리팩토링: 코드 최적화

AGENTS.md

@@ -52,6 +52,8 @@ lib/
   redis.ts                  # Redis Client 싱글턴
 store/
   gameStore.ts              # Zustand 전역 게임 상태
+types/
+  *.d.ts                    # 타입 선언이 없는 서드파티 모듈 보강
 prisma/
   schema.prisma             # MariaDB 모델 정의
 .gitea/workflows/deploy.yml # CI/CD 워크플로우
@@ -76,6 +78,14 @@ prisma/
 
 - 전역 게임 상태(점수, 진행도, 선택한 모드·유형)는 `store/gameStore.ts`의 Zustand store로 관리한다.
 - 컴포넌트 내부의 로컬 상태는 `useState`를 사용한다.
+- Zustand selector 안에서 매번 새 객체·배열을 반환하는 함수(`score()` 등)를 호출하지 않는다. 필요한 파생값은 구독한 state를 기준으로 컴포넌트 내부에서 계산하거나 안정적인 selector로 분리한다.
+- store에는 세션 원본 상태와 상태 변경 action을 우선 두고, 렌더링 전용 파생값은 컴포넌트 또는 별도 순수 유틸에서 계산한다.
+
+### 컴포넌트 배치
+
+- 게임 화면에서 재사용되는 입력, 피드백, 점수 요약 UI는 `components/game/` 하위에 둔다.
+- 수식 렌더링 전용 컴포넌트는 `components/math/` 하위에 둔다.
+- 라우트별 조립 컴포넌트(`PlayClient` 등)는 해당 `app/` 라우트 폴더에 둘 수 있다.
 
 ### API / 백엔드
 
@@ -90,6 +100,7 @@ prisma/
 - 문제는 AI 호출 없이 알고리즘으로 생성한다. 외부 AI API를 문제 생성에 사용하지 않는다.
 - 미지수의 계수는 항상 정수이어야 한다.
 - 생성 파라미터: 숫자 자릿수, 괄호 깊이(`()` / `(){}` / `(){}[]`), 괄호 개수(1–3), 미지수(없음/x/x,y/x,y,z).
+- 문제 세션에서 중복을 방지할 때는 랜덤 id가 아니라 수학적 문제 조건을 나타내는 안정적인 key를 기준으로 한다.
 
 ---
 

app/(game)/play/PlayClient.tsx

@@ -1,16 +1,20 @@
 "use client";
 
-import Link from "next/link";
+import { useEffect, useState } from "react";
-import { FormEvent, useEffect, useState } from "react";
+import type { FormEvent } from "react";
 
+import AnswerForm from "@/components/game/AnswerForm";
+import FeedbackPanel from "@/components/game/FeedbackPanel";
+import ScoreSummary from "@/components/game/ScoreSummary";
 import KatexRenderer from "@/components/math/KatexRenderer";
 import { useGameStore } from "@/store/gameStore";
 
 function parseAnswer(value: string) {
-  if (value.trim() === "") return null;
+  const trimmed = value.trim();
 
-  const parsed = Number.parseInt(value, 10);
+  if (!/^-?\d+$/.test(trimmed)) return null;
-  return Number.isNaN(parsed) ? null : parsed;
+
+  return Number(trimmed);
 }
 
 export default function PlayClient() {
@@ -76,37 +80,11 @@ export default function PlayClient() {
 
   if (isComplete) {
     return (
-      <main className="flex min-h-screen items-center bg-slate-50 px-6 py-12 text-slate-950">
+      <ScoreSummary
-        <section className="mx-auto flex w-full max-w-3xl flex-col gap-8">
+        correctCount={correctCount}
-          <div className="space-y-3">
+        totalCount={totalCount}
-            <p className="text-sm font-semibold text-emerald-700">
+        onRestart={resetSession}
-              괄호 음수 분배
+      />
-            </p>
-            <h1 className="text-4xl font-bold tracking-normal sm:text-5xl">
-              풀이 결과
-            </h1>
-            <p className="text-xl font-semibold text-slate-800">
-              {correctCount} / {totalCount} 정답
-            </p>
-          </div>
-
-          <div className="flex flex-wrap gap-3">
-            <button
-              type="button"
-              onClick={resetSession}
-              className="inline-flex h-12 items-center justify-center rounded-md bg-emerald-700 px-6 text-base font-semibold text-white transition hover:bg-emerald-800 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2"
-            >
-              다시 시작
-            </button>
-            <Link
-              href="/"
-              className="inline-flex h-12 items-center justify-center rounded-md border border-slate-300 px-6 text-base font-semibold text-slate-800 transition hover:bg-white focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2"
-            >
-              처음으로
-            </Link>
-          </div>
-        </section>
-      </main>
     );
   }
 
