// ==UserScript==
// @name         PlayNext@115.com
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Add next button for 115 HTML5 player
// @author       zaypen
// @match        http*://*/*
// @require      https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js
// @grant        none
// @downloadURL none
// ==/UserScript==

/*jslint browser:true*/
/*global _ */
(function() {
    'use strict';

    function main() {
        var items = Array.apply(null, document.querySelectorAll('.video-playlist .vpl-container .item-list li'));
        var remainingItems = _.dropWhile(items, function (item) {
            return item.className !== 'hover';
        });
        var nextItem = _.head(_.tail(remainingItems));
        var playNext = function(e) {
            window.location.href = nextItem.querySelector('a').href;
        };
        var nextButton = document.createElement('a');
        nextButton.href = 'javascript:;';
        nextButton.innerHTML = '<i class="icon-operate iop-playing" style="background-size: 400% 200%;"></i>';
        nextButton.className = 'btn-switch';
        nextButton.onclick = playNext;

        var playButton = document.querySelector('.operate-bar a[btn="play"]');
        if (playButton && nextItem) {
            playButton.insertAdjacentElement('afterend', nextButton);
            document.body.addEventListener('keyup', function(e) {
                if (e.key === "PageDown") {
                    playNext();
                }
            });
            return true;
        }
    }

    function retry(fn, interval, times) {
        var ret = fn();
        if (!ret && times) {
            setTimeout(function () {
                retry(fn, interval, times--);
            }, interval);
        }
    }

    retry(main, 500, 10);
})();