/**
 * scripts/generate-docs/lib/markdown-parser.ts
 *
 * Reads `docs-src/*.md`, splits frontmatter (gray-matter) from body, and
 * converts the body to HTML (marked). Returns `PageMeta[]` ready for the
 * context builder.
 *
 * Frontmatter shape (per page):
 *   slug: string                  # output filename (slug.html)
 *   title: string | { fr, en }    # full page title (used in <title> + header)
 *   pageTitle: string | { fr, en }# short title shown in the header bar
 *   icon: string                  # emoji or short string
 *   page: string                  # `pages/<x>.hbs` template name (default: slug)
 *   breadcrumb: Array<string | { fr, en }>  # optional crumb trail
 */
import { readFileSync, readdirSync } from 'node:fs';
import { join, basename } from 'node:path';
import matter from 'gray-matter';
import { marked } from 'marked';

const DOCS_SRC = join(__dirname, '..', '..', '..', 'docs-src');

export type LocalisedString = string | { fr: string; en: string };

export interface PageMeta {
  /** Filename slug (without extension): `installation`, `ba-develop`, … */
  slug: string;
  /** Full HTML <title> + sidebar tooltip */
  title: LocalisedString;
  /** Short label rendered in the header bar */
  pageTitle: LocalisedString;
  /** Emoji or short string */
  icon: string;
  /** Handlebars template file (without `.hbs`) — defaults to slug */
  pageTemplate: string;
  /** Optional breadcrumb segments, leftmost first */
  breadcrumb: LocalisedString[];
  /** Raw markdown body — Handlebars-preprocessed then rendered at build time */
  bodyMarkdown: string;
  /** Pre-rendered HTML from the markdown body (no Handlebars preprocessing) */
  bodyHtml: string;
  /** Absolute path of the source markdown file */
  sourcePath: string;
}

/** Render a markdown string to HTML with the generator's marked config. */
export function markdownToHtml(md: string): string {
  return String(marked.parse(md));
}

function configureMarked(): void {
  marked.setOptions({
    gfm: true,
    breaks: false,
  });
}
configureMarked();

export function parsePageFile(absPath: string): PageMeta {
  const raw = readFileSync(absPath, 'utf-8');
  const { data, content } = matter(raw);
  const slug = (data.slug as string) || basename(absPath, '.md');

  const bodyHtml = String(marked.parse(content));

  return {
    slug,
    title: (data.title as LocalisedString) || slug,
    pageTitle: (data.pageTitle as LocalisedString) || (data.title as LocalisedString) || slug,
    icon: (data.icon as string) || '📄',
    pageTemplate: (data.page as string) || slug,
    breadcrumb: (data.breadcrumb as LocalisedString[]) || [],
    bodyMarkdown: content,
    bodyHtml,
    sourcePath: absPath,
  };
}

/**
 * Walks `docs-src/*.md` (excluding `_data/` and `_partials/`), parses each,
 * and returns them sorted by slug.
 */
export function parseAllPages(): PageMeta[] {
  const entries = readdirSync(DOCS_SRC, { withFileTypes: true });
  const pages: PageMeta[] = [];
  for (const entry of entries) {
    if (!entry.isFile()) continue;
    if (!entry.name.endsWith('.md')) continue;
    if (entry.name.startsWith('_')) continue;
    pages.push(parsePageFile(join(DOCS_SRC, entry.name)));
  }
  pages.sort((a, b) => a.slug.localeCompare(b.slug));
  return pages;
}