var cache = null;

const Search = {
    lastSearch: null,
    lastSearchFilter: null,
    resultsInCategory: false,
    searchTermLength: 3,

    getCache: function () {
        if (cache === null) {
            let prefix = '';
            if ($('meta[name="studip-cache-prefix"]').length > 0) {
                prefix = $('meta[name="studip-cache-prefix"]').attr('content');
            }
            cache = STUDIP.Cache.getInstance(prefix);
        }
        return cache;
    },

    /**
     * This function starts the actual search via AJAX call.
     *
     * @param {Object} filter object with filter information (e.g. 'category', 'semester', etc.)
     *               that is set by the filter selects in the sidebar.
     */
    doSearch: function (filter) {

        var cache        = STUDIP.Search.getCache();
        var searchterm   = $('#search-input').val().trim() || cache.get('searchterm');
        var hasValue     = searchterm && searchterm.length >= STUDIP.Search.searchTermLength;
        var resultsDiv   = $('#search-results');
        var wrapper      = $('#search');
        const data       = resultsDiv.data();
        const limit      = 100;

        if (searchterm === '') {
            return;
        }

        if (!hasValue) {
            $('#search-term-invalid .searchtermlen').text(STUDIP.Search.searchTermLength);
            $('#search-term-invalid').show();
        } else {
            $('#search-term-invalid').hide();
        }

        if (!hasValue || STUDIP.Search.lastSearch === searchterm
            && JSON.stringify(STUDIP.Search.lastSearchFilter) === JSON.stringify(filter)) {
            return;
        }

        STUDIP.Search.resultsInCategory = false;

        $('#search-no-result').hide();
        $('#reset-search').show();

        STUDIP.Search.resetSearchCategories();
        STUDIP.Search.greyOutSearchCategories();

        cache.set('searchterm', searchterm);
        STUDIP.Search.lastSearch = searchterm;
        STUDIP.Search.lastSearchFilter = filter;

        // Display spinner symbol, user should always see something is happening.
        wrapper.addClass('is-searching');

        // Call AJAX endpoint and get search results.
        $.getJSON(STUDIP.URLHelper.getURL('dispatch.php/globalsearch/find/' + limit), {
            search: searchterm,
            filters: JSON.stringify(filter)
        }).done(function (json) {
            // Trigger searched event (regardless of successful or not)
            $(document).trigger('searched.studip', {
                needle: searchterm,
                category: STUDIP.Search.getActiveCategory()
            });

            resultsDiv.empty();

            // No results found...
            if (!$.isPlainObject(json) || $.isEmptyObject(json)) {
                wrapper.removeClass('is-searching');
                $('#search-no-result .searchterm').text(searchterm);
                $('#search-no-result').show();
                STUDIP.Search.setActiveCategory('show_all_categories');
                return;
            }

            // Iterate over each result category.
            $.each(json, function (name, value) {
                var category = STUDIP.Search.printCategory(name, value, data);
                resultsDiv.append(category);
            });

            if (STUDIP.Search.getActiveCategory()
                && STUDIP.Search.getActiveCategory() !== 'show_all_categories')
            {
                STUDIP.Search.expandCategory(STUDIP.Search.getActiveCategory());
                if (!STUDIP.Search.resultsInCategory) {
                    $('#search-no-result .searchterm').text(searchterm);
                    $('#search-no-result').show();
                }
            }

            wrapper.removeClass('is-searching');
        }).fail(function (xhr, status, error) {
            if (error) {
                window.alert(error);
            }
        });
    },

    printCategory: function (name, value, data) {
        // Create an <article> for category.
        var allResultsText  = data.allResults;
        var category = $(`<article id="search-${name}" class="studip padding-less">`);
        var header = $('<header>').appendTo(category);
        var categoryBodyDiv = $(`<div id="${name}-body">`).appendTo(category);
        var counter = 0;
        var isActive = STUDIP.Search.getActiveCategory() === name;

        if (isActive) {
            STUDIP.Search.resultsInCategory = true;
        }

        // Create header name
        $(`<h1 class="search-category" data-category="${name}">`)
            .append(`<a href="#">${value.name}</a>`)
            .appendTo(header);

        if (value.more) {
            $(`<div id="show-all-categories-${name}" class="search-more-results">`)
                .append(`<a href="#">${allResultsText}</a>`)
                .toggle(isActive)
                .appendTo(header);
        }

