Add reward reveal, pick, and skip functions to run module

src/run.js

@@ -13,6 +13,27 @@ export function createRunState(character) {
   };
 }
 
+export function revealRewards(run) {
+  const count = Math.min(3, run.cardRewardsDeck.length);
+  const revealed = run.cardRewardsDeck.slice(0, count);
+  const cardRewardsDeck = run.cardRewardsDeck.slice(count);
+  return { revealed, run: { ...run, cardRewardsDeck } };
+}
+
+export function pickReward(run, revealed, index) {
+  return {
+    ...run,
+    deck: [...run.deck, revealed[index]],
+  };
+}
+
+export function skipRewards(run, revealed) {
+  return {
+    ...run,
+    cardRewardsDeck: shuffle([...run.cardRewardsDeck, ...revealed]),
+  };
+}
+
 function buildRewardsDeck(character) {
   const ids = [];
   for (const card of getAllCards()) {

src/run.test.js

@@ -1,7 +1,12 @@
 import { beforeAll, describe, expect, test } from "bun:test";
 import { getAllCards, initCards } from "./cards.js";
 import { initEnemies } from "./enemies.js";
-import { createRunState } from "./run.js";
+import {
+  createRunState,
+  pickReward,
+  revealRewards,
+  skipRewards,
+} from "./run.js";
 
 beforeAll(async () => {
   await Promise.all([initCards(), initEnemies()]);
@@ -49,3 +54,58 @@ describe("createRunState", () => {
     expect(allSorted).toBe(false);
   });
 });
+
+describe("rewards", () => {
+  test("revealRewards removes 3 from rewards deck and returns them", () => {
+    const run = createRunState("ironclad");
+    const originalLen = run.cardRewardsDeck.length;
+    const { revealed, run: updated } = revealRewards(run);
+    expect(revealed).toHaveLength(3);
+    expect(updated.cardRewardsDeck).toHaveLength(originalLen - 3);
+  });
+
+  test("revealRewards handles deck with fewer than 3 cards", () => {
+    const run = createRunState("ironclad");
+    const modified = { ...run, cardRewardsDeck: ["card_a", "card_b"] };
+    const { revealed, run: updated } = revealRewards(modified);
+    expect(revealed).toHaveLength(2);
+    expect(updated.cardRewardsDeck).toHaveLength(0);
+  });
+
+  test("revealRewards with empty deck returns empty revealed", () => {
+    const run = { ...createRunState("ironclad"), cardRewardsDeck: [] };
+    const { revealed, run: updated } = revealRewards(run);
+    expect(revealed).toHaveLength(0);
+    expect(updated.cardRewardsDeck).toHaveLength(0);
+  });
+
+  test("pickReward adds picked card to deck", () => {
+    const run = createRunState("ironclad");
+    const originalDeckLen = run.deck.length;
+    const { revealed, run: afterReveal } = revealRewards(run);
+    const updated = pickReward(afterReveal, revealed, 0);
+    expect(updated.deck).toHaveLength(originalDeckLen + 1);
+    expect(updated.deck).toContain(revealed[0]);
+  });
+
+  test("pickReward discards unpicked cards", () => {
+    const run = createRunState("ironclad");
+    const { revealed, run: afterReveal } = revealRewards(run);
+    const rewardsDeckLen = afterReveal.cardRewardsDeck.length;
+    const updated = pickReward(afterReveal, revealed, 1);
+    // unpicked cards are gone, not returned to rewards deck
+    expect(updated.cardRewardsDeck).toHaveLength(rewardsDeckLen);
+    expect(updated.deck).not.toContain(revealed[0]);
+    expect(updated.deck).toContain(revealed[1]);
+    expect(updated.deck).not.toContain(revealed[2]);
+  });
+
+  test("skipRewards reshuffles all 3 back into rewards deck", () => {
+    const run = createRunState("ironclad");
+    const { revealed, run: afterReveal } = revealRewards(run);
+    const rewardsDeckLen = afterReveal.cardRewardsDeck.length;
+    const updated = skipRewards(afterReveal, revealed);
+    expect(updated.cardRewardsDeck).toHaveLength(rewardsDeckLen + 3);
+    expect(updated.deck).toHaveLength(run.deck.length); // deck unchanged
+  });
+});