(function () {
    window.initStagSuggest = function () {

        let suggestionsOuter = null;

        const debounce = (func, wait) => {
            let timeout;
            return function executedFunction(...args) {
                const later = () => {
                    clearTimeout(timeout);
                    func(...args);
                };
                clearTimeout(timeout);
                timeout = setTimeout(later, wait);
            };
        };

        var lastTerm = '';
        var returnedFunction = debounce(function (elem) {
            let term = elem.val();
            if (!!term && lastTerm !== term) {
                let ep = $(elem).attr('stag-suggest-ep');
                $.get(ep + '?term=' + $.trim(term), function (_data) {

                    /*
                    expected return format:
                    {
                        success: true,
                        data: [
                            {
                                x: ...,
                                y: ...,
                                text: ...    // "text" key is "mandatory"
                            },
                            {
                                x: ...,
                                y: ...,
                                text: ...    // "text" key is "mandatory"
                            },
                            ...
                        ]
                    }
                     */

                    suggestionsOuter.empty();
                    if(!hasResponseError(_data) && _data.data && _data.data.length) {
                        for (let i = 0; i < _data.data.length; i++) {
                            let item = $('<a native href="#" class="d-block suggest-item stag-suggest text-nowrap"/>');
                            for(let x in _data.data[i]) {
                                if(_data.data[i].hasOwnProperty(x) && x !== 'text') {
                                    item.attr('data-' + x, _data.data[i][x]);
                                }
                            }
                            item.data('suggest-data', _data.data[i]);
                            item.html(_data.data[i].text);
                            suggestionsOuter.append(item);
                        }
                    }
                    else {
                        suggestionsOuter.html('<span class="d-block no-suggest-items">No matches!</span>');
                    }

                    suggestionsOuter.removeClass('d-none');
                }, 'json');
                lastTerm = term;
            } else {
                suggestionsOuter.addClass('d-none');
            }
        }, 250);

        function handleKeydown(elem, e) {
            let term = $.trim(elem.val());
            let activeItem = suggestionsOuter.find('.suggest-item.active');
            switch (e.which) {
                case 27:
                    suggestionsOuter.addClass('d-none');
                    return false;
                case 38:
                    if (activeItem.prev().length) {
                        activeItem.prev()
                            .addClass('active')
                            .siblings().removeClass('active');
                        activeItem = suggestionsOuter.find('.suggest-item.active');
                        if (activeItem.length) {
                            activeItem[0].scrollIntoView();
                        }
                    }
                    return false;
                case 40:
                    if (activeItem.next().length) {
                        activeItem.next()
                            .addClass('active')
                            .siblings().removeClass('active');
                        activeItem = suggestionsOuter.find('.suggest-item.active');
                        if (activeItem.length) {
                            activeItem[0].scrollIntoView();
                        }
                    }
                    return false;
                case 13:
                    if (activeItem.length) {
                        activeItem.first().click();
                    }
                    return false;
                default:
                    if (!!term) {
                        suggestionsOuter
                            .html('<span class="d-block no-suggest-items">Searching...</span>')
                            .removeClass('d-none');
                        returnedFunction(elem);
                    } else {
                        suggestionsOuter.addClass('d-none');
                    }
                    break;
            }
        }

        function handleKeypress(elem, e) {
            var term = $.trim(elem.val());
            if (!!term) {
                suggestionsOuter
                    .html('<span class="d-block no-suggest-items">Searching...</span>')
                    .removeClass('d-none');
                returnedFunction(elem);
            } else {
                suggestionsOuter.addClass('d-none');
            }
        }

        $('[stag-suggest]:not([stag-suggest-initialized])').each(function () {
            let elem = $(this);
            elem.next('.stag-suggestions-container').remove();
            $('<div class="stag-suggestions-container position-relative">' +
                '<div class="suggestions-outer stag-suggestions position-absolute d-none"></div>' +
                '</div>').insertAfter(elem);

            elem
                .off('keydown.stag-suggest')
                .on('keydown.stag-suggest', function (e) {
                    suggestionsOuter = $(this).next('.stag-suggestions-container').find('>.suggestions-outer');
                    return handleKeydown($(this), e);
                })
                .off('keypress.stag-suggest')
                .on('keypress.stag-suggest', function (e) {
                    suggestionsOuter = $(this).next('.stag-suggestions-container').find('>.suggestions-outer');
                    return handleKeypress($(this), e);
                });

            $(this).attr('stag-suggest-initialized', 1);
        });

        // on auto-suggest selection
        $(document).off('click', '.suggest-item.stag-suggest');
        $(document).on('click', '.suggest-item.stag-suggest', function () {

            $('.suggestions-outer.stag-suggestions').addClass('d-none');

            let data = $(this).data('suggest-data'),
                label = $.trim($(this).text());

            // set value
            let input = $(this).closest('.position-relative').prev('[stag-suggest]');
            input.val(label);
            input.data('suggest-data', data);

            let scope = input.attr('stag-suggest-scope');
            if(!scope) scope = 'form';
            scope = $(scope);

            for(let x in data) {
                if(data.hasOwnProperty(x)) {
                    input.attr('data-' + x, data[x]);

                    // auto-populate if there's a field matching data-name="x" in the scope
                    if(scope.find('[data-name="' + x + '"]').length) {
                        scope.find('[data-name="' + x + '"]').val(data[x]).trigger('change');
                    }

                }
            }
            input.trigger('input');
            input.trigger('change');

            input.trigger('stag-suggest-selected', [input, data]);

            return false;
        });

    }
    addMCInitializer('stag-suggest', window.initStagSuggest);
})();