        // Process results and create corresponding entries.
        $.each(value.content, function (index, result) {
            STUDIP.Search.printSingleResult(name, data, result, counter, value.fullsearch, categoryBodyDiv);
            counter += 1;
        });

        $(`a#search_category_${name}`)
            .removeClass('no-result')
            .text(`${value.name}  (${counter}${value.plus ? '+' : ''})`)
            .attr('tabindex', '0');

        // We have more search results than shown, provide link to
        // full search if available.
        if (value.more) {
            var footer = $('<footer class="search-more-results">');
            $(`<a id="link_all_results_${name}" href="#">`).text(`alle ${counter} ${value.name} anzeigen`)
                .click(function() {
                    STUDIP.Search.toggleLinkText(name);
                    STUDIP.Search.expandCategory(name);
                    STUDIP.Search.setActiveCategory(name);
                })
                .toggle(!isActive)
                .appendTo(footer);
            $(`<a id="link_results_${name}" href="#">`).text(allResultsText).hide()
                .click(function() {
                    STUDIP.Search.toggleLinkText(name);
                    STUDIP.Search.showAllCategories(name);
                    STUDIP.Search.setActiveCategory(name);
                })
                .toggle(isActive)
                .appendTo(footer);
            footer.appendTo(category);
        }

        return category;
    },

    printSingleResult: function(
        categoryName,
        { resultsPerType, imgAdd, imgRemove },
        result,
        counter,
        fullsearch,
        categoryBodyDiv
    ) {
        var hasSubcourses   = (categoryName === 'GlobalSearchMyCourses' || categoryName === 'GlobalSearchCourses') && result.has_children;

        // Create single result entry.
        var single          = $('<section>');
        var data            = $('<div class="search-result-data">');
        var details         = $('<div class="search-result-details">');
        var information     = $('<div class="search-result-information">');

        if (counter >= resultsPerType) {
            single.addClass('search-extended-result');
        }
        // Which result types should be opened via dialog?
        const openInDialog = ['GlobalSearchFiles', 'GlobalSearchMessages'];
        var dataDialog = (openInDialog.indexOf(categoryName) >= 0 ? dataDialog = 'data-dialog' : dataDialog = '');
        var link = $(`<a href="${result.url}" ${dataDialog}>`)
            .appendTo(single);

        // Optional image...
        if (result.img !== null) {
            $('<div class="search-result-img hidden-tiny-down">')
                .append(`<img src="${result.img}">`)
                .appendTo(link);
        }

        link.append(data);

        // add/remove icon for courses with sub courses
        if (hasSubcourses) {
            // initially show the 'add' icon
            $(`<a href="#" id="show-subcourses-${result.id}" class="search-has-subcourses">`)
                .click(function(e) {
                    STUDIP.Search.showSubcourses(result.id);
                    e.preventDefault();
                })
                .html(imgAdd)
                .appendTo(data);
            // initially hide the 'remove' icon
            $(`<a href="#" id="hide-subcourses-${result.id}" class="search-has-subcourses">`)
                .click(function(e) {
                    STUDIP.Search.hideSubcourses(result.id);
                    e.preventDefault();
                })
                .html(imgRemove)
                .appendTo(data)
                .hide();
        }

        // Name/title
        $('<div class="search-result-title">')
            .html(result.name)
            .appendTo(data);

        if (result.number !== null) {
            $('<div class="search-result-number">')
                .html(result.number)
                .appendTo(details);
        }

        // Details: Descriptional text
        if (result.description !== null) {
            $('<div class="search-result-description">')
                .html(result.description)
                .appendTo(details);
        }

        if (result.dates !== null) {
            $('<div class="search-result-dates">')
                .html(result.dates)
                .appendTo(details);
        }

        data.append(details);

        // Date/Time of entry
        if (result.date !== null) {
            $('<div class="search-result-time">')
                .html(result.date)
                .appendTo(information);
        }

        // Course Admission State as Img
        if (result.admission_state !== null) {
            $('<div class="search-result-admission-state">')
                .html(result.admission_state)
                .appendTo(information);
        }


        // Details: Additional information
        var additional = $('<div class="search-result-additional">');
        if (result.additional !== null) {
            additional.html(result.additional);

