Paginator.php

<?php

class Paginator implements \IteratorAggregate
{
    const TPL_WRAPPER = 'wrapper';
    const TPL_NUM = 'num';
    const TPL_NUM_CURRENT = 'currentNum';
    const TPL_TAG = 'tag';
    const TPL_NEXT = 'next';
    const TPL_PREV = 'prev';
    const TPL_TEXT = 'text';
    const CFG_FIELD_NAME = 'fieldName';
    /**
     * 当前页前后显示几页
     */
    const CFG_NUM_MIDDLE = 'middleNum';
    /**
     * 末页前显示几页
     */
    const CFG_NUM_TAIL = 'tailNum';
    /**
     * 首页后显示几页
     */
    const CFG_NUM_HEAD = 'headNum';

    protected $app;
    protected $data;

    /**
     * @var IListProvider
     */
    protected $list;

    protected $config = [
        self::CFG_NUM_HEAD => 1,
        self::CFG_NUM_TAIL => 1,
        self::CFG_NUM_MIDDLE => 2,
        self::CFG_FIELD_NAME => 'page',
    ];

    protected $template = [
        self::TPL_WRAPPER => <<<'HTML'
<div class="page_right fontsize9 fontcolor3">%s</div>
HTML
        ,
        self::TPL_NUM => <<<'HTML'
<a class="p_num" href="%2$s">%1$d</a>
HTML
        ,
        self::TPL_NUM_CURRENT => <<<'HTML'
<a class="p_num selected">%1$d</a>
HTML
        ,
        self::TPL_TAG => <<<'HTML'
<a class="p_num first_or_last" href="%2$s">%1$s</a>
HTML
        ,
        self::TPL_TEXT => <<<'HTML'
<span class="page_dian">%s</span>
HTML
        ,
        self::TPL_NEXT => <<<'HTML'
<a class="p_num next" href="%1$s">下一页</a>
HTML
        ,
        self::TPL_PREV => <<<'HTML'
<a class="p_num previous" href="%1$s">上一页</a>
HTML
        ,
    ];
    /**
     * @var string
     */
    protected $urlBase;

    /**
     * @param Site $app
     * @param IListProvider $list
     * @param string $urlBase
     */
    public function __construct(Site $app, IListProvider $list, $urlBase = null)
    {
        if (is_null($urlBase)) {
            $urlBase = $app->request->getPath();
        }

        $this->app = $app;
        $this->list = $list;
        $this->urlBase = $urlBase;
    }

    /**
     * (PHP 5 &gt;= 5.0.0)<br/>
     * Retrieve an external iterator
     * @link http://php.net/manual/en/iteratoraggregate.getiterator.php
     * @return Traversable An instance of an object implementing <b>Iterator</b> or
     * <b>Traversable</b>
     */
    public function getIterator()
    {
        return new \ArrayIterator($this->getData());
    }

    public function renderPaginator()
    {
        $maxPage = $this->getMaxPage();
        $curPage = $this->getCurrentPage();

        if($maxPage <= 1) {
            return '';
        }

        $contents = [];
//        $contents[] = $this->renderTpl(self::TPL_TAG, '首页', $this->getUrlForPage(1));
        if ($curPage !== 1) {
            $contents[] = $this->renderTpl(self::TPL_PREV, $this->getUrlForPage($curPage - 1));
        }

        for ($i = 1; $i <= $maxPage; $i++) {
            $middleCount = $this->config[self::CFG_NUM_MIDDLE];
            switch (true) {
                case $i === $curPage:
                    $contents[] = $this->renderTpl(self::TPL_NUM_CURRENT, $i);
                    break;
                case $i >= $curPage - $middleCount && $i <= $curPage + $middleCount:
                case $i <= $this->config[self::CFG_NUM_HEAD]:
                case $i > $maxPage - $this->config[self::CFG_NUM_TAIL]:
                    $contents[] = $this->renderTpl(self::TPL_NUM, $i, $this->getUrlForPage($i));
                    break;
                default:
                    if ($i < $curPage) {
                        $contents[] = $this->renderTpl(self::TPL_TEXT, '...');
                        $i = $curPage - $middleCount - 1;
                    } else {
                        $contents[] = $this->renderTpl(self::TPL_TEXT, '...');
                        $i = $maxPage - $this->config[self::CFG_NUM_TAIL];
                    }
            }
        }

        if ($curPage !== $maxPage) {
            $contents[] = $this->renderTpl(self::TPL_NEXT, $this->getUrlForPage($curPage + 1));
        }
//        $contents[] = $this->renderTpl(self::TPL_TAG, '末页', $this->getUrlForPage($maxPage));

        return $this->renderTpl(self::TPL_WRAPPER, implode('', $contents));
    }

    public function getUrlForPage($page)
    {
        $part = parse_url($this->urlBase);
        $query = [];
        if (isset($part['query'])) {
            parse_str($part['query'], $query);
        }
        $query[$this->config[self::CFG_FIELD_NAME]] = $page;

        if (!isset($part['path'])) {
            $part['path'] = '/';
        }

        return sprintf('%s?%s', $part['path'], http_build_query($query));
    }

    protected function renderTpl($tpl)
    {
        $args = func_get_args();
        $args[0] = $this->template[$tpl];

        return call_user_func_array('sprintf', $args);
    }

    /**
     * @return int
     */
    protected function getCurrentPage()
    {
        $page = intval($this->app->request->get($this->config[self::CFG_FIELD_NAME]));

        return min(max($page, 1), $this->getMaxPage());
    }

    protected function getPager()
    {
        return $this->list->getPager();
    }

    public function getItemCount()
    {
        $pager = $this->getPager();

        return intval($pager['count']);
    }

    public function getMaxPage()
    {
        $pager = $this->getPager();

        return intval($pager['maxPage']);
    }

    /**
     * @return array
     */
    protected function getData()
    {
        if (!isset($this->data)) {
            $this->data = $this->list->fetch($this->getCurrentPage());
        }

        return $this->data;
    }
}