EID: add helper for conditional item descriptions

Author: vulpya

src/Feature.ts

@@ -1,18 +1,9 @@
 import type { DamageFlag } from "isaac-typescript-definitions";
-import type { ModUpgraded } from "isaacscript-common";
 import { ModFeature } from "isaacscript-common";
 import type { EIDExtended } from "./compat/EID";
 
 /** Abstract base class representing a custom feature. */
 export abstract class Feature extends ModFeature {
-  constructor(mod: ModUpgraded, init?: boolean) {
-    super(mod, init);
-    const ExEID = EID as EIDExtended | undefined;
-    if (this.setupEID && ExEID) {
-      this.setupEID(ExEID);
-    }
-  }
-
   onGameExit?(): void;
 
   onGameStart?(isContinued: boolean): void;
@@ -158,6 +149,7 @@ export abstract class Feature extends ModFeature {
    *
    * @param eid The extended EID API instance used to register descriptions and modify how the item
    *            appears in External Item Descriptions.
+   * @param player The Player entity.
    */
-  setupEID?(eid: EIDExtended): void;
+  setupEID?(eid: EIDExtended, player: EntityPlayer): void;
 }

src/characters/Character.ts

@@ -1,8 +1,16 @@
+import type { EIDExtended } from "../compat/EID";
 import { Feature } from "../Feature";
 
 export interface PlayerData {
   fireDelayInit?: boolean;
 }
 
 /** Abstract base class representing a custom character. */
-export abstract class Character extends Feature {}
+export abstract class Character extends Feature {
+  override postPlayerInit(player: EntityPlayer): void {
+    const ExEID = EID as EIDExtended | undefined;
+    if (this.setupEID && ExEID) {
+      this.setupEID(ExEID, player);
+    }
+  }
+}

src/characters/Miku/MikuCharacter.ts

@@ -69,6 +69,11 @@ export class MikuCharacter extends Character {
     }
   }
 
+  @Callback(ModCallback.POST_PLAYER_INIT)
+  override postPlayerInit(player: EntityPlayer): void {
+    super.postPlayerInit(player);
+  }
+
   @Callback(ModCallback.EVALUATE_CACHE, CacheFlag.FIRE_DELAY)
   override cacheFireDelay(player: EntityPlayer): void {
     if (!isMiku(player)) {

src/characters/Miku/MikuTaintedCharacter.ts

@@ -13,7 +13,6 @@ import {
 } from "isaac-typescript-definitions";
 import type { SaveData } from "isaacscript-common";
 import {
-  addCollectibleCostume,
   anyPlayerIs,
   Callback,
   CallbackCustom,
@@ -25,11 +24,11 @@ import {
   jsonEncode,
   ModCallbackCustom,
   ReadonlyMap,
-  removeCollectibleCostume,
   spawnEffect,
   VectorZero,
 } from "isaacscript-common";
 import type { EIDExtended } from "../../compat/EID";
+import { appendToDescription } from "../../compat/EID";
 import { spawnNotePickup } from "../../entities/pickups/helper";
 import type { NoteInstance } from "../../entities/pickups/NotePickup/NotePickup";
 import {
@@ -41,6 +40,7 @@ import type { GlitchNoteTearData } from "../../entities/tears/GlitchNoteTear/Gli
 import { CollectibleTypeCustom } from "../../items/enum";
 import { mod } from "../../mod";
 import { getFireRateMultiplier, setFireRate } from "../../util/calc";
+import { updateCollectibleCostumes } from "../../util/costumes";
 import { getData } from "../../util/data";
 import { Debugger } from "../../util/debug";
 import { setTearColor } from "../../util/effects";
@@ -72,6 +72,11 @@ const ITEM_REPLACEMENTS: Partial<Record<CollectibleType, CollectibleType>> = {
   [CollectibleType.DR_FETUS]: CollectibleTypeCustom.DR_FETUS_NOTE,
 } as const;
 
+const ITEM_COSTUMES: Partial<Record<CollectibleType, CollectibleType>> = {
+  [CollectibleTypeCustom.BRIMSTONE_NOTE]: CollectibleType.BRIMSTONE,
+  [CollectibleTypeCustom.DR_FETUS_NOTE]: CollectibleType.DR_FETUS,
+} as const;
+
 const FIRE_RATE_ITEM_MULTIPLIERS: Partial<Record<CollectibleType, number>> = {
   [CollectibleType.MONSTROS_LUNG]: 0.35,
 } as const;
@@ -90,7 +95,7 @@ export class MikuTaintedCharacter extends Character {
   /** Font for the uses text of the notes. */
   private font: Font | undefined = undefined;
 
