<?php
/**
 * patTemplate modfifier Tail
 *
 * $Id$
 *
 * @package patTemplate
 * @package Modifiers
 * @author gERD Schaufelberger <gerd@php-tools.net>
 */

/**
 * patTemplate modifier Tail
 *
 * Parameter:
 *
 * @package patTemplate
 * @package Modifiers
 * @author gERD Schaufelberger <gerd@php-tools.net>
 */
class patTemplate_Modifier_Tail extends patTemplate_Modifier
{
    /**
     * modify the value
     *
     * @param string value
     * @param array list of parameter
     * @return string modified value
     */
    public function modify($value, $params = array())
    {
        $params =   array_merge(array(
                    'start'     =>  1,
                    'lines'     =>  0,
                    ), $params);
        $params['start']    =   intval($params['start']);
        $params['lines']    =   intval($params['lines']);

        $lines  =   explode("\n", $value);
        $cnt    =   count($lines);

        // start from top or bottom
        if (0 > $params['start']) {
            $params['start']    =   max(array(0, $cnt + $params['start']));
        }

        // start after the end?
        if ($cnt < $params['start']) {
            return '';
        }

        $out    =   array();
        for ($i = 0; $i < count($lines); ++$i) {
            if ($i > $params['start']) {
                continue;
            }

            $out[]  =   $lines[$i];
            if (0 < $params['lines'] && $params['lines'] <= count($out)) {
                break;
            }
        }

        return implode("\n", $out);
    }

}