<?php namespace ProcessWire;

require_once(dirname(__FILE__) . '/PagerNav.php'); 

/**
 * MarkupPagerNav Module for generating pagination markup
 * 
 * ProcessWire 3.x, Copyright 2016 by Ryan Cramer
 * https://processwire.com
 *
 * #pw-summary Module for generating pagination markup automatically for paginated WireArray types. 
 * #pw-var $pager
 * #pw-instantiate $pager = $modules->get('MarkupPagerNav'); 
 * #pw-summary-options-methods Specific to setting certain options that are typically set automatically. Not necessary to use these unless for a specific purpose. 
 * 
 * #pw-body =
 * This module can create pagination for a `PageArray` or any other kind of `PaginatedArray` type. 
 * Below is an example of creating pagination for a PageArray returned from `$pages->find()`. 
 * ~~~~~
 * // $items can be PageArray or any other kind of PaginatedArray type
 * $items = $pages->find("id>0, limit=10"); // replace id>0 with your selector
 * if($items->count()) {
 *   $pager = $modules->get("MarkupPagerNav");
 *   echo "<ul>" . $items->each("<li>{title}</li>") . "</ul>";
 *   echo $pager->render($items); // render the pagination navigation
 * } else {
 *   echo "<p>Sorry there were no items found</p>";
 * }
 * ~~~~~
 * Here’s a shortcut alternative that you can use for PageArray types (thanks to the `MarkupPageArray` module).
 * Note that in this case, it’s not necessary to load the MarkupPagerNav module yourself:
 * ~~~~~
 * $items = $pages->find("id>0, limit=10"); // replace id>0 with your selector
 * if($items->count()) {
 *   echo "<ul>" . $items->each("<li>{title}</li>") . "</ul>";
 *   echo $items->renderPager(); // render the pagination navigation
 * } else {
 *   echo "<p>Sorry there were no items found</p>";
 * }
 * ~~~~~
 * It’s common to specify different markup and/or classes specific to the need when rendering
 * pagination. This is done by providing an `$options` array to the `MarkupPagerNav::render()` call.
 * In the example below, we'll specify Uikit markup rather then the default markup: 
 * ~~~~~
 * // Change options for Uikit "uk-pagination" navigation
 * $options = array(
 *   'numPageLinks' => 5,
 *   'listClass' => 'uk-pagination',
 *   'linkMarkup' => "<a href='{url}'>{out}</a>",
 *   'currentItemClass' => 'uk-active',
 *   'separatorItemLabel' => '<span>&hellip;</span>',
 *   'separatorItemClass' => 'uk-disabled',
 *   'currentLinkMarkup' => "<span>{out}</span>"
 *   'nextItemLabel' => '<i class="uk-icon-angle-double-right"></i>',
 *   'previousItemLabel' => '<i class="uk-icon-angle-double-left"></i>',
 *   'nextItemClass' => '', // blank out classes irrelevant to Uikit
 *   'previousItemClass' => '',
 *   'lastItemClass' => '',
 * );
 * 
 * $items = $pages->find("id>0, limit=10"); // replace id>0 with your selector
 * 
 * if($items->count()) {
 *   $pager = $modules->get('MarkupPagerNav');
 *   echo "<ul>" . $items->each("<li>{title}</li>") . "</ul>";
 *   echo $pager->render($items, $options); // provide the $options array
 * } else {
 *   echo "<p>Sorry there were no items found</p>";
 * }
 * ~~~~~
 * The full list of options can be seen below. Please note that most options are set automatically since this module can
 * determine most of the needed information directly from the WireArray that it’s given. As a result, it’s often
 * not necessary to change any of the default options unless you want to change the markup and/or classes used in output. 
 * #pw-body
 *
 * @property int $numPageLinks The number of links that the pagination navigation should have, minimum 5 (default=10). #pw-group-general-options
 * @property array $getVars GET vars that should appear in the pagination, or leave empty and populate $input->whitelist (recommended). #pw-group-general-options
 * @property string $baseUrl The base URL from which the navigation item links will start (default=''). #pw-group-general-options
 * @property null|Page $page The current Page, or leave NULL to autodetect. #pw-group-general-options
