feat: 支持关卡配置分享

src/modules/share/share.service.ts

@@ -0,0 +1,111 @@
+import {
+  Injectable,
+  NotFoundException,
+  BadRequestException,
+} from '@nestjs/common';
+import { nanoid } from 'nanoid';
+import { ShareConfigRepository } from './repositories/share-config.repository';
+import { ShareParticipantRepository } from './repositories/share-participant.repository';
+import { LevelRepository } from '../wechat-game/repositories/level.repository';
+import { CreateShareDto } from './dto/create-share.dto';
+import {
+  CreateShareResponseDto,
+  JoinShareResponseDto,
+  ShareLevelDto,
+} from './dto/share-response.dto';
+
+@Injectable()
+export class ShareService {
+  constructor(
+    private readonly shareConfigRepository: ShareConfigRepository,
+    private readonly shareParticipantRepository: ShareParticipantRepository,
+    private readonly levelRepository: LevelRepository,
+  ) {}
+
+  async createShare(
+    userId: string,
+    dto: CreateShareDto,
+  ): Promise<CreateShareResponseDto> {
+    const uniqueIds = [...new Set(dto.levelIds)];
+    if (uniqueIds.length !== 6) {
+      throw new BadRequestException('关卡ID不能重复，需要恰好6个不同的关卡');
+    }
+
+    // 单次查询验证所有关卡存在
+    const levels = await this.levelRepository.findByIds(uniqueIds);
+    if (levels.length !== uniqueIds.length) {
+      const foundIds = new Set(levels.map((l) => l.id));
+      const missing = uniqueIds.filter((id) => !foundIds.has(id));
+      throw new NotFoundException(`以下关卡不存在: ${missing.join(', ')}`);
+    }
+
+    // 生成 8 位分享码（碰撞重试）
+    let shareCode: string;
+    let attempts = 0;
+    do {
+      shareCode = nanoid(8);
+      const existing =
+        await this.shareConfigRepository.findByShareCode(shareCode);
+      if (!existing) break;
+      attempts++;
+    } while (attempts < 3);
+
+    if (attempts >= 3) {
+      throw new BadRequestException('生成分享码失败，请重试');
+    }
+
+    const config = await this.shareConfigRepository.create({
+      shareCode,
+      title: dto.title,
+      sharerId: userId,
+      levelIds: dto.levelIds,
+    });
+
+    return {
+      shareCode: config.shareCode,
+      title: config.title,
+      levelCount: config.levelIds.length,
+    };
+  }
+
+  async joinShare(
+    userId: string,
+    code: string,
+  ): Promise<JoinShareResponseDto> {
+    const config = await this.shareConfigRepository.findByShareCode(code);
+    if (!config) {
+      throw new NotFoundException('分享不存在或已过期');
+    }
+
+    if (userId !== config.sharerId) {
+      await this.shareParticipantRepository.addParticipant(config.id, userId);
+    }
+
+    // 单次查询获取所有关卡，再按 levelIds 顺序排列
+    const allLevels = await this.levelRepository.findByIds(config.levelIds);
+    const levelMap = new Map(allLevels.map((l) => [l.id, l]));
+
+    const levels: ShareLevelDto[] = config.levelIds.map((id, index) => {
+      const level = levelMap.get(id);
+      if (!level) {
+        throw new NotFoundException(`关卡 ${id} 不存在`);
+      }
+      return {
+        id: level.id,
+        level: index + 1,
+        imageUrl: level.imageUrl,
+        answer: level.answer,
+        hint1: level.hint1,
+        hint2: level.hint2,
+        hint3: level.hint3,
+        sortOrder: level.sortOrder,
+      };
+    });
+
+    return {
+      shareCode: config.shareCode,
+      title: config.title,
+      levels,
+    };
+  }
+}