const API = {
  async request(endpoint, options = {}) {
    const url = `${API_CONFIG.baseUrl}${endpoint}`;
    try {
      const response = await fetch(url, {
        headers: {
          'Content-Type': 'application/json',
          ...(options.headers || {}),
        },
        credentials: 'include',
        ...options,
      });
      const text = await response.text();
      if (!response.ok) {
        let error;
        try {
          error = JSON.parse(text);
        } catch {
          error = { message: text || 'Unbekannter Fehler' };
        }
        throw new Error(error.message || 'API-Fehler');
      }
      return text ? JSON.parse(text) : null;
    } catch (err) {
      console.error('API error:', err);
      throw err;
    }
  },
  getKurse() {
    return this.request(API_CONFIG.endpoints.kurse);
  },
  getBetriebe() {
    return this.request(API_CONFIG.endpoints.betriebe);
  },
  anmelden(data) {
    return this.request(API_CONFIG.endpoints.anmeldung, {
      method: 'POST',
      body: JSON.stringify(data),
    });
  },
  getBerichtBetrieb() {
    return this.request(API_CONFIG.endpoints.berichtBetrieb);
  },
  getBerichtKurs() {
    return this.request(API_CONFIG.endpoints.berichtKurs);
  },
  getRechnung(betriebId) {
    return this.request(`${API_CONFIG.endpoints.rechnung}${betriebId}`);
  },
  login(email, password) {
    return this.request(API_CONFIG.endpoints.login, {
      method: 'POST',
      body: JSON.stringify({ email, password }),
    });
  },
  logout() {
    return this.request(API_CONFIG.endpoints.logout, { method: 'POST' });
  },
  me() {
    return this.request(API_CONFIG.endpoints.me);
  },
};