 * @property string $listMarkup List container markup. Place {out} where you want the individual items rendered and {class} where you want the list class (default="<ul class='{class}' aria-label='{aria-label}'>{out}</ul>"). #pw-group-markup-options
 * @property string $listClass The class name to use in the $listMarkup (default='MarkupPageNav'). #pw-group-class-options
 * @property string $itemMarkup List item markup. Place {class} for item class (required), and {out} for item content. (default="<li class='{class}' aria-label='{aria-label}'>{out}</li>"). #pw-group-markup-options
 * @property string $linkMarkup Link markup. Place {url} for href attribute, and {out} for label content. (default="<a href='{url}'><span>{out}</span></a>"). #pw-group-markup-options
 * @property string $currentLinkMarkup Link markup for current page. Place {url} for href attribute and {out} for label content. (default="<a href='{url}'><span>{out}</span></a>"). #pw-group-markup-options
 * @property string $nextItemLabel label used for the 'Next' button (default='Next'). #pw-group-label-options
 * @property string $previousItemLabel label used for the 'Previous' button (default='Prev'). #pw-group-label-options
 * @property string $separatorItemMarkup Markup to use for the "..." separator item, or NULL to use $itemMarkup (default=NULL). #pw-group-markup-options
 * @property string $separatorItemLabel label used in the separator item (default='&hellip;'). #pw-group-label-options
 * @property string $separatorItemClass Class for separator item (default='MarkupPagerNavSeparator'). #pw-group-class-options
 * @property string $firstItemClass Class for first item (default='MarkupPagerNavFirst'). #pw-group-class-options
 * @property string $firstNumberItemClass Class for first numbered item (default='MarkupPagerNavFirstNum'). #pw-group-class-options
 * @property string $nextItemClass Class for next item (default='MarkupPagerNavNext'). #pw-group-class-options
 * @property string $previousItemClass Class for previous item (default='MarkupPagerNavPrevious'). #pw-group-class-options
 * @property string $lastItemClass Class for last item (default='MarkupPagerNavLast'). #pw-group-class-options
 * @property string $lastNumberItemClass Class for last numbered item (default='MarkupPagerNavLastNum'). #pw-group-class-options
 * @property string $currentItemClass Class for current item (default='MarkupPagerNavOn'). #pw-group-class-options
 * @property string $listAriaLabel Label announcing pagination to screen readers (default='Pagination links'). #pw-group-label-options
 * @property string $itemAriaLabel Label announcing page number to screen readers (default='Page {n}'). #pw-group-label-options
 * @property string $currentItemAriaLabel Label announcing current page to screen readers (default='Page {n}, current page'). #pw-group-label-options
 * @property-write bool $arrayToCSV When arrays are present in getVars, they will be translated to CSV strings in the queryString "?var=a,b,c". If set to false, then arrays will be kept in traditional format: "?var[]=a&var[]=b&var=c". (default=true) #pw-group-other-options
 * @property int $totalItems Get total number of items to paginate (set automatically). #pw-group-other-options
 * @property-read int $itemsPerPage Get number of items to display per page (set automatically, pulled from limit=n). #pw-group-other-options
 * @property int $pageNum Get or set the current page number (1-based, set automatically). #pw-group-other-options
 * @property string $queryString Get or set query string used in links (set automatically, based on $input->whitelist or getVars array). #pw-group-other-options
 * @property-read bool $isLastPage Is the current pagination the last? Set automatically after a render() call. #pw-internal
 * 
 * @method string render(WirePaginatable $items, $options = array())
 *
 */
class MarkupPagerNav extends Wire implements Module {

