const express = require('express');
const bodyParser = require('body-parser');
const { translate } = require('./translate');
const cors = require('cors');
const fs = require('fs');
const app = express();
const PORT = 7860;

app.use(cors({ origin: '*' }));
app.use(bodyParser.json());

let delay = 1500;
const delayIncrement = 100;
const maxDelay = 5000;
let currentTranslations = 0;

function delayFileTermination(delay) {
  if (fs.existsSync('delay.txt')) {
    delay = parseInt(fs.readFileSync('delay.txt', 'utf8'));
  } else {
    fs.writeFile('delay.txt', `delay:${delay}`, function (err) {
      if (err === null) {
        console.log('success');
      } else {
        console.log('fail');
      }
    });
  }
}

console.log('File system loaded');

app.post('/translate', async (req, res) => {
  console.log('Translate start');
  currentTranslations++;

  const { text, source_lang, target_lang } = req.body;

  try {
    await new Promise((resolve) => setTimeout(resolve, delay));
    const result = await translate(text, source_lang, target_lang);
    const responseData = {
      alternatives: result.alternatives,
      code: 200,
      data: result.text,
      id: Math.floor(Math.random() * 10000000000),
      method: 'Free',
      source_lang,
      target_lang,
    };
    res.json(responseData);
  } catch (error) {
    console.error(`Translation failed: ${error}`);
    res.status(500).json({ error: 'Translation failed' });
    delay += delayIncrement;
    if (delay > maxDelay) {
      delay = maxDelay;
    }
    delayFileTermination(delay);
    console.log(`현재 Delay 타임: ${delay}ms`);
  } finally {
    currentTranslations--;
  }
});

app.get('/', (req, res) => {
  const delayMessage = fs.existsSync('delay.txt')
    ? fs.readFileSync('delay.txt', 'utf8')
    : '0';
  const statusMessage = `서버가 구동되었습니다. 현재 딜레이 시간은 ${delay}ms이며, 현재 처리 중인 번역 요청 수는 ${currentTranslations}건입니다.`;
  res.send(statusMessage);
});

app.listen(PORT, () => {
  console.log(`Server is running on http://localhost:${PORT}`);
});