<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	http://codeigniter.com
 * @since	Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Pagination Class
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Pagination
 * @author		EllisLab Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/pagination.html
 */
class CI_Pagination {

    /**
     * Base URL
     *
     * The page that we're linking to
     *
     * @var	string
     */
    protected $base_url		= '';

    /**
     * Prefix
     *
     * @var	string
     */
    protected $prefix = '';

    /**
     * Suffix
     *
     * @var	string
     */
    protected $suffix = '';

    /**
     * Total number of items
     *
     * @var	int
     */
    protected $total_rows = 0;

    /**
     * Number of links to show
     *
     * Relates to "digit" type links shown before/after
     * the currently viewed page.
     *
     * @var	int
     */
    protected $num_links = 2;

    /**
     * Items per page
     *
     * @var	int
     */
    public $per_page = 10;

    /**
     * Current page
     *
     * @var	int
     */
    public $cur_page = 0;

    /**
     * Use page numbers flag
     *
     * Whether to use actual page numbers instead of an offset
     *
     * @var	bool
     */
    protected $use_page_numbers = FALSE;

    /**
     * First link
     *
     * @var	string
     */
    protected $first_link = '&lsaquo; First';

    /**
     * Next link
     *
     * @var	string
     */
    protected $next_link = '&gt;';

    /**
     * Previous link
     *
     * @var	string
     */
    protected $prev_link = '&lt;';

    /**
     * Last link
     *
     * @var	string
     */
    protected $last_link = 'Last &rsaquo;';

    /**
     * URI Segment
     *
     * @var	int
     */
    protected $uri_segment = 0;

    /**
     * Full tag open
     *
     * @var	string
     */
    protected $full_tag_open = '';

    /**
     * Full tag close
     *
     * @var	string
     */
    protected $full_tag_close = '';

    /**
     * First tag open
     *
     * @var	string
     */
    protected $first_tag_open = '';

    /**
     * First tag close
     *
     * @var	string
     */
    protected $first_tag_close = '';

    /**
     * Last tag open
     *
     * @var	string
     */
    protected $last_tag_open = '';

    /**
     * Last tag close
     *
     * @var	string
     */
    protected $last_tag_close = '';

    /**
     * First URL
     *
     * An alternative URL for the first page
     *
     * @var	string
     */
    protected $first_url = '';

    /**
     * Current tag open
     *
     * @var	string
     */
    protected $cur_tag_open = '<strong>';

    /**
     * Current tag close
     *
     * @var	string
     */
    protected $cur_tag_close = '</strong>';

    /**
     * Next tag open
     *
     * @var	string
     */
    protected $next_tag_open = '';

    /**
     * Next tag close
     *
     * @var	string
     */
    protected $next_tag_close = '';

    /**
     * Previous tag open
     *
     * @var	string
     */
    protected $prev_tag_open = '';

    /**
     * Previous tag close
     *
     * @var	string
     */
    protected $prev_tag_close = '';

    /**
     * Number tag open
     *
     * @var	string
     */
    protected $num_tag_open = '';

    /**
     * Number tag close
     *
     * @var	string
     */
    protected $num_tag_close = '';

    /**
     * Page query string flag
     *
     * @var	bool
     */
    protected $page_query_string = FALSE;

    /**
     * Query string segment
     *
     * @var	string
     */
    protected $query_string_segment = 'per_page';

    /**
     * Display pages flag
     *
     * @var	bool
     */
    protected $display_pages = TRUE;

    /**
     * Attributes
     *
     * @var	string
     */
    protected $_attributes = '';

    /**
     * Link types
     *
     * "rel" attribute
     *
     * @see	CI_Pagination::_attr_rel()
     * @var	array
     */
    protected $_link_types = array();

    /**
     * Reuse query string flag
     *
     * @var	bool
     */
    protected $reuse_query_string = FALSE;

    /**
     * Use global URL suffix flag
     *
     * @var	bool
     */
    protected $use_global_url_suffix = FALSE;

    /**
     * Data page attribute
     *
     * @var	string
     */
    protected $data_page_attr = 'data-ci-pagination-page';

    /**
     * CI Singleton
     *
     * @var	object
     */
    protected $CI;

