import axios, { AxiosInstance, AxiosRequestConfig } from 'axios';
import Cookies from 'js-cookie';

class ApiClient {
  private client: AxiosInstance;
  private baseURL: string;

  constructor() {
    this.baseURL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8000';
    
    this.client = axios.create({
      baseURL: this.baseURL,
      headers: {
        'Content-Type': 'application/json',
        'Accept': 'application/json',
      },
      timeout: 10000,
      withCredentials: true,
    });

    // Add request interceptor for auth token
    this.client.interceptors.request.use(
      (config) => {
        const token = Cookies.get('auth_token') || Cookies.get('access_token');
        if (token) {
          config.headers.Authorization = `Bearer ${token}`;
        }
        
        // Add session ID if available
        const sessionId = sessionStorage.getItem('tracking_session_id');
        if (sessionId) {
          config.headers['X-Session-ID'] = sessionId;
        }
        
        return config;
      },
      (error) => Promise.reject(error)
    );

    // Add response interceptor for error handling
    this.client.interceptors.response.use(
      (response) => response,
      (error) => {
        if (error.response?.status === 401) {
          // Handle unauthorized
          console.warn('Authentication required');
        }
        console.error('API Error:', error.response?.data || error.message);
        return Promise.reject(error);
      }
    );
  }

  public async post<T = any>(
    url: string,
    data?: any,
    config?: AxiosRequestConfig
  ): Promise<T> {
    const response = await this.client.post<T>(url, data, config);
    return response.data;
  }

  public async get<T = any>(
    url: string,
    config?: AxiosRequestConfig
  ): Promise<T> {
    const response = await this.client.get<T>(url, config);
    return response.data;
  }

  public async put<T = any>(
    url: string,
    data?: any,
    config?: AxiosRequestConfig
  ): Promise<T> {
    const response = await this.client.put<T>(url, data, config);
    return response.data;
  }

  public async delete<T = any>(
    url: string,
    config?: AxiosRequestConfig
  ): Promise<T> {
    const response = await this.client.delete<T>(url, config);
    return response.data;
  }

  public getBaseURL(): string {
    return this.baseURL;
  }

  public getClient(): AxiosInstance {
    return this.client;
  }
}

export const apiClient = new ApiClient();