            // "Expand" attribute for further, result-related search
            // (e.g. search in course of found forum entry)
            if (result.expand !== null && result.expand !== fullsearch) {
                additional.wrapInner(`<a href="${result.expand}" title="${result.expandtext}">`);
            }
            additional.appendTo(information);
        }

        link.append(information);

        categoryBodyDiv.append(single);

        if (hasSubcourses) {
            $.each(result.children,  function(key, child) {
                var subcourse = STUDIP.Search.printSingleResult(name, data, child, counter, fullsearch, categoryBodyDiv);
                subcourse.addClass('search-is-subcourse');
                subcourse.addClass(`search-subcourse-${result.id}`);
                subcourse.hide();
            });
        }

        return single;
    },

    /**
     * Clear search term and category from the cache,
     * reload the page and reset the active category.
     */
    resetSearch: function () {
        var cache = STUDIP.Search.getCache();
        STUDIP.Search.lastSearch = null;
        cache.remove('searchterm');
        cache.remove('search_category');
        // reload without parameters
        if (location.href.includes('?')) {
            location = location.href.split('?')[0];
        } else {
            location.reload();
        }
        STUDIP.Search.setActiveCategory('show_all_categories');
    },

    /**
     * Show all possible categories in the sidebar without result numbers.
     */
    resetSearchCategories: function () {
        $('a[id^="search_category_"]').each(function () {
            var category = $(this).text();
            if (category.includes('(')) {
                category = category.substr(0, category.indexOf('(') - 1);
                $(this).text(category);
            }
        }).show();
    },

    /**
     * Grey out all categories in the sidebar with no results.
     */
    greyOutSearchCategories: function () {
        $('a[id^="search_category_"]').addClass('no-result').attr('tabindex', '-1');
    },

    /**
     * Hide all select filters in the sidebar.
     */
    hideAllFilters: function () {
        $('div[id$="_filter"]').hide();
    },

    /**
     * Show the select filters for a given category in the sidebar. Default: semester filter.
     *
     * @param {string} category Given category for which specific select filters should be shown.
     */
    showFilter: function (category) {
        var filters = $('#search-results').data('filters');
        STUDIP.Search.hideAllFilters();
        if (filters && filters[category] !== undefined && category != 'show_all_categories') {
            for (let i = 0; i < filters[category].length; i++) {
                $(`#${filters[category][i]}_filter`).show();
            }
        } else if (category === 'show_all_categories') {
            $('#semester_filter').show();
        }
    },

    /**
     * Set the specified category active (highlighted) in the sidebar.
     * <li class="active">
     *
     * @param {string} category Given category which should be highlighted in the sidebar.
     */
    setActiveCategory: function (category) {
        var cache = STUDIP.Search.getCache();
        cache.set('search_category', category);
        // remove all active classes
        $('#show_all_categories').closest('li').removeClass('active');
        $('a[id^="search_category_"]').closest('li').removeClass('active');

        // set clicked class active
        if (category === 'show_all_categories') {
            $('#show_all_categories').closest('li').addClass('active');
        } else {
            $(`#search_category_${category}`).closest('li').addClass('active');
            $(`#search_category_${category}`).attr('tabindex', '0');
        }
        STUDIP.Search.showFilter(category);

        $(document).trigger('search-category-change.studip', {category: category});
    },

    /**
     * Get the current values from the filter selects in the sidebar that are relevant.
     *
     * @return {Object} filter object with the filter values set by the user.
     */
    getFilter: function () {
        var filters = $('#search-results').data('filters');
        var category = STUDIP.Search.getActiveCategory();
        var filter = {category: category};
        if (filters !== undefined) {
            var active_filters = filters[category];
            $('select[id$="_select"]').each(function () {
                var selected = this.id.substr(0, this.id.lastIndexOf('_'));
                if ($.inArray(selected, active_filters) !== -1) {
                    filter[selected] = $('option:selected', this).val();
                }
            });
        }
        return filter;
    },

    /**
     * Set a specific sidebar filter select to the given value.
     *
     * @param {string} filter filter that should be set.
     * @param {string} value value that the filter should be set to.
     */
    setFilter: function (filter, value) {
        $(`#${filter}_select`).val(value);
    },

    /**
     * Reset all sidebar filters except for the semester filter to their default value ('all').
     */
    resetFilters: function () {
        $('select[id$="_select"]').not('#semester_select').val('').change();
    },

    /**
     * Getter for the selected (active) category.
     *
     * @return {string} The active (currently selected) category in the sidebar widget.
     */
    getActiveCategory: function () {
        var cache = STUDIP.Search.getCache();
        return cache.get('search_category');
    },