    // --------------------------------------------------------------------

    /**
     * Constructor
     *
     * @param	array	$params	Initialization parameters
     * @return	void
     */
    public function __construct($params = array())
    {
        $this->CI =& get_instance();
        $this->CI->load->language('pagination');
        foreach (array('first_link', 'next_link', 'prev_link', 'last_link') as $key)
        {
            if (($val = $this->CI->lang->line('pagination_'.$key)) !== FALSE)
            {
                $this->$key = $val;
            }
        }

        $this->initialize($params);
        log_message('info', 'Pagination Class Initialized');
    }

    // --------------------------------------------------------------------

    /**
     * Initialize Preferences
     *
     * @param	array	$params	Initialization parameters
     * @return	CI_Pagination
     */
    public function initialize(array $params = array())
    {
        isset($params['attributes']) OR $params['attributes'] = array();
        if (is_array($params['attributes']))
        {
            $this->_parse_attributes($params['attributes']);
            unset($params['attributes']);
        }

        // Deprecated legacy support for the anchor_class option
        // Should be removed in CI 3.1+
        if (isset($params['anchor_class']))
        {
            empty($params['anchor_class']) OR $attributes['class'] = $params['anchor_class'];
            unset($params['anchor_class']);
        }

        foreach ($params as $key => $val)
        {
            if (property_exists($this, $key))
            {
                $this->$key = $val;
            }
        }

        if ($this->CI->config->item('enable_query_strings') === TRUE)
        {
            $this->page_query_string = TRUE;
        }

        if ($this->use_global_url_suffix === TRUE)
        {
            $this->suffix = $this->CI->config->item('url_suffix');
        }

        return $this;
    }

    // --------------------------------------------------------------------

    /**
     * Generate the pagination links
     *
     * @return	string
     */
    public function create_links()
    {
        // If our item count or per-page total is zero there is no need to continue.
        // Note: DO NOT change the operator to === here!
        if ($this->total_rows == 0 OR $this->per_page == 0)
        {
            return '';
        }

        // Calculate the total number of pages
        $num_pages = (int) ceil($this->total_rows / $this->per_page);

        // Is there only one page? Hm... nothing more to do here then.
        if ($num_pages === 1)
        {
            return '';
        }

        // Check the user defined number of links.
        $this->num_links = (int) $this->num_links;

        if ($this->num_links < 0)
        {
            show_error('Your number of links must be a non-negative number.');
        }

        // Keep any existing query string items.
        // Note: Has nothing to do with any other query string option.
        if ($this->reuse_query_string === TRUE)
        {
            $get = $this->CI->input->get();

            // Unset the controll, method, old-school routing options
            unset($get['c'], $get['m'], $get[$this->query_string_segment]);
        }
        else
        {
            $get = array();
        }

        // Put together our base and first URLs.
        // Note: DO NOT append to the properties as that would break successive calls
        $base_url = trim($this->base_url);
        $first_url = $this->first_url;

        $query_string = '';
        $query_string_sep = (strpos($base_url, '?') === FALSE) ? '?' : '&amp;';

        // Are we using query strings?
        if ($this->page_query_string === TRUE)
        {
            // If a custom first_url hasn't been specified, we'll create one from
            // the base_url, but without the page item.
            if ($first_url === '')
            {
                $first_url = $base_url;

                // If we saved any GET items earlier, make sure they're appended.
                if ( ! empty($get))
                {
                    $first_url .= $query_string_sep.http_build_query($get);
                }
            }

            // Add the page segment to the end of the query string, where the
            // page number will be appended.
            $base_url .= $query_string_sep.http_build_query(array_merge($get, array($this->query_string_segment => '')));
        }
        else
        {
            // Standard segment mode.
            // Generate our saved query string to append later after the page number.
            if ( ! empty($get))
            {
                $query_string = $query_string_sep.http_build_query($get);
                $this->suffix .= $query_string;
            }

            // Does the base_url have the query string in it?
            // If we're supposed to save it, remove it so we can append it later.
            if ($this->reuse_query_string === TRUE && ($base_query_pos = strpos($base_url, '?')) !== FALSE)
            {
                $base_url = substr($base_url, 0, $base_query_pos);
            }

            if ($first_url === '')
            {
                $first_url = $base_url.$query_string;
            }

            $base_url = rtrim($base_url, '/').'/';
        }

        // Determine the current page number.
        $base_page = ($this->use_page_numbers) ? 1 : 0;

