AI hooks

function useGeneration(options?: {
  endpoint?: string;      // 默认 '/api/ai/chat'
  model?: string;
  onFinish?: (text: string) => void;
}): {
  text: string;
  status: 'idle' | 'streaming' | 'done' | 'error' | 'cancelled';
  error: string | null;
  isStreaming: boolean;
  generate: (input: { messages: ChatMessage[]; model?: string }) => Promise<string>;
  cancel: () => void;
  reset: () => void;
}

const { text, isStreaming, generate, cancel } = useGeneration({
  onFinish: (final) => setMessages((p) => [...p, { role: 'assistant', content: final }]),
});

await generate({ messages: [{ role: 'user', content: 'hi' }] });

function useTask<T>(options: {
  startEndpoint: string;
  pollEndpoint: string;        // hook 自动追加 `?id=<id>`
  intervalMs?: number;         // 默认 1500
  parse: (json: unknown) => Pick<TaskState<T>, 'status' | 'result' | 'error' | 'progress'>;
}): TaskState<T> & { start: (input: unknown) => Promise<void>; cancel: () => void };

type TaskStatus = 'idle' | 'queued' | 'running' | 'succeeded' | 'failed' | 'cancelled';

const task = useTask<{ images: { url: string }[] }>({
  startEndpoint: '/api/ai/image',
  pollEndpoint: '/api/ai/image/status',
  parse: (json) => json as ReturnType<typeof task.parse>,
});

await task.start({ prompt: 'a cat astronaut' });

function useCredits(endpoint?: string): {
  balance: number | null;     // null = 未登录，不是错误
  isLoading: boolean;
  error: string | null;
  refetch: () => Promise<void>;
};

const { balance, refetch } = useCredits();
// 一次 AI 调用成功后：
useEffect(() => { void refetch(); }, [lastCallId]);

function useHistory(endpoint?: string): {
  rows: AICallHistoryRow[];
  isLoading: boolean;
  error: string | null;
  hasMore: boolean;
  loadMore: () => Promise<void>;
  refetch: () => Promise<void>;
};

const { rows, hasMore, loadMore } = useHistory();
return rows.map((r) => <HistoryRow key={r.id} row={r} />);