-  @CallbackCustom(ModCallbackCustom.POST_GAME_STARTED_REORDERED, true)
+  @CallbackCustom(ModCallbackCustom.POST_GAME_STARTED_REORDERED, undefined)
   override onGameStart(isContinued: boolean): void {
     if (!isContinued || !mod.HasData()) {
       return;
@@ -166,6 +171,7 @@ export class MikuTaintedCharacter extends Character {
    */
   @Callback(ModCallback.POST_PLAYER_INIT, PlayerVariant.PLAYER)
   override postPlayerInit(player: EntityPlayer): void {
+    super.postPlayerInit(player);
     if (!isMiku(player, true)) {
       return;
     }
@@ -179,6 +185,8 @@ export class MikuTaintedCharacter extends Character {
     playerData.erased = saved.erased;
     playerData.notes = saved.notes;
     playerData.useNotes = saved.useNotes;
+
+    this.postPlayerInit(player);
   }
 
   @CallbackCustom(
@@ -226,8 +234,7 @@ export class MikuTaintedCharacter extends Character {
       FIRE_RATE_ITEM_MULTIPLIERS,
     );
 
-    // If no item with extra multiplier was found, return to default item eval.
-    if (multiplier === 1) {
+    if (multiplier === -1) {
       return;
     }
 
@@ -326,8 +333,11 @@ export class MikuTaintedCharacter extends Character {
       const isRightSide = controllerSides[index] ?? false;
 
       // HUD layout config
-      const startX = isRightSide ? 300 : 45;
-      const startY = 45;
+      const hudOffset = Options.HUDOffset;
+      const hudX = hudOffset * 20;
+
+      const startX = isRightSide ? 300 - hudX : 45 + hudX;
+      const startY = 60;
       const spacing = 16;
       const baseSize = 14;
       const maxPerRow = 5;
@@ -478,17 +488,7 @@ export class MikuTaintedCharacter extends Character {
         }
       }
 
-      if (player.HasCollectible(CollectibleTypeCustom.BRIMSTONE_NOTE)) {
-        addCollectibleCostume(player, CollectibleType.BRIMSTONE);
-      } else {
-        removeCollectibleCostume(player, CollectibleType.BRIMSTONE);
-      }
-
-      if (player.HasCollectible(CollectibleTypeCustom.DR_FETUS_NOTE)) {
-        addCollectibleCostume(player, CollectibleType.DR_FETUS);
-      } else {
-        removeCollectibleCostume(player, CollectibleType.DR_FETUS);
-      }
+      updateCollectibleCostumes(player, ITEM_COSTUMES);
     }
   }
 
@@ -585,6 +585,12 @@ export class MikuTaintedCharacter extends Character {
     const synergyNote = ITEM_SYNERGIES[itemID];
     const replaceItem = ITEM_REPLACEMENTS[itemID];
 
+    // FIXME: Solution until I find a better one...
+    if (itemID === CollectibleType.LUDOVICO_TECHNIQUE) {
+      player.AddCollectible(CollectibleType.TECH_5);
+      return undefined;
+    }
+
     if (synergyNote === undefined || replaceItem === undefined) {
       return undefined;
     }
@@ -640,5 +646,22 @@ export class MikuTaintedCharacter extends Character {
       `${NAME} (Tainted)`,
       "Add description and birthright description.",
     );
+
+    // TODO: Implement with loop.
+    appendToDescription(
+      eid,
+      "Brimstone",
+      PlayerTypeCustom.MIKU_B,
+      `#{{Player${PlayerTypeCustom.MIKU_B}}} Replaces {{Collectible118}} Brimstone#{{Collectible${CollectibleTypeCustom.BRIMSTONE_NOTE}}} Brimstone Notes can now drop from enemies`,
+      () => anyPlayerIs(PlayerTypeCustom.MIKU_B),
+    );
+
+    appendToDescription(
+      eid,
+      "Dr. Fetus",
+      PlayerTypeCustom.MIKU_B,
+      `#{{Player${PlayerTypeCustom.MIKU_B}}} Replaces {{Collectible52}} Dr. Fetus#{{Collectible${CollectibleTypeCustom.DR_FETUS_NOTE}}} Dr. Fetus Explosive Notes can now drop from enemies`,
+      () => anyPlayerIs(PlayerTypeCustom.MIKU_B),
+    );
   }
 }

src/compat/EID.ts

@@ -1,3 +1,5 @@
+import type { PlayerType } from "isaac-typescript-definitions";
+
 export interface EIDExtended extends EIDInterface {
   addCharacterInfo: (
     characterId: int,
@@ -11,3 +13,31 @@ export interface EIDExtended extends EIDInterface {
     callback: (descObj: EIDDescriptionObject) => void,
   ) => void;
 }
+
+/**
+ * Registers an **External Item Descriptions (EID)** description modifier that appends additional
+ * text to an item description for a specific condition when a runtime condition is met.
+ *
+ * @param eid The `EIDExtended` instance used to register the description modifier.
+ * @param name The name of the player used to generate a unique modifier identifier.
+ * @param type The player type associated with the modifier.
+ * @param description The text to append to Brimstone's EID description.
+ * @param condition A callback that determines whether the description should be appended.
+ * @see {@link EIDExtended}
+ */
+export const appendToDescription = (
+  eid: EIDExtended,
+  name: string,
+  type: PlayerType,
+  description: string,
+  condition: () => boolean,
+): void => {
+  eid.addDescriptionModifier(
+    `${name}-${type}`,
+    (descObj) => condition() && descObj.Name === name,
+    (oldDescription) => {
+      eid.appendToDescription(oldDescription, description);
+      return oldDescription;
+    },
+  );
+};