	public static function getModuleInfo() {
		return array(
			'title' => 'Pager (Pagination) Navigation', 
			'summary' => 'Generates markup for pagination navigation', 
			'version' => 105,
			'permanent' => false, 
			'singular' => false, 
			'autoload' => false, 
			);
	}

	/**
	 * Options to modify the behavior and output of MarkupPagerNav
	 *
	 * Many of these are set automatically. 
	 *
	 */
	protected $options = array(

		// number of links that the pagination navigation should have, minimum 5 (typically 10) 
		'numPageLinks' => 10,	

		// get vars that should appear in the pagination, or leave empty and populate $input->whitelist (preferred)
		'getVars' => array(), 	

		// the baseUrl from which the navigiation item links will start
		'baseUrl' => '',	

		// the current Page, or leave NULL to autodetect
		'page' => null, 	

		// List container markup. Place {out} where you want the individual items rendered. 
		'listMarkup' => "\n<ul class='{class}' role='navigation' aria-label='{aria-label}'>{out}\n</ul>",

		// class attribute for <ul> pagination list
		'listClass' => 'MarkupPagerNav', 

		// List item markup. Place {class} for item class (required), and {out} for item content. 
		'itemMarkup' => "\n\t<li aria-label='{aria-label}' class='{class}' {attr}>{out}</li>",
	
		// Item separator "...", null makes it use the 'itemMarkup' instead (default)
		'separatorItemMarkup' => null,

		// Link markup. Place {url} for href attribute, and {out} for label content. 
		'linkMarkup' => "<a href='{url}'><span>{out}</span></a>", 

		// Link markup for current page. Place {url} for href attribute and {out} for label content. 
		'currentLinkMarkup' => "<a href='{url}'><span>{out}</span></a>", 

		// label used for the 'Next' button
		'nextItemLabel' => 'Next', 

		// label used for the 'Previous' button
		'previousItemLabel' => 'Prev', 

		// label used in the separator item
		'separatorItemLabel' => '&hellip;', 

		// default classes used for list items, according to the type. 
		'separatorItemClass' => 'MarkupPagerNavSeparator', 
		'firstItemClass' => 'MarkupPagerNavFirst', 
		'firstNumberItemClass' => 'MarkupPagerNavFirstNum', 
		'nextItemClass' => 'MarkupPagerNavNext', 
		'previousItemClass' => 'MarkupPagerNavPrevious', 
		'lastItemClass' => 'MarkupPagerNavLast', 
		'lastNumberItemClass' => 'MarkupPagerNavLastNum',
		'currentItemClass' => 'MarkupPagerNavOn', 
		
		// any extra attributes for current item
		'currentItemExtraAttr' => "aria-current='true'",
		
		// aria labels
		'listAriaLabel' => 'Pagination links',
		'itemAriaLabel' => 'Page {n}',
		'currentItemAriaLabel' => 'Page {n}, current page',
		'nextItemAriaLabel' => 'Next page', 
		'previousItemAriaLabel' => 'Previous page',
		'lastItemAriaLabel' => 'Page {n}, last page', 

		/*
		 * NOTE: The following options are set automatically and should not be provided in your $options,
	 	 * because anything you specify will get overwritten. 
		 *
		 */

		// total number of items to paginate (set automatically)
		'totalItems' => 0,	

		// number of items to display per page (set automatically) 
		'itemsPerPage' => 10,	

		// the current page number (1-based, set automatically)
		'pageNum' => 1,		

		// when arrays are present in getVars, they will be translated to CSV strings in the queryString: ?var=a,b,c
		// if set to false, then arrays will be kept in traditional format: ?var[]=a&var[]=b&var=c 
		'arrayToCSV' => true,

		// the queryString used in links (set automatically, based on whitelist or getVars array)
		'queryString' => '', 	
	
		);

	/**
	 * True when the current page is also the last page
	 * 
	 * @var bool|null
	 * 
	 */
	protected $isLastPage = null;

	/**
	 * Prefix to identify page numbers in URL, i.e. page123 or page=123
	 * 
	 * @var string
	 * 
	 */
	protected $pageNumUrlPrefix = 'page';

	/**
	 * Construct
	 * 
	 */
	public function __construct() {
		$this->options['nextItemLabel'] = $this->_('Next');
		$this->options['previousItemLabel'] = $this->_('Prev');
		$this->options['listAriaLabel'] = $this->_('Pagination links');
		$this->options['itemAriaLabel'] = $this->_('Page {n}'); // Page number label // Note that {n} is replaced with pagination number
		$this->options['currentItemAriaLabel'] = $this->_('Page {n}, current page');
		$this->options['nextItemAriaLabel'] = $this->_('Next page');
		$this->options['previousItemAriaLabel'] = $this->_('Previous page');
		$this->options['lastItemAriaLabel'] = $this->_('Page {n}, last page');
	
		// check for all-instance options
		$options = $this->wire('config')->MarkupPagerNav;
		if(is_array($options)) $this->options = array_merge($this->options, $options);
	}

