PicoYALinker.php

<?php
/**
 * Pico Yet Another Linker Plugin
 *
 * @author Huidae Cho
 * @link https://github.com/HuidaeCho/PicoYALinker
 * @license http://opensource.org/licenses/MIT
 * @version 0.1.0
 */

class PicoYALinker extends AbstractPicoPlugin {

    const API_VERSION = 3;

    public function onParsedownRegistered(Parsedown &$parsedown)
    {
        $pico = $this->getPico();
        $config = $pico->getConfig();

        // https://example.com/pico => /pico
        $root_url = preg_replace('/^[^\/]*\/\/[^\/]*(\/.*?)\/*$/', '\1', $config['base_url']);
        // https://example.com/pico/current-page => /current-page
        $current_route = '/'.$pico->getRequestUrl();
        // Current Page Title
        $current_title = $pico->getFileMeta()['title'];

        $utf8_slugs = $config['yalinker_utf8_slugs'];

        $className = ($this->config['content_config']['extra'] ? 'ParsedownExtra' : 'Parsedown').'YALinker';
        $parsedown = new $className($utf8_slugs, $root_url, $current_route, $current_title);
        $parsedown->setBreaksEnabled((bool) $config['content_config']['breaks']);
        $parsedown->setMarkupEscaped((bool) $config['content_config']['escape']);
        $parsedown->setUrlsLinked((bool) $config['content_config']['auto_urls']);
    }
}

class ParsedownYALinker extends Parsedown
{
    protected $utf8_slugs;
    protected $root_url;
    protected $current_route;
    protected $current_title;

    public function __construct($utf8_slugs, $root_url, $current_route, $current_title)
    {
        $this->utf8_slugs = $utf8_slugs;
        $this->root_url = $root_url;
        $this->current_route = $current_route;
        $this->current_title = $current_title;
    }

    protected function inlineLink($excerpt)
    {
        $link = parent::inlineLink($excerpt);
        if ($link === null)
            $link = yalink($excerpt, $this->utf8_slugs, $this->root_url, $this->current_route, $this->current_title);
        return $link;
    }
}

class ParsedownExtraYALinker extends ParsedownExtra
{
    protected $utf8_slugs;
    protected $root_url;
    protected $current_route;
    protected $current_title;

    public function __construct($utf8_slugs, $root_url, $current_route, $current_title)
    {
        $this->utf8_slugs = $utf8_slugs;
        $this->root_url = $root_url;
        $this->current_route = $current_route;
        $this->current_title = $current_title;
    }

    protected function inlineLink($excerpt)
    {
        $link = parent::inlineLink($excerpt);
        if ($link === null)
            $link = yalink($excerpt, $this->utf8_slugs, $this->root_url, $this->current_route, $this->current_title);
        return $link;
    }
}

function yalink($excerpt, $utf8_slugs, $root_url, $current_route, $current_title)
{
    // syntax: [[(link)?(|(text)?)?]]
    // * [[]] => <a href="/current">Current Title</a>
    // * [[|]] => <a href="/current">/current</a>
    // * [[.|]] => <a href="/current">.</a>
    // * [[page]] => <a href="/current/page">page</a>
    // * [[page|]] => <a href="/current/page">page</a>
    // * [[page|text]] => <a href="/current/page">text</a>
    // * [[../page]] => <a href="/page">page</a>
    // * [[../page|]] => <a href="/page">../page</a>
    // * [[../page|text]] => <a href="/page">text</a>
    // * [[/folder/slashes//in page title]] => <a href="/folder/slashes-in-page-title">slashes/in page title</a>
    // * [[/folder/slashes//in page title|]] => <a href="/folder/slashes-in-page-title">/folder/slashes/in page title</a>
    // * [[/folder/slashes//in page title|text]] => <a href="/folder/slashes-in-page-title">text</a>
    // * [[url]] => <a href="url">url</a>
    // * [[mailto:...]] => <a href="mailto:...">mailto:...</a>
    // * [[mail:...]] => <a href="mailto:...">...</a>
    if (strpos($excerpt['text'], '[[') === 0 &&
        strpos($excerpt['text'], ']]') !== false &&
        preg_match('/^\[\[(.*?)(?:\|(.+?))?\]\]/', $excerpt['text'], $matches)) {
        $extent = strlen($matches[0]);
        $href = $matches[1];
        $has_text = isset($matches[2]);

