/**
 * @license
 * SPDX-License-Identifier: Apache-2.0
 */

class ApiClient {
  private getHeaders() {
    const headers: Record<string, string> = {
      'Content-Type': 'application/json',
      'Accept': 'application/json',
    };
    if (typeof window !== 'undefined') {
      const token = localStorage.getItem('stateless_ops_token');
      if (token) {
        headers['Authorization'] = `Bearer ${token}`;
      }
    }
    return headers;
  }

  async request<T>(path: string, options: RequestInit = {}): Promise<T> {
    const url = path;
    const headers = { ...this.getHeaders(), ...options.headers };
    
    // FormData 전송 시 Content-Type 헤더가 없어야 브라우저가 boundary를 자동으로 지정합니다.
    if (options.body instanceof FormData) {
      delete headers['Content-Type'];
    }

    const response = await fetch(url, { ...options, headers });

    if (response.status === 401) {
      if (typeof window !== 'undefined') {
        localStorage.removeItem('stateless_ops_token');
        localStorage.removeItem('stateless_ops_user_id');
        window.location.href = '/ops/login';
      }
      throw new Error('인증이 만료되었습니다. 다시 로그인해주세요.');
    }

    if (!response.ok) {
      const errData = await response.json().catch(() => ({ detail: '알 수 없는 서버 오류' }));
      throw new Error(errData.detail || 'API 요청 실패');
    }

    if (response.status === 204) {
      return {} as T;
    }

    return response.json() as Promise<T>;
  }

  get<T>(path: string, options?: RequestInit): Promise<T> {
    return this.request<T>(path, { ...options, method: 'GET' });
  }

  post<T>(path: string, body?: any, options?: RequestInit): Promise<T> {
    const isFormData = body instanceof FormData;
    return this.request<T>(path, {
      ...options,
      method: 'POST',
      body: isFormData ? body : (body ? JSON.stringify(body) : undefined),
    });
  }

  put<T>(path: string, body?: any, options?: RequestInit): Promise<T> {
    return this.request<T>(path, {
      ...options,
      method: 'PUT',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  patch<T>(path: string, body?: any, options?: RequestInit): Promise<T> {
    return this.request<T>(path, {
      ...options,
      method: 'PATCH',
      body: body ? JSON.stringify(body) : undefined,
    });
  }

  delete<T>(path: string, options?: RequestInit): Promise<T> {
    return this.request<T>(path, { ...options, method: 'DELETE' });
  }
}

export const apiClient = new ApiClient();