// EOF and Stop drain submissions. Shutdown cancels invocations and preserves durable tasks for restart.
export async function serve(harness: any, context: any, afterSubmit?: () => Promise<void>, api?: any, defaultConversation?: () => Promise<number>) {
  const pending = new Set<Promise<void>>();
  const track = (work: Promise<void>) => {
    const task = work.catch(error => Deno.core.ops.op_output(`${String(error)}\n`)).finally(() => pending.delete(task));
    pending.add(task);
  };
  while (true) {
    const input = await Deno.core.ops.op_input();
    if (input?.type === 'shutdown') {
      // Close cancels invocations without terminal outcomes, so durable tasks resume after restart.
      await harness.close(context);
      await Promise.all(pending);
      return;
    }
    if (input === null || input.type === 'stop') {
      await harness.waitForIdle(context);
      await Promise.all(pending);
      return;
    }
    if (input.type === 'api') {
      track(api.handle(input));
      continue;
    }
    const id = defaultConversation ? await defaultConversation() : input.conversation;
    const conversation = await harness.conversation(id, context);
    if (!conversation) throw new Error(`Unknown conversation: ${id}`);
    const submission = await conversation.submit({
      type: 'input', content: input.content, requestId: input.requestId,
    }, context);
    if (afterSubmit) {
      track(submission.wait(context).then(async (result: any) => {
        await afterSubmit();
        if (result.status !== 'done') throw new Error(`Run ended: ${JSON.stringify(result)}`);
      }));
    }
  }
}