@@ -151,78 +129,23 @@ export default function PlayClient() {
           </div>
         </div>
 
-        <form
+        <AnswerForm
+          answerA={answerA}
+          answerB={answerB}
+          disabled={submitted}
+          error={inputError}
+          onAnswerAChange={setAnswerA}
+          onAnswerBChange={setAnswerB}
           onSubmit={handleSubmit}
-          className="rounded-md bg-white p-6 shadow-sm ring-1 ring-slate-200 sm:p-8"
+        />
-        >
-          <div className="grid gap-4 sm:grid-cols-2">
-            <label className="flex flex-col gap-2 text-sm font-semibold text-slate-700">
-              첫째 항
-              <input
-                value={answerA}
-                onChange={(event) => setAnswerA(event.target.value)}
-                disabled={submitted}
-                inputMode="numeric"
-                className="h-12 rounded-md border border-slate-300 px-4 text-lg font-semibold text-slate-950 outline-none transition focus:border-emerald-600 focus:ring-2 focus:ring-emerald-200 disabled:bg-slate-100"
-              />
-            </label>
-            <label className="flex flex-col gap-2 text-sm font-semibold text-slate-700">
-              둘째 항
-              <input
-                value={answerB}
-                onChange={(event) => setAnswerB(event.target.value)}
-                disabled={submitted}
-                inputMode="numeric"
-                className="h-12 rounded-md border border-slate-300 px-4 text-lg font-semibold text-slate-950 outline-none transition focus:border-emerald-600 focus:ring-2 focus:ring-emerald-200 disabled:bg-slate-100"
-              />
-            </label>
-          </div>
-
-          {inputError ? (
-            <p className="mt-3 text-sm font-semibold text-red-700">
-              {inputError}
-            </p>
-          ) : null}
-
-          <div className="mt-6 flex flex-wrap gap-3">
-            <button
-              type="submit"
-              disabled={submitted}
-              className="inline-flex h-12 items-center justify-center rounded-md bg-emerald-700 px-6 text-base font-semibold text-white transition hover:bg-emerald-800 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2 disabled:cursor-not-allowed disabled:bg-slate-300"
-            >
-              제출
-            </button>
-            <Link
-              href="/"
-              className="inline-flex h-12 items-center justify-center rounded-md border border-slate-300 px-6 text-base font-semibold text-slate-800 transition hover:bg-slate-50 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2"
-            >
-              처음으로
-            </Link>
-          </div>
-        </form>
 
         {currentResult ? (
-          <div
+          <FeedbackPanel
-            className={`rounded-md p-6 shadow-sm ring-1 ${
+            result={currentResult}
-              currentResult.correct
+            answerLatex={currentProblem.latexAfter}
-                ? "bg-emerald-50 text-emerald-950 ring-emerald-200"
+            isLastProblem={isLastProblem}
-                : "bg-red-50 text-red-950 ring-red-200"
+            onNext={nextProblem}
-            }`}
+          />
-          >
-            <p className="text-lg font-bold">
-              {currentResult.correct ? "정답입니다." : "오답입니다."}
-            </p>
-            <div className="mt-3 text-xl font-semibold">
-              <KatexRenderer latex={currentProblem.latexAfter} />
-            </div>
-            <button
-              type="button"
-              onClick={nextProblem}
-              className="mt-5 inline-flex h-11 items-center justify-center rounded-md bg-slate-950 px-5 text-base font-semibold text-white transition hover:bg-slate-800 focus:outline-none focus:ring-2 focus:ring-slate-500 focus:ring-offset-2"
-            >
-              {isLastProblem ? "결과 보기" : "다음 문제"}
-            </button>
-          </div>
         ) : null}
       </section>
     </main>

