/*Escript de paginación*/
function Pager(tableName, itemsPerPage) {
    this.tableName = tableName;
    this.itemsPerPage = itemsPerPage;
    this.currentPage = 1;
    this.pages = 0;//0
    this.inited = false;
    
    this.showRecords = function(from, to) {        
        var rows = document.getElementById(tableName).rows;
        // i  from 1 para evitar el encabezado
        for (var i = 1; i < rows.length; i++) {
            if (i < from || i > to)  
                rows[i].style.display = 'none';
            else
                rows[i].style.display = '';
        }
    }
    
    this.showPage = function(pageNumber) {
    	if (! this.inited) {
    		alert("not inited");
    		return;
    	}

        var oldPageAnchor = document.getElementById('pg'+this.currentPage);
        oldPageAnchor.className = 'pg-normal';
        
        this.currentPage = pageNumber;
        this.showPageNav('pager','pageNavPosition', this.currentPage);
		var newPageAnchor = document.getElementById('pg'+this.currentPage);
        newPageAnchor.className = 'pg-selected';
        
		var PrevStyle = document.getElementById('Pre');
		var NextStyle = document.getElementById('Nex');
		if(pageNumber==1)
			PrevStyle.className='disapear';
		else
			PrevStyle.className='pg-normal';
		if(pageNumber==this.pages)
			NextStyle.className='disapear';
		else
			NextStyle.className='pg-normal';
		
        var from = (pageNumber -1) * itemsPerPage + 1;
        var to = from + itemsPerPage - 1;
        this.showRecords(from, to);
		
		
    }   
    
    this.prev = function() {
        if (this.currentPage > 1)
            this.showPage(this.currentPage - 1);
    }
    
    this.next = function() {
        if (this.currentPage < this.pages) {
            this.showPage(this.currentPage + 1);
        }
    }                        
    
    this.init = function() {
        var rows = document.getElementById(tableName).rows;
        var records = (rows.length - 1); 
        this.pages = Math.ceil(records / itemsPerPage);
        this.inited = true;
    }

    this.showPageNav = function(pagerName,positionId, current) {
    	if (! this.inited) {
    		alert("not inited");
    		return;
    	}
    	var element = document.getElementById(positionId);
    	
		
			//muesta el simbolo de anterior <<
			var pagerHtml = '<span id="Pre" onclick="'+pagerName+'.prev();" class="pg-normal"> &#171 Anterior </span> | ';
		
				
		if(this.pages<6 ){
			first=1;
			last=this.pages;
		} 
		else{ 
			if(current<3){
				first=1;
				//last=5;
			}
			else
				first=current-2;
	
			if(current>this.pages-2){
				last=this.pages;
				//first=this.pages-5;
			}
			else
				last=current+2;
		}
		
			//muestra los numeros de pagina
			for (var page =first ; page <=last ; page++){ 
			pagerHtml += '<span id="pg' + page + '" class="pg-normal" onclick="'+pagerName+'.showPage(' + page + ');">' + page + '</span> | ';
		}
					
			//muesta el simbolo de siguiente >>
			pagerHtml += '<span id="Nex" onclick="'+pagerName+'.next();" class="pg-normal"> Siguiente &#187;</span>';
		
		element.innerHTML = pagerHtml;
    }
}