joelhooks__joelclaw/apps/web/lib/remark-obsidian.ts

import type { Image, Link, Root, Text } from "mdast";
import { SKIP, visit } from "unist-util-visit";

const WIKILINK_PATTERN = /(!)?\[\[([^[\]]+)\]\]/g;
const IMAGE_EXTENSIONS = new Set([
  "png",
  "jpg",
  "jpeg",
  "gif",
  "webp",
  "svg",
  "avif",
]);

function splitTargetAndAlias(value: string): { target: string; alias?: string } {
  const pipeIndex = value.indexOf("|");
  if (pipeIndex === -1) return { target: value.trim() };
  return {
    target: value.slice(0, pipeIndex).trim(),
    alias: value.slice(pipeIndex + 1).trim(),
  };
}

function stripMarkdownExtension(value: string): string {
  return value.replace(/\.mdx?$/i, "");
}

function toAdrHref(target: string): string {
  const normalized = stripMarkdownExtension(target)
    .replace(/\\/g, "/")
    .replace(/^\.?\//, "")
    .trim();
  return `/adrs/${encodeURI(normalized)}`;
}

function toImageHref(target: string): string {
  const normalized = stripMarkdownExtension(target)
    .replace(/\\/g, "/")
    .replace(/^\.?\//, "")
    .trim();
  return `/images/${encodeURI(normalized)}`;
}

function isImagePath(target: string): boolean {
  const ext = target.split(".").pop()?.toLowerCase();
  return ext ? IMAGE_EXTENSIONS.has(ext) : false;
}

/**
 * Convert Obsidian wikilinks/embeds to standard markdown nodes for MDX.
 *
 * Examples:
 * - ![[adr/foo.jpg|Alt]] -> ![Alt](/images/adr/foo.jpg)
 * - [[0077-memory-system-next-phase]] -> [0077-memory-system-next-phase](/adrs/0077-memory-system-next-phase)
 * - ![[0077-memory-system-next-phase]] -> [0077-memory-system-next-phase](/adrs/0077-memory-system-next-phase)
 */
export function remarkObsidian() {
  return (tree: Root) => {
    visit(tree, "text", (node: Text, index, parent) => {
      if (!parent || index === undefined) return;
      if (parent.type === "link") return;

      const source = node.value;
      if (!source.includes("[[")) return;

      WIKILINK_PATTERN.lastIndex = 0;
      let lastIndex = 0;
      let matched = false;
      let match: RegExpExecArray | null;
      const replacementNodes: Array<Text | Link | Image> = [];

      while ((match = WIKILINK_PATTERN.exec(source)) !== null) {
        const isEmbed = Boolean(match[1]);
        const rawInner = match[2];
        if (!rawInner) continue;
        matched = true;

        if (match.index > lastIndex) {
          replacementNodes.push({
            type: "text",
            value: source.slice(lastIndex, match.index),
          });
        }

        const { target, alias } = splitTargetAndAlias(rawInner);
        const cleanTarget = stripMarkdownExtension(target).trim();

        if (!cleanTarget) {
          replacementNodes.push({ type: "text", value: match[0] });
          lastIndex = match.index + match[0].length;
          continue;
        }

        if (isEmbed && isImagePath(cleanTarget)) {
          replacementNodes.push({
            type: "image",
            url: toImageHref(cleanTarget),
            alt: alias || cleanTarget.split("/").pop() || cleanTarget,
          });
        } else {
          const label = alias || cleanTarget;
          replacementNodes.push({
            type: "link",
            url: toAdrHref(cleanTarget),
            children: [{ type: "text", value: label }],
          });
        }

        lastIndex = match.index + match[0].length;
      }

      if (!matched) return;

      if (lastIndex < source.length) {
        replacementNodes.push({
          type: "text",
          value: source.slice(lastIndex),
        });
      }

      parent.children.splice(index, 1, ...replacementNodes);
      return [SKIP, index + replacementNodes.length];
    });
  };
}