components/game/AnswerForm.tsx

@@ -0,0 +1,67 @@
+"use client";
+
+import type { FormEvent } from "react";
+
+interface AnswerFormProps {
+  answerA: string;
+  answerB: string;
+  disabled: boolean;
+  error: string;
+  onAnswerAChange: (value: string) => void;
+  onAnswerBChange: (value: string) => void;
+  onSubmit: (event: FormEvent<HTMLFormElement>) => void;
+}
+
+export default function AnswerForm({
+  answerA,
+  answerB,
+  disabled,
+  error,
+  onAnswerAChange,
+  onAnswerBChange,
+  onSubmit,
+}: AnswerFormProps) {
+  return (
+    <form
+      onSubmit={onSubmit}
+      className="rounded-md bg-white p-6 shadow-sm ring-1 ring-slate-200 sm:p-8"
+    >
+      <div className="grid gap-4 sm:grid-cols-2">
+        <label className="flex flex-col gap-2 text-sm font-semibold text-slate-700">
+          첫째 항
+          <input
+            value={answerA}
+            onChange={(event) => onAnswerAChange(event.target.value)}
+            disabled={disabled}
+            inputMode="numeric"
+            className="h-12 rounded-md border border-slate-300 px-4 text-lg font-semibold text-slate-950 outline-none transition focus:border-emerald-600 focus:ring-2 focus:ring-emerald-200 disabled:bg-slate-100"
+          />
+        </label>
+        <label className="flex flex-col gap-2 text-sm font-semibold text-slate-700">
+          둘째 항
+          <input
+            value={answerB}
+            onChange={(event) => onAnswerBChange(event.target.value)}
+            disabled={disabled}
+            inputMode="numeric"
+            className="h-12 rounded-md border border-slate-300 px-4 text-lg font-semibold text-slate-950 outline-none transition focus:border-emerald-600 focus:ring-2 focus:ring-emerald-200 disabled:bg-slate-100"
+          />
+        </label>
+      </div>
+
+      {error ? (
+        <p className="mt-3 text-sm font-semibold text-red-700">{error}</p>
+      ) : null}
+
+      <div className="mt-6 flex flex-wrap gap-3">
+        <button
+          type="submit"
+          disabled={disabled}
+          className="inline-flex h-12 items-center justify-center rounded-md bg-emerald-700 px-6 text-base font-semibold text-white transition hover:bg-emerald-800 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2 disabled:cursor-not-allowed disabled:bg-slate-300"
+        >
+          제출
+        </button>
+      </div>
+    </form>
+  );
+}

components/game/FeedbackPanel.tsx

@@ -0,0 +1,42 @@
+"use client";
+
+import KatexRenderer from "@/components/math/KatexRenderer";
+import type { GradeResult } from "@/lib/engine/types";
+
+interface FeedbackPanelProps {
+  result: GradeResult;
+  answerLatex: string;
+  isLastProblem: boolean;
+  onNext: () => void;
+}
+
+export default function FeedbackPanel({
+  result,
+  answerLatex,
+  isLastProblem,
+  onNext,
+}: FeedbackPanelProps) {
+  return (
+    <div
+      className={`rounded-md p-6 shadow-sm ring-1 ${
+        result.correct
+          ? "bg-emerald-50 text-emerald-950 ring-emerald-200"
+          : "bg-red-50 text-red-950 ring-red-200"
+      }`}
+    >
+      <p className="text-lg font-bold">
+        {result.correct ? "정답입니다." : "오답입니다."}
+      </p>
+      <div className="mt-3 text-xl font-semibold">
+        <KatexRenderer latex={answerLatex} />
+      </div>
+      <button
+        type="button"
+        onClick={onNext}
+        className="mt-5 inline-flex h-11 items-center justify-center rounded-md bg-slate-950 px-5 text-base font-semibold text-white transition hover:bg-slate-800 focus:outline-none focus:ring-2 focus:ring-slate-500 focus:ring-offset-2"
+      >
+        {isLastProblem ? "결과 보기" : "다음 문제"}
+      </button>
+    </div>
+  );
+}

