import express from "express";
import multer from "multer";
import mammoth from "mammoth";
import { MODEL_CAPS, MAX_FILE_BYTES } from "../lib/modelCaps.js";

const router = express.Router();
const upload = multer({ storage: multer.memoryStorage(), limits: { fileSize: MAX_FILE_BYTES } });

function extOf(name = "") { return (name.split(".").pop() || "").toLowerCase(); }

async function extractText(file) {
  const ext = extOf(file.originalname);
  if (["txt", "md", "csv", "json", "js", "ts", "py", "html", "css", "java", "c", "cpp"].includes(ext)) {
    return file.buffer.toString("utf8");
  }
  if (ext === "docx") {
    const { value } = await mammoth.extractRawText({ buffer: file.buffer });
    return value;
  }
  if (ext === "pdf") {
    // pdf-parse عبر import ديناميكي (CJS)
    const pdfParse = (await import("pdf-parse")).default;
    const data = await pdfParse(file.buffer);
    return data.text;
  }
  return "";
}

// POST /api/upload  (multipart: file, model)
router.post("/upload", upload.single("file"), async (req, res) => {
  try {
    const model = (req.body.model || "flash").toLowerCase();
    const caps = MODEL_CAPS[model] || MODEL_CAPS.flash;
    const file = req.file;
    if (!file) return res.status(400).json({ error: "no_file" });

    const ext = extOf(file.originalname);
    const isImage = file.mimetype.startsWith("image/");

    // تحقق من دعم النموذج لهذا النوع
    if (isImage) {
      if (!caps.vision || !caps.imageMimes.includes(file.mimetype)) {
        return res.status(415).json({ error: "unsupported", message: `النموذج (${model}) لا يدعم الصور.` });
      }
      const b64 = file.buffer.toString("base64");
      return res.json({
        kind: "image",
        name: file.originalname,
        dataUrl: `data:${file.mimetype};base64,${b64}`,
      });
    }

    if (!caps.docExts.includes(ext)) {
      return res.status(415).json({ error: "unsupported", message: `النموذج (${model}) لا يدعم ملفات .${ext}` });
    }

    let text = await extractText(file);
    if (text.length > 20000) text = text.slice(0, 20000) + "\n...[truncated]";
    return res.json({ kind: "text", name: file.originalname, text });
  } catch (err) {
    console.error("upload error:", err);
    res.status(500).json({ error: "upload_failed", message: String(err?.message || err) });
  }
});

export default router;