feat(be): chatting list (#208)

* feat: throw error for changing host certification by myself

* feat: implements getting chats for infinite scroll

Author: wlgh1553

apps/server/src/chats/chats.controller.ts

@@ -0,0 +1,22 @@
+import { Controller, Get, Param, ParseIntPipe, Query } from '@nestjs/common';
+import { ApiTags } from '@nestjs/swagger';
+
+import { ChatsService } from './chats.service';
+import { GetChatsSwagger } from './swagger/get-chats.swagger';
+
+import { BaseDto } from '@common/base.dto';
+
+@Controller('chats')
+@ApiTags('Chats')
+export class ChatsController {
+  private readonly CHAT_FETCH_LIMIT = 20;
+
+  constructor(private readonly chatsService: ChatsService) {}
+
+  @Get(':chatId?')
+  @GetChatsSwagger()
+  async getChats(@Query() data: BaseDto, @Param('chatId', new ParseIntPipe({ optional: true })) chatId?: number) {
+    const chats = await this.chatsService.getChatsForInfiniteScroll(data.sessionId, this.CHAT_FETCH_LIMIT, chatId);
+    return { chats };
+  }
+}

apps/server/src/chats/chats.module.ts

@@ -1,5 +1,6 @@
 import { Module } from '@nestjs/common';
 
+import { ChatsController } from './chats.controller';
 import { ChatsRepository } from './chats.repository';
 import { ChatsService } from './chats.service';
 
@@ -9,5 +10,6 @@ import { PrismaModule } from '@prisma-alias/prisma.module';
   imports: [PrismaModule],
   providers: [ChatsRepository, ChatsService],
   exports: [ChatsService, ChatsRepository],
+  controllers: [ChatsController],
 })
 export class ChatsModule {}

apps/server/src/chats/chats.service.ts

@@ -2,6 +2,9 @@ import { Injectable } from '@nestjs/common';
 
 import { ChatsRepository } from './chats.repository';
 
+import { DatabaseException } from '@common/exceptions/resource.exception';
+import { PrismaService } from '@prisma-alias/prisma.service';
+
 export interface ChatSaveDto {
   sessionId: string;
   token: string;
@@ -10,11 +13,48 @@ export interface ChatSaveDto {
 
 @Injectable()
 export class ChatsService {
-  constructor(private readonly chatsRepository: ChatsRepository) {}
+  constructor(
+    private readonly chatsRepository: ChatsRepository,
+    private readonly prisma: PrismaService,
+  ) {}
 
   async saveChat(data: ChatSaveDto) {
     const chat = await this.chatsRepository.save(data);
     const { chattingId, createUserTokenEntity, body: content } = chat;
     return { chattingId, nickname: createUserTokenEntity?.user?.nickname || '익명', content };
   }
+
+  async getChatsForInfiniteScroll(sessionId: string, count: number, chatId?: number) {
+    try {
+      const chats = await this.prisma.chatting.findMany({
+        where: {
+          sessionId,
+          ...(chatId && { chattingId: { lt: chatId } }),
+        },
+        include: {
+          createUserTokenEntity: {
+            include: {
+              user: true,
+            },
+          },
+        },
+        orderBy: {
+          chattingId: 'desc',
+        },
+        take: count,
+      });
+      return chats.map((x) => {
+        const { createUserTokenEntity, chattingId, body: content } = x;
+        const { user } = createUserTokenEntity;
+        const nickname = user?.nickname || '익명';
+        return {
+          chattingId,
+          nickname,
+          content,
+        };
+      });
+    } catch (error) {
+      throw DatabaseException.read('chatting');
+    }
+  }
 }