components/game/ScoreSummary.tsx

@@ -0,0 +1,49 @@
+"use client";
+
+import Link from "next/link";
+
+interface ScoreSummaryProps {
+  correctCount: number;
+  totalCount: number;
+  onRestart: () => void;
+}
+
+export default function ScoreSummary({
+  correctCount,
+  totalCount,
+  onRestart,
+}: ScoreSummaryProps) {
+  return (
+    <main className="flex min-h-screen items-center bg-slate-50 px-6 py-12 text-slate-950">
+      <section className="mx-auto flex w-full max-w-3xl flex-col gap-8">
+        <div className="space-y-3">
+          <p className="text-sm font-semibold text-emerald-700">
+            괄호 음수 분배
+          </p>
+          <h1 className="text-4xl font-bold tracking-normal sm:text-5xl">
+            풀이 결과
+          </h1>
+          <p className="text-xl font-semibold text-slate-800">
+            {correctCount} / {totalCount} 정답
+          </p>
+        </div>
+
+        <div className="flex flex-wrap gap-3">
+          <button
+            type="button"
+            onClick={onRestart}
+            className="inline-flex h-12 items-center justify-center rounded-md bg-emerald-700 px-6 text-base font-semibold text-white transition hover:bg-emerald-800 focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2"
+          >
+            다시 시작
+          </button>
+          <Link
+            href="/"
+            className="inline-flex h-12 items-center justify-center rounded-md border border-slate-300 px-6 text-base font-semibold text-slate-800 transition hover:bg-white focus:outline-none focus:ring-2 focus:ring-emerald-500 focus:ring-offset-2"
+          >
+            처음으로
+          </Link>
+        </div>
+      </section>
+    </main>
+  );
+}

components/math/KatexRenderer.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { BlockMath, InlineMath } from "react-katex";
+import { renderToString } from "katex";
 
 interface KatexRendererProps {
   latex: string;
@@ -11,5 +11,11 @@ export default function KatexRenderer({
   latex,
   displayMode = false,
 }: KatexRendererProps) {
-  return displayMode ? <BlockMath math={latex} /> : <InlineMath math={latex} />;
+  const html = renderToString(latex, {
+    displayMode,
+    throwOnError: false,
+  });
+  const Tag = displayMode ? "div" : "span";
+
+  return <Tag dangerouslySetInnerHTML={{ __html: html }} />;
 }

lib/engine/parenthesis-sign.ts

@@ -25,7 +25,12 @@ function formatLatexTermPair(first: number, second: number) {
   return `${first} ${operator} ${Math.abs(second)}`;
 }
 
-function createProblem({ multiplier, a, operator, b }: ProblemSeed) {
+function createProblem({
+  multiplier,
+  a,
+  operator,
+  b,
+}: ProblemSeed): ParenthesisSignProblem {
   const distributedA = multiplier * a;
   const distributedB = operator === "-" ? multiplier * -b : multiplier * b;
   const key = `${multiplier}:${a}:${operator}:${b}`;
@@ -65,6 +70,8 @@ function createAllProblemSeeds() {
   return seeds;
 }
 
+const ALL_PROBLEM_SEEDS = createAllProblemSeeds();
+
 function shuffle<T>(items: T[]) {
   const shuffled = [...items];
 
@@ -103,7 +110,7 @@ export function generateSession(count = 10): ParenthesisSignProblem[] {
     throw new Error(`count cannot exceed ${MAX_PROBLEM_COUNT}.`);
   }
 
-  return shuffle(createAllProblemSeeds()).slice(0, count).map(createProblem);
+  return shuffle(ALL_PROBLEM_SEEDS).slice(0, count).map(createProblem);
 }
 
 export function gradeAnswer(

package.json

@@ -14,7 +14,6 @@
     "next": "14.2.35",
     "react": "^18",
     "react-dom": "^18",
-    "react-katex": "^3.1.0",
     "zustand": "^5.0.13"
   },
   "devDependencies": {

pnpm-lock.yaml

@@ -20,9 +20,6 @@ importers:
       react-dom:
         specifier: ^18
         version: 18.3.1(react@18.3.1)
-      react-katex:
-        specifier: ^3.1.0
-        version: 3.1.0(prop-types@15.8.1)(react@18.3.1)
       zustand:
         specifier: ^5.0.13
         version: 5.0.13(@types/react@18.3.29)(react@18.3.1)
@@ -1339,10 +1336,6 @@ packages:
     resolution: {integrity: sha512-ZZow9HBI5O6EPgSJLUb8n2NKgmVWTwCvHGwFuJlMjvLFqlGG6pjirPhtdsseaLZjSibD8eegzmYpUZwoIlj2cQ==}
     engines: {node: '>=4.0'}
 
