markdown.ts

import type { PathLike } from 'node:fs';
import { readdir, readFile } from 'node:fs/promises';
import { config } from '../env.js';

/**
 * Resolves a path that works in both dev (src/) and prod (dist/) environments
 *
 * @param devPath - Path relative to the calling file in dev (e.g., './subjects/')
 * @param prodPath - Path relative to dist/index.js in prod (e.g., './commands/tips/subjects/')
 * @param baseUrl - import.meta.url from the calling file
 * @returns URL that works in both environments
 */
export const resolveAssetPath = (devPath: string, prodPath: string, baseUrl: string): URL => {
  const isProduction = config.ENV === 'production';
  const path = isProduction ? prodPath : devPath;
  return new URL(path, baseUrl);
};

/**
 * A simple markdown parser that extracts frontmatter and content
 *
 * @param string - The markdown string to parse
 * @returns
 */
export const parseMarkdown = async <T extends Record<string, unknown>>(
  string: string
): Promise<{
  frontmatter: Partial<T>;
  content: string;
}> => {
  const frontmatterRegex = /^---\n([\s\S]+?)\n---/;
  const match = string.match(frontmatterRegex);
  let frontmatter: Partial<T> = {};
  let content = string;

  if (match) {
    const yaml = match[1];
    frontmatter = Object.fromEntries(
      yaml.split('\n').map((line) => {
        const [key, ...rest] = line.split(':');
        return [key.trim(), rest.join(':').trim()];
      })
    ) as Partial<T>;
    content = string.slice(match[0].length).trim();
  }

  return { frontmatter, content };
};

/** Load markdown files from a directory and parse them
 *
 * @param path - The path to the directory containing markdown files
 * @param name - Optional specific file name to load (must include .md extension)
 * @returns An array of parsed markdown files with frontmatter and content
 */
export const loadMarkdownOptions = async <T extends Record<string, unknown>>(
  path: PathLike,
  name?: string
): Promise<
  Array<{
    frontmatter: Partial<T>;
    content: string;
  }>
> => {
  const files = await readdir(path);
  const markdownFiles = files.filter(
    (file) => file.endsWith('.md') && (name ? file === name : true)
  );

  const results: Array<{ frontmatter: Partial<T>; content: string }> = [];

  for (const file of markdownFiles) {
    const filePath = new URL(`${path}/${file}`, import.meta.url);

    const fileContent = await readFile(filePath, 'utf-8');
    const result = await parseMarkdown<T>(fileContent);
    results.push(result);
  }
  return results;
};