import type { Element, MarkdownConfig } from '@lezer/markdown';
import { styleTags, tags } from '@lezer/highlight';

export const wikilink: MarkdownConfig = {
    defineNodes: [
      'Wikilink',
      'WikilinkMeta',
      'WikilinkHref',
      'WikilinkTitle',
    ],
    parseInline: [{
        name: 'Wikilink',
        before: 'Link',
        parse(cx, next, pos)
        {
            // 91 == '['
            if (next !== 91 || cx.slice(pos, pos + 1).charCodeAt(0) !== 91) return -1;
            
            const match = /!?\[\[([^\[\]\|\#]+)?(#+[^\[\]\|\#]+)?(\|[^\[\]\|\#]+)?\]\]/.exec(cx.slice(pos, cx.end));
            if(!match) return -1;

            const start = pos, children: Element[] = [], end = start + match[0].length;

            children.push(cx.elt('WikilinkMeta', start, start + 2));

            if(match[1] && !match[2] && !match[3]) //Link only
            {
                children.push(cx.elt('WikilinkTitle', start + 2, end - 2));
            }
            else if(!match[1] && match[2] && match[3]) //Hash and title
            {
                children.push(cx.elt('WikilinkHref', start + 2, start + 2 + match[2].length));
                children.push(cx.elt('WikilinkMeta', start + 2 + match[2].length, start + 2 + match[2].length + 1));
                children.push(cx.elt('WikilinkTitle', start + 2 + match[2].length + 1, start + 2 + match[2].length + match[3].length));
            }
            else if(!match[1] && !match[2] && match[3]) //Hash only
            {
                children.push(cx.elt('WikilinkTitle', start + 2, end - 2));
            }
            else if(match[1] && match[2] && !match[3]) //Link and hash
            {
                children.push(cx.elt('WikilinkHref', start + 2, start + 2 + match[1].length));
                children.push(cx.elt('WikilinkTitle', start + 2 + match[1].length, start + 2 + match[1].length + match[2].length));
            }
            else if(match[1] && !match[2] && match[3]) //Link and title
            {
                children.push(cx.elt('WikilinkHref', start + 2, start + 2 + match[1].length));
                children.push(cx.elt('WikilinkMeta', start + 2 + match[1].length, start + 2 + match[1].length + 1));
                children.push(cx.elt('WikilinkTitle', start + 2 + match[1].length + 1, start + 2 + match[1].length + match[3].length));
            }
            else if(match[1] && match[2] && match[3]) //Link, hash and title
            {
                children.push(cx.elt('WikilinkHref', start + 2, start + 2 + match[1].length + match[2].length));
                children.push(cx.elt('WikilinkMeta', start + 2 + match[1].length + match[2].length, start + 2 + match[1].length + match[2].length + 1));
                children.push(cx.elt('WikilinkTitle', start + 2 + match[1].length + match[2].length + 1, start + 2 + match[1].length + match[2].length + match[3].length));
            }

            children.push(cx.elt('WikilinkMeta', end - 2, end));

            return cx.addElement(cx.elt('Wikilink', start, end, children));
        },
    }],
    props: [
        styleTags({
            'Wikilink': tags.special(tags.content),
            'WikilinkMeta': tags.meta,
            'WikilinkHref': tags.link,
            'WikilinkTitle': tags.special(tags.link),
        })
    ]
};