-  katex@0.16.47:
-    resolution: {integrity: sha512-Eeo8Ys1doU1z+x8AZsPpQu+p/QcZBI5PeOo7QGQdy2x2m0MU/hYagBbGOmXwr5KVbEfVuWv9LpnQWeehogurjg==}
-    hasBin: true
-
   katex@0.17.0:
     resolution: {integrity: sha512-Vdw0ATsQ9V+LuegM/BTwQqV/6cTl5lbGcIrU+BCgLxyf6bo38ybOr372tuSIxir3CN720flu1meYR6XzNMwQnw==}
     hasBin: true
@@ -1714,12 +1707,6 @@ packages:
   react-is@16.13.1:
     resolution: {integrity: sha512-24e6ynE2H+OKt4kqsOvNd8kBpV65zoxbA4BVsEOB3ARVWQki/DHzaUoC5KuON/BiccDaCCTZBuOcfZs70kR8bQ==}
 
-  react-katex@3.1.0:
-    resolution: {integrity: sha512-At9uLOkC75gwn2N+ZXc5HD8TlATsB+3Hkp9OGs6uA8tM3dwZ3Wljn74Bk3JyHFPgSnesY/EMrIAB1WJwqZqejA==}
-    peerDependencies:
-      prop-types: ^15.8.1
-      react: '>=15.3.2 <20'
-
   react@18.3.1:
     resolution: {integrity: sha512-wS+hAgJShR0KhEvPJArfuPVN1+Hz1t0Y6n5jLrGQbkb4urgPE/0Rve+1kMB1v/oWgHgm4WIcV+i7F2pTVj+2iQ==}
     engines: {node: '>=0.10.0'}
@@ -3552,10 +3539,6 @@ snapshots:
       object.assign: 4.1.7
       object.values: 1.2.1
 
-  katex@0.16.47:
-    dependencies:
-      commander: 8.3.0
-
   katex@0.17.0:
     dependencies:
       commander: 8.3.0
@@ -3884,12 +3867,6 @@ snapshots:
 
   react-is@16.13.1: {}
 
-  react-katex@3.1.0(prop-types@15.8.1)(react@18.3.1):
-    dependencies:
-      katex: 0.16.47
-      prop-types: 15.8.1
-      react: 18.3.1
-
   react@18.3.1:
     dependencies:
       loose-envify: 1.4.0

store/gameStore.ts

@@ -10,7 +10,7 @@ import type {
   UserAnswer,
 } from "@/lib/engine/types";
 
-interface GameSession {
+export interface GameSession {
   problems: ParenthesisSignProblem[];
   currentIndex: number;
   results: (GradeResult | null)[];
@@ -22,10 +22,6 @@ interface GameState {
   submitAnswer: (answer: UserAnswer) => void;
   nextProblem: () => void;
   resetSession: () => void;
-  currentProblem: () => ParenthesisSignProblem | null;
-  currentResult: () => GradeResult | null;
-  isComplete: () => boolean;
-  score: () => { correct: number; total: number };
 }
 
 const DEFAULT_SESSION_COUNT = 10;
@@ -79,31 +75,4 @@ export const useGameStore = create<GameState>((set, get) => ({
   resetSession: () => {
     set({ session: createSession() });
   },
-  currentProblem: () => {
-    const { session } = get();
-
-    if (!session) return null;
-    return session.problems[session.currentIndex] ?? null;
-  },
-  currentResult: () => {
-    const { session } = get();
-
-    if (!session) return null;
-    return session.results[session.currentIndex] ?? null;
-  },
-  isComplete: () => {
-    const { session } = get();
-
-    return Boolean(session && session.currentIndex >= session.problems.length);
-  },
-  score: () => {
-    const { session } = get();
-
-    if (!session) return { correct: 0, total: 0 };
-
-    return {
-      correct: session.results.filter((result) => result?.correct).length,
-      total: session.problems.length,
-    };
-  },
 }));

types/react-katex.d.ts

@@ -1,10 +0,0 @@
-declare module "react-katex" {
-  import type { ComponentType } from "react";
-
-  interface MathComponentProps {
-    math: string;
-  }
-
-  export const InlineMath: ComponentType<MathComponentProps>;
-  export const BlockMath: ComponentType<MathComponentProps>;
-}