(function(factory, window){
  "use strict";
  if (typeof define === 'function' && define.amd) {
    define(['leaflet'], factory);
  } else if (typeof exports === 'object') {
    module.exports = factory(require('leaflet'));
  }
  if (typeof window !== 'undefined' && window.L) {
    window.L.Ruler = factory(L);
  }
}(function (L) {
  "use strict";
  L.Control.Ruler = L.Control.extend({
    options: {
      position: 'topright',
      circleMarker: {
        color: 'red',
        radius: 2
      },
      lineStyle: {
        color: 'red',
        dashArray: '1,6'
      },
      lengthUnit: {
        display: 'km',
        decimal: 2,
        factor: null,
        label: '距离:'
      },
      angleUnit: {
        display: '°',
        decimal: 2,
        factor: null,
        label: '方位:'
      }
    },
    onAdd: function(map) {
      this._map = map;
      this._container = L.DomUtil.create('div', 'leaflet-bar');
      this._container.classList.add('leaflet-ruler');
      L.DomEvent.disableClickPropagation(this._container);
      L.DomEvent.on(this._container, 'click', this._toggleMeasure, this);
      this._choice = false;
      this._defaultCursor = this._map._container.style.cursor;
      this._allLayers = L.layerGroup();
      return this._container;
    },
    onRemove: function() {
      L.DomEvent.off(this._container, 'click', this._toggleMeasure, this);
    },
    _toggleMeasure: function() {
      this._choice = !this._choice;
      this._clickedLatLong = null;
      this._clickedPoints = [];
      this._totalLength = 0;
      if (this._choice){
        this._map.doubleClickZoom.disable();
        L.DomEvent.on(this._map._container, 'keydown', this._escape, this);
        L.DomEvent.on(this._map._container, 'dblclick', this._closePath, this);
        this._container.classList.add("leaflet-ruler-clicked");
        this._clickCount = 0;
        this._tempLine = L.featureGroup().addTo(this._allLayers);
        this._tempPoint = L.featureGroup().addTo(this._allLayers);
        this._pointLayer = L.featureGroup().addTo(this._allLayers);
        this._polylineLayer = L.featureGroup().addTo(this._allLayers);
        this._allLayers.addTo(this._map);
        this._map._container.style.cursor = 'crosshair';
        this._map.on('click', this._clicked, this);
        this._map.on('mousemove', this._moving, this);
      }
      else {
        this._map.doubleClickZoom.enable();
        L.DomEvent.off(this._map._container, 'keydown', this._escape, this);
        L.DomEvent.off(this._map._container, 'dblclick', this._closePath, this);
        this._container.classList.remove("leaflet-ruler-clicked");
        this._map.removeLayer(this._allLayers);
        this._allLayers = L.layerGroup();
        this._map._container.style.cursor = this._defaultCursor;
        this._map.off('click', this._clicked, this);
        this._map.off('mousemove', this._moving, this);
      }
    },
    _clicked: function(e) {
      this._clickedLatLong = e.latlng;
      this._clickedPoints.push(this._clickedLatLong);
      L.circleMarker(this._clickedLatLong, this.options.circleMarker).addTo(this._pointLayer);
      if(this._clickCount > 0 && !e.latlng.equals(this._clickedPoints[this._clickedPoints.length - 2])){
        if (this._movingLatLong){
          L.polyline([this._clickedPoints[this._clickCount-1], this._movingLatLong], this.options.lineStyle).addTo(this._polylineLayer);
        }
        var text;
        this._totalLength += this._result.Distance;
        if (this._clickCount > 1){
          text = '<b>' + this.options.angleUnit.label + '</b>&nbsp;' + this._result.Bearing.toFixed(this.options.angleUnit.decimal) + '&nbsp;' + this.options.angleUnit.display + '<br><b>' + this.options.lengthUnit.label + '</b>&nbsp;' + this._totalLength.toFixed(this.options.lengthUnit.decimal) + '&nbsp;' +  this.options.lengthUnit.display;
        }
        else {