	/**
	 * Render pagination markup
	 * 
	 * ~~~~~
	 * $items = $pages->find("id>0, limit=10"); // replace id>0 with your selector
	 * if($items->count()) {
	 *   echo "<ul>" . $items->each("<li>{title}</li>") . "</ul>";
	 *   $pager = $modules->get("MarkupPagerNav");
	 *   $options = [ 'numPageLinks' => 5 ];
	 *   echo $pager->render($items, $options); // render the pagination navigation
	 * } else {
	 *   echo "<p>Sorry there were no items found</p>";
	 * }
	 * ~~~~~
	 *
	 * @param WirePaginatable|PageArray|PaginatedArray $items Items used in the pagination that have had a "limit=n" selector applied when they were loaded. 
	 * @param array $options Any options to override the defaults. See the `MarkupPagerNav` reference for all options. 
	 * @return string
	 * @see MarkupPageArray::renderPager()
	 *
	 */
	public function ___render(WirePaginatable $items, $options = array()) {

		$config = $this->wire('config');
		$this->isLastPage = true; 
		$this->totalItems = $items->getTotal();
		if(!$this->totalItems) return '';

		$this->options = array_merge($this->options, $options); 
		$limit = $items->getLimit();
		if($limit) $this->itemsPerPage = $limit;
		$this->pageNum = $items->getStart() < $this->itemsPerPage  ? 1 : ceil($items->getStart() / $this->itemsPerPage)+1; 

		if(is_null($this->options['page'])) {
			$this->options['page'] = $this->wire('page');
		}

		if(!strlen($this->queryString)) {
			$whitelist = $this->wire('input')->whitelist->getArray(); 
			if(!count($this->options['getVars']) && count($whitelist)) {
				$this->setGetVars($whitelist);
			} else if(count($this->options['getVars'])) {
				$this->setGetVars($this->getVars);
			}
		}
		
		if($config->pageNumUrlPrefix) {
			$this->pageNumUrlPrefix = $config->pageNumUrlPrefix;
		}

		$pagerNav = new PagerNav($this->totalItems, $this->itemsPerPage, $this->pageNum); 
		$pagerNav->setLabels($this->options['previousItemLabel'], $this->options['nextItemLabel']); 
		$pagerNav->setNumPageLinks($this->numPageLinks); 
		$pager = $pagerNav->getPager();
		$out = '';
	
		$pagerCount = count($pager);
		if($pagerCount > 1) $this->isLastPage = false; 
		$firstNumberKey = null;
		$lastNumberKey = null;

		// determine first and last numbered items
		foreach($pager as $key => $item) {
			if(!ctype_digit("$item->label")) continue;
			if(is_null($firstNumberKey)) $firstNumberKey = $key;
			$lastNumberKey = $key;
		}
		
		$_url = ''; // URL from previous loop interation
		$nextURL = '';
		$prevURL = '';
		$lastWasCurrent = false; // was the last iteration for the current page item?
		
		foreach($pager as $key => $item) {

			if($item->type == 'separator') {
				$out .= $this->renderItemSeparator();
				continue; 
			} 
			
			$url = $this->getURL($item->pageNum); 
			$classes = array();
			
			if($item->type != 'first' && $item->type != 'last' && isset($this->options[$item->type . 'ItemClass'])) {
				$classes[] = $this->options[$item->type . 'ItemClass'];
			}

			if(!$key) {
				$classes[] = $this->options['firstItemClass'];
			} else if($key == ($pagerCount-1)) {
				$classes[] = $this->options['lastItemClass'];
			}

			if($key === $firstNumberKey) {
				$classes[] = $this->options['firstNumberItemClass'];
			} else if($key === $lastNumberKey) {
				$classes[] = $this->options['lastNumberItemClass'];
				if($item->type == 'current') $this->isLastPage = true; 
			}

			$itemExtraAttr = '';
			if($item->type == 'current') {
				$itemAriaLabel = $this->options['currentItemAriaLabel'];
				$itemExtraAttr = ' ' . $this->options['currentItemExtraAttr'];
			} else if($item->type == 'previous') {
				$itemAriaLabel = $this->options['previousItemAriaLabel'];
			} else if($item->type == 'next') {
				$itemAriaLabel = $this->options['nextItemAriaLabel'];
			} else if($item->type == 'last') {
				$itemAriaLabel = $this->options['lastItemAriaLabel'];
			} else {
				$itemAriaLabel = $this->options['itemAriaLabel'];
			}
			$itemAriaLabel = str_replace('{n}', $item->pageNum, $itemAriaLabel);
			
			if(isset($this->options[$item->type . 'LinkMarkup'])) {
				$linkMarkup = $this->options[$item->type . 'LinkMarkup'];
			} else {
				$linkMarkup = $this->options['linkMarkup'];
			}
			$link = str_replace(array('{url}', '{out}'), array($url, $item->label), $linkMarkup);
			
