Fix: NPCs spawned under a target couldn't attack

engine/src/main/kotlin/world/gregs/voidps/engine/entity/character/mode/combat/CombatMovement.kt

@@ -16,9 +16,7 @@ import world.gregs.voidps.engine.entity.character.player.chat.cantReach
 import world.gregs.voidps.engine.entity.item.Item
 import world.gregs.voidps.engine.get
 import world.gregs.voidps.engine.map.Overlap
-import world.gregs.voidps.type.Direction
 import world.gregs.voidps.type.Tile
-import world.gregs.voidps.type.random
 import kotlin.math.abs
 
 /**
@@ -60,7 +58,6 @@ class CombatMovement(
         if (!attack()) {
             var skip: Boolean
             if (Overlap.isUnder(character.tile, character.size, target.tile, target.size)) {
-                stepOut()
                 skip = true
             } else {
                 val wasEmpty = character.steps.isEmpty()
@@ -81,17 +78,8 @@ class CombatMovement(
         }
     }
 
-    private fun stepOut() {
-        clearSteps()
-        if (target.mode is CombatMovement || target.mode is Interact) {
-            return
-        }
-        val direction = Direction.cardinal.random(random)
-        if (!canStep(direction.delta.x, direction.delta.y)) {
-            return
-        }
-        character.steps.queueStep(strategy.tile.add(direction))
-    }
+    override fun shouldQueueStepOut(): Boolean =
+        target.mode !is CombatMovement && target.mode !is Interact
 
     private fun attack(): Boolean {
         val attackRange = attackRange()

engine/src/main/kotlin/world/gregs/voidps/engine/entity/character/mode/interact/Interact.kt

@@ -8,10 +8,14 @@ import world.gregs.voidps.engine.entity.character.Character
 import world.gregs.voidps.engine.entity.character.mode.EmptyMode
 import world.gregs.voidps.engine.entity.character.mode.move.Movement
 import world.gregs.voidps.engine.entity.character.mode.move.target.TargetStrategy
+import world.gregs.voidps.engine.entity.character.npc.NPC
 import world.gregs.voidps.engine.entity.character.player.Player
 import world.gregs.voidps.engine.entity.character.player.chat.cantReach
 import world.gregs.voidps.engine.entity.character.player.chat.noInterest
+import world.gregs.voidps.engine.map.Overlap
 import world.gregs.voidps.engine.suspend.resumeSuspension
+import world.gregs.voidps.type.Direction
+import world.gregs.voidps.type.random
 
 /**
  * Moves a player within interact distance of [target]
@@ -86,6 +90,18 @@ open class Interact(
             return
         }
         updateRange = false
+        val target = target
+        val npc = character as? NPC
+        if (npc != null && !npc.def["allowed_under", false] && target is Character &&
+            Overlap.isUnder(npc.tile, npc.size, target.tile, target.size)) {
+            clearSteps()
+            val direction = Direction.cardinal.random(random)
+            if (canStep(direction.delta.x, direction.delta.y)) {
+                character.steps.queueStep(npc.tile.add(direction))
+            }
+            super.tick()
+            return
+        }
         calculate()
         val interacted = processInteraction()
         if (interacted && interactionFinished()) {

engine/src/main/kotlin/world/gregs/voidps/engine/entity/character/mode/move/Movement.kt

@@ -26,6 +26,7 @@ import world.gregs.voidps.type.Delta
 import world.gregs.voidps.type.Direction
 import world.gregs.voidps.type.Tile
 import world.gregs.voidps.type.equals
+import world.gregs.voidps.type.random
 import kotlin.math.sign
 
 open class Movement(
@@ -53,6 +54,30 @@ open class Movement(
         needsCalculation = false
     }
 
+    /**
+     * Clears steps and queues a random cardinal step when an NPC overlaps its character target and isn't permitted to stand there.
+     */
+    protected open fun stepOut(): Boolean {
+        val strategy = strategy ?: return false
+        if (strategy.shape != -2) return false
+        val npc = character as? NPC ?: return false
+        if (npc.def["allowed_under", false]) return false
+        if (!Overlap.isUnder(npc.tile, npc.size, npc.size, strategy.tile, strategy.width, strategy.height)) return false
+        clearSteps()
+        if (shouldQueueStepOut()) {
+            val direction = Direction.cardinal.random(random)
+            if (canStep(direction.delta.x, direction.delta.y)) {
+                character.steps.queueStep(npc.tile.add(direction))
+            }
+        }
+        return true
+    }
+
+    /**
+     * Whether [stepOut] should queue a random step after clearing, or let normal recalculation handle repositioning.
+     */
+    protected open fun shouldQueueStepOut(): Boolean = true
+
     override fun tick() {
         val character = character
         if (character is Player && character.viewport?.loaded == false) {
@@ -61,7 +86,9 @@ open class Movement(
         if (hasDelay() && !canMove() && !character.steps.destination.noCollision) {
             return
         }
-        calculate()
+        if (!stepOut()) {
+            calculate()
+        }
         if (step(runStep = false) && character.running) {
             if (character.steps.isNotEmpty()) {
                 step(runStep = true)

game/src/test/kotlin/content/entity/combat/CombatMovementTest.kt

@@ -129,6 +129,16 @@ internal class CombatMovementTest : WorldTest() {
         assertTrue(npc.mode is CombatMovement)
     }
 
+    @Test
+    fun `Npc spawned under player steps out to attack`() {
+        val player = createPlayer(emptyTile)
+        val npc = createNPC("guard_falador", emptyTile)
+        npc.interactPlayer(player, "Attack")
+        tick(2)
+        assertTrue(npc.tile != emptyTile)
+        assertTrue(npc.mode is CombatMovement)
+    }
+
     companion object {
         private const val MAX_EXP = 14000000.0
     }