From abd269aa78d72392278e1491bf69ec3f191eed51 Mon Sep 17 00:00:00 2001
From: Taylor Otwell <taylorotwell@gmail.com>
Date: Wed, 20 Jul 2011 23:31:02 -0500
Subject: [PATCH] initial version of pagination library.

---
 system/db/query.php  |  21 ++++-
 system/html.php      |  12 +++
 system/paginator.php | 220 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 252 insertions(+), 1 deletion(-)
 create mode 100644 system/paginator.php

diff --git a/system/db/query.php b/system/db/query.php
index 68aaae4e..c763c431 100644
--- a/system/db/query.php
+++ b/system/db/query.php
@@ -1,8 +1,8 @@
 <?php namespace System\DB;
 
 use System\DB;
-use System\Config;
 use System\Str;
+use System\Config;
 
 class Query {
 
@@ -447,6 +447,25 @@ class Query {
 		return $this->first()->aggregate;
 	}
 
+	/**
+	 * Get paginated query results.
+	 *
+	 * @param  int        $per_page
+	 * @return Paginator
+	 */
+	public function paginate($per_page)
+	{
+		$total = $this->count();
+
+		// Reset the SELECT clause so we can execute another query to get the results.
+		$this->select = null;
+
+		// Get the current page from the Paginator. The Paginator class will validate the page number.
+		$page = \System\Paginator::page(ceil($total / $per_page));
+
+		return new \System\Paginator($this->skip(($page - 1) * $per_page)->take($per_page)->get(), $total, $per_page);
+	}
+
 	/**
 	 * Execute an INSERT statement.
 	 *
diff --git a/system/html.php b/system/html.php
index b568efc5..5410d301 100644
--- a/system/html.php
+++ b/system/html.php
@@ -35,6 +35,18 @@ class HTML {
 		return '<link href="'.static::entities(URL::to_asset($url)).'" rel="stylesheet" type="text/css" media="'.$media.'">'.PHP_EOL;
 	}
 
