feat: add multi-model support

app/client/types.ts

@@ -0,0 +1,39 @@
+import { DEFAULT_MODELS } from "../constant";
+
+export interface LLMUsage {
+  used: number;
+  total: number;
+  available: boolean;
+}
+
+export interface LLMModel {
+  name: string;
+  available: boolean;
+}
+
+export const ROLES = ["system", "user", "assistant"] as const;
+export type MessageRole = (typeof ROLES)[number];
+
+export type ChatModel = (typeof DEFAULT_MODELS)[number]["name"];
+
+export interface RequestMessage {
+  role: MessageRole;
+  content: string;
+}
+
+export interface ChatOptions {
+  messages: RequestMessage[];
+  shouldSummarize?: boolean;
+
+  onUpdate?: (message: string, chunk: string) => void;
+  onFinish: (message: string) => void;
+  onError?: (err: Error) => void;
+  onController?: (controller: AbortController) => void;
+}
+
+export type LLMClient = {
+  chat(options: ChatOptions): Promise<void>;
+  chatStream(options: ChatOptions): Promise<void>;
+  usage(): Promise<LLMUsage>;
+  models(): Promise<LLMModel[]>;
+};