/**
 * Check if item exists in main table by prDetailsId
 * @param {string|number} prDetailsId - The prDetailsId to check
 * @returns {boolean} True if item exists, false otherwise
 */
function isItemExistInMainTable(prDetailsId) {
    if (!poDataTable) return false;

    const data = poDataTable.data().toArray();
    return data.some(item => item.prDetailsId === prDetailsId);
}

/**
 * Get all existing prDetailsIds from main table
 * @returns {Array} Array of existing prDetailsIds
 */
function getExistingItemIds() {
    if (!poDataTable) return [];

    return poDataTable.data().toArray().map(item => item.prDetailsId);
}

/**
 * Remove items from PRItemTable that already exist in main table
 * Call this after adding items to main table
 */
function removeExistingItemsFromPRTable() {
    if (!PRItemTable) return;

    const existingIds = getExistingItemIds();

    // Clear selections for existing items
    existingIds.forEach(prDetailsId => {
        // Find and remove from selectedProductsMap using the composite key
        Object.keys(selectedProductsMap).forEach(key => {
            const item = selectedProductsMap[key];
            if (item && item.prDetailsId === prDetailsId) {
                delete selectedProductsMap[key];
            }
        });
    });

    // Redraw table to update checkbox states
    PRItemTable.draw();

    // Update the count
    if (totalSelectedLabel) {
        totalSelectedLabel.text(getSelectedCount(selectedProductsMap));
    }
}

/**
 * Enhanced initializeTableSelection with duplicate checking
 * Add this to your existing initializeTableSelection config when calling it
 */
function initializeTableSelectionWithDuplicateCheck(config) {
    const originalConfig = { ...config };

    // Enhance the individual checkbox change handler
    const originalCheckboxHandler = function () {
        const $row = $(this).closest('tr');
        const rowData = originalConfig.dataTable.row($row).data();

        if (!rowData) {
            console.error('No row data found');
            return;
        }

        // Check for duplicates before allowing selection
        if ($(this).prop('checked')) {
            if (isItemExistInMainTable(rowData.prDetailsId)) {
                // Item already exists, prevent selection
                $(this).prop('checked', false);
                alert(`Item ${rowData.itemNo || rowData.prNo} already exists in the main table.`);
                return;
            }
        }

        const itemId = originalConfig.idKey2 ?
            `${rowData[originalConfig.idKey]}|${rowData[originalConfig.idKey2] || ''}` :
            rowData[originalConfig.idKey];

        if ($(this).prop('checked')) {
            $row.addClass(originalConfig.selectedRowClass || 'selected-row');
            originalConfig.selectedItemsMap[itemId] = rowData;
        } else {
            $row.removeClass(originalConfig.selectedRowClass || 'selected-row');
            delete originalConfig.selectedItemsMap[itemId];
        }

        originalConfig.updateCountCallback();
        updateSelectAllCheckboxStateWithDuplicateCheck();
    };

    // Enhanced select all checkbox handler
    const originalSelectAllHandler = function () {
        const isChecked = $(this).prop('checked');
        const checkboxClass = originalConfig.checkboxClass || '.selected-Item-checkbox';
        const selectedRowClass = originalConfig.selectedRowClass || 'selected-row';

        $(originalConfig.tableName + ' tbody tr:visible').each(function () {
            const $row = $(this);
            const $checkbox = $row.find(checkboxClass);

            if ($checkbox.length === 0) return;

            const rowData = originalConfig.dataTable.row($row).data();
            if (!rowData) return;

            // Check for duplicates when selecting all
            if (isChecked && isItemExistInMainTable(rowData.prDetailsId)) {
                // Skip items that already exist
                return;
            }

            const itemId = originalConfig.idKey2 ?
                `${rowData[originalConfig.idKey]}|${rowData[originalConfig.idKey2] || ''}` :
                rowData[originalConfig.idKey];

            $checkbox.prop('checked', isChecked);
            if (isChecked) {
                $row.addClass(selectedRowClass);
                originalConfig.selectedItemsMap[itemId] = rowData;
            } else {
                $row.removeClass(selectedRowClass);
                delete originalConfig.selectedItemsMap[itemId];
            }
        });

        originalConfig.updateCountCallback();
        updateSelectAllCheckboxStateWithDuplicateCheck();
    };

    // Enhanced select all state update function
    function updateSelectAllCheckboxStateWithDuplicateCheck() {
        const selectAllClass = originalConfig.selectAllClass || '.select-all-checkbox';
        const checkboxClass = originalConfig.checkboxClass || '.selected-Item-checkbox';

        const $selectAllCheckbox = $(originalConfig.tableName + ' ' + selectAllClass);
        const $visibleCheckboxes = $(originalConfig.tableName + ' tbody ' + checkboxClass + ':visible');

