wildalmighty/BattleShips

"use strict";
(function () {

    //attach click handler
    document.body.addEventListener('click', fireHandler, false);
    function fireHandler(e) {
        e = e || window.event;
        var target = e.target || e.srcElement;
        if (target.className.match(/col/)) {
            var dataCoordinates = target.getAttribute("data-coordinates");
            var coordinates = dataCoordinates.split("-");
            fire(coordinates[0], coordinates[1]);
        }
    }

    /**
     * Attack coordinates from the boards, defined by row and col
     * @param {int} row
     * @param {int} col
     * @returns {undefined}
     */
    function fire(row, col) {
        post("index.php?action=fire",
            {row: row,col: col},
            function (response) {
                if (response.status) {
                    //reload board
                    document.getElementById("board").innerHTML = response.html;
                    //update tries
                    document.getElementById("tries").innerHTML = response.tries;
                }
                //show message
                document.getElementById("msg").innerHTML = response.msg;
            }
        );
    }

    /**
     * Posts AJAX request to an URL
     * @param {String} url
     * @param {object} data
     * @param {function} callback
     * @returns {undefined}
     */
    function post(url, data, callback) {
        var xhttp = new XMLHttpRequest();
        xhttp.onreadystatechange = function () {
            if (xhttp.readyState === 4 && xhttp.status === 200) {
                var response = JSON.parse(xhttp.responseText);
                if (typeof callback === 'function') {
                    callback(response);
                }
            }
        };
        xhttp.open("POST", url, true);
        xhttp.setRequestHeader("Accept", "application/json; charset=utf-8");
        xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        xhttp.send(urlEncode(data));
    }

    /**
     * Returns URL encoded string
     * @param {object} obj
     * @param {String} prefix
     * @returns {String}
     */
    function urlEncode(obj, prefix) {
        var str = [];
        for (var p in obj) {
            if (obj.hasOwnProperty(p)) {
                var k = prefix ? prefix + "[" + p + "]" : p, v = obj[p];
                str.push(typeof v === "object" ?
                        serialize(v, k) :
                        encodeURIComponent(k) + "=" + encodeURIComponent(v));
            }
        }
        return str.join("&");
    };

}());