        // Are we using query strings?
        if ($this->page_query_string === TRUE)
        {
            $this->cur_page = $this->CI->input->get($this->query_string_segment);
        }
        else
        {
            // Default to the last segment number if one hasn't been defined.
            if ($this->uri_segment === 0)
            {
                $this->uri_segment = count($this->CI->uri->segment_array());
            }

            $this->cur_page = $this->CI->uri->segment($this->uri_segment);

            // Remove any specified prefix/suffix from the segment.
            if ($this->prefix !== '' OR $this->suffix !== '')
            {
                $this->cur_page = str_replace(array($this->prefix, $this->suffix), '', $this->cur_page);
            }
        }

        // If something isn't quite right, back to the default base page.
        if ( ! ctype_digit($this->cur_page) OR ($this->use_page_numbers && (int) $this->cur_page === 0))
        {
            $this->cur_page = $base_page;
        }
        else
        {
            // Make sure we're using integers for comparisons later.
            $this->cur_page = (int) $this->cur_page;
        }

        // Is the page number beyond the result range?
        // If so, we show the last page.
        if ($this->use_page_numbers)
        {
            if ($this->cur_page > $num_pages)
            {
                $this->cur_page = $num_pages;
            }
        }
        elseif ($this->cur_page > $this->total_rows)
        {
            $this->cur_page = ($num_pages - 1) * $this->per_page;
        }

        $uri_page_number = $this->cur_page;

        // If we're using offset instead of page numbers, convert it
        // to a page number, so we can generate the surrounding number links.
        if ( ! $this->use_page_numbers)
        {
            $this->cur_page = (int) floor(($this->cur_page/$this->per_page) + 1);
        }

        // Calculate the start and end numbers. These determine
        // which number to start and end the digit links with.
        $start	= (($this->cur_page - $this->num_links) > 0) ? $this->cur_page - ($this->num_links - 1) : 1;
        $end	= (($this->cur_page + $this->num_links) < $num_pages) ? $this->cur_page + $this->num_links : $num_pages;

        // And here we go...
        $output = '';

        // Render the "First" link.
        if ($this->first_link !== FALSE && $this->cur_page > ($this->num_links + 1 + ! $this->num_links))
        {
            // Take the general parameters, and squeeze this pagination-page attr in for JS frameworks.
            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, 1);

            $output .= $this->first_tag_open.'<a href="'.$first_url.'"'.$attributes.$this->_attr_rel('start').'>'
                .$this->first_link.'</a>'.$this->first_tag_close;
        }

        // Render the "Previous" link.
        if ($this->prev_link !== FALSE && $this->cur_page !== 1)
        {
            $i = ($this->use_page_numbers) ? $uri_page_number - 1 : $uri_page_number - $this->per_page;

            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, ($this->cur_page - 1));

            if ($i === $base_page)
            {
                // First page
                $output .= $this->prev_tag_open.'<a href="'.$first_url.'"'.$attributes.$this->_attr_rel('prev').'>'
                    .$this->prev_link.'</a>'.$this->prev_tag_close;
            }
            else
            {
                $append = $this->prefix.$i.$this->suffix;
                $output .= $this->prev_tag_open.'<a href="'.$base_url.$append.'"'.$attributes.$this->_attr_rel('prev').'>'
                    .$this->prev_link.'</a>'.$this->prev_tag_close;
            }

        }

        // Render the pages
        if ($this->display_pages !== FALSE)
        {
            // Write the digit links
            for ($loop = $start - 1; $loop <= $end; $loop++)
            {
                $i = ($this->use_page_numbers) ? $loop : ($loop * $this->per_page) - $this->per_page;

                $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, $loop);

                if ($i >= $base_page)
                {
                    if ($this->cur_page === $loop)
                    {
                        // Current page
                        $output .= $this->cur_tag_open.$loop.$this->cur_tag_close;
                    }
                    elseif ($i === $base_page)
                    {
                        // First page
                        $output .= $this->num_tag_open.'<a href="'.$first_url.'"'.$attributes.$this->_attr_rel('start').'>'
                            .$loop.'</a>'.$this->num_tag_close;
                    }
                    else
                    {
                        $append = $this->prefix.$i.$this->suffix;
                        $output .= $this->num_tag_open.'<a href="'.$base_url.$append.'"'.$attributes.'>'
                            .$loop.'</a>'.$this->num_tag_close;
                    }
                }
            }
        }

