/** * ======================================================================================== * @file source.ts - runtime content source (git-as-CMS) * ======================================================================================== * @description * - returns a flat path→body map of content/, the same shape pages.ts consumed from the bundle * - production (workerd) fetches content/ from the `main` branch via the GitHub API at runtime, *   so pushing to main publishes without a deploy; results are cached under CACHE_CONTENT_TAG * - dev/CI (node) reads the local content/ folder from disk for instant, hermetic previews * @see src/cms/pages.ts, scripts/content.mjs, src/apis/githubFetch.ts */import { unstable_cache } from "next/cache";import { githubFetch, githubHeaders } from "@/apis/githubFetch";import {  REPO_OWNER,  REPO_NAME,  REPO_BRANCH,  CACHE_CONTENT_TAG,  CACHE_CONTENT_REVALIDATE,} from "@/utilities/githubRepo";const CONTENT_PREFIX = "content/";export type ContentMap = Record<string, string>;// Prod (no fs) must use GitHub; dev uses fs for instant local preview. CONTENT_SOURCE// overrides both — CI sets it to "local" so builds/e2e are hermetic (tested against the// branch's own content, not whatever currently sits on main).function chooseSource(): "local" | "github" {  const override = process.env.CONTENT_SOURCE;  if (override === "local" || override === "github") return override;  return process.env.NODE_ENV === "production" ? "github" : "local";}// Memoized per request (React cache): getAllPages, populatePageContent, and getContent// share a single fetch within one render.export const getContentMap = async (): Promise<ContentMap> => {  return chooseSource() === "local" ? readLocalContent() : getCachedGithubContent();};/* -------------------------------------------------------------------------- *//* local source (dev / CI): read content/ from disk                            *//* -------------------------------------------------------------------------- */async function readLocalContent(): Promise<ContentMap> {  // Dynamic import keeps node:fs out of the workerd bundle's evaluated path.  const { readdir, readFile } = await import("node:fs/promises");  const { join } = await import("node:path");  const root = join(process.cwd(), "content");  const out: ContentMap = {};  async function walk(dir: string, base = ""): Promise<void> {    for (const entry of await readdir(dir, { withFileTypes: true })) {      // finder artifact that gitignore can't filter on raw fs walk      if (entry.name === ".DS_Store") continue;      const rel = base ? `${base}/${entry.name}` : entry.name;      if (entry.isDirectory()) await walk(join(dir, entry.name), rel);      else if (entry.isFile()) out[rel] = await readFile(join(dir, entry.name), "utf-8");    }  }  await walk(root);  return out;}/* -------------------------------------------------------------------------- *//* github source (production): fetch content/ from the main branch             *//* -------------------------------------------------------------------------- */const FETCH_CONCURRENCY = 12;// Concurrency-limited map so a cold load doesn't burst ~100 requests at GitHub at once// (which self-throttles into 503s).async function mapLimit<T, R>(items: T[], limit: number, fn: (item: T) => Promise<R>): Promise<R[]> {  const results: R[] = new Array(items.length);  let cursor = 0;  async function worker(): Promise<void> {    while (cursor < items.length) {      const index = cursor++;      results[index] = await fn(items[index]);    }  }  await Promise.all(Array.from({ length: Math.min(limit, items.length) }, worker));  return results;}const getCachedGithubContent = unstable_cache(  async (): Promise<ContentMap> => {    const paths = await listContentPaths();    const entries = await mapLimit(      paths,      FETCH_CONCURRENCY,      async (rel) => [rel, await fetchRawFile(rel)] as const,    );    return Object.fromEntries(entries);  },  ["content-map"],  { tags: [CACHE_CONTENT_TAG], revalidate: CACHE_CONTENT_REVALIDATE });// One recursive tree call lists every file under content/ (paths relative to content/).async function listContentPaths(): Promise<string[]> {  const url = `https://api.github.com/repos/${REPO_OWNER}/${REPO_NAME}/git/trees/${REPO_BRANCH}?recursive=1`;  const res = await githubFetch(url, {    headers: await githubHeaders("cms"),  });  if (!res.ok) throw new Error(`GitHub tree fetch failed: ${res.status} ${res.statusText}`);  const data = (await res.json()) as { tree?: { path: string; type: string }[] };  return (data.tree ?? [])    .filter((node) => node.type === "blob" && node.path.startsWith(CONTENT_PREFIX))    .map((node) => node.path.slice(CONTENT_PREFIX.length));}// Bodies come from raw.githubusercontent (public CDN, no auth needed, generous limits).async function fetchRawFile(rel: string): Promise<string> {  const encoded = rel.split("/").map(encodeURIComponent).join("/");  const url = `https://raw.githubusercontent.com/${REPO_OWNER}/${REPO_NAME}/${REPO_BRANCH}/${CONTENT_PREFIX}${encoded}`;  const res = await githubFetch(url, {});  if (!res.ok) throw new Error(`GitHub raw fetch failed (${res.status}): ${rel}`);  return res.text();}