// Automated bundle server

export async function processRequest(
  req: Request,
  hostpath: string,
  runner = Deno.run,
  fetcher = fetch,
): Promise<Response> {
  if (req.method == "OPTIONS") {
    return new Response(undefined, {
      headers: {
        "Access-Control-Allow-Origin": "*",
      },
    });
  }
  if (req.method != "GET") {
    return new Response(undefined, { status: 405 });
  }

  const params = req.url.split("/").filter((x) => !!x).slice(2);
  if (params.length < 2) {
    return new Response(undefined, { status: 404 });
  }

  const [lib, version] = params[0].split("@", 2);
  const file = params.slice(1).join("/");
  const branch = version || "master";
  const path = `https://${hostpath}/${lib}/raw/${branch}/${file}`;
  if (!isName(lib) || !isName(branch) || !isPath(file)) {
    return new Response(
      `console.error("bundler error - Invalid path ${path}");`,
      { status: 400 },
    );
  }

  if (path.endsWith(".js")) {
    return await bundle(path.slice(0, -3) + ".ts", runner);
  } else {
    return await fetcher(path, { redirect: "follow" });
  }
}

async function bundle(
  path: string,
  runner: typeof Deno.run,
): Promise<Response> {
  const process = runner({
    cmd: ["deno", "bundle", path],
    stdout: "piped",
  });
  const output = await process.output();
  const status = await process.status();
  if (status.success) {
    return new Response(output, {
      headers: {
        "Content-Type": "text/javascript",
        "Access-Control-Allow-Origin": "*",
      },
    });
  } else {
    return new Response(
      `console.error("bundler error - Failed to bundle ${path}");`,
      { status: 500 },
    );
  }
}

export async function serveBundles(hostpath: string, port: number) {
  const listen = { hostname: "0.0.0.0", port };
  console.log(
    `Serving ${hostpath} bundles on ${listen.hostname}:${listen.port} ...`,
  );

  for await (const conn of Deno.listen(listen)) {
    for await (const req of Deno.serveHttp(conn)) {
      try {
        const response = await processRequest(req.request, hostpath);
        await req.respondWith(response);
      } catch (err) {
        console.error(err);
        await req.respondWith(Response.error());
      }
    }
  }
}

function isName(input: string): boolean {
  return !!input.match(/^[a-zA-Z0-9_\-\.]+$/);
}

function isPath(input: string): boolean {
  return !input.split("/").some((part) => !isName(part));
}