var GeoInfo = function() {
    if (!GeoInfo.prototype.instance) {
        GeoInfo.prototype.instance = this;
    } else return GeoInfo.prototype.instance;
    GeoInfo.prototype.getInfo = function(name, type) {
        GeoInfo.prototype.name = name;
        GeoInfo.prototype.type = type;
        var query;
        if (type == "fedDistrict") {
            query = "http://nominatim.openstreetmap.org/search?q=" + name + "&country=russia&format=json&polygon_geojson=1";
        } else if (type == "region") {
            query = "http://nominatim.openstreetmap.org/search?state=" + name + "&country=russia&format=json&polygon_geojson=1";
        } else {
            console.warn("Unexpected type '" + type + "', expecting 'fedDistrict' or 'region'");
            return false;
        }
        if (typeof localStorage == "undefined") {
            console.warn("Your browser not support local storage");
        } else {
            var polygons = localStorage.polygons;
            if (typeof polygons !== "undefined") {
                polygons = JSON.parse(polygons);
                if (polygons.constructor === Array) {
                    var i;
                    for (i = 0; i < polygons.length; i++) {
                        if (polygons[i].name == name && polygons[i].type == type) {
                            console.log("Cache was used");
                            return {coordinates: polygons[i].coordinates, center: polygons[i].center};
                        }
                    }
                }
            }
        }
        $.ajax({
            async: false,
            url: query,
            type: "GET",
            dataType: "json",
            success: function(json) {
                var coordinates;
                if (json[0].geojson.type.toLowerCase() == "multipolygon") {
                    coordinates = json[0].geojson.coordinates;
                } else coordinates = [json[0].geojson.coordinates];
                var polygon = getLargestPolygon(coordinates);
                var centroid = getCentroid(polygon.area, polygon.coordinates[0]);
                if (typeof localStorage.polygons != "undefined") {
                    var polygons = JSON.parse(localStorage.polygons);
                } else var polygons = [];
                polygons.push({name: GeoInfo.prototype.name, type: GeoInfo.prototype.type, coordinates: polygon.coordinates[0], center: centroid});
                localStorage.polygons = JSON.stringify(polygons);
                response = {coordinates: polygon.coordinates[0], center: centroid};
                console.log(response);
                return response;
            },
            error: function(xhr, status, error) {
                console.warn("Connection error:" + error);
                return false;
            }
        })
    }
    function getCentroid(area, coordinates) {
        var i, sumX = 0, sumY = 0, p1, p2;
        for (i = 0; i < coordinates.length - 1; i++) {
            p1 = coordinates[i];
            p2 = coordinates[i+1];
            sumX += (p1[0] + p2[0]) * (p1[0]*p2[1] - p2[0]*p1[1]);
            sumY += (p1[1] + p2[1]) * (p1[0]*p2[1] - p2[0]*p1[1]);
        }
        return [1/(6*area)*sumX, 1/(6*area)*sumY];
    }
    function getLargestPolygon(coordinates) {
        var polygon;
        var areas = [];
        var largestPolygon;
        for (polygon = 0; polygon < coordinates.length; polygon++) {
            var coords = coordinates[polygon][0];
            var area = 0;
            var i;
            for (i = 0; i < coords.length - 1; i++) {
                area += coords[i][0]*coords[i+1][1]-coords[i][1]*coords[i+1][0];
            }
            area /= 2;
            if (!(typeof largestPolygon === "undefined")) {
                if (Math.abs(areas[largestPolygon]) < Math.abs(area)) largestPolygon = polygon;
            } else largestPolygon = polygon;
            areas.push(area);
        }
        return {area: areas[largestPolygon], coordinates: coordinates[largestPolygon]};
    }
}
var foo = new GeoInfo;
bar = foo.getInfo("Самарская область", "region");
console.log(bar);