Add Focus Band item

src/modifier/modifier-type.ts

@@ -533,6 +533,9 @@ const modifierTypes = {
   BERRY_POUCH: () => new ModifierType('BERRY POUCH', 'Adds a 25% chance that a used berry will not be consumed',
     (type, _args) => new Modifiers.PreserveBerryModifier(type)),
 
+  FOCUS_BAND: () => new PokemonHeldItemModifierType('FOCUS BAND', 'Adds a 10% chance to survive with 1 HP after being damaged enough to faint',
+    (type, args) => new Modifiers.SurviveDamageModifier(type, (args[0] as Pokemon).id)),
+
   LEFTOVERS: () => new PokemonHeldItemModifierType('LEFTOVERS', 'Heals 1/16 of a POKéMON\'s maximum HP every turn',
     (type, args) => new Modifiers.TurnHealModifier(type, (args[0] as Pokemon).id)),
   SHELL_BELL: () => new PokemonHeldItemModifierType('SHELL BELL', 'Heals 1/8 of a POKéMON\'s dealt damage',
@@ -613,6 +616,7 @@ const modifierPool = {
     new WeightedModifierType(modifierTypes.CANDY_JAR, 3),
     //new WeightedModifierType(modifierTypes.OVAL_CHARM, 1),
     new WeightedModifierType(modifierTypes.HEALING_CHARM, 1),
+    new WeightedModifierType(modifierTypes.FOCUS_BAND, 3),
     new WeightedModifierType(modifierTypes.LEFTOVERS, 2),
     new WeightedModifierType(modifierTypes.SHELL_BELL, 2),
     new WeightedModifierType(modifierTypes.BERRY_POUCH, 3),
@@ -641,6 +645,7 @@ const enemyModifierPool = {
   ].map(m => { m.setTier(ModifierTier.GREAT); return m; }),
   [ModifierTier.ULTRA]: [
     new WeightedModifierType(modifierTypes.ATTACK_TYPE_BOOSTER, 5),
+    new WeightedModifierType(modifierTypes.FOCUS_BAND, 2),
     new WeightedModifierType(modifierTypes.LUCKY_EGG, 2),
   ].map(m => { m.setTier(ModifierTier.ULTRA); return m; }),
   [ModifierTier.MASTER]: [

src/modifier/modifier.ts

@@ -349,6 +349,41 @@ export class AttackTypeBoosterModifier extends PokemonHeldItemModifier {
   }
 }
 
+export class SurviveDamageModifier extends PokemonHeldItemModifier {
+  constructor(type: ModifierType, pokemonId: integer, stackCount?: integer) {
+    super(type, pokemonId, stackCount);
+  }
+
+  matchType(modifier: Modifier) {
+    return modifier instanceof SurviveDamageModifier;
+  }
+
+  clone() {
+    return new SurviveDamageModifier(this.type, this.pokemonId, this.stackCount);
+  }
+
+  shouldApply(args: any[]): boolean {
+    return super.shouldApply(args) && args.length === 2 && args[1] instanceof Utils.BooleanHolder;
+  }
+
+  apply(args: any[]): boolean {
+    const pokemon = args[0] as Pokemon;
+    const surviveDamage = args[1] as Utils.BooleanHolder;
+
+    if (!surviveDamage.value && (this.getStackCount() === this.getMaxStackCount() || Utils.randInt(10) < this.getStackCount())) {
+      surviveDamage.value = true;
+
+      pokemon.scene.queueMessage(getPokemonMessage(pokemon, ` hung on\nusing its ${this.type.name}!`));
+    }
+
+    return true;
+  }
+
+  getMaxStackCount(): number {
+    return 5;
+  }
+}
+
 export class TurnHealModifier extends PokemonHeldItemModifier {
   constructor(type: ModifierType, pokemonId: integer, stackCount?: integer) {
     super(type, pokemonId, stackCount);
@@ -374,7 +409,7 @@ export class TurnHealModifier extends PokemonHeldItemModifier {
   }
 
   getMaxStackCount(): number {
-    return 16;
+    return 4;
   }
 }
 
@@ -403,7 +438,7 @@ export class HitHealModifier extends PokemonHeldItemModifier {
   }
 
   getMaxStackCount(): number {
-    return 16;
+    return 4;
   }
 }
 
@@ -733,6 +768,10 @@ export class HealingBoosterModifier extends PersistentModifier {
 
     return true;
   }
+
+  getMaxStackCount(): number {
+    return 4;
+  }
 }
 
 export class ExpBoosterModifier extends PersistentModifier {