#!/usr/bin/env nodejs

var osmtogeojson = require('osmtogeojson');
var fs = require('fs');
var DOMParser = require("xmldom").DOMParser;
var async = require('async');

var levels = [1, 3, 4, 5];

async.map(levels, function(level, callback) {

    fs.readFile('level-' + level + '.osm', 'utf8', function(err, data) {
      if (err) {
          callback(err);
          return;
      }

      xml = (new DOMParser()).parseFromString(data, 'text/xml');

      var geojson = osmtogeojson(xml, {
          flatProperties: true,
          polygonFeatures: function(feature) { return true; }
      });

      var featuresWithLevels = geojson.features.forEach(function(feature) {
          feature.properties.level = level;
      });

      callback(null, geojson.features);
    });
}, function(err, features) {
    var featureCollection = {
        type: "FeatureCollection",
        features: []
    };

    features.forEach(function(featureArray) {
        featureArray.forEach(function(feature) {
            delete feature.id;
            delete feature.properties.id;

            featureCollection.features.push(feature);
        });
    });

    console.log(JSON.stringify(featureCollection, null, 4));
});