			$out .= str_replace(
				array(
					'{class}', 
					'{out}', 
					'{aria-label}', 
					' {attr}',
					'{attr}'
				), 
				array(
					implode(' ', $classes),
					$link, 
					$itemAriaLabel,
					$itemExtraAttr,
					$itemExtraAttr
				), 
				$this->options['itemMarkup']
			);
			
			if($item->type == 'current') {
				$prevURL = $_url;
				$lastWasCurrent = true;
			} else {
				if($lastWasCurrent) $nextURL = $url;
				$lastWasCurrent = false;
			}
			
			$_url = $url; // remember previous url
		}

		if($out) {
			$out = str_replace(array(
				'{class}',
				'{aria-label}',
				'{out}',
				" class=''", 
				' class=""'
			), array(
				$this->options['listClass'],
				$this->options['listAriaLabel'],
				$out,
				'',
				''
			), $this->options['listMarkup']);

			if($nextURL || $prevURL) $this->updateConfigVars($nextURL, $prevURL); 
		}
		
		return $out; 
	}

	/**
	 * Render the "..." item separator 
	 * 
	 * @return string
	 * 
	 */
	protected function renderItemSeparator() {
		if($this->options['separatorItemMarkup'] !== null) {
			$markup = $this->options['separatorItemMarkup'];
		} else {
			$markup = $this->options['itemMarkup'];
		}
		return str_replace(
			array(
				'{class}',
				'{out}',
				'{aria-label}',
				' {attr}', // optionally with leading space
				'{attr}'
			),
			array(
				$this->options['separatorItemClass'],
				$this->options['separatorItemLabel'],
				'',
				'',
				''
			),
			$markup
		);
	}

	/**
	 * Retrieve a MarkupPagerNav option as an object property
	 * 
	 * @param string $property
	 * @return mixed
	 *
	 */
	public function __get($property) {
		if(isset($this->options[$property])) return $this->options[$property]; 
		if($property == 'isLastPage') return $this->isLastPage; 
		return null;
	}

	/**
	 * Set a MarkupPagerNav option as an object property
	 * 
	 * @param string $property
	 * @param mixed $value
	 *
	 */
	public function __set($property, $value) {
		if(isset($this->options[$property])) $this->options[$property] = $value; 
	}

	/**
	 * Returns true when the current pagination is the last one
	 *
	 * Only set after a render() call. Prior to that it is null.
	 * 
	 * #pw-internal
	 *
	 * @return bool|null
	 *
	 */
	public function isLastPage() {
		return $this->isLastPage;
	}

	/**
	 * Get all options or set options
	 * 
	 * - See the main `MarkupPagerNav` documentation for a list of all available options. 
	 * - When used to set options this method should be called before the `MarkupPagerNav::render()` method.
	 * - Options can also be set as a 2nd argument to the `MarkupPagerNav::render()` method. 
	 * 
	 * ~~~~~
	 * // Getting options
	 * echo "<pre>" . print_r($pager->options(), true) . "</pre>";
	 * 
	 * // Setting options
	 * $pager->options([ 'numPageLinks' => 5 ]); 
	 * echo $pager->render($items);
	 * 
	 * // Alternative that does the same as above
	 * echo $pager->render($items, [ 'numPageLinks' => 5 ]); 
	 * ~~~~~
	 * 
	 * @param array $options Associative array of options you want to set, or omit to just return all available/current options.
	 * @return array Returns associative array if options with all current values.
	 * @since 3.0.44
	 * 
	 */
	public function options(array $options = array()) {
		if(!empty($options)) {
			$this->options = array_merge($this->options, $options);
		}
		return $this->options;
	}

	/*************************************************************************************************
	 * All the methods below are optional and typically set automatically, or via the $options param. 
	 *
	 */
	
	/**
	 * Set the getVars for this MarkupPagerNav
	 *
	 * Generates $this->options['queryString'] automatically.
	 * 
	 * #pw-group-method-options
	 *
	 * @param array $vars Array of GET vars indexed as ($key => $value)
	 *
	 */
	public function setGetVars(array $vars) {
		$this->options['getVars'] = $vars;
		$queryString = "?";
		foreach($this->options['getVars'] as $key => $value) {
			if(is_array($value)) {
				if($this->options['arrayToCSV']) {
					$a = $value;
					$value = '';
					foreach($a as $k => $v) $value .= "$v,";
					$value = rtrim($value, ", ");
					$queryString .= "$key=" . urlencode($value) . "&";
				} else {
					foreach($value as $k => $v) $queryString .= "$key%5B%5D=" . urlencode($v) . "&";
				}