apps/server/src/chats/swagger/get-chats.swagger.ts

@@ -0,0 +1,84 @@
+import { applyDecorators } from '@nestjs/common';
+import { ApiOperation, ApiParam, ApiQuery, ApiResponse } from '@nestjs/swagger';
+
+export const GetChatsSwagger = () =>
+  applyDecorators(
+    ApiOperation({
+      summary: 'Chatting list 조회 API',
+      description: `
+채팅 목록을 가져오는 API입니다. Infinite scroll 구현을 위한 페이지네이션을 지원합니다.
+
+- chatId 파라미터가 없는 경우: 최신 채팅 20개를 반환
+- chatId 파라미터가 있는 경우: 해당 chatId보다 이전의 채팅 20개를 반환 (chatId보다 작은 ID를 가진 채팅)`,
+    }),
+    ApiParam({
+      name: 'chatId',
+      required: false,
+      description: '기준이 되는 채팅 ID. 이 ID보다 이전의 채팅들을 조회합니다.',
+      type: 'number',
+      example: 3592,
+    }),
+    ApiQuery({
+      name: 'sessionId',
+      required: true,
+      description: '채팅 세션 ID',
+      type: 'string',
+    }),
+    ApiResponse({
+      status: 200,
+      description: '채팅 목록 조회 성공',
+      schema: {
+        example: {
+          chats: [
+            {
+              chattingId: 3593,
+              nickname: '익명',
+              content: 'gggg',
+            },
+            {
+              chattingId: 3592,
+              nickname: 'jiho',
+              content: 'asdfdasd',
+            },
+            {
+              chattingId: 3591,
+              nickname: '익명',
+              content: 'd',
+            },
+          ],
+        },
+        properties: {
+          chats: {
+            type: 'array',
+            description: '채팅 목록 (최대 20개)',
+            items: {
+              type: 'object',
+              properties: {
+                chattingId: {
+                  type: 'number',
+                  description: '채팅 고유 ID (내림차순 정렬)',
+                },
+                nickname: {
+                  type: 'string',
+                  description: '사용자 닉네임',
+                },
+                content: {
+                  type: 'string',
+                  description: '채팅 내용',
+                },
+              },
+            },
+          },
+        },
+      },
+    }),
+    ApiResponse({
+      status: 400,
+      description: '잘못된 요청 (chatId가 숫자가 아닌 경우)',
+      schema: {
+        example: {
+          messages: ['Validation failed (numeric string is expected)'],
+        },
+      },
+    }),
+  );

apps/server/src/questions/questions.service.ts

@@ -39,10 +39,13 @@ export class QuestionsService {
 
   async getQuestionsBySession(data: GetQuestionDto) {
     const { sessionId, token } = data;
-    const questions = await this.questionRepository.findQuestionsWithDetails(sessionId);
-    const session = await this.sessionRepository.findById(sessionId);
+    const [questions, session, sessionHostTokens] = await Promise.all([
+      this.questionRepository.findQuestionsWithDetails(sessionId),
+      this.sessionRepository.findById(sessionId),
+      this.sessionAuthRepository.findHostTokensInSession(sessionId),
+    ]);
+
     const expired = session.expiredAt < new Date();
-    const sessionHostTokens = await this.sessionAuthRepository.findHostTokensInSession(sessionId);
     const isHost = sessionHostTokens.some(({ token: hostToken }) => hostToken === token);
     const mapLikesAndOwnership = <
       T extends {

apps/server/src/sessions-auth/sessions-auth.service.ts

@@ -1,4 +1,4 @@
-import { ForbiddenException, Injectable, NotFoundException } from '@nestjs/common';
+import { BadRequestException, ForbiddenException, Injectable, NotFoundException } from '@nestjs/common';
 
 import { SessionAuthDto } from './dto/session-auth.dto';
 import { UpdateHostDto } from './dto/update-host.dto';
@@ -39,9 +39,15 @@ export class SessionsAuthService {
     if (!(await this.validateSuperHost(sessionId, token)))
       throw new ForbiddenException('세션 생성자만이 호스트 권한을 부여 할 수 있습니다.');
     const targetToken = await this.sessionsAuthRepository.findTokenByUserId(userId, sessionId);
+
     if (!targetToken) {
       throw new NotFoundException('존재하지 않는 userId입니다.');
     }
+
+    if (token === targetToken) {
+      throw new BadRequestException('자신의 권한을 변경하려는 요청은 허용되지 않습니다.');
+    }
+
     const { user, isHost: updatedIsHost } = await this.sessionsAuthRepository.updateIsHost(targetToken, isHost);
     return { userId: user.userId, nickname: user.nickname, isHost: updatedIsHost };
   }