require('dotenv').config();
const { createClient } = require('webdav');
const fs = require('fs');
const path = require('path');

// init db
const low = require('lowdb');
const FileSync = require('lowdb/adapters/FileSync');
const adapter = new FileSync('db.json');
const db = low(adapter);
db.defaults({ files: [], count: 0}).write();

// create webdav-client
const client = createClient(
  process.env.WEBDAV_URL,
  {
      username: process.env.WEBDAV_USER,
      password: process.env.WEBDAV_PW
  }
);

/**
 * webserver
 */
const express = require('express');
const { stringify } = require('querystring');
const app = express();

const expressWs = require('express-ws')(app);
app.ws('/watchdog', function(ws, req) {
  ws.on('message', function(msg) {
    // echo
    ws.send(msg);
  });
});

app.use('/files', express.static(path.join(__dirname, 'files')));
app.get('/api/files', (req, res) => {
  res.json({resource: db.get('files').value()});
});
app.use(express.static(path.join(__dirname, 'public')));
app.listen(process.env.PORT, () => console.log(`Example app listening at http://localhost:${process.env.PORT}`));

/**
 * backend functions
 */

async function listDir(dir = process.env.WEBFRAME_PATH) {
  const directoryItems = await client.getDirectoryContents(dir);
  return directoryItems;
}

async function dlFile(file, dir = process.env.WEBFRAME_PATH) {
  const isDirExists = fs.existsSync(dir) && fs.lstatSync(dir).isDirectory();
  if (!isDirExists) {
    fs.mkdirSync(dir, { recursive: true });
    console.log('Created dir:', dir);
  }
  // return client.createReadStream(dir+'/'+file).pipe(fs.createWriteStream('./files/'+file));
  return client.getFileContents(dir+'/'+file);
}

async function loadImages() {
  try {
    const data = await client.exists(process.env.WEBFRAME_PATH);
    if (data) {
      const list = await listDir(process.env.WEBFRAME_PATH);
      for (let i = 0; i < list.length; i++) {
        const file = list[i];
        const path = './files/'
        const inDb = db.get('files').find({ basename: file.basename }).value() !== undefined ? true : false;
        if (!inDb) {
          const blob = await dlFile(file.basename);
          console.log('Downloaded new File:', file.basename);
          fs.writeFile(path+file.basename, blob, () => {
            db.get('files').push(file).write();
            db.update('count', n => n + 1).write();
            // notify clients via ws            
            expressWs.getWss().clients.forEach(ws => ws.send(JSON.stringify({
              code: 201,
              message: 'pls update'
            })));
          });
        }
      }
    }  
    setTimeout(() => loadImages(), 2000); //process.env.POLL_TIMEOUT);
   } catch (e) {
     console.error('[loadImages]', e);
   }
}

loadImages();