        // Render the "next" link
        if ($this->next_link !== FALSE && $this->cur_page < $num_pages)
        {
            $i = ($this->use_page_numbers) ? $this->cur_page + 1 : $this->cur_page * $this->per_page;

            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, $this->cur_page + 1);

            $output .= $this->next_tag_open.'<a href="'.$base_url.$this->prefix.$i.$this->suffix.'"'.$attributes
                .$this->_attr_rel('next').'>'.$this->next_link.'</a>'.$this->next_tag_close;
        }

        // Render the "Last" link
        if ($this->last_link !== FALSE && ($this->cur_page + $this->num_links + ! $this->num_links) < $num_pages)
        {
            $i = ($this->use_page_numbers) ? $num_pages : ($num_pages * $this->per_page) - $this->per_page;

            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, $num_pages);

            $output .= $this->last_tag_open.'<a href="'.$base_url.$this->prefix.$i.$this->suffix.'"'.$attributes.'>'
                .$this->last_link.'</a>'.$this->last_tag_close;
        }

        // Kill double slashes. Note: Sometimes we can end up with a double slash
        // in the penultimate link so we'll kill all double slashes.
        $output = preg_replace('#([^:"])//+#', '\\1/', $output);

        // Add the wrapper HTML if exists
        return $this->full_tag_open.$output.$this->full_tag_close;
    }

    // --------------------------------------------------------------------

    /**
     * Parse attributes
     *
     * @param	array	$attributes
     * @return	void
     */
    protected function _parse_attributes($attributes)
    {
        isset($attributes['rel']) OR $attributes['rel'] = TRUE;
        $this->_link_types = ($attributes['rel'])
            ? array('start' => 'start', 'prev' => 'prev', 'next' => 'next')
            : array();
        unset($attributes['rel']);

        $this->_attributes = '';
        foreach ($attributes as $key => $value)
        {
            $this->_attributes .= ' '.$key.'="'.$value.'"';
        }
    }

    // --------------------------------------------------------------------

    /**
     * Add "rel" attribute
     *
     * @link	http://www.w3.org/TR/html5/links.html#linkTypes
     * @param	string	$type
     * @return	string
     */
    protected function _attr_rel($type)
    {
        if (isset($this->_link_types[$type]))
        {
            unset($this->_link_types[$type]);
            return ' rel="'.$type.'"';
        }

        return '';
    }


    // --------------------------------------------------------------------

    /**
     * Generate the pagination links (v2)
     *
     * @return	string
     */
    public function dr_links()
    {
        // If our item count or per-page total is zero there is no need to continue.
        if ($this->total_rows === 0 OR $this->per_page === 0)
        {
            return '';
        }

        // Calculate the total number of pages
        $num_pages = (int) ceil($this->total_rows / $this->per_page);

        // Is there only one page? Hm... nothing more to do here then.
        if ($num_pages === 1)
        {
            return '';
        }

        // Check the user defined number of links.
        $this->num_links = (int) $this->num_links;

        if ($this->num_links < 1)
        {
            show_error('Your number of links must be a positive number.');
        }

        $CI =& get_instance();

        // Keep any existing query string items.
        // Note: Has nothing to do with any other query string option.
        if ($this->reuse_query_string === TRUE)
        {
            $get = $CI->input->get();

            // Unset the controll, method, old-school routing options
            unset($get['c'], $get['m'], $get[$this->query_string_segment]);
        }
        else
        {
            $get = array();
        }

        // Put together our base and first URLs.
        $this->base_url = trim($this->base_url);
        $this->first_url = $this->base_url;


        // Determine the current page number.
        $base_page = ($this->use_page_numbers) ? 1 : 0;

        $this->cur_page = max(1, (int)$CI->input->get($this->query_string_segment));

        // If something isn't quite right, back to the default base page.
        if ( $this->use_page_numbers && (int) $this->cur_page === 0)
        {
            $this->cur_page = $base_page;
        }
        else
        {
            // Make sure we're using integers for comparisons later.
            $this->cur_page = (int) $this->cur_page;
        }

        // Is the page number beyond the result range?
        // If so, we show the last page.
        if ($this->use_page_numbers)
        {
            if ($this->cur_page > $num_pages)
            {
                $this->cur_page = $num_pages;
            }
        }
        elseif ($this->cur_page > $this->total_rows)
        {
            $this->cur_page = ($num_pages - 1) * $this->per_page;
        }

        $uri_page_number = $this->cur_page;

