import { db } from "../../../db/index";
import { uploads, courses } from "../../../db/schema";
import { eq } from "drizzle-orm";
import { randomUUID } from "crypto";
import { writeFile, mkdir } from "fs/promises";
import { resolve } from "path";
import { parsePdf } from "../../../utils/parsePdf";
import { detectUploadType } from "../../../utils/detectUploadType";

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

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

  const formData = await readFormData(event);
  const file = formData.get("file") as File | null;

  if (!file) {
    throw createError({ statusCode: 400, message: "file is required" });
  }

  const uploadDir = resolve(process.cwd(), "uploads", id);
  await mkdir(uploadDir, { recursive: true });

  const uploadId = randomUUID();
  const safeFilename = `${uploadId}-${file.name.replace(/[^a-zA-Z0-9._-]/g, "_")}`;
  const storedPath = resolve(uploadDir, safeFilename);

  const buffer = Buffer.from(await file.arrayBuffer());
  await writeFile(storedPath, buffer);

  let extractedText: string | null = null;
  try {
    extractedText = await parsePdf(buffer);
  } catch {
    // non-fatal
  }

  const detectedType = await detectUploadType(file.name, extractedText ?? "");

  await db.insert(uploads).values({
    id: uploadId,
    courseId: id,
    filename: file.name,
    type: detectedType,
    storedPath,
    extractedText,
  });

  return { uploadId, filename: file.name, type: detectedType };
});