<?php


namespace App\Services;


class Paging
{
    private $each_disNums; //每页显示的条目数
    private $nums; //总条目数
    private $current_page; //当前被选中的页
    private $sub_pages; //每次显示的页数
    private $pageNums; //总页数
    private $page_array = array(); //用来构造分页的数组
    private $subPage_link; //每个分页的链接
    private $subPage_type; //显示分页的类型

    /*
      construct是SubPages的构造函数，用来在创建类的时候自动运行.
      @$each_disNums   每页显示的条目数  自定义一个变量赋值为页数：$page = 2;
      @nums     总条目数  (统计表中要查找的记录数)
      @current_num     当前被选中的页（在subpage_link这个参数中传输一个值：Messageshow.php?cur_page=，在接收页面接收）
      @sub_pages       每次显示的页数（每次显示的页数=总条目数/每页显示的条目数）
      @subPage_link    每个分页的链接（显示这些记录的页面）
      @subPage_type    显示分页的类型
      当@subPage_type=1的时候为普通分页模式
      example：   共4523条记录,每页显示10条,当前第1/453页 [首页] [上页] [下页] [尾页]
      当@subPage_type=2的时候为经典分页样式
      example：   当前第1/453页 [首页] [上页] 1 2 3 4 5 6 7 8 9 10 [下页] [尾页]
     */

    function __construct($each_disNums, $nums, $current_page, $sub_pages, $subPage_link, $subPage_type = 2)
    {
        $this->each_disNums = intval($each_disNums);
        $this->nums = intval($nums);
        if (!$current_page) {
            $this->current_page = 1;
        } else {
            $this->current_page = intval($current_page);
        }
        $this->sub_pages = intval($sub_pages);
        $this->pageNums = ceil($nums / $each_disNums);
        $this->subPage_link = $subPage_link;
        //$this->show_SubPages($subPage_type);
    }

    /*
      __destruct析构函数，当类不在使用的时候调用，该函数用来释放资源。
    */

    function __destruct()
    {
        //释放变量
        unset($each_disNums);
        unset($nums);
        unset($current_page);
        unset($sub_pages);
        unset($pageNums);
        unset($page_array);
        unset($subPage_link);
        unset($subPage_type);
    }

    /*
      show_SubPages函数用在构造函数里面。而且用来判断显示什么样子的分页
     */

    function show_SubPages($subPage_type)
    {
        if ($subPage_type == 1) {
            $this->subPageCss1();
        } elseif ($subPage_type == 2) {
            $this->subPageCss2();
        }
    }

    /*      用来给建立分页的数组初始化的函数。
     */

    function initArray()
    {
        for ($i = 0; $i < $this->sub_pages; $i++) {
            $this->page_array[$i] = $i;
        }
        return $this->page_array;
    }

    /* construct_num_Page该函数使用来构造显示的条目
     * 即使：[1][2][3][4][5][6][7][8][9][10]
     */

    function construct_num_Page()
    {
        if ($this->pageNums < $this->sub_pages) {
            $current_array = array();
            for ($i = 0; $i < $this->pageNums; $i++) {
                $current_array[$i] = $i + 1;
            }
        } else {
            $current_array = $this->initArray();
            if ($this->current_page <= 3) {
                for ($i = 0; $i < count($current_array); $i++) {
                    $current_array[$i] = $i + 1;
                }
            } elseif ($this->current_page <= $this->pageNums && $this->current_page > $this->pageNums - $this->sub_pages + 1) {
                for ($i = 0; $i < count($current_array); $i++) {
                    $current_array[$i] = ($this->pageNums) - ($this->sub_pages) + 1 + $i;
                }
            } else {
                for ($i = 0; $i < count($current_array); $i++) {
                    $current_array[$i] = $this->current_page - 2 + $i;
                }
            }
        }
        return $current_array;
    }

    /* 构造普通模式的分页
     * 共4523条记录,每页显示10条,当前第1/453页 [首页] [上页] [下页] [尾页]
     *
     */

    function subPageCss1()
    {
        $subPageCss1Str = "";
        $subPageCss1Str .= "共" . $this->nums . "条记录，";
        $subPageCss1Str .= "每页显示" . $this->each_disNums . "条，";
        $subPageCss1Str .= "当前第" . $this->current_page . "/" . $this->pageNums . "页 ";
        if ($this->current_page > 1) {
            $firstPageUrl = $this->subPage_link . "1";
            $prewPageUrl = $this->subPage_link . ($this->current_page - 1);
            $subPageCss1Str .= "[<a href='$firstPageUrl'>首页</a>] ";
            $subPageCss1Str .= "[<a href='$prewPageUrl'>上一页</a>] ";
        } else {
            $subPageCss1Str .= "[首页] ";
            $subPageCss1Str .= "[上一页] ";
        }
        if ($this->current_page < $this->pageNums) {
            $lastPageUrl = $this->subPage_link . $this->pageNums;
            $nextPageUrl = $this->subPage_link . ($this->current_page + 1);
            $subPageCss1Str .= " [<a href='$nextPageUrl'>下一页</a>] ";
            $subPageCss1Str .= "[<a href='$lastPageUrl'>尾页</a>] ";
        } else {
            $subPageCss1Str .= "[下一页] ";
            $subPageCss1Str .= "[尾页] ";
        }
        echo $subPageCss1Str;
    }

    /*
     * 构造经典模式的分页
     * 当前第1/453页 [首页] [上页] 1 2 3 4 5 6 7 8 9 10 [下页] [尾页]
     */

    public function subPageCss2()
    {
        $subPageCss2Str = "共有" . $this->nums . "条记录 ";
        $subPageCss2Str .= "当前第" . $this->current_page . "/" . $this->pageNums . "页 ";
        if ($this->nums > 0) {
            if ($this->current_page > 1) {
                $firstPageUrl = $this->subPage_link . "1";
                $prewPageUrl = $this->subPage_link . ($this->current_page - 1);
                $subPageCss2Str .= "[<a href='$firstPageUrl'>首页</a>] ";
                $subPageCss2Str .= "[<a href='$prewPageUrl'>上一页</a>] ";
            } else {
                $subPageCss2Str .= "[首页] ";
                $subPageCss2Str .= "[上一页] ";
            }
            $a = $this->construct_num_Page();
            for ($i = 0; $i < count($a); $i++) {
                $s = $a[$i];
                if ($s == $this->current_page) {
                    $subPageCss2Str .= "[<span style='color:red;font-weight:bold;'>" . $s . "</span>]";
                } else {
                    $url = $this->subPage_link . $s;
                    $subPageCss2Str .= "[<a href='$url'>" . $s . "</a>]";
                }
            }
            if ($this->current_page < $this->pageNums) {
                $lastPageUrl = $this->subPage_link . $this->pageNums;
                $nextPageUrl = $this->subPage_link . ($this->current_page + 1);
                $subPageCss2Str .= " [<a href='$nextPageUrl'>下一页</a>] ";
                $subPageCss2Str .= "[<a href='$lastPageUrl'>尾页</a>] ";
            } else {
                $subPageCss2Str .= "[下一页] ";
                $subPageCss2Str .= "[尾页] ";
            }
        }

        return $subPageCss2Str;
    }
}