+	/**
+	 * Generate an HTML span tag.
+	 *
+	 * @param  string  $value
+	 * @param  array   $attributes
+	 * @return string
+	 */
+	public static function span($value, $attributes = array())
+	{
+		return '<span'.static::attributes($attributes).'>'.static::entities($value).'</span>';
+	}
+
 	/**
 	 * Generate a HTML link.
 	 *
diff --git a/system/paginator.php b/system/paginator.php
new file mode 100644
index 00000000..7989615e
--- /dev/null
+++ b/system/paginator.php
@@ -0,0 +1,220 @@
+<?php namespace System;
+
+class Paginator {
+
+	/**
+	 * The results for the current page.
+	 *
+	 * @var array
+	 */
+	public $results;
+
+	/**
+	 * The total number of results.
+	 *
+	 * @var int
+	 */
+	public $total;
+
+	/**
+	 * The current page.
+	 *
+	 * @var int
+	 */
+	public $page;
+
+	/**
+	 * The number of items per page.
+	 *
+	 * @var int
+	 */
+	public $per_page;
+
+	/**
+	 * The last page number.
+	 *
+	 * @var int
+	 */
+	public $last_page;
+
+	/**
+	 * Create a new Paginator instance.
+	 *
+	 * @param  array  $results
+	 * @param  int    $total
+	 * @param  int    $per_page
+	 * @return void
+	 */
+	public function __construct($results, $total, $per_page)
+	{
+		$this->per_page = $per_page;
+		$this->results = $results;
+		$this->total = $total;
+
+		// Validate and set the current page. If the given page is greater than the last page, the
+		// current page will be set to the last page. If the given page is not an integer or is less
+		// than 1, the current page will be set to 1.
+		$this->page = static::page($this->last_page());
+	}
+
+	/**
+	 * Get the current page from the request query string.
+	 *
+	 * @param  int  $last_page
+	 * @return int
+	 */
+	public static function page($last_page)
+	{
+		$page = Input::get('page', 1);
+
+		if (is_numeric($page) and $page > $last_page)
+		{
+			return $last_page;
+		}
+
+		return (filter_var($page, FILTER_VALIDATE_INT) === false or $page < 1) ? 1 : $page;
+	}
+
+	/**
+	 * Create the HTML pagination links.
+	 *
+	 * @param  int     $adjacent
+	 * @return string
+	 */
+	public function links($adjacent = 3)
+	{
+		if ($this->last_page() > 1)
+		{
+			return '<div class="pagination">'.$this->previous().$this->numbers($adjacent).$this->next();
+		}
+
+		return '';
+	}
+
+	/**
+	 * Generate the HTML numeric page links.
+	 *
+	 * @param  int     $adjacent
+	 * @return string
+	 */
+	public function numbers($adjacent = 3)
+	{
+		// If there are not enough pages to make it worth sliding, we will show all of the pages.
+		//
+		// We add "7" for the constant elements in a slider: the first and last two links, the
+		// current page, and the two "..." strings.
+		return ($this->last_page() < 7 + ($adjacent * 2)) ? $this->range(1, $this->last_page()) : $this->slider($adjacent);
+	}
+
+	/**
+	 * Build sliding list of HTML numeric page links.
+	 *
+	 * @param  int     $adjacent
+	 * @return string
+	 */
+	protected function slider($adjacent)
+	{
+		$pagination = '';
+
+		if ($this->page <= $adjacent * 2)
+		{
+			// Buffer the current page with four pages to the right. Any more pages will interfere with hiding.
+			$pagination .= $this->range(1, 4 + ($adjacent * 2)).$this->ending();
+		}
+		elseif ($this->page >= $this->last_page() - ($adjacent * 2))
+		{
+			// Buffer with at least two pages to the left of the current page.
+			$pagination .= $this->beginning().$this->range($this->last_page() - 2 - ($adjacent * 2), $this->last_page());
+		}
+		else
+		{
+			$pagination .= $this->beginning().$this->range($this->page - $adjacent, $this->page + $adjacent).$this->ending();
+		}
+
+		return $pagination;
+	}
+
+	/**
+	 * Generate the "previous" HTML link.
+	 *
+	 * @param  string  $value
+	 * @return string
+	 */
+	public function previous($value = '&laquo; Previous')
+	{
+		if ($this->page > 1)
+		{
+			return HTML::link(Request::uri().'?page='.($this->page - 1), $value, array('class' => 'prev_page')).' ';
+		}
+
+		return HTML::span($value, array('class' => 'disabled prev_page')).' ';
+	}
+
+	/**
+	 * Generate the "next" HTML link.
+	 *
+	 * @param  string  $value
+	 * @return string
+	 */
+	public function next($value = 'Next &raquo;')
+	{
+		if ($this->page < $this->last_page())
+		{
+			return HTML::link(Request::uri().'?page='.($this->page + 1), $value, array('class' => 'next_page'));
+		}
+
+		return HTML::span($value, array('class' => 'disabled next_page'));
+	}
+
+	/**
+	 * Build the first two page links for a sliding page range.
+	 *
+	 * @return string
+	 */
+	protected function beginning()
+	{
+		return $this->range(1, 2).' ... ';
+	}
+
+	/**
+	 * Build the last two page links for a sliding page range.
+	 *
+	 * @return string
+	 */
+	protected function ending()
+	{
+		return ' ... '.$this->range($this->last_page() - 1, $this->last_page());
+	}
+
+	/**
+	 * Calculate the last page based on the last page and the items per page.
+	 *
+	 * @return int
+	 */
+	protected function last_page()
+	{
+		return ceil($this->total / $this->per_page);
+	}
+
+	/**
+	 * Build a range of page links. 
+	 *
+	 * For the current page, an HTML span element will be generated instead of a link.
+	 *
+	 * @param  int  $start
+	 * @param  int  $end
+	 * @return string
+	 */
+	protected function range($start, $end)
+	{
+		$pages = '';
+
+		for ($i = $start; $i <= $end; $i++)
+		{
+			$pages .= ($this->page == $i) ? HTML::span($i, array('class' => 'current')).' ' : HTML::link(Request::uri().'?page='.$i, $i).' ';
+		}
+
+		return $pages;
+	}
+
+}
\ No newline at end of file