import { db } from "../../../db/index";
import { topics, lessons } from "../../../db/schema";
import { eq, and } from "drizzle-orm";
import { generateLesson } from "../../../utils/generateLesson";

export default defineEventHandler(async (event) => {
  const id = getRouterParam(event, "id")!;

  const topic = await db.query.topics.findFirst({ where: eq(topics.id, id) });
  if (!topic) throw createError({ statusCode: 404, message: "Topic not found" });

  if (topic.status === "ready") {
    return { status: "ready" };
  }

  if (topic.status === "generating") {
    return { status: "generating" };
  }

  try {
    await generateLesson(id);

    // pre-generate the next topic silently
    const currentTopic = await db.query.topics.findFirst({ where: eq(topics.id, id) });
    const nextTopic = await db.query.topics.findFirst({
      where: and(
        eq(topics.courseId, currentTopic!.courseId),
        eq(topics.order, currentTopic!.order + 1),
        eq(topics.status, "pending")
      )
    });
    if (nextTopic) generateLesson(nextTopic.id).catch((e) => console.error("[pre-gen]", e));

    return { status: "ready" };
  } catch (err: any) {
    console.error(`[generate.post] topic ${id} failed: ${err?.message ?? err}`);
    return { status: "error" };
  }
});