[feature/44-favorite-category-preference] - 찜 기반 카테고리 성향 분석 기능 추가

src/favorites/controller/favorite.controller.ts

@@ -55,4 +55,14 @@ export class FavoritesController {
     const token = this.getAccessToken(req);
     return this.favoritesService.getFavorites(token);
   }
+
+  // 찜 기반 선호도 분석 조회
+  @Get('preference')
+  @Header('Cache-Control', 'no-store, no-cache, must-revalidate, private')
+  @Header('Pragma', 'no-cache')
+  @Header('Expires', '0')
+  async getMyPreference(@Req() req: AuthRequest) {
+    const token = this.getAccessToken(req);
+    return this.favoritesService.getPreference(token);
+  }
 }

src/favorites/service/favorites.service.ts

@@ -4,6 +4,12 @@ import { Model, Types } from 'mongoose';
 import { UserFavorite, UserFavoriteDocument } from '../schemas/user-favorite.schema';
 import { Token, TokenDocument } from '../../auth/schemas/token.schema';
 import { Menu, MenuDocument } from '../../menus/schemas/menu.schemas';
+import {
+  analyzeCategoryPreference,
+  PreferenceResult,
+} from '../../menus/service/category-preference';
+
+import { MenuCategory } from 'src/menus/enum/menu-category.enum';
 
 @Injectable()
 export class FavoritesService {
@@ -29,6 +35,22 @@ export class FavoritesService {
     return tokenDoc.userId.toString();
   }
 
+  // 사용자 찜한 메뉴 카테고리 성향 분석
+  async getPreference(accessToken: string): Promise<PreferenceResult> {
+    const userId = await this.validateTokenAndGetUserId(accessToken);
+
+    const favorites = await this.userFavoriteModel
+      .find({ userId })
+      .populate<{ menuId: Pick<Menu, 'category'> }>('menuId', 'category')
+      .lean<Array<UserFavorite & { menuId?: Pick<Menu, 'category'> }>>();
+
+    const categories = favorites
+      .map((fav) => fav.menuId?.category)
+      .filter((c): c is MenuCategory => c !== undefined);
+
+    return analyzeCategoryPreference(categories);
+  }
+
   async getFavorites(accessToken: string) {
     const userId = await this.validateTokenAndGetUserId(accessToken);
 

src/menus/service/category-preference.ts

@@ -0,0 +1,125 @@
+export type PreferenceStatus = 'CONFIDENT' | 'WEAK' | 'HINT' | 'EMPTY';
+
+export interface PreferenceResult {
+  status: PreferenceStatus;
+  topCategories: string[];
+  distribution?: Record<string, number>;
+  summary: string;
+}
+
+// 받침 유무 확인
+function hasFinalConsonant(word: string): boolean {
+  if (!word) return false;
+  const code = word.charCodeAt(word.length - 1);
+  // 한글 음절 범위: AC00–D7A3
+  if (code < 0xac00 || code > 0xd7a3) return false;
+  return (code - 0xac00) % 28 !== 0;
+}
+
+// 목적어 조사 (을/를)
+function withObjectParticle(word: string): string {
+  return hasFinalConsonant(word) ? `${word}을` : `${word}를`;
+}
+
+// 접속 조사 (과/와)
+function withAndParticle(word: string): string {
+  return hasFinalConsonant(word) ? `${word}과` : `${word}와`;
+}
+
+// 여러 단어를 접속 조사로 연결
+function joinWithAnd(words: string[]): string {
+  if (words.length === 0) return '';
+  if (words.length === 1) return words[0];
+
+  return words.map((w, i) => (i === words.length - 1 ? w : withAndParticle(w))).join(' ');
+}
+
+function joinWithAndAndObjectParticle(words: string[]): string {
+  if (words.length === 0) return '';
+  if (words.length === 1) return withObjectParticle(words[0]);
+
+  const joined = joinWithAnd(words);
+  const last = words[words.length - 1];
+  const particle = hasFinalConsonant(last) ? '을' : '를';
+
+  return `${joined}${particle}`;
+}
+
+export function analyzeCategoryPreference(categories: string[] = []): PreferenceResult {
+  const validCategories = categories.map((c) => c?.trim()).filter((c): c is string => Boolean(c));
+  const validTotal = validCategories.length;
+
+  if (validTotal === 0) {
+    return {
+      status: 'EMPTY',
+      topCategories: [],
+      summary: '찜한 메뉴가 쌓이면 요즘 취향을 알려드려요.',
+    };
+  }
+
+  const counts = new Map<string, number>();
+  for (const c of validCategories) {
+    counts.set(c, (counts.get(c) || 0) + 1);
+  }
+
+  const sorted = Array.from(counts.entries()).sort((a, b) => b[1] - a[1]);
+  const topCount = sorted[0][1];
+  const topCategories = sorted.filter(([, v]) => v === topCount).map(([k]) => k);
+
+  const status: PreferenceStatus =
+    validTotal === 1 ? 'HINT' : validTotal === 2 ? 'WEAK' : 'CONFIDENT';
+
+  let distribution: Record<string, number> | undefined;
+
+  if (validTotal >= 2) {
+    const raw = sorted.map(([k, v]) => [k, (v / validTotal) * 100] as const);
+
+    const rounded: Record<string, number> = {};
+    let sum = 0;
+
+    for (const [k, v] of raw) {
+      const r = Math.round(v);
+      rounded[k] = r;
+      sum += r;
+    }
+
+    // 반올림 보정
+    const diff = 100 - sum;
+    if (diff !== 0) {
+      const firstKey = raw[0][0];
+      rounded[firstKey] += diff;
+    }
+
+    distribution = Object.fromEntries(sorted.map(([k]) => [k, rounded[k]]));
+  }
+
+  let summary = '';
+
+  if (status === 'HINT') {
+    summary = `현재는 ${withObjectParticle(topCategories[0])} 한 번 찜하셨어요.`;
+  } else if (topCategories.length > 1) {
+    const phrase = joinWithAndAndObjectParticle(topCategories);
+    summary = `현재는 ${phrase} 비슷한 편으로 찜하고 있어요.`;
+  } else {
+    const primary = topCategories[0];
+    const secondCount = sorted[1]?.[1] ?? 0;
+    const diff = topCount - secondCount;
+
+    if (diff === 0) {
+      summary = `현재는 ${withObjectParticle(primary)} 다른 메뉴들과 비슷하게 찜하고 있어요.`;
+    } else if (diff === 1) {
+      summary = `현재는 ${withObjectParticle(primary)} 조금 더 찜하는 편이에요.`;
+    } else {
+      summary = `현재는 ${withObjectParticle(primary)} 상대적으로 더 자주 찜하고 있어요.`;
+    }
+  }
+
+  return {
+    status,
+    topCategories,
+    distribution,
+    summary,
+  };
+}
+
+export default analyzeCategoryPreference;