const mongoose = require('mongoose');
mongoose.connect('mongodb://backone_inspect:backone_inspect@mongodb.prod.proit.id:27017/backone_inspect_0')
  .then(async (m) => {
    const pipeline = [
      { $group: {
          _id:      '$app_label',
          download: { $sum: '$download' },
          upload:   { $sum: '$upload' },
          flows:    { $sum: '$flows' },
      }},
      { $sort: { download: -1 } },
      { $limit: 3 }
    ];
    let result = await m.connection.db.collection('appstats').aggregate(pipeline).toArray();
    if (result.length === 0) {
      console.log('Falling back to flows...');
      result = await m.connection.db.collection('flows').aggregate([
        { $match: { app_label: { $ne: null, $ne: '' } } },
        { $group: {
            _id:      '$app_label',
            download: { $sum: '$download' },
            upload:   { $sum: '$upload' },
            flows:    { $sum: 1 },
        }},
        { $sort: { download: -1 } },
        { $limit: 3 }
      ]).toArray();
    }
    console.log(result);
    process.exit(0);
  });