import { createRequire } from 'module';
import os from 'os';
import { fileURLToPath } from "url";

const require = createRequire(import.meta.url);
const express = require("express");
const fs = require("fs");
const path = require("path");
const crypto = require("crypto");
const bodyParser = require("body-parser");
const app = express();
const PORT = 7860;
const fss = fs.promises;
import { fileTypeFromBuffer } from "file-type";
let __dirname = path.dirname(fileURLToPath(import.meta.url));

app.use(bodyParser.json());

const SECRET = "Vornshade";
const FILE_DIR = path.join(__dirname, "files");

const FILE_MAP = {
  "L001": "L_ENTRY_001_SoftSilence.zip",
  "L018": "L_ENTRY_018_WhiteTears.zip",
  "L031": "L_ENTRY_031_YourVoiceInStatic.zip",
  "L042": "L_ENTRY_042_VoidLullaby.zip",
  "L057": "L_ENTRY_057_LastLoginEcho.zip",
  "L073": "L_ENTRY_073_FinalSync_2025.zip",
  "L" : "noted.txt"
};

function validateToken(id, token) {
  const timeWindow = 60;
  const now = Math.floor(Date.now() / 1000);

  for (let i = 0; i <= timeWindow; i++) {
    const time = (now - i).toString();
    const validToken = crypto.createHash("sha256").update(id + time + SECRET).digest("hex");
    if (token === validToken) return true;
  }
  return false;
}

app.post("/secure-fetch", (req, res) => {
  const { id, token } = req.body;
  const filename = FILE_MAP[id];
  if (!filename) return res.status(404).json({ error: "Invalid file ID" });

  if (!validateToken(id, token)) return res.status(403).json({ error: "Invalid or expired token" });

  const filePath = path.join(FILE_DIR, filename);
  if (!fs.existsSync(filePath)) return res.status(404).json({ error: "File not found" });

  res.setHeader("Content-Disposition", `attachment; filename=${filename}`);
  fs.createReadStream(filePath).pipe(res);
});

app.listen(PORT, () => console.log(`File DB server running on port ${PORT}`));