Implement facade for simple chat.

[sethladd]

TLDR: Wish for an easy way to add GenUI to my existing Chat App (Firebase AI Logic first)
TLDR: Non-invasive way to integrate the Gen UI surface widgets and state with an existing chat UI implementation

I have an existing app which already has a chat experience. For example, https://github.com/sethladd/throwaway-genui-test

I want to add GenUI to my chat.

I think we need additional APIs to make it more straight forward, assuming the user is already using Firebase AI Logic and already has a chat feature.

[sethladd]

cc @jacobsimionato , the thing we talked about

[sethladd]

cc @polina-c what we just talked about

[jacobsimionato]

For this, the thing I was imagining is to decouple the GenUiManager and ChatWidget / ConversationWidget so that developers can implement the latter themselves, based on their existing chat view. I think we're already seeing good signals to do this:

• Seth wanted to own his own chat view
• We ourselves have already created two separate implementations - ConversationWidget and ChatWidget
• We are accumulating lots of visual options like userPromptBuilder, showInternalMessages, which could be more simply handled by allowing for custom implementations.

Open questions:

• Should the developer own the source of truth of the conversation state, e.g. the list of messages, currently in GenuiManager._chatHistory, or should that be held inside Gen UI?

Straw person sketch:

in MyApp.dart:

final manager = GenuiManager()

  @override
  Widget build(BuildContext context) {
      return MyConversationView(manager: manager)
   }

in MyConversationView.dart:

  @override
  Widget build(BuildContext context) {
      return StreamBuilder(
      stream: manager.conversationStream,
      initialData: const <ChatMessage>[],
      builder: (context, snapshot) {
}
   }

[sethladd]

As the owner of the app that already has a chat, I'm OK with:

• writing my system prompt with no knowledge of GenUI
• prepending or appending some prompt created by GenUI into my prompt (programmatically)
• handing responses from the LLM which may or may not include widgets. That is, I'm ok updating my chat logic to not assume I'm always getting text back.
• registering widgets I created into GenUI, as part of my app initialization
• teaching Firebase AI Logic that it can be aware of GenUI

[polina-c]

There are two options to integrate existing chat with GenUi:

1. Black-boxed: we ask flutter_genui to wrap the existing responses from your agent/model into nice UI

2. Deep integration: we ask flutter_genui two things:
   a. to rephrase requests to your agent/model, so that your agent/model shapes the responses as UI
   b. to render the response

@jacobsimionato , I think we want to keep number of possible options to integrate with GenUI by having flexible core and number of facade helpers, that suggest different shapes of integration.

Instead of sying that we have two separate implementations - ConversationWidget and ChatWidget, I suggest that we have core flexible implementation and two shaped: ConversationWidget and ChatWidget.

Going forward we will add/remove the shaped options as needed.

How does it sound?

[polina-c]

I’ve put together the prototype for the facade for FirebaseAi: #122

This is how Seth’s app will consume it: https://github.com/sethladd/throwaway-genui-test/pull/4

@jacobsimionato is planning to provide alternative suggestion.