import { db } from "../../../../db/index";
import { lessons } from "../../../../db/schema";
import { eq } from "drizzle-orm";
import {
  generateStepTTS,
  generateQuestionTTS,
  generateOptionTTS,
} from "../../../../utils/generateTTS";
import { verifyLicenseKey } from "../../../../utils/license";

export default defineEventHandler(async (event) => {
  const key = getHeader(event, "x-license-key") ?? "";
  if (!verifyLicenseKey(key)) {
    throw createError({ statusCode: 401, message: "Unauthorized" });
  }

  const topicId = getRouterParam(event, "id")!;

  const lesson = await db.query.lessons.findFirst({ where: eq(lessons.topicId, topicId) });
  if (!lesson) throw createError({ statusCode: 404, message: "Lesson not found" });

  const content = JSON.parse(lesson.content);
  const steps: any[] = content.steps ?? [];

  type Task = () => Promise<void>;
  const tasks: Task[] = [];

  for (let si = 0; si < steps.length; si++) {
    const step = steps[si];
    const siCopy = si;

    if (step.type === "concept" || step.type === "example") {
      const text = [step.body, step.callout].filter(Boolean).join(" ");
      if (!text.trim()) continue;

      tasks.push(async () => {
        const r = await generateStepTTS(text, lesson.id, siCopy);
        if (r) { step.audioPath = r.audioPath; step.audioChunks = r.audioChunks; }
      });

    } else if (step.type === "summary") {
      const text = Array.isArray(step.bullets) ? step.bullets.join(". ") : "";
      if (!text.trim()) continue;

      tasks.push(async () => {
        const r = await generateStepTTS(text, lesson.id, siCopy);
        if (r) { step.audioPath = r.audioPath; step.audioChunks = r.audioChunks; }
      });

    } else if (step.type === "question") {
      if (step.body?.trim()) {
        tasks.push(async () => {
          const r = await generateQuestionTTS(step.body, lesson.id, siCopy);
          if (r) { step.questionAudioPath = r.audioPath; step.questionAudioChunks = r.audioChunks; }
        });
      }

      if (Array.isArray(step.options)) {
        step.optionAudioPaths = new Array(step.options.length).fill(null);
        for (let oi = 0; oi < step.options.length; oi++) {
          const optText = step.options[oi];
          const oiCopy = oi;
          if (optText?.trim()) {
            tasks.push(async () => {
              const r = await generateOptionTTS(optText, lesson.id, siCopy, oiCopy);
              if (r) step.optionAudioPaths[oiCopy] = r.audioPath;
            });
          }
        }
      }
    }
  }

  const BATCH = 3;
  for (let i = 0; i < tasks.length; i += BATCH) {
    await Promise.all(tasks.slice(i, i + BATCH).map((fn) => fn()));
  }

  content.steps = steps;
  await db.update(lessons).set({ content: JSON.stringify(content) }).where(eq(lessons.id, lesson.id));

  return { status: "ready" };
});