src/items/DrFetusNote/DrFetusNote.ts

@@ -0,0 +1,14 @@
+import type { EIDExtended } from "../../compat/EID";
+import { Debugger } from "../../util/debug";
+import { Item } from "../Item";
+import { CollectibleTypeCustom } from "../enum";
+
+const NAME = "Dr. Fetus Note";
+const DESCRIPTION = `Replaces {{Collectible52}} Dr. Fetus#{{Collectible${CollectibleTypeCustom.DR_FETUS_NOTE}}} Dr. Fetus Explosive Notes can now drop from enemies`;
+
+export class DrFetusNote extends Item {
+  override setupEID(eid: EIDExtended): void {
+    eid.addCollectible(CollectibleTypeCustom.DR_FETUS_NOTE, DESCRIPTION);
+    Debugger.eid(NAME, "Add description.");
+  }
+}

src/main.ts

@@ -11,12 +11,18 @@ import { GlitchNoteTear } from "./entities/tears/GlitchNoteTear/GlitchNoteTear";
 import { MusicalNoteTear } from "./entities/tears/MusicalNoteTear/MusicalNoteTear";
 import { BrimstoneNoteItem } from "./items/BrimstoneNoteItem/BrimstoneNoteItem";
 import { BrokenVoiceItem } from "./items/BrokenVoiceItem/BrokenVoiceItem";
+import { DrFetusNote } from "./items/DrFetusNote/DrFetusNote";
 import { EncoreItem } from "./items/EncoreItem/EncoreItem";
 import { MicrophoneItem } from "./items/MicrophoneItem/MicrophoneItem";
 import { VirtualIdolItem } from "./items/VirtualIdolItem/VirtualIdolItem";
 import { mod, MOD_NAME } from "./mod";
 
-const PASSIVE_ITEMS = [VirtualIdolItem, EncoreItem, BrimstoneNoteItem] as const;
+const PASSIVE_ITEMS = [
+  VirtualIdolItem,
+  EncoreItem,
+  BrimstoneNoteItem,
+  DrFetusNote,
+] as const;
 
 const ACTIVE_ITEMS = [MicrophoneItem, BrokenVoiceItem] as const;
 
@@ -26,14 +32,16 @@ const PICKUPS = [NotePickup] as const;
 
 const CHARACTERS = [MikuCharacter, MikuTaintedCharacter] as const;
 
+const FEATURES = [
+  ...PASSIVE_ITEMS,
+  ...ACTIVE_ITEMS,
+  ...TEARS,
+  ...PICKUPS,
+  ...CHARACTERS,
+] as const;
+
 export const main = (): void => {
-  initModFeatures(mod, [
-    ...PASSIVE_ITEMS,
-    ...ACTIVE_ITEMS,
-    ...TEARS,
-    ...PICKUPS,
-    ...CHARACTERS,
-  ]);
+  initModFeatures(mod, FEATURES);
 
   NotePickup.register();
 

src/util/costumes.ts

@@ -0,0 +1,29 @@
+import type { CollectibleType } from "isaac-typescript-definitions";
+import {
+  addCollectibleCostume,
+  removeCollectibleCostume,
+} from "isaacscript-common";
+
+/**
+ * Updates collectible costumes based on a mapping of owned collectibles.
+ * - Adds the corresponding costume when the player owns the mapped collectible.
+ * - Removes the costume when the collectible is no longer owned.
+ *
+ * @param player The player whose collectible costumes should be updated.
+ * @param costumes A mapping of collectible IDs to the costume collectible they should apply.
+ */
+export const updateCollectibleCostumes = (
+  player: EntityPlayer,
+  costumes: Partial<Record<CollectibleType, CollectibleType>>,
+): void => {
+  for (const [item, costume] of Object.entries(costumes)) {
+    const collectible = Number(item) as CollectibleType;
+    const costumeCollectible = costume;
+
+    if (player.HasCollectible(collectible)) {
+      addCollectibleCostume(player, costumeCollectible);
+    } else {
+      removeCollectibleCostume(player, costumeCollectible);
+    }
+  }
+};

src/util/debug.ts

@@ -6,7 +6,7 @@ const DEBUG = {
   ITEMS: false,
   TEAR: false,
   PICKUP: false,
-  EID: false,
+  EID: true,
 } as const;
 
 /** Debugging utility functions for the mod. */