.bausystem.utils.ItemUtils
+import de.steamwar.core.SWPlayer
+import de.steamwar.inventory.SWItem
+import de.steamwar.linkage.Linked
+import org.bukkit.Material
+import org.bukkit.event.EventHandler
+import org.bukkit.event.Listener
+import org.bukkit.event.player.PlayerItemHeldEvent
+import org.bukkit.inventory.ItemStack
+
+@Linked
+object CannonCoreWand: Listener {
+    val wandId = "CANNON_CORE_WAND"
+    val wandMaterial = Material.BREEZE_ROD
+
+
+    fun getWandItem(): ItemStack {
+        val title = "Cannon Core Wand"
+        val lore = listOf(
+            "§eRight Click §8- §7Create a new cannon core"
+        )
+
+        val wand = SWItem(wandMaterial, title, lore, false, null)
+        val item = wand.itemStack
+        return  ItemUtils.setItem(item, wandId)
+    }
+
+    fun isWandItem(itemStack: ItemStack): Boolean {
+        return ItemUtils.isItem(itemStack, wandId)
+    }
+
+    @EventHandler
+    fun onPlayerEquip(event: PlayerItemHeldEvent) {
+        val player = event.player
+        val swPlayer = SWPlayer.of(event.player)
+        val item = swPlayer.inventory.itemInMainHand
+
+        if(!isWandItem(item)) {
+            swPlayer.removeComponent(EmptyCannonCoreWandDisplay::class.java)
+        }
+        else {
+            // TODO add handling for bound wand
+            val newCursor = EmptyCannonCoreWandDisplay(player)
+            swPlayer.setComponent(newCursor)
+        }
+    }
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/CannonCoresDisplay.kt

@@ -0,0 +1,42 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+import de.steamwar.core.SWPlayer
+import de.steamwar.entity.REntityServer
+import org.bukkit.entity.Player
+
+class CannonCoresDisplay: SWPlayer.Component {
+    val displayServer = REntityServer()
+    val unlisten: () -> Unit
+
+    constructor(owner: Player) {
+        displayServer.addPlayer(owner)
+        unlisten = CannonCore.activeCores.observe( { cores ->
+            displayServer.entities.forEach { it.die() }
+            cores.forEach { CannonCoreEntity(displayServer, it.location) { _, _ -> println("Handler clicked at ${it.location}") } }
+        })
+    }
+
+    override fun onUnmount(player: SWPlayer?) {
+        super.onUnmount(player)
+        unlisten()
+    }
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/EmptyCannonCoreWandDisplay.kt

@@ -0,0 +1,47 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+import de.steamwar.core.SWPlayer
+import de.steamwar.cursor.Cursor
+import de.steamwar.entity.REntity
+import org.bukkit.Location
+import org.bukkit.Material
+import org.bukkit.entity.Player
+import org.bukkit.event.block.Action
+import java.util.Optional
+
+class EmptyCannonCoreWandDisplay : SWPlayer.Component {
+    val coresDisplay: CannonCoresDisplay
+    val cursor: Cursor
+
+    constructor(owner: Player) {
+        coresDisplay = CannonCoresDisplay(owner)
+
+        cursor = Cursor(
+            coresDisplay.displayServer, owner, Material.GLASS, Material.COMMAND_BLOCK,
+            listOf(
+                Cursor.CursorMode.BLOCK_ALIGNED
+            ),
+        ) { location, hitEntity, action ->
+            print("Hello")
+        }
+    }
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/cannonCore/Observable.kt

@@ -0,0 +1,47 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2026 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.features.cannonCore
+
+typealias Observer<T> = (currentValue: T) -> Unit
+
+class Observable<T>(var value: T) {
+    private val observers = ArrayList<Observer<T>>()
+
+    fun set(value: T) {
+        val oldValue = this.value
+        this.value = value
+
+        observers.forEach { it.invoke(value) }
+    }
+
+    fun get(): T {
+        return value
+    }
+
+    fun observe(observer: Observer<T>): () -> Unit {
+        observers.add(observer)
+        observer(value)
+        return {removeObserver(observer)}
+    }
+
+    fun removeObserver(observer: Observer<T>) {
+        observers.remove(observer)
+    }
+}

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/utils/ItemUtils.java

@@ -37,8 +37,9 @@ public class ItemUtils {
         return value != null && value.equals(tag);
     }
 
-    public void setItem(ItemStack itemStack, String tag) {
+    public ItemStack setItem(ItemStack itemStack, String tag) {
         setTag(itemStack, ITEM_KEY, tag);
+        return itemStack;
     }
 
     public String getTag(ItemStack itemStack, NamespacedKey key) {

settings.gradle.kts

@@ -21,6 +21,10 @@ import org.apache.tools.ant.taskdefs.condition.Os
 import java.net.URI
 import java.util.*
 
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention") version "0.10.0"
+}
+
 rootProject.name = "SteamWar"
 
 private val isInCi by lazy { Os.isFamily(Os.FAMILY_UNIX) && ProcessBuilder("hostname").start().inputStream.bufferedReader().readText().startsWith("steamwar.de") }