import { useState, useCallback } from 'react';
import api from '../api';

// Generic API error handling
export function formatApiError(error: any, defaultMessage: string): string {
  if (error.response) {
    const data = error.response.data;
    
    // Handle FastAPI validation errors (detail is an array)
    if (data?.detail && Array.isArray(data.detail)) {
      return data.detail.map((err: any) => {
        if (typeof err === 'string') return err;
        if (err.msg) return `${err.loc?.join('.') || 'field'}: ${err.msg}`;
        return JSON.stringify(err);
      }).join(', ');
    }
    
    // Handle other error formats
    if (typeof data?.detail === 'string') return data.detail;
    if (typeof data?.message === 'string') return data.message;
    if (typeof data === 'string') return data;
    
    return defaultMessage;
  } else if (error.request) {
    return 'Keine Antwort vom Server erhalten';
  } else {
    return error.message || defaultMessage;
  }
}

// Type for API request options
export interface ApiRequestOptions<T> {
  url: string;
  method: 'get' | 'post' | 'put' | 'delete';
  data?: T;
  params?: Record<string, string | number | boolean>;
  additionalConfig?: Record<string, any>; // For responseType, headers, etc.
}

// Hook for making API requests with consistent error handling
export function useApiRequest<RequestData = any, ResponseData = any>() {
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const request = useCallback(async ({
    url,
    method,
    data,
    params,
    additionalConfig = {}
  }: ApiRequestOptions<RequestData>): Promise<ResponseData> => {
    setIsLoading(true);
    setError(null);

    try {
      const response = await api({
        url,
        method,
        data,
        params,
        ...additionalConfig
      });
      return response.data;
    } catch (error: any) {
      const errorMessage = formatApiError(error, `Fehler bei ${method.toUpperCase()} ${url}`);
      setError(errorMessage);
      throw new Error(String(errorMessage)); // Ensure it's a string
    } finally {
      setIsLoading(false);
    }
  }, []);

  return {
    request,
    isLoading,
    error
  };
}