// Circle overlay extension for Google Maps
// App Delegate Inc <http://appdelegateinc.com> 2010

// This file adds a new CircleOverlay to GMaps2 to draw a circle on a map with stroke and fill
// If you include the library at http://appdelegateinc.com/blog/2010/05/16/point-in-polygon-checking/ you can also check to see if a point resides within the circle.

// Constructor
var CircleOverlay = function (map, latLng, radius, strokeColor, strokeWidth, strokeOpacity, fillColor, fillOpacity, numPoints) {
    this.map = map;
    this.setMap(map);
    this.latLng = latLng;
    this.radius = radius;
    this.strokeColor = strokeColor;
    this.strokeWidth = strokeWidth;
    this.strokeOpacity = strokeOpacity;
    this.fillColor = fillColor;
    this.fillOpacity = fillOpacity;

    // Set resolution of polygon
    if (typeof (numPoints) == 'undefined') {
        this.numPoints = 45;
    } else {
        this.numPoints = numPoints;
    }
}

// Inherit from GOverlay
CircleOverlay.prototype = new google.maps.OverlayView();

// Reset overlay
CircleOverlay.prototype.clear = function () {
    if (this.polygon != null && this.map != null) {
        this.polygon.setMap(null);
    }
}

// Calculate all the points of the circle and draw them
CircleOverlay.prototype.draw = function (force) {
    var d2r = Math.PI / 180;
    circleLatLngs = new Array();

    // Convert statute miles into degrees latitude
    var circleLat = this.radius * 0.014483;
    var circleLng = circleLat / Math.cos(this.latLng.lat() * d2r);

    // Create polygon points (extra point to close polygon)
    for (var i = 0; i < this.numPoints + 1; i++) {
        // Convert degrees to radians
        var theta = Math.PI * (i / (this.numPoints / 2));
        var vertexLat = this.latLng.lat() + (circleLat * Math.sin(theta));
        var vertexLng = this.latLng.lng() + (circleLng * Math.cos(theta));
        var vertextLatLng = new google.maps.LatLng(vertexLat, vertexLng);
        circleLatLngs.push(vertextLatLng);
    }

    this.clear();
    this.polygon = new google.maps.Polygon({
        paths: circleLatLngs,
        strokeColor: this.strokeColor,
        strokeWeight: this.strokeWidth,
        strokeOpacity: this.strokeOpacity,
        fillColor: this.fillColor,
        fillOpacity: this.fillOpacity
    });
    this.polygon.setMap(this.map);
}

// Remove circle method
//CircleOverlay.prototype.remove = function () {
//    this.clear();
//}

CircleOverlay.prototype.remove = function () {
    this.clear();
    this.polygon = null;
    this.map = null;
}


// Can use this method if the library at is included at http://appdelegateinc.com/blog/2010/05/16/point-in-polygon-checking/
CircleOverlay.prototype.containsLatLng = function (latLng) {
    if (this.polygon.containsLatLng) {
        return this.polygon.containsLatLng(latLng);
    }
}

// Set radius of circle
CircleOverlay.prototype.setRadius = function (radius) {
    this.radius = radius;
}

// Set center of circle
CircleOverlay.prototype.setLatLng = function (latLng) {
    this.latLng = latLng;
}