<?php

/**
 * DokuWiki Plugin linkheading (Syntax Component)
 *
 * Creates clickable headings linking to internal DokuWiki pages.
 *
 * @license MIT
 * @author Jens Mohr
 */

use dokuwiki\Extension\SyntaxPlugin;

class syntax_plugin_linkheading extends SyntaxPlugin
{
    /**
     * @return string Syntax mode type
     */
    public function getType()
    {
        return 'substition';
    }

    /**
     * @return string Paragraph type
     */
    public function getPType()
    {
        return 'block';
    }

    /**
     * @return int Sort order
     */
    public function getSort()
    {
        return 155;
    }

    /**
     * Connect syntax pattern to lexer.
     *
     * @param string $mode Parser mode
     */
    public function connectTo($mode)
    {
        $this->Lexer->addSpecialPattern(
            '\{\{linkheading>[^}]+\}\}',
            $mode,
            'plugin_linkheading'
        );
    }

    /**
     * Parse plugin syntax.
     *
     * Supported forms:
     *
     * {{linkheading>target|Heading}}
     * {{linkheading>4|target|Heading}}
     *
     * @inheritDoc
     */
    public function handle($match, $state, $pos, Doku_Handler $handler)
    {
        $content = substr($match, 14, -2);
        $parts = explode('|', $content);

        if (
            count($parts) >= 3 &&
            preg_match('/^[1-6]$/', trim($parts[0]))
        ) {
            $level  = (int) trim(array_shift($parts));
            $target = trim(array_shift($parts));
            $title  = trim(implode('|', $parts));
        } else {
            $level  = 2;
            $target = trim(array_shift($parts));
            $title  = trim(implode('|', $parts));
        }

        if ($title === '') {
            $title = $target;
        }

        return [
            'level'  => $level,
            'target' => $target,
            'title'  => $title,
        ];
    }

    /**
     * Render linked heading.
     *
     * @inheritDoc
     */
    public function render($mode, Doku_Renderer $renderer, $data)
    {
        $level  = max(1, min(6, (int) $data['level']));
        $target = $data['target'];
        $title  = $data['title'];

        if ($mode === 'xhtml') {
            $renderer->doc .= '<h' . $level . ' class="linkheading">';
            $renderer->internallink($target, $title);
            $renderer->doc .= '</h' . $level . '>';

            return true;
        }

        if ($mode === 'metadata') {
            $renderer->internallink($target, $title);

            return true;
        }

        return false;
    }
}