/**
 * @copyright   (C) 2017 Open Source Matters, Inc. <https://www.joomla.org>
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

/**
 * JavaScript behavior to allow selected tab to be remained after save or page reload
 * keeping state in sessionStorage with better handling of multiple tab widgets per page
 * and not saving the state if there is no id in the url (like on the CREATE page of content)
 */

jQuery(function ($) {

    // Ensure in IE8 we can use xpath
    if (typeof wgxpath.install === "function") {
        wgxpath.install();
    }

    /**
     * Tiny jQuery extension to allow getting of url params
     * @use jQuery.urlParam('param') or $.urlParam('myRegex|anotherRegex')
     * If no trailing equals sign in name, add one, allows for general reuse
     */
    $.urlParam = function (name) {
        if (!new RegExp("=$").exec(name)) {
            name = name + '=';
        }
        var results = new RegExp("[\\?&](" + name + ")([^&#]*)").exec(window.location.href);
        return results ? results[1] : null;
    };

    // jQuery extension to get the XPATH of a DOM element
    $.getXpath = function (el) {
        if (typeof el == "string") {
            return document.evaluate(el, document, null, 0, null);
        }
        if (!el || el.nodeType != 1) {
            return "";
        }
        if (el.id) {
            return "//*[@id='" + el.id + "']";
        }
        var a = [];
        var sames = a.filter.call(el.parentNode.children, function (x) {
            return x.tagName == el.tagName;
        });
        var b = [];
        return $.getXpath(el.parentNode) + "/" + el.tagName.toLowerCase() + (sames.length > 1 ? "[" + (b.indexOf.call(sames, el) + 1) + "]" : "");
    };

    // jQuery extension to get the DOM element from an XPATH
    $.findXpath = function (exp, ctxt) {
        var item;
        var coll = [];
        var result = document.evaluate(exp, ctxt || document, null, 5, null);

        while (item = result.iterateNext()) {
            coll.push(item);
        }

        return $(coll);
    };

    var loadTabs = function () {

        /**
         * Remove an item from an array
         */
        function remove_item(activeTabsHrefs, tabCollection) {
            for (var i = 0; i < activeTabsHrefs.length; i++) {
                if (activeTabsHrefs[i].indexOf(tabCollection) > -1) {
                    activeTabsHrefs.splice(i, 1);
                }
            }

            return activeTabsHrefs;
        }

        /**
         * Generate the sessionStorage key we will use
         * This is the URL minus some cleanup
         */
        function getStorageKey() {
            return window.location.href.toString().split(window.location.host)[1].replace(/&return=[a-zA-Z0-9%]+/, "").split('#')[0];
        }

        /**
         * Save this tab to the storage in the form of a pseudo keyed array
         */
        function saveActiveTab(event) {

            // Get a new storage key, normally the full url we are on with some cleanup
            var storageKey = getStorageKey();

            // get this tabs own href
            var href = $(event.target).attr("href");

            // find the collection of tabs this tab belongs to, and calcuate the unique xpath to it
            var tabCollection = $.getXpath($(event.target).closest(".nav-tabs").first().get(0));

            // error handling
            if (!tabCollection || typeof href == "undefined") {
                return;
            }

            // Create a dummy keyed array as js doesnt allow keyed arrays
            var storageValue = tabCollection + "|" + href;

            // Get the current array from the storage
            var activeTabsHrefs = JSON.parse(sessionStorage.getItem(storageKey));

            // If none start a new array
            if (!activeTabsHrefs) {
                var activeTabsHrefs = [];
            } else {
                // Avoid Duplicates in the storage
                remove_item(activeTabsHrefs, tabCollection);
            }

            // Save clicked tab, with relationship to tabCollection to the array
            activeTabsHrefs.push(storageValue);

            // Store the selected tabs as an array in sessionStorage
            sessionStorage.setItem(storageKey, JSON.stringify(activeTabsHrefs));
        }

        // Array with active tabs hrefs
        var activeTabsHrefs = JSON.parse(sessionStorage.getItem(getStorageKey()));

        // jQuery object with all tabs links
        var alltabs = $("a[data-toggle='tab']");

        // When a tab is clicked, save its state!
        alltabs.on("click", function (e) {
            saveActiveTab(e);
        });

        // Clean default tabs
        alltabs.parent(".active").removeClass("active");

        // If we cannot find a tab storage for this url, see if we are coming from a save of a new item
        if (!activeTabsHrefs) {
            var unSavedStateUrl = getStorageKey().replace(/\&id=[0-9]*|[a-z]\&{1}_id=[0-9]*/, '');
            activeTabsHrefs = JSON.parse(sessionStorage.getItem(unSavedStateUrl));
            sessionStorage.removeItem(unSavedStateUrl);
        }

        // we have some tab states to restore, if we see a hash then let that trump the saved state
        if (activeTabsHrefs !== null && !window.location.hash) {

            // When moving from tab area to a different view
            $.each(activeTabsHrefs, function (index, tabFakexPath) {

                // Click the tab
                var parts = tabFakexPath.split("|");
                $.findXpath(parts[0]).find("a[data-toggle='tab'][href='" + parts[1] + "']").click();

            });

        } else { // clean slate start

            // a list of tabs to click
            var tabsToClick = [];

            // If we are passing a hash then this trumps everything
            if (window.location.hash) {

                // for each set of tabs on the page
                alltabs.parents("ul").each(function (index, ul) {

                    // If no tabs is saved, activate first tab from each tab set and save it
                    var tabToClick = $(ul).find("a[href='" + window.location.hash + "']");

                    // If we found some|one
                    if (tabToClick.length) {

                        // if we managed to locate its selector directly
                        if (tabToClick.selector) {

                            // highlight tab of the tabs if the hash matches
                            tabsToClick.push(tabToClick);
                        } else {

                            // highlight first tab of the tabs
                            tabsToClick.push(tabToClick.first());
                        }

                        var parentPane = tabToClick.closest('.tab-pane');

                        // bubble up for nested tabs (like permissions tabs in the permissions pane)
                        if (parentPane) {
                            var id = parentPane.attr('id');
                            if (id) {
                                var parentTabToClick = $(parentPane).find("a[href='#" + id + "']");
                                if (parentTabToClick) {
                                    tabsToClick.push(parentTabToClick);
                                }
                            }
                        }
                    }

                    // cleanup for another loop
                    parentTabToClick = null;
                    tabToClick = null;
                    parentPane = null;
                    id = null;
                });

                // run in the right order bubbling up
                tabsToClick.reverse();

                // for all queued tabs
                for (var i = 0; i < tabsToClick.length; i++) {

                    // click the tabs, thus storing them
                    jQuery(tabsToClick[i].selector).click();
                }

                // Remove the #hash in the url - with support for older browsers with no flicker
                var scrollV, scrollH, loc = window.location;
                if ("pushState" in history)
                    history.pushState("", document.title, loc.pathname + loc.search);
                else {
                    // Prevent scrolling by storing the page's current scroll offset
                    scrollV = document.body.scrollTop;
                    scrollH = document.body.scrollLeft;
                    loc.hash = "";
                    // Restore the scroll offset, should be flicker free
                    document.body.scrollTop = scrollV;
                    document.body.scrollLeft = scrollH;
                }

            } else {
                alltabs.parents("ul").each(function (index, ul) {
                    // If no tabs is saved, activate first tab from each tab set and save it
                    $(ul).find("a").first().click();
                });
            }
        }
    };

    setTimeout(loadTabs, 100);
});
