var NCMB = require('ncmb');

module.exports = function(req, res) {
  var application_key = req.query.application_key;
  var client_key      = req.query.client_key;
  var ncmb = new NCMB(application_key, client_key);
  var ClassName       = ncmb.DataStore(req.query.className);
  var d = new Date;
  var filename = req.query.className + "_" + d.getFullYear() + (d.getMonth() + 1) + d.getDate() + ".csv";
  var user = new ncmb.User({userName: req.query.userName, password: req.query.password});
  user.login()
    .then(function(user) {
      var data = [];
      var limit = 1000;
      var loop = function(page) {
        return new Promise(function(resolve, reject) {
          ClassName
            .limit(limit)
            .skip(limit * page)
            .fetchAll()
            .then(function(results) {
              if (Object.keys(results).length == 0) {
                return resolve(true);
              }
              for (var i in results) {
                data.push(results[i]);
              }
              loop(page + 1)
                .then(function() {
                  resolve(true);
                }, function(error) {
                  reject(error);
                })
            })
            .catch(function(error) {
              reject(error);
            })
        });
      }
      loop(0)
        .then(function() {
          csv = [];
          header = [];
          for(var i in data) {
            var ary = Object.keys(data[i]);
            for (var j in ary) {
              if (ary[j] == 'acl') {
                continue;
              }
              if (header.indexOf(ary[j]) < 0) {
                header.push(ary[j]);
              }
            }
          }
          csv = [header.join("\t")];
          for(var i in data) {
            var row = data[i];
            var line = [];
            for (var j in header) {
              if (header[j] == 'acl') {
                continue;
              }
              var val = row[header[j]];
              switch (typeof val) {
              case 'boolean':
              case 'number':
                line.push(val)
                break;
              case 'object':
                switch (val.__type) {
                case 'Date':
                line.push(val.iso);
                  break;
                case 'GeoPoint':
                  line.push(val.latitude + "," + val.longitude);
                  break;
                default:
                  line.push(JSON.stringify(val).replace(/"/g, '""'));
                  break;
                }
                break;
              default:
                try {
                  line.push((val || "").replace(/"/g, '""'))
                }catch(e){
                  console.log(val, typeof val)
                }
              }
            }
            csv.push('"' + line.join('"\t"') + '"');
          }
          // var blob = new Blob(csv.join("\r\n"), {type: "text/csv"});
          buf = new Buffer(csv.join("\r\n"), 'UTF-8');
          ncmb.File.upload(filename, buf)
            .then(function() {
              res.status(200).json("アップロードされました。" + filename);
            })
            .catch(function(error) {
              console.log(error)
            })
        }, function(error) {
          res.status(500).json(error);
        });

    })
};