import type { SessionEntry, ChatMessage, Message } from 'apps/Chat';
import { useAuth } from 'hooks/useAuth';
import { useClient } from 'hooks/useClient';
import { useQuery, useQueryClient } from '@tanstack/react-query';

type SessionWithMessages = {
  id: string;
  title: string;
  model: string;
  cwd: string;
  groupSlug?: string | null;
  createdAt: number;
  updatedAt: number;
  messageCount: number;
  cost: {
    inputTokens: number;
    outputTokens: number;
    totalUSD: number;
  };
  messages: Message[];
};

export function useChatSessions() {
  const client = useClient();
  const queryClient = useQueryClient();
  const { isAuthenticated } = useAuth();

  const { data: sessions = [] } = useQuery<SessionEntry[]>({
    queryKey: ['PI_SESSIONS'],
    enabled: isAuthenticated,
    queryFn: () => client.post<{ sessions: SessionEntry[] }>('/api/pi/sessions').then((r) => r.sessions),
  });

  function getSession(sessionId: string) {
    return client.get<{ session: SessionWithMessages }>(`/api/pi/sessions/${sessionId}`);
  }

  function saveMessages(sessionId: string, messages: ChatMessage[]) {
    return client.put(`/api/pi/sessions/${sessionId}/messages`, messages);
  }

  async function renameSession(sessionId: string, title: string) {
    await client.patch(`/api/pi/sessions/${sessionId}`, { title });
    queryClient.invalidateQueries({ queryKey: ['PI_SESSIONS'] });
  }

  async function deleteSession(sessionId: string) {
    await client.delete(`/api/pi/sessions/${sessionId}`);
    queryClient.setQueryData<SessionEntry[]>(
      ['PI_SESSIONS'],
      (prev) => prev?.filter((s) => s.id !== sessionId) ?? [],
    );
  }

  function searchSessions(query: string) {
    return client.get<{ results: SessionEntry[] }>(`/api/pi/sessions/search?q=${encodeURIComponent(query)}`);
  }

  return {
    sessions,
    getSession,
    saveMessages,
    renameSession,
    deleteSession,
    searchSessions,
  };
}