import { Context, Next, send } from "@oak/oak";
import { OG_SITE_NAME, SITE_EMOJI } from "../config.ts";
import { emojiToCodepoint } from "./site-icons.ts";

const ICON_VERSION = emojiToCodepoint(SITE_EMOJI);

async function serveIndexHtml(
  context: Context<Record<string, object>>,
  root: string,
) {
  const filePath = `${root}/index.html`;
  const raw = await Deno.readTextFile(filePath);
  const html = raw
    .replaceAll("__SITE_NAME__", OG_SITE_NAME)
    .replaceAll("__SITE_EMOJI__", SITE_EMOJI)
    .replaceAll("__ICON_VERSION__", ICON_VERSION);
  context.response.type = "text/html";
  context.response.body = html;
}

export function routeStaticFilesFrom(staticPaths: string[]) {
  return async (context: Context<Record<string, object>>, next: Next) => {
    const pathname = context.request.url.pathname;

    // Serve index.html with runtime placeholder replacement
    if (pathname === "/" || pathname === "/index.html") {
      await serveIndexHtml(context, staticPaths[0]);
      return;
    }

    for (const path of staticPaths) {
      try {
        await send(context, pathname, { root: path });
        return;
      } catch {
        continue;
      }
    }

    // SPA fallback: serve index.html so client-side routes work on direct navigation
    await serveIndexHtml(context, staticPaths[0]);
    await next();
  };
}