          text = '<b>' + this.options.angleUnit.label + '</b>&nbsp;' + this._result.Bearing.toFixed(this.options.angleUnit.decimal) + '&nbsp;' + this.options.angleUnit.display + '<br><b>' + this.options.lengthUnit.label + '</b>&nbsp;' + this._result.Distance.toFixed(this.options.lengthUnit.decimal) + '&nbsp;' +  this.options.lengthUnit.display;
        }
        L.circleMarker(this._clickedLatLong, this.options.circleMarker).bindTooltip(text, {permanent: true, className: 'result-tooltip'}).addTo(this._pointLayer).openTooltip();
      }
      this._clickCount++;
    },
    _moving: function(e) {
      if (this._clickedLatLong){
        L.DomEvent.off(this._container, 'click', this._toggleMeasure, this);
        this._movingLatLong = e.latlng;
        if (this._tempLine){
          this._map.removeLayer(this._tempLine);
          this._map.removeLayer(this._tempPoint);
        }
        var text;
        this._addedLength = 0;
        this._tempLine = L.featureGroup();
        this._tempPoint = L.featureGroup();
        this._tempLine.addTo(this._map);
        this._tempPoint.addTo(this._map);
        this._calculateBearingAndDistance();
        this._addedLength = this._result.Distance + this._totalLength;
        L.polyline([this._clickedLatLong, this._movingLatLong], this.options.lineStyle).addTo(this._tempLine);
        if (this._clickCount > 1){
          text = '<b>' + this.options.angleUnit.label + '</b>&nbsp;' + this._result.Bearing.toFixed(this.options.angleUnit.decimal) + '&nbsp;' + this.options.angleUnit.display + '<br><b>' + this.options.lengthUnit.label + '</b>&nbsp;' + this._addedLength.toFixed(this.options.lengthUnit.decimal) + '&nbsp;' +  this.options.lengthUnit.display + '<br><div class="plus-length">(+' + this._result.Distance.toFixed(this.options.lengthUnit.decimal) + ')</div>';
        }
        else {
          text = '<b>' + this.options.angleUnit.label + '</b>&nbsp;' + this._result.Bearing.toFixed(this.options.angleUnit.decimal) + '&nbsp;' + this.options.angleUnit.display + '<br><b>' + this.options.lengthUnit.label + '</b>&nbsp;' + this._result.Distance.toFixed(this.options.lengthUnit.decimal) + '&nbsp;' +  this.options.lengthUnit.display;
        }
        L.circleMarker(this._movingLatLong, this.options.circleMarker).bindTooltip(text, {sticky: true, offset: L.point(0, -40) ,className: 'moving-tooltip'}).addTo(this._tempPoint).openTooltip();
      }
    },
    _escape: function(e) {
      if (e.keyCode === 27){
        if (this._clickCount > 0){
          this._closePath();
        }
        else {
          this._choice = true;
          this._toggleMeasure();
        }
      }
    },
    _calculateBearingAndDistance: function() {
      var f1 = this._clickedLatLong.lat, l1 = this._clickedLatLong.lng, f2 = this._movingLatLong.lat, l2 = this._movingLatLong.lng;
      var toRadian = Math.PI / 180;
      // haversine formula
      // bearing
      var y = Math.sin((l2-l1)*toRadian) * Math.cos(f2*toRadian);
      var x = Math.cos(f1*toRadian)*Math.sin(f2*toRadian) - Math.sin(f1*toRadian)*Math.cos(f2*toRadian)*Math.cos((l2-l1)*toRadian);
      var brng = Math.atan2(y, x)*((this.options.angleUnit.factor ? this.options.angleUnit.factor/2 : 180)/Math.PI);
      brng += brng < 0 ? (this.options.angleUnit.factor ? this.options.angleUnit.factor : 360) : 0;
      // distance
      var R = this.options.lengthUnit.factor ? 6371 * this.options.lengthUnit.factor : 6371; // kilometres
      var deltaF = (f2 - f1)*toRadian;
      var deltaL = (l2 - l1)*toRadian;
      var a = Math.sin(deltaF/2) * Math.sin(deltaF/2) + Math.cos(f1*toRadian) * Math.cos(f2*toRadian) * Math.sin(deltaL/2) * Math.sin(deltaL/2);
      var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
      var distance = R * c;
      this._result = {
        Bearing: brng,
        Distance: distance
      };
    },
    _closePath: function() {
      this._map.removeLayer(this._tempLine);
      this._map.removeLayer(this._tempPoint);
      this._choice = false;
      L.DomEvent.on(this._container, 'click', this._toggleMeasure, this);
      this._toggleMeasure();
    }
  });
  L.control.ruler = function(options) {
    return new L.Control.Ruler(options);
  };
}, window));