<?php
    /**
     * @class PageHandler
     * @author zero (zero@nzeo.com)
     * @brief handles page navigation
     * @version 0.1
     *
     * @remarks Getting total counts, number of pages, current page number, number of items per page, 
     *          this class implements methods and contains variables for page navigation
     **/

    class PageHandler extends Handler {

        var $total_count = 0; ///< number of total items
        var $total_page = 0; ///< number of total pages
        var $cur_page = 0; ///< current page number
        var $page_count = 10; ///< number of page links displayed at one time
        var $first_page = 1; ///< first page number
        var $last_page = 1; ///< last page number
        var $point = 0; ///< increments per getNextPage() 

        /**
         * @brief constructor
         * @param[in] $total_count number of total items
         * @param[in] $total_page number of total pages
         * @param[in] $cur_page current page number
         * @param[in] $page_count number of page links displayed at one time 
         **/
        function PageHandler($total_count, $total_page, $cur_page, $page_count = 10) {
            $this->total_count = $total_count;
            $this->total_page = $total_page;
            $this->cur_page = $cur_page;
            $this->page_count = $page_count;
            $this->point = 0;

            $first_page = $cur_page - (int)($page_count/2);
            if($first_page<1) $first_page = 1;
            $last_page = $total_page;
            if($last_page>$total_page) $last_page = $total_page;

            $this->first_page = $first_page;
            $this->last_page = $last_page;

            if($total_page < $this->page_count) $this->page_count = $total_page;
        }

        /**
         * @brief request next page
         * @return next page number
         **/
        function getNextPage() {
            $page = $this->first_page+$this->point++;
            if($this->point > $this->page_count || $page > $this->last_page) $page = 0;
            return $page;
        }
    }
?>