			} else {
				$queryString .= "$key=" . urlencode($value) . "&";
			}
		}
		$this->queryString = htmlspecialchars(rtrim($queryString, "?&"));
	}


	/**
	 * Set the current page number
	 * 
	 * #pw-group-method-options
	 * 
	 * @param int $n
	 * 
	 */
	public function setPageNum($n) { $this->pageNum = $n; }

	/**
	 * Set the number of items shown per page
	 * 
	 * #pw-group-method-options
	 * 
	 * @param int $n
	 * 
	 */
	public function setItemsPerPage($n) { $this->itemsPerPage = $n; }

	/**
	 * Set the total number of items
	 * 
	 * #pw-group-method-options
	 * 
	 * @param int $n
	 * 
	 */
	public function setTotalItems($n) { $this->totalItems = $n; }

	/**
	 * Set the number of pagination links to use
	 * 
	 * #pw-group-method-options
	 * 
	 * @param int $n
	 * 
	 */
	public function setNumPageLinks($n) { $this->numPageLinks = $n; }

	/**
	 * Set the query string
	 * 
	 * #pw-group-method-options
	 * 
	 * @param string $s Already-sanitized/validated query string
	 * 
	 */
	public function setQueryString($s) { $this->queryString = $s; }

	/**
	 * Set the base URL for pagination
	 * 
	 * #pw-group-method-options
	 * 
	 * @param string $url
	 * 
	 */
	public function setBaseUrl($url) { $this->baseUrl = $url; }

	/**
	 * Set the "next" and "prev" labels
	 * 
	 * #pw-group-method-options
	 * 
	 * @param string $next
	 * @param string $prev
	 * 
	 */
	public function setLabels($next, $prev) { 
		$this->options['nextItemLabel'] = $next; 
		$this->options['previousItemLabel'] = $prev; 
	}

	/**
	 * Get URL for given pagination number
	 * 
	 * Requires that render() method has already started or been previously called. 
	 *
	 * @param int $pageNum
	 * @param bool $http Include scheme and hostname?
	 * @return string
	 *
	 */
	public function getURL($pageNum, $http = false) {

		/** @var Page $page */
		$page = $this->options['page'];
		$template = $page->template;
		if($this->baseUrl) {
			$url = $this->baseUrl;
		} else if($http) {
			$url = $page->httpUrl();
		} else {
			$url = $page->url();
		}

		if($pageNum > 1) {
			if($template->allowPageNum) {
				// if allowPageNum is true, then we can use urlSegment style page numbers rather than GET var page numbers	
				if($template->slashUrls === 0) $url .= '/'; // enforce a trailing slash, regardless of slashUrls template setting
				$url .= $this->pageNumUrlPrefix . $pageNum;
				if($template->slashPageNum > 0) $url .= '/';
				$url .= $this->queryString;
			} else {
				// query string style pagination
				$url .= $this->queryString . (strlen($this->queryString) ? "&" : "?") . "$this->pageNumUrlPrefix=$pageNum";
			}
		} else {
			$url .= $this->queryString;
		}

		return $url;
	}

	/**
	 * Populate $config->urls->next, $config->urls->prev, and $config->pagerHeadTags
	 *
	 * @param string $nextURL
	 * @param string $prevURL
	 *
	 */
	protected function updateConfigVars($nextURL, $prevURL) {

		/** @var Config $config */
		$config = $this->wire('config');
		$httpRoot = $this->wire('input')->httpHostUrl();
		$pagerHeadTags = '';

		if($nextURL) {
			$config->urls->next = $nextURL;
			$pagerHeadTags .= "<link rel=\"next\" href=\"$httpRoot$nextURL\" />";
		}

		if($prevURL) {
			$config->urls->prev = $prevURL;
			$pagerHeadTags .= "<link rel=\"prev\" href=\"$httpRoot$prevURL\" />";
		}

		$config->set('pagerHeadTags', $pagerHeadTags);
	}
	
	/* 
	 * The following methods are specific to the Module interface 
 	 *
	 */

	public function init() { }	
	public function ___install() { }
	public function ___uninstall() { }

}