Implement Tailwind (#398)

Added a new ArenaTagType for Tailwind. Lasts 4 turns including the turn used.

src/data/arena-tag.ts

@@ -482,6 +482,20 @@ export class GravityTag extends ArenaTag {
   }
 }
 
+class TailwindTag extends ArenaTag {
+  constructor(turnCount: integer, sourceId: integer, side: ArenaTagSide) {
+    super(ArenaTagType.TAILWIND, turnCount, Moves.TAILWIND, sourceId, side);
+  }
+
+  onAdd(arena: Arena): void {
+    arena.scene.queueMessage(`The Tailwind blew from behind${this.side === ArenaTagSide.PLAYER ? '\nyour' : this.side === ArenaTagSide.ENEMY ? '\nthe opposing' : ''} team!`);
+  }
+
+  onRemove(arena: Arena): void {
+    arena.scene.queueMessage(`${this.side === ArenaTagSide.PLAYER ? 'Your' : this.side === ArenaTagSide.ENEMY ? 'The opposing' : ''} team's Tailwind petered out!`);
+  }
+}
+
 export function getArenaTag(tagType: ArenaTagType, turnCount: integer, sourceMove: Moves, sourceId: integer, targetIndex?: BattlerIndex, side: ArenaTagSide = ArenaTagSide.BOTH): ArenaTag {
   switch (tagType) {
     case ArenaTagType.MIST:
@@ -513,5 +527,7 @@ export function getArenaTag(tagType: ArenaTagType, turnCount: integer, sourceMov
       return new LightScreenTag(turnCount, sourceId, side);
     case ArenaTagType.AURORA_VEIL:
       return new AuroraVeilTag(turnCount, sourceId, side);
+    case ArenaTagType.TAILWIND:
+      return new TailwindTag(turnCount, sourceId, side);
   }
 }

src/data/enums/arena-tag-type.ts

@@ -15,5 +15,6 @@ export enum ArenaTagType {
   GRAVITY = "GRAVITY",
   REFLECT = "REFLECT",
   LIGHT_SCREEN = "LIGHT_SCREEN",
-  AURORA_VEIL = "AURORA_VEIL"
+  AURORA_VEIL = "AURORA_VEIL",
+  TAILWIND = "TAILWIND"
 }

src/data/move.ts

@@ -4805,8 +4805,8 @@ export function initMoves() {
       .partial(),
     new StatusMove(Moves.TAILWIND, Type.FLYING, -1, 15, -1, 0, 4)
       .windMove()
-      .target(MoveTarget.USER_SIDE)
-      .unimplemented(),
+      .attr(AddArenaTagAttr, ArenaTagType.TAILWIND, 4, true)
+      .target(MoveTarget.USER_SIDE),
     new StatusMove(Moves.ACUPRESSURE, Type.NORMAL, -1, 30, -1, 0, 4)
       .attr(StatChangeAttr, BattleStat.RAND, 2)
       .target(MoveTarget.USER_OR_NEAR_ALLY),

src/field/pokemon.ts

@@ -589,6 +589,11 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
           ret *= 1.5;
         break;
       case Stat.SPD:
+        // Check both the player and enemy to see if Tailwind should be multiplying the speed of the Pokemon
+        if    ((this.isPlayer() && this.scene.arena.getTagOnSide(ArenaTagType.TAILWIND, ArenaTagSide.PLAYER)) 
+          ||  (!this.isPlayer() && this.scene.arena.getTagOnSide(ArenaTagType.TAILWIND, ArenaTagSide.ENEMY)))
+          ret *= 2;
+
         if (this.getTag(BattlerTagType.SLOW_START))
           ret >>= 1;
         if (this.status && this.status.effect === StatusEffect.PARALYSIS)