const express = require("express");
const { CaptchaGenerator } = require("captcha-canvas");
const fs = require("fs");
const os = require("os");
const path = require("path");
const crypto = require("crypto");

const app = express();
app.set('json spaces', 4)
const tempDir = os.tmpdir();

function generateRandomHex(length) {
    return crypto.randomBytes(length).toString("hex");
}

const rand = (length) => 
  [...Array(length)].map(() => "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"[Math.floor(Math.random() * 62)]).join('');

const deleteOldFiles = (folderPath, maxAgeMinutes = 10) => {
  setInterval(() => {
    fs.readdir(folderPath, (err, files) => {
      if (err) return;
      const now = Date.now(), maxAgeMs = maxAgeMinutes * 60 * 1000;
      files.forEach(file => {
        const filePath = path.join(folderPath, file);
        fs.stat(filePath, (err, stats) => {
          if (!err && now - stats.mtimeMs > maxAgeMs) fs.unlink(filePath, () => {});
        });
      });
    });
  }, 60000);
};

const exp = (minutes) => Date.now() - minutes * 60 * 1000;

deleteOldFiles(tempDir, 5)
app.use("/tmp", express.static(tempDir));

app.all("/", async (req, res) => {
    const captcha = new CaptchaGenerator({ height: 200, width: 600 })
      .setCaptcha({ text: rand(6) })
    const fileName = `temp_${generateRandomHex(8)}.png`;
    const filePath = path.join(tempDir, fileName);
  
    const buffer = await captcha.generateSync()

    fs.writeFile(filePath, buffer, (err) => {
        if (err) return res.status(500).json({ error: "Failed to save captcha" });

        res.json({
            expired: `${exp(5)} mins.`,
            text: captcha.text,
            image: `https://${req.hostname}/tmp/${fileName}`
        });
    });
});

app.listen(7860, () => console.log("Server running on port 7860"));