feat: spear

src/combat/index.ts

@@ -1 +1,2 @@
 require('./pushing');
+require('./spear');

src/combat/spear.ts

@@ -0,0 +1,76 @@
+import { Material } from 'org.bukkit';
+import { Attribute } from 'org.bukkit.attribute';
+import {
+  AbstractHorse,
+  Donkey,
+  EntityType,
+  Horse,
+  Mule,
+  Player,
+} from 'org.bukkit.entity';
+import { EntityDamageByEntityEvent } from 'org.bukkit.event.entity';
+import { CustomItem } from '../common/items/CustomItem';
+
+const MAX_DISTANCE = 4;
+const MIN_DISTANCE = 2;
+const HORSE_MAX_SPEED = 0.3375;
+const MULTIPLIER = 8;
+
+const Spear = new CustomItem({
+  id: 7,
+  name: 'Keihäs',
+  type: Material.IRON_HOE,
+  modelId: 7,
+});
+
+registerEvent(EntityDamageByEntityEvent, (event) => {
+  const damager = event.damager;
+  if (!damager) return;
+  if (damager.type !== EntityType.PLAYER) return;
+  const attacker = damager as Player;
+
+  const item = attacker.itemInHand;
+  if (!item) return;
+  if (!Spear.check(item)) return;
+
+  // The weapon has cooled down if the value is 1
+  if (attacker.attackCooldown < 1) return;
+
+  const target = event.entity;
+  if (target.type !== EntityType.PLAYER) return;
+
+  const vehicle = target.vehicle;
+  if (!vehicle) return;
+  if (!(vehicle instanceof AbstractHorse)) return;
+
+  // Calculate the chance of dropping the enemy
+  const distance = attacker.location.distance(target.location);
+  const chance1 = 1 - minMaxScale(distance, MIN_DISTANCE, MAX_DISTANCE);
+  const chance2 = getSpeed(attacker);
+  const total = 1 - Math.pow(1 - chance1 * chance2, MULTIPLIER);
+  if (Math.random() > total) return;
+
+  // Drop the target
+  vehicle.eject();
+});
+
+function getSpeed(player: Player) {
+  const vehicle = player.vehicle;
+
+  let speed = 0;
+  if (vehicle instanceof AbstractHorse) {
+    // Max speed of the horse
+    speed =
+      vehicle.getAttribute(Attribute.GENERIC_MOVEMENT_SPEED)?.value || speed;
+  } else {
+    // Max speed of the player (but only 30% effective)
+    0.3 * (player.getAttribute(Attribute.GENERIC_MOVEMENT_SPEED)?.value || 0);
+  }
+  return minMaxScale(speed, 0, HORSE_MAX_SPEED);
+}
+
+function minMaxScale(val: number, min: number, max: number) {
+  if (val < min) return 0;
+  if (val > max) return 1;
+  return (val - min) / (max - min);
+}