    /**
     * Toggle the link text for 'show all' results of one category and 'show all categories'
     * with max. 3 results each.
     *
     * @param {string} category Category for which the link text should be toggled
     */
    toggleLinkText: function (category) {
        var visible = $(`a#link_all_results_${category}`).is(':visible');
        $(`a#link_all_results_${category}`).toggle(!visible);
        $(`a#link_results_${category}`).toggle(visible);
        $(`div#show-all-categories-${category}`).toggle(visible);
    },

    /**
     * When clicked on toggle the icon ('+' -> '-' and vice versa)
     * belonging to a parent course which has sub courses.
     *
     * @param {string} id parent course ID with add/remove Icon
     */
    toggleParentCourseIcon: function (id) {
        var visible = $(`a#show-subcourses-${id}`).is(':visible');
        $(`a#show-subcourses-${id}`).toggle(!visible);
        $(`a#hide-subcourses-${id}`).toggle(visible);
    },

    /**
     * Shows all sub courses for a specific parent course.
     *
     * @param {string} id parent course ID with sub courses
     */
    showSubcourses: function (id) {
        STUDIP.Search.toggleParentCourseIcon(id);
        $(`section.search-subcourse-${id}`).show();
    },

    /**
     * Hides all sub courses for a specific parent course.
     *
     * @param {string} id parent course ID with sub courses
     */
    hideSubcourses: function (id) {
        STUDIP.Search.toggleParentCourseIcon(id);
        $(`section.search-subcourse-${id}`).hide();
    },

    /**
     * Expand a single category, showing more results, and hide other categories.
     *
     * @param {string} category Category that should be expanded.
     * @returns {boolean} false
     */
    expandCategory: function (category) {
        // Hide other categories.
        $(`#search-results article:not([id="search-${category}"])`).hide();
        $('#search-no-result').hide();
        // Show all results.
        $(`#search-${category} section.search-extended-result`)
            .removeClass('search-extended-result');
        // Reassign category click to closing extended view.
        var selector = [
            `#search-results article#search-${category} header a`,
            `#link_all_results_${category}`,
            `#link_results_${category}`,
            `#show-all-categories-${category}`
        ].join(',');
        $(selector).off('click').on('click', function () {
            STUDIP.Search.toggleLinkText(category);
            STUDIP.Search.showAllCategories(category);
            return false;
        });
        return false;
    },

    /**
     * Close expanded view of a single category, showing normal view with
     * all categories again.
     *
     * @param {string} currentCategory Category that was previously selected.
     * @return {boolean} false
     */
    showAllCategories: function (currentCategory) {
        var selector = [
            `#search-results article#search-${currentCategory} header a`,
            `#link_all_results_${currentCategory}`,
            `#link_results_${currentCategory}`
        ].join(',');
        $(selector).off('click').on('click', function () {
            STUDIP.Search.toggleLinkText(currentCategory);
            STUDIP.Search.expandCategory(currentCategory);
            STUDIP.Search.setActiveCategory(currentCategory);
            return false;
        });
        var resultCount = $('#search-results').data('results-per-type') - 1;
        $(`#search-${currentCategory} section:gt(${resultCount})`)
            .addClass('search-extended-result');
        $('#search-results').children(`article:not([id="search-${currentCategory}"])`).show();
        STUDIP.Search.setActiveCategory('show_all_categories');
        $('#search-no-result').hide();
        return false;
    },

    /**
     * Show active filters based on active category
     *
     * @param {Object} filter object with filter information (e.g. 'category', 'semester', etc.)
     * @return {boolean} false
     */
    showActiveFilters: function (filter) {
        var container = $('#search-active-filters').find('.filter-items');
        container.empty();
        var emptyFilter = true;
        for ( var item in filter) {
            if (item != 'category') {
                var value = filter[item];
                if (value.trim()) {
                    var name = $(`#${item}_filter .sidebar-widget-header`).text().trim();
                    var value_text = $(`#${item}_select option:selected`).text().trim();
                    var filterItem = $('<button></button>').addClass('button remove-filter').text(name + ': ' + value_text).attr('data-filter-name', item);
                    filterItem.on('click', function () {
                        var filter_name = $(this).data('filter-name');
                        $(`#${filter_name}_select`).val("");
                        $(`#${filter_name}_select`).trigger('change');
                        return false;
                    });
                    container.append(filterItem);
                    emptyFilter = false;
                }
            }
        }
        if (emptyFilter) {
            $('#search-active-filters').hide();
        } else {
            $('#search-active-filters').show();
        }
        return false;
    }
};

export default Search;