fixate/pw-mvc-boilerplate

<?php

trait SEO
{
  public static function __seoInitialize($obj)
  {
    $obj->add_view_vars($obj->get_seo_vars());
    $obj->helper('render_seo_rel_next_prev_links');
  }

  private $__seo_opts = array(
    'limit' => false,
  );

  protected function seo_set_opt($opt, $value)
  {
    $this->__seo_opts[$opt] = $value;
  }

  public function get_seo_vars()
  {
    return array(
      'seo_title' => $this->get_seo_title(),
      'seo_desc' => $this->get_seo_desc(),
      'seo_noindex' => $this->get_seo_noindex(),
    );
  }

  public function render_seo_rel_next_prev_links($total_items = 0)
  {
    $page = &$this->page;
    $total_items = $total_items ? $total_items : $page->children->count;
    $input = &$this->input;
    $config = &$this->config;
    $html = '';
    $limit = $this->__seo_opts['limit'];
    $protocol = $config->https ? 'https://' : 'http://';
    $href = $protocol . $config->httpHost . $page->url;
    $prefix = $config->pageNumUrlPrefix;

    if (empty($limit)) {
      return $html;
    }

    if ($input->pageNum > 1) {
      $html .= '<link rel="prev" href="';
      $html .= $href . ($input->pageNum > 2 ? $prefix . ($input->pageNum - 1) : '');
      $html .= '">';
    }

    if ($limit > 0 && $input->pageNum < $total_items / $limit) {
      $html .= '<link rel="next" href="';
      $html .= $href . $prefix . ($input->pageNum + 1);
      $html .= '">';
    }

    $html .= "<link rel='canonical' href='{$href}' >";

    return $html;
  }

  protected function get_seo_title()
  {
    $page = &$this->page;

    if (!($seo_title = $page->seo_title)) {
      $seo_title = $page->title;
    }

    if (method_exists($this, 'setting') && $this->setting('site_name')) {
      $seo_title .= ' ' . $this->get_seo_separator() . ' ' . $this->setting('site_name');
    }

    return $seo_title;
  }

  protected function get_seo_desc()
  {
    $page = &$this->page;
    $input = &$this->input;

    /*
         * don't output meta description if we are using pagination
         * - http://moz.com/blog/pagination-best-practices-for-seo-user-experience
         */
    if ($page->seo_description && $input->pageNum < 2) {
      $desc = str_replace('"', "'", $page->seo_description);

      return "<meta name='description' content=\"{$desc}\">";
    }

    return false;
  }

  protected function get_seo_noindex()
  {
    $page = &$this->page;

    if ($page->seo_noindex) {
      return "<meta name='robots' content='noindex, nofollow'>";
    }

    return "<meta name='robots' content='index, follow'>";
  }

  private function get_seo_separator()
  {
    if (!($seo_separator = $this->setting('seo_separator'))) {
      $seo_separator = '|';
    }

    return $seo_separator;
  }
}