// Shared pager accessibility helpers for PublicModule grids
(function () {
    function enhancePagerDropdownAccessibility() {

        const grid = $('.table_grid').data('kendoGrid');
        if (!grid) {
            return;
        }
        const $gridWrapper = grid.wrapper || grid.element || $('.table_grid');

        setTimeout(function () {
            $gridWrapper
                .find('.k-pager-wrap .k-link, .k-pager-numbers li a.k-link')
                .attr('tabindex', 0);

            const dropdown = $gridWrapper
                .find('.k-pager-sizes select')
                .data('kendoDropDownList');

            if (!dropdown) {
                return;
            }
            const $wrapper = dropdown.wrapper;

            const gridElementId =
                (grid.element && grid.element.attr && grid.element.attr('id')) ||
                grid._uid ||
                'default';

            const liveRegionId = 'pager-dropdown-live-region-' + gridElementId;
            let $liveRegion = $gridWrapper.find('#' + liveRegionId);

            if ($liveRegion.length === 0) {
                $liveRegion = $('<span>')
                    .attr('id', liveRegionId)
                    .attr('aria-live', 'assertive')
                    .attr('aria-atomic', 'true')
                    .addClass('sr-only')
                    .css({
                        position: 'absolute',
                        left: '-9999px',
                        width: '1px',
                        height: '1px',
                        overflow: 'hidden'
                    });
                $wrapper.after($liveRegion);
            }

            const announceFocusedItem = function () {
                let itemToAnnounce = dropdown.ul.find('.k-state-focused');
                if (itemToAnnounce.length === 0) {
                    itemToAnnounce = dropdown.ul.find('.k-state-selected');
                }

                if (itemToAnnounce.length > 0) {
                    const text = itemToAnnounce.text().trim();
                    $liveRegion.text(text + ' items per page');
                }
            };

            const announceDropdownOpened = function () {
                const selectedItem = dropdown.ul.find('.k-state-selected');
                if (selectedItem.length > 0) {
                    const text = selectedItem.text().trim();
                    $liveRegion.text(text + ' selected');
                }
            };

            const announcePageSize = function (pageSize) {
                $liveRegion.text('Showing ' + pageSize + ' items per page');
            };

            const pagerDropdown = $wrapper[0];

            // Remove any previous capture handler if present
            if (pagerDropdown && pagerDropdown._pagerArrowDownCapture) {
                try { pagerDropdown.removeEventListener('keydown', pagerDropdown._pagerArrowDownCapture, true); } catch (e) {}
            }

            pagerDropdown._pagerArrowDownCapture = function (e) {
                const isOpen = dropdown.popup.visible();

                if (e.key === 'ArrowDown' && !isOpen) {
                    e.preventDefault();
                    e.stopPropagation();
                    e.stopImmediatePropagation();

                    dropdown.open();
                }
            };

            pagerDropdown.addEventListener('keydown', pagerDropdown._pagerArrowDownCapture, true);

            const updateAriaLabel = function () {
                const currentValue = dropdown.value();
                $wrapper.attr('aria-label', 'Items per page, ' + currentValue);
            };

            $wrapper.attr({
                tabindex: 0,
                'aria-haspopup': 'listbox',
                'aria-expanded': 'false',
                'aria-label': 'Items per page'
            });

            updateAriaLabel();

            $wrapper.off('keydown.accessibility');

            $wrapper.on('keydown.accessibility', function (e) {
                const isOpen = dropdown.popup.visible();

                switch (e.key) {
                    case 'Enter':
                        e.preventDefault();
                        if (!isOpen) {
                            dropdown.open();
                        }
                        break;

                    case ' ':
                        e.preventDefault();
                        if (isOpen) {
                            const pageSize = dropdown.value();

                            grid.dataSource.pageSize(parseInt(pageSize, 10));
                            announcePageSize(pageSize);
                            updateAriaLabel();

                            dropdown.close();
                            $wrapper.focus();
                        } else {
                            dropdown.open();
                        }
                        break;

                    case 'ArrowDown':
                        if (isOpen) {
                            setTimeout(announceFocusedItem, 50);
                        }
                        break;

                    case 'ArrowUp':
                        if (e.altKey && isOpen) {
                            e.preventDefault();
                            e.stopPropagation();
                            e.stopImmediatePropagation();

                            const pageSize = dropdown.value();

                            grid.dataSource.pageSize(parseInt(pageSize, 10));
                            announcePageSize(pageSize);
                            updateAriaLabel();

                            dropdown.close();
                            $wrapper.focus();
                            return;
                        }

                        e.preventDefault();

                        if (!isOpen) {
                            dropdown.open();
                            setTimeout(function () {
                                dropdown.select(0);
                            }, 0);
                        } else {
                            setTimeout(announceFocusedItem, 50);
                        }
                        break;

                    case 'Home':
                        e.preventDefault();
                        if (!isOpen) {
                            dropdown.open();
                        } else {
                            setTimeout(announceFocusedItem, 50);
                        }
                        break;

                    case 'End':
                        e.preventDefault();
                        if (!isOpen) {
                            dropdown.open();
                        } else {
                            setTimeout(announceFocusedItem, 50);
                        }
                        break;

                    case 'Escape':
                        if (isOpen) {
                            e.preventDefault();
                            e.stopPropagation();
                            dropdown.close();
                        }
                        break;
                }
            });

            const handleOpen = function () {
                $wrapper.attr('aria-expanded', 'true');

                dropdown.ul.closest('.k-list-container').attr({
                    role: 'listbox',
                    'aria-label': 'Page size options'
                });

                dropdown.ul.find('li').each(function () {
                    const $item = $(this);
                    $item.attr('role', 'option');
                    const isSelected = $item.hasClass('k-state-selected');
                    $item.attr('aria-selected', isSelected ? 'true' : 'false');
                });

                setTimeout(announceDropdownOpened, 100);
            };

            const handleClose = function () {
                $wrapper.attr('aria-expanded', 'false');
                setTimeout(() => $wrapper.focus(), 0);
            };

            const handleChange = function () {
                const pageSize = dropdown.value();
                if (pageSize) {
                    announcePageSize(pageSize);
                    updateAriaLabel();
                }
            };

            dropdown.unbind('open', handleOpen);
            dropdown.bind('open', handleOpen);

            dropdown.unbind('close', handleClose);
            dropdown.bind('close', handleClose);

            dropdown.unbind('change', handleChange);
            dropdown.bind('change', handleChange);

            const initialPageSize = dropdown.value();
            if (initialPageSize) {
                setTimeout(() => announcePageSize(initialPageSize), 300);
            }
        }, 150);
    }

    // Expose on window so views can call it without bundling changes
    window.afPagerAccessibility = window.afPagerAccessibility || {};
    window.afPagerAccessibility.enhancePagerDropdownAccessibility = enhancePagerDropdownAccessibility;
})();