const express = require('express');
const cors = require('cors');
const fs = require('fs');
const path = require('path');
const { LRUCache } = require('lru-cache');

const app = express();
const PORT = process.env.PORT || 7860;
const dbDirectory = path.join(__dirname, 'database');

if (!fs.existsSync(dbDirectory)) {
  fs.mkdirSync(dbDirectory);
}

const cache = new LRUCache({
  max: 500,
  ttl: 1000 * 60 * 60 * 24 * 30,
  allowStale: false,
  updateAgeOnGet: true,
  updateAgeOnHas: true,
});

function loadDatabasesIntoCache() {
  const ownerDirs = fs.readdirSync(dbDirectory);
  for (const owner of ownerDirs) {
    const ownerPath = path.join(dbDirectory, owner);
    if (fs.statSync(ownerPath).isDirectory()) {
      const files = fs.readdirSync(ownerPath);
      for (const file of files) {
        if (path.extname(file) === '.json') {
          const dbName = path.basename(file, '.json');
          const filePath = path.join(ownerPath, file);
          const cacheKey = `${owner}_${dbName}`;
          try {
            const data = fs.readFileSync(filePath, 'utf8');
            cache.set(cacheKey, JSON.parse(data));
          } catch (e) {
            console.error(`Gagal memuat ${file} untuk owner ${owner} ke cache.`, e);
          }
        }
      }
    }
  }
  console.log('Semua database dari disk telah dimuat ke LRU Cache.');
}

app.use(cors());
app.use(express.json({ limit: '50mb' }));

app.get('/db/:owner/:name', (req, res) => {
  const { owner, name } = req.params;
  const cacheKey = `${owner}_${name}`;
  const data = cache.get(cacheKey);
  
  if (data) {
    return res.status(200).json(data);
  }
  
  const filePath = path.join(dbDirectory, owner, `${name}.json`);
  if (fs.existsSync(filePath)) {
    try {
      const fileData = JSON.parse(fs.readFileSync(filePath, 'utf8'));
      cache.set(cacheKey, fileData);
      return res.status(200).json(fileData);
    } catch (e) {
      return res.status(500).json({ success: false, message: 'Gagal membaca database.' });
    }
  } else {
    return res.status(200).json({});
  }
});

app.post('/db/:owner/:name', (req, res) => {
  try {
    const { owner, name } = req.params;
    const data = req.body;
    const cacheKey = `${owner}_${name}`;
    
    cache.set(cacheKey, data);
    
    const ownerDir = path.join(dbDirectory, owner);
    if (!fs.existsSync(ownerDir)) {
      fs.mkdirSync(ownerDir, { recursive: true });
    }
    
    const filePath = path.join(ownerDir, `${name}.json`);
    fs.writeFileSync(filePath, JSON.stringify(data, null, 2));
    
    res.status(200).json({ success: true, message: 'Database berhasil disimpan.' });
  } catch (error) {
    res.status(500).json({ success: false, message: 'Terjadi kesalahan internal.' });
  }
});

app.listen(PORT, () => {
  loadDatabasesIntoCache();
  console.log(`Server database multi-tenant berjalan di port ${PORT}.`);
});