feat: 重构关卡接口

src/modules/level/next-level.helper.ts

@@ -0,0 +1,35 @@
+import { Level } from '../wechat-game/entities/level.entity';
+import { NextLevelDto } from './dto/next-level.dto';
+import { pickLevelImageFields } from '../wechat-game/level-fields.helper';
+
+/**
+ * Convert a Level entity to a NextLevelDto for client consumption.
+ */
+export function toNextLevelDto(level: Level): NextLevelDto {
+  return {
+    id: level.id,
+    level: level.sortOrder,
+    ...pickLevelImageFields(level),
+    answer: level.answer,
+    timeLimit: level.timeLimit,
+  };
+}
+
+/**
+ * Given all levels (sorted by sortOrder ASC) and the set of completed level IDs,
+ * return the next `count` uncompleted levels.
+ */
+export function findNextUncompletedLevels(
+  allLevelsOrdered: Level[],
+  completedLevelIds: Set<string>,
+  count: number,
+): Level[] {
+  const result: Level[] = [];
+  for (const level of allLevelsOrdered) {
+    if (!completedLevelIds.has(level.id)) {
+      result.push(level);
+      if (result.length >= count) break;
+    }
+  }
+  return result;
+}