smol

import { adapt } from "./adapt.ffi.mjs";
import { started } from "./smol.mjs";
import { upgrade } from "./smol.ffi.mjs";

import {
  Builder$Builder$handler,
  Builder$Builder$port,
  Builder$Builder$interface,
  Builder$Builder$on_error,
  Builder$Builder$after_start,
} from "./smol/internal/builder.mjs";

export function start(builder) {
  const handler = adapt(Builder$Builder$handler(builder));

  return new Promise((resolve) => {
    const server = Deno.serve({
      port: Builder$Builder$port(builder),
      hostname: Builder$Builder$interface(builder),

      async handler(req) {
        const response = await handler(req);

        if (response.body[upgrade]) {
          const runtime = response.body[upgrade];
          const { socket, response: wsResponse } = Deno.upgradeWebSocket(req);

          runtime.send = (message) => socket.send(message);
          runtime.close = () => socket.close();

          socket.addEventListener("open", runtime.onOpen);
          socket.addEventListener("message", (event) =>
            runtime.onMessage(event.data),
          );
          socket.addEventListener("close", runtime.onClose);

          return wsResponse;
        } else {
          return response;
        }
      },

      onListen({ port, hostname }) {
        let disposed = false;
        const stop = async () => {
          if (disposed) {
            return;
          }
          disposed = true;

          await server.shutdown();
        };

        // TODO: doesn't seem like Deno lets us bind to SIGINT?

        Builder$Builder$after_start(builder)(port, hostname);

        resolve(started(port, hostname, stop));
      },

      onError(error) {
        Builder$Builder$on_error(builder)(error.stack, error);
        return new Response("Internal Server Error", { status: 500 });
      },
    });
  });
}