var nItems = 0;
var currentItem = 0;
var lock = false;
var isRollmupsAuto = true;

function homeActivityPrev(){
    if ( lock ) return false;
    lock = true;

    var position = jQuery('.activity-items').position();
    var newTop = position.top;
    if ( isNaN(newTop) )
        newTop = 0;

    // Check bound
    step = currentItem + 3;
    if ( step > nItems - 3 ) {
        step = nItems - 3;
    }
        
    // We go down 3 items
    for ( i = currentItem; i < step; i++ ) {
        newTop -= jQuery('.activity-items .item').eq(i).height();           
    }
    currentItem = step;
      
    jQuery('.activity-items').animate({'top' : newTop + 'px'}, 'fast', function() { lock = false; });
}

function homeActivityNext(){
    if ( lock ) return false;
    lock = true;   

    var position = jQuery('.activity-items').position();
    var newTop = position.top;
    if ( isNaN(newTop) )
        newTop = 0;

    // Check bound
    step = currentItem - 3;
    if ( step < 0 ) {
        step = 0;
    }
      
    for ( i = currentItem; i > step; i-- ) {
        newTop += jQuery('.activity-items .item').eq(i - 1).height();
    }          
    currentItem = step;
      
    jQuery('.activity-items').animate({'top' : newTop + 'px'}, 'fast', function() { lock = false; });    
}

jQuery(document).ready(function() {
    jQuery('.activity-items').css('position', 'relative');
    nItems = jQuery('.activity-items .item').length;
      
    jQuery('.activity .down').click(function(){
        homeActivityPrev();
        return false;
    });
    jQuery('.activity .up').click(function(){
        homeActivityNext();
        return false;
    });
        
});