main.js

const express = require("express");
const multer = require("multer");
const fs = require("fs");
const path = require("path");
const { v4: uuidv4 } = require("uuid");
const cors = require("cors");

const app = express();
app.use(cors());
app.use(express.json());

const UPLOAD_DIR = path.join(__dirname, "uploads");
if (!fs.existsSync(UPLOAD_DIR)) fs.mkdirSync(UPLOAD_DIR);

app.get("/", (req, res) => {
    res.sendFile(__dirname + '/index.html')
})

// Step 1: Create upload session
app.post("/create-upload", (req, res) => {
    const uploadId = uuidv4();
    const dir = path.join(UPLOAD_DIR, uploadId);
    fs.mkdirSync(dir);
    res.json({ uploadId, chunkSize: 1024 * 1024 }); // 1 MB chunks
});

// Step 2: Upload chunk
const storage = multer.memoryStorage();
const upload = multer({ storage });

app.post("/upload-chunk", upload.single("chunk"), (req, res) => {
    const { uploadid, index } = req.body;
    const chunkDir = path.join(UPLOAD_DIR, uploadid);
    if (!fs.existsSync(chunkDir)) return res.status(400).send("Invalid uploadId");

    const chunkPath = path.join(chunkDir, `chunk_${index}`);
    fs.writeFileSync(chunkPath, req.file.buffer);
    res.json({ status: "ok" });
});

// Step 3: Assemble chunks
app.post("/assemble", (req, res) => {
    const { uploadid, totalChunks, filename } = req.body;
    const chunkDir = path.join(UPLOAD_DIR, uploadid);
    const finalPath = path.join(UPLOAD_DIR, filename);

    const writeStream = fs.createWriteStream(finalPath);
    for (let i = 0; i < totalChunks; i++) {
        const chunkPath = path.join(chunkDir, `chunk_${i}`);
        const data = fs.readFileSync(chunkPath);
        writeStream.write(data);
        fs.unlinkSync(chunkPath);
    }
    writeStream.end();
    fs.rmdirSync(chunkDir);
    res.json({ status: "done", path: finalPath });
});

app.listen(9090, () => console.log("Server running on http://localhost:9090"));