// scrolltable.js - scroll functions for dataTable

function scrollAndFocus(rootId, tableId, txtId) {
    scrollToBottom(rootId + ":" + tableId);
    $(rootId +":" + txtId).focus();
}

function scrollToBottom(idDataTable) {
    pTable = digestTable(idDataTable);
    
    scrollToRow(pTable, 9999);
}

function digestTable(idDataTable) {
    pTable = {
        id: idDataTable
    }
    pTable.jqId = '#' + idDataTable.replaceAll(':', '\\:');
    pTable.jqData = pTable.jqId + "_data";
    pTable.heignt = $(pTable.jqId + " .ui-datatable-scrollable-body").height();
    //var lichildren = $(pTable.jqId).children("tr");
    var lichildren = $(pTable.jqId).find("tr");
    pTable.itemHeight = lichildren.height();
    pTable.itemCount = lichildren.length;
    pTable.visibleItemCount = pTable.height / pTable.itemHeight;
    return pTable;    
}


function scrollToRow(pTable, selItem) {   
    var maxScrollItem = pTable.itemCount - pTable.visibleItemCount;
    var scrollTopInPx; 
    if(selItem >= maxScrollItem)
    {
        // scroll table to the bottom
        scrollTopInPx = pTable.itemCount * pTable.itemHeight;
    }
    else if(selItem < 2)
    {
        // scroll table to the top
        scrollTopInPx = 0;
    }
        else
    {
        // scroll selected item to the 1.2 th position
        scrollTopInPx = (selItem - 1.2) * pTable.itemHeight;
    }

    //$(pTable.jqId + " .ui-datatable-scrollable-body").animate({scrollTop:scrollTopInPx, duration: 20}, scrollTopInPx); 
    $(pTable.jqId + " .ui-datatable-scrollable-body").scrollTop(scrollTopInPx);
}

/**
 * This function scrolls the selected Item of a 
 * <p:dataTable id="idDataTable" selectionMode="single" 
 * into the visible area
 * <p:dataTable renderes to a scroll-container with the css-class: ui-datatable-scrollable-body (inside the element with the id : "idDataTable")
 * and to a container holding all items with the id: "idDataTable"_data 
 *
 * @param idDataTable   z.B.: idForm:idDataTable
 */
function autoScrollPDatatable(idDataTable) 
{
    // for selection in JQuery the ids with : must be encoded with \\:
    var primfcid = idDataTable.replace(':', '\\:');
    var idDataTbl = '#' + primfcid;
    var idDataContainer = idDataTbl  + "_data";

    var totalHeight = $(idDataTbl + " .ui-datatable-scrollable-body").height();
    var lichildren = $(idDataContainer).children("tr");
    var itemHeight = $(idDataContainer).children("tr").height();
    var anzItems = lichildren.length;
    var anzVisItems = totalHeight / itemHeight;
    var selItem = detectDataTableScrollPos(lichildren); 
    if(selItem == -1)
        {
        // no selection found...
        return;
    }

    var maxScrollItem = anzItems - anzVisItems;
    var scrollTopInPx; 
    if(selItem >= maxScrollItem)
    {
        // scroll table to the bottom
        scrollTopInPx = maxScrollItem * itemHeight;
    }
    else if(selItem < 2)
    {
        // scroll table to the top
        scrollTopInPx = 0;
    }
        else
    {
        // scroll selected item to the 1.2 th position
        scrollTopInPx = (selItem - 1.2) * itemHeight;
    }

    $(idDataTbl + " .ui-datatable-scrollable-body").animate({scrollTop:scrollTopInPx}, scrollTopInPx);  
}

function detectDataTableScrollPos(liChildren)
{
    for (i=0;i< liChildren.length;++i)
    {
        var chd = liChildren[i];
        var x = chd.getAttribute("aria-selected");
        if(x === "true")
        {
            return i;
        }
    }
    return -1;
}