        $show_path = false;
        if ($has_text)
            $text = $matches[2];
        else {
            $len = strlen($href);
            if ($len && $href[$len - 1] == '|') {
                $href = substr($href, 0, $len - 1);
                $show_path = true;
            }
            $text = $href;
        }

        // if url
        if (preg_match('/^(?:https?:\/\/|mail(?:to)?:)/', $href))
            $text = preg_replace('/\|$/', '', $text);
        else {
        // if page
            // escape non-folder slashes
            if (strpos($href, '//') !== false) {
                $href = preg_replace('/\/{2,}/', '-', $href);
                if (!$has_text)
                    // for now, // => \x00
                    $text = preg_replace('/\/{2,}/', '\x00', $text);
            }

            // pre-clean up path in href
            if (strpos($href, '...') !== false)
                // a/...../b => a/../b
                $href = preg_replace('/\.{3,}/', '..', $href);
            if (strpos($href, '/./') !== false)
                // a/./././b => a/b
                $href = preg_replace('/(?:\/\.)+\//', '/', $href);
            if (strpos($href, './') === 0)
                // ./a => a
                $href = substr($href, 2);

            $path_prefix = $current_route;
            if (preg_match('/^([\/.]*)\/(.*)$/', $href, $matches)) {
                if (strlen($matches[1]) && $matches[1][0] != '/')
                    // relative path
                    $path_prefix .= '/'.$matches[1];
                else
                    // absolute path
                    $path_prefix = '';
                $href = $matches[2];
            }

            switch ($href) {
            case '':
                if (!$has_text)
                    $text = $show_path ? $path_prefix : $current_title;
                break;
            case '.':
                $href = '';
                break;
            }

            // add back path prefix that may has been removed by the slug() function
            $href = $path_prefix.($href ? '/'.slugify($href, $utf8_slugs) : '');

            // post-clean up path in href
            $paths = explode('/', $href);
            $npaths = count($paths);
            for ($i = 0; $i < $npaths; $i++) {
                if ($paths[$i] == '..')
                    $paths[$i - 1] = $paths[$i] = '';
            }
            $href = join('/', $paths);
            $href = $root_url.preg_replace('/\/\/+/', '/', $href);

            if (!$has_text) {
                // handle page path in text
                if (!$show_path && preg_match('/^(?:[\/.]*\/)?(?:[^\/]+\/)*(.*)$/', $text, $matches))
                    // show page title only if requested (no | at the end)
                    $text = $matches[1];

                // convert escaped non-folder slashes back to slashes
                $text = str_replace('\x00', '/', $text);
            }
        }

        // if mail, hide mailto from text
        if (strpos($href, 'mail:') === 0) {
            $href = substr_replace($href, 'mailto:', 0, 5);
            if (!$has_text)
                $text = substr_replace($text, '', 0, 5);
        }

        return [
            'extent' => $extent,
            'element' => [
                'name' => 'a',
                'text' => $text,
                'attributes' => [
                    'href' => $href,
                ],
            ],
        ];
    }
}

function slugify($str, $utf8_slugs)
{
    if (!$utf8_slugs) {
        // Adopted from Grav's Admin plugin (user/plugins/admin/classes/utils.php)
        if (function_exists('transliterator_transliterate')) {
            $str = transliterator_transliterate('Any-Latin; NFD; [:Nonspacing Mark:] Remove; NFC;', $str);
        } else {
            $str = iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $str);
        }

        $str = strtolower($str);
        $str = preg_replace('/[\s.]+/', '-', $str);
        // leave slashes as is
        $str = preg_replace('/[^a-z0-9\/-]/', '', $str);
    } else {
        // replace forbidden characters by -
        // leave slashes as is
        $str = preg_replace('/[ \t`~!@#\$%^&*=+\\\\|;:\'",?()\[\]{}<>_.]+/', '-', $str);
        // trim
        $str = trim($str, '-');
        // lowercase
        $str = strtolower($str);
    }

    // page-/-slug => page/slug
    $str = preg_replace('/-?\/-?/', '/', $str);
    $str = trim($str, '-');

    return $str;
}