backup

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
var async = require('async');
var fs = require('fs');
const {
  exec
} = require('child_process');
var argv = process.argv;
var fromDate = new Date();
var databaseName = "accio_publishers"
const fromurl = 'mongodb://localhost:27017';

var execCommand = function(cmd, cb) {
  console.log(cmd);
  exec(cmd, function(err, stdout, stderr) {
    if (err) {
      return cb(err);
    } else {
      return cb(null, stderr)
    }
  });
}

var getDumpFromCollections = function(db, collection, query, cb) {
  var dbname = db["databaseName"];
  var command = "mongodump -o dump/full --host localhost --port 27017 -d '" + dbname + "' -c '" + collection + "'";
  var command2 = "mongodump -o dump/delta --host localhost --port 27017 -d '" + dbname + "' -c '" + collection + "'";
  if (query) {
    command2 += " -q '" + JSON.stringify(query) + "'"
  }
  return execCommand(command2, cb)
}


var zipAndMail = function(cb) {
  var command = "zip -r mongodump.zip dump/"
  return execCommand(command, cb)
}
var collectToServer = function(url, dbName, cb) {
  console.log("connecting to mongo server ...");
  MongoClient.connect(url, function(err, client) {
    if (err) {
      console.log("connection failed");
      cb(err)
    } else {
      console.log("connected to mongo server");
      cb(null, client, client.db(dbName))
    }
  });
}

var getListofDatabase = function(client, db, cb) {
  var adminDb = db.admin();
  adminDb.listDatabases(function(err, dbs) {
    cb(err, client, dbs)
  });
}

var getAllCollectionsFromDatabase = function(db, cb) {
  db.listCollections().toArray().then(function(collection) {
    var newColl = collection.map(function(c) {
      return c.name
    });
    cb(null, db, newColl);
  }).catch(function(err) {
    cb(err);
  });
}



var interateCollection = function(db, collections, cb) {
  async.map(collections, function(collection, mapcb) {
    var dbcollection = db.collection(collection);
    /*
      count;
      delta:
      deleted
      backup
     */
    getDumpFromCollections(db, collection, "", function(err, data) {
      dbcollection.count({}, function(err, count) {
        var d = {}
        d[collection] = count;
        mapcb(err, d)
      })
    })
  }, function(err, results) {
    cb(null, results)
  })
}

var interateDatabases = function(client, dbs, cb) {
  // console.log(dbs); // save this file
  async.map(dbs.databases, function(database, mapcb) {
    console.log(database.name);
    var db = client.db(database.name)
    async.waterfall([
      function(waterfallcb) {
        getAllCollectionsFromDatabase(db, function(err, dbObj, collections) {
          console.log(collections);
          waterfallcb(err, dbObj, collections)
        })
      },
      interateCollection
    ], function(err, results) {
      mapcb(err, results)
    })
  }, function(err, results) {
    console.log();
    cb(err, results)
  })
}

var takeBackup = function() {
  async.waterfall([
    function(callback) {
      collectToServer(fromurl, databaseName, function(err, client, db) {
        callback(err, client, db)
      })
    },
    getListofDatabase,
    interateDatabases,
  ], function(err, results) {
    if (err) {
      console.log(err);
    }
    console.log(results);
    zipAndMail(function(err, info) {
      process.exit();
    })
  })
}
takeBackup();

// mongorestore --host localhost --port 27017  -d 'dbname' -c 'collections'  /Users/Ritesh/Documents/workspace/dbname/mongodump/dbname/collections.bson