import { __ } from '@wordpress/i18n';
import axios, { AxiosInstance } from 'axios';
import { AjaxResponse } from './ajax.service.types';

interface AjaxServiceInitParams {
  ajaxUrl: string;
  nonce: string;
}

class AjaxService {
  private axiosInstance: AxiosInstance;
  private ajaxUrl!: string;
  private nonce!: string;

  constructor() {
    this.axiosInstance = axios.create({
      headers: {
        'Content-Type': 'multipart/form-data',
      },
    });
  }

  init(params: AjaxServiceInitParams) {
    this.ajaxUrl = params.ajaxUrl;
    this.nonce = params.nonce;
  }

  /**
   * Send POST AJAX request with JSON payload converted to FormData
   */
  async post<T = any>(action: string, payload: Record<string, any>): Promise<T> {
    if (!this.ajaxUrl) {
      throw new Error(__('AjaxService not initialized', 'timetailor-salon-booking'));
    }

    try {
      const ajaxPayload = {
        action,
        security: this.nonce,
        ...payload,
      };
      const formData = this.jsonToFormData(ajaxPayload);

      const response = await this.axiosInstance.post<AjaxResponse<T>>(this.ajaxUrl, formData);

      // If success is true, return the data object
      if (response.data.success) {
        return response.data.data;
      }

      // If success is false, throw the data as error
      throw response.data.data || new Error(__('Request failed', 'timetailor-salon-booking'));
    } catch (error) {
      // If it's already the data object we threw, re-throw it
      if (error && typeof error === 'object' && !(error instanceof Error)) {
        throw error;
      }

      if (axios.isAxiosError(error) && error.response) {
        // If server returned an error response, try to parse it
        const responseData = error.response.data;
        if (responseData && typeof responseData === 'object' && 'data' in responseData) {
          throw responseData.data || new Error(__('Request failed', 'timetailor-salon-booking'));
        }
        throw new Error(responseData?.message || __('Request failed', 'timetailor-salon-booking'));
      }
      throw new Error(__('Network error or request failed', 'timetailor-salon-booking'));
    }
  }

  private jsonToFormData(payload: Record<string, any>): FormData {
    const formData = new FormData();

    Object.keys(payload).forEach((key) => {
      const value = payload[key];
      if (value !== null && value !== undefined) {
        formData.append(key, value);
      }
    });

    return formData;
  }
}

export const ajaxService = new AjaxService();