        // If we're using offset instead of page numbers, convert it
        // to a page number, so we can generate the surrounding number links.
        if ( ! $this->use_page_numbers)
        {
            $this->cur_page = (int) floor(($this->cur_page/$this->per_page) + 1);
        }

        // Calculate the start and end numbers. These determine
        // which number to start and end the digit links with.
        $start	= (($this->cur_page - $this->num_links) > 0) ? $this->cur_page - ($this->num_links - 1) : 1;
        $end	= (($this->cur_page + $this->num_links) < $num_pages) ? $this->cur_page + $this->num_links : $num_pages;

        // And here we go...
        $output = '';

        // Render the "First" link.
        if ($this->first_link !== FALSE && $this->cur_page > ($this->num_links + 1))
        {
            // Take the general parameters, and squeeze this pagination-page attr in for JS frameworks.
            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, 1);

            $output .= $this->first_tag_open.'<a href="'.str_replace('{page}', 1, $this->base_url).'"'.$attributes.$this->_attr_rel('start').'>'
                .$this->first_link.'</a>'.$this->first_tag_close;
        }

        // Render the "Previous" link.
        if ($this->prev_link !== FALSE && $this->cur_page !== 1)
        {
            $i = ($this->use_page_numbers) ? $uri_page_number - 1 : $uri_page_number - $this->per_page;

            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, (int) $i);

            if ($i === $base_page)
            {
                // First page
                $output .= $this->prev_tag_open.'<a href="'.str_replace('{page}', $i, $this->base_url).'"'.$attributes.$this->_attr_rel('prev').'>'
                    .$this->prev_link.'</a>'.$this->prev_tag_close;
            }
            else
            {
                $output .= $this->prev_tag_open.'<a href="'.str_replace('{page}', $i, $this->base_url).'"'.$attributes.$this->_attr_rel('prev').'>'
                    .$this->prev_link.'</a>'.$this->prev_tag_close;
            }

        }

        // Render the pages
        if ($this->display_pages !== FALSE)
        {
            // Write the digit links
            for ($loop = $start -1; $loop <= $end; $loop++)
            {
                $i = ($this->use_page_numbers) ? $loop : ($loop * $this->per_page) - $this->per_page;

                $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, (int) $i);

                if ($i >= $base_page)
                {
                    if ($this->cur_page === $loop)
                    {
                        // Current page
                        $output .= $this->cur_tag_open.$loop.$this->cur_tag_close;
                    }
                    elseif ($i === $base_page)
                    {
                        // First page
                        $output .= $this->num_tag_open.'<a href="'.str_replace('{page}', 1, $this->base_url).'"'.$attributes.$this->_attr_rel('start').'>'
                            .$loop.'</a>'.$this->num_tag_close;
                    }
                    else
                    {
                        $output .= $this->num_tag_open.'<a href="'.str_replace('{page}', $i, $this->base_url).'"'.$attributes.$this->_attr_rel('start').'>'
                            .$loop.'</a>'.$this->num_tag_close;
                    }
                }
            }
        }

        // Render the "next" link
        if ($this->next_link !== FALSE && $this->cur_page < $num_pages)
        {
            $i = ($this->use_page_numbers) ? $this->cur_page + 1 : $this->cur_page * $this->per_page;

            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, (int) $i);

            $output .= $this->next_tag_open.'<a href="'.str_replace('{page}', $i, $this->base_url).'"'.$attributes
                .$this->_attr_rel('next').'>'.$this->next_link.'</a>'.$this->next_tag_close;
        }

        // Render the "Last" link
        if ($this->last_link !== FALSE && ($this->cur_page + $this->num_links) < $num_pages)
        {
            $i = ($this->use_page_numbers) ? $num_pages : ($num_pages * $this->per_page) - $this->per_page;

            $attributes = sprintf('%s %s="%d"', $this->_attributes, $this->data_page_attr, (int) $i);

            $output .= $this->last_tag_open.'<a href="'.str_replace('{page}', $i, $this->base_url).'"'.$attributes.'>'
                .$this->last_link.'</a>'.$this->last_tag_close;
        }

        // Kill double slashes. Note: Sometimes we can end up with a double slash
        // in the penultimate link so we'll kill all double slashes.
        $output = preg_replace('#([^:])//+#', '\\1/', $output);

        // Add the wrapper HTML if exists
        return $this->full_tag_open.$output.$this->full_tag_close;
    }
}