        // Filter out checkboxes for items that already exist in main table
        const $availableCheckboxes = $visibleCheckboxes.filter(function () {
            const $row = $(this).closest('tr');
            const rowData = originalConfig.dataTable.row($row).data();
            return rowData && !isItemExistInMainTable(rowData.prDetailsId);
        });

        const checkedCount = $availableCheckboxes.filter(':checked').length;
        const totalAvailable = $availableCheckboxes.length;

        if (totalAvailable === 0) {
            $selectAllCheckbox.prop('indeterminate', false).prop('checked', false);
        } else if (checkedCount === totalAvailable) {
            $selectAllCheckbox.prop('indeterminate', false).prop('checked', true);
        } else if (checkedCount > 0) {
            $selectAllCheckbox.prop('indeterminate', true).prop('checked', false);
        } else {
            $selectAllCheckbox.prop('indeterminate', false).prop('checked', false);
        }
    }

    // Enhanced row state update function
    function updateRowStatesWithDuplicateCheck() {
        const checkboxClass = originalConfig.checkboxClass || '.selected-Item-checkbox';
        const selectedRowClass = originalConfig.selectedRowClass || 'selected-row';

        $(originalConfig.tableName + ' tbody tr').each(function () {
            const $row = $(this);
            const rowData = originalConfig.dataTable.row($row).data();
            if (rowData) {
                const $checkbox = $row.find(checkboxClass);

                // Check if item exists in main table
                if (isItemExistInMainTable(rowData.prDetailsId)) {
                    // Disable checkbox and add visual indicator
                    $checkbox.prop('checked', false).prop('disabled', true);
                    $row.addClass('item-already-exists').removeClass(selectedRowClass);

                    // Remove from selection map if it exists
                    const itemId = originalConfig.idKey2 ?
                        `${rowData[originalConfig.idKey]}|${rowData[originalConfig.idKey2] || ''}` :
                        rowData[originalConfig.idKey];
                    delete originalConfig.selectedItemsMap[itemId];
                } else {
                    // Enable checkbox and restore normal state
                    $checkbox.prop('disabled', false);
                    $row.removeClass('item-already-exists');

                    const itemId = originalConfig.idKey2 ?
                        `${rowData[originalConfig.idKey]}|${rowData[originalConfig.idKey2] || ''}` :
                        rowData[originalConfig.idKey];

                    if (originalConfig.selectedItemsMap[itemId]) {
                        $checkbox.prop('checked', true);
                        $row.addClass(selectedRowClass);
                    } else {
                        $checkbox.prop('checked', false);
                        $row.removeClass(selectedRowClass);
                    }
                }
            }
        });
    }

    // Call the original initializeTableSelection with enhanced handlers
    initializeTableSelection(originalConfig);

    // Replace the handlers with enhanced versions
    $(originalConfig.tableName).off('change', originalConfig.checkboxClass || '.selected-Item-checkbox');
    $(originalConfig.tableName).off('change', originalConfig.selectAllClass || '.select-all-checkbox');

    $(originalConfig.tableName).on('change', originalConfig.checkboxClass || '.selected-Item-checkbox', originalCheckboxHandler);
    $(originalConfig.tableName).on('change', originalConfig.selectAllClass || '.select-all-checkbox', originalSelectAllHandler);

    // Enhanced draw event handler
    originalConfig.dataTable.off('draw.tableSelection');
    originalConfig.dataTable.on('draw.tableSelection', function () {
        updateRowStatesWithDuplicateCheck();
        updateSelectAllCheckboxStateWithDuplicateCheck();
    });

    // Initial state update
    setTimeout(() => {
        updateRowStatesWithDuplicateCheck();
        updateSelectAllCheckboxStateWithDuplicateCheck();
    }, 100);
}

/**
 * Call this function after successfully adding items to the main table
 * Example: after your AJAX call that adds selected items to PODataTable
 */
function afterAddingItemsToMainTable() {
    // Refresh the main table
    if (poDataTable) {
        poDataTable.ajax.reload(null, false);
    }

    // Remove existing items from PR table and update states
    setTimeout(() => {
        removeExistingItemsFromPRTable();
    }, 500);
}

// Add CSS for visual indication of existing items
const duplicateItemStyles = `
<style>
.item-already-exists {
    background-color: #f8f9fa !important;
    opacity: 0.6;
}

.item-already-exists td {
    color: #6c757d !important;
}

.item-already-exists input[type="checkbox"]:disabled {
    opacity: 0.3;
}
</style>
`;

// Inject styles into head
if (!document.querySelector('#duplicate-item-styles')) {
    const styleElement = document.createElement('style');
    styleElement.id = 'duplicate-item-styles';
    styleElement.textContent = `
        .item-already-exists {
            background-color: #f8f9fa !important;
            opacity: 0.6;
        }

        .item-already-exists td {
            color: #6c757d !important;
        }

        .item-already-exists input[type="checkbox"]:disabled {
            opacity: 0.3;
        }
    `;
    document.head.appendChild(styleElement);
}