import { db } from "../../db/index";
import { courses, topics } from "../../db/schema";
import { inArray } from "drizzle-orm";

export default defineEventHandler(async () => {
  const allCourses = await db.query.courses.findMany({
    orderBy: (c, { desc }) => desc(c.createdAt),
  });

  if (allCourses.length === 0) return [];

  const courseIds = allCourses.map((c) => c.id);

  const allTopics = await db.query.topics.findMany({ where: inArray(topics.courseId, courseIds) });

  const topicsByCourse = new Map<string, string[]>();
  for (const t of allTopics) {
    const arr = topicsByCourse.get(t.courseId) ?? [];
    arr.push(t.id);
    topicsByCourse.set(t.courseId, arr);
  }

  return allCourses.map((course) => ({
    ...course,
    topicCount: topicsByCourse.get(course.id)?.length ?? 0,
    topicIds: topicsByCourse.get(course.id) ?? [],
  }));
});