From 030b701910377850c0011a3918d393d01b38d7d0 Mon Sep 17 00:00:00 2001
From: AJ Fontaine <36677462+Fontbane@users.noreply.github.com>
Date: Wed, 20 Aug 2025 19:55:16 -0400
Subject: [PATCH] [Refactor] Change rare egg rate consts to array, rare egg
 move common egg boosted chance boosted (#6305)

* Change rare egg rate consts to array

* Update rates.ts

1/24 -> 1/16

* Make new arrays use readonly type hint

---------

Co-authored-by: Sirz Benjie <142067137+SirzBenjie@users.noreply.github.com>
Co-authored-by: damocleas <damocleas25@gmail.com>
---
 src/data/balance/rates.ts |  8 ++++----
 src/data/egg.ts           | 30 +++++++++++++++---------------
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/data/balance/rates.ts b/src/data/balance/rates.ts
index c5eaf40e608..06f3ee78efd 100644
--- a/src/data/balance/rates.ts
+++ b/src/data/balance/rates.ts
@@ -42,10 +42,10 @@ export const SAME_SPECIES_EGG_HA_RATE = 8;
 export const MANAPHY_EGG_MANAPHY_RATE = 8;
 export const GACHA_EGG_HA_RATE = 192;
 
-// 1/x for legendary eggs, 1/x*2 for epic eggs, 1/x*4 for rare eggs, and 1/x*8 for common eggs
-export const GACHA_DEFAULT_RARE_EGGMOVE_RATE = 6;
-export const SAME_SPECIES_EGG_RARE_EGGMOVE_RATE = 3;
-export const GACHA_MOVE_UP_RARE_EGGMOVE_RATE = 3;
+// Odds are 1/x
+// [COMMON, RARE, EPIC/MANAPHY, LEGEND]
+export const RARE_EGGMOVE_RATES: readonly number[] = [48, 24, 12, 6];
+export const BOOSTED_RARE_EGGMOVE_RATES: readonly number[] = [16, 12, 6, 3];
 
 // #region Variant properties
 // The chance x/10 of a shiny being a variant, then of being specifically an epic variant
diff --git a/src/data/egg.ts b/src/data/egg.ts
index 2c567686fc2..5fab276f327 100644
--- a/src/data/egg.ts
+++ b/src/data/egg.ts
@@ -3,17 +3,16 @@ import { globalScene } from "#app/global-scene";
 import Overrides from "#app/overrides";
 import { pokemonPrevolutions } from "#balance/pokemon-evolutions";
 import {
+  BOOSTED_RARE_EGGMOVE_RATES,
   EGG_PITY_EPIC_THRESHOLD,
   EGG_PITY_LEGENDARY_THRESHOLD,
   EGG_PITY_RARE_THRESHOLD,
   GACHA_DEFAULT_COMMON_EGG_THRESHOLD,
   GACHA_DEFAULT_EPIC_EGG_THRESHOLD,
   GACHA_DEFAULT_RARE_EGG_THRESHOLD,
-  GACHA_DEFAULT_RARE_EGGMOVE_RATE,
   GACHA_DEFAULT_SHINY_RATE,
   GACHA_EGG_HA_RATE,
   GACHA_LEGENDARY_UP_THRESHOLD_OFFSET,
-  GACHA_MOVE_UP_RARE_EGGMOVE_RATE,
   GACHA_SHINY_UP_SHINY_RATE,
   HATCH_WAVES_COMMON_EGG,
   HATCH_WAVES_EPIC_EGG,
@@ -21,8 +20,8 @@ import {
   HATCH_WAVES_MANAPHY_EGG,
   HATCH_WAVES_RARE_EGG,
   MANAPHY_EGG_MANAPHY_RATE,
+  RARE_EGGMOVE_RATES,
   SAME_SPECIES_EGG_HA_RATE,
-  SAME_SPECIES_EGG_RARE_EGGMOVE_RATE,
   SAME_SPECIES_EGG_SHINY_RATE,
   SHINY_EPIC_CHANCE,
   SHINY_VARIANT_CHANCE,
@@ -355,21 +354,22 @@ export class Egg {
   // #region Private methods
   ////
 
+  /**
+   * Rolls which egg move slot the egg will have.
+   * 1/x chance for rare, (x-1)/3 chance for each common move.
+   * x is determined by Egg Tier. Boosted rates used for eggs obtained through Move Up Gacha and Candy.
+   * @returns the slot for the egg move
+   */
   private rollEggMoveIndex() {
-    let baseChance = GACHA_DEFAULT_RARE_EGGMOVE_RATE;
-    switch (this._sourceType) {
-      case EggSourceType.SAME_SPECIES_EGG:
-        baseChance = SAME_SPECIES_EGG_RARE_EGGMOVE_RATE;
-        break;
-      case EggSourceType.GACHA_MOVE:
-        baseChance = GACHA_MOVE_UP_RARE_EGGMOVE_RATE;
-        break;
-      default:
-        break;
+    const tierNum = this.isManaphyEgg() ? 2 : this.tier;
+    let baseChance: number;
+    if (this._sourceType === EggSourceType.SAME_SPECIES_EGG || this._sourceType === EggSourceType.GACHA_MOVE) {
+      baseChance = BOOSTED_RARE_EGGMOVE_RATES[tierNum];
+    } else {
+      baseChance = RARE_EGGMOVE_RATES[tierNum];
     }
 
-    const tierMultiplier = this.isManaphyEgg() ? 2 : Math.pow(2, 3 - this.tier);
-    return randSeedInt(baseChance * tierMultiplier) ? randSeedInt(3) : 3;
+    return randSeedInt(baseChance) ? randSeedInt(3) : 3;
   }
 
   private getEggTierDefaultHatchWaves(eggTier?: EggTier): number {