'use strict';

/* global mapboxgl:false */

var fs = require('fs');
var gui = require('nw.gui');
var turf = require('turf');

var CREDS = require('./creds.json');
var PNG = 'output.png';
var LOG = 'log.txt';
var DELAY = 2000;

mapboxgl.accessToken = CREDS.accessToken;

var opts = {
  // container id
  container: 'map',

  // stylesheet location
  style: 'mapbox://styles/mapbox/light-v9',

  // starting position
  center: [-73.6, 45.50],

  // starting zoom
  zoom: 12,

  // required for image exports
  preserveDrawingBuffer: true
};

var geojson = turf.point([-73.6, 45.50]);

// main
plot(opts, geojson)
  .then(exportImage)
  .then(quit);

function plot(opts, geojson) {
  return new Promise(function(resolve, reject) {
    var map = new mapboxgl.Map(opts);

    map.on('load', function() {
      drawData(map, geojson);

      resolve(map);
    });
  });
}

function drawData(map, geojson) {
  map.addSource('source', {
    type: 'geojson',
    data: geojson
  });

  map.addLayer({
    id: 'layer',
    source: 'source',
    type: 'circle'
  });
}

function exportImage(map) {
  return new Promise(function(resolve, reject) {
    setTimeout(function() {
      var dataURL = map.getCanvas().toDataURL();
      var imgData = dataURL.replace(/^data:image\/\w+;base64,/, '');
      var img = new Buffer(imgData, 'base64');

      fs.writeFile(PNG, img, function(err) {
        if(err) reject(err);

        resolve('success');
      });

    }, DELAY);
  });
}

function quit(result) {
  var str = [
    result,
    'mapbox-gl version: ' + mapboxgl.version,
    'nw.js version: ' + (process.versions['nw'] || process.versions['node-webkit']),
    'node.js version: ' + process.version,
    'chromium version: ' + process.versions['chromium'],
    ''
  ].join('\n');

  fs.writeFile(LOG, str, function(err) {
    if(err) throw err;

    gui.App.quit();
  });
}