import { AxiosError } from 'axios';

export interface ApiError {
  message: string;
  code?: string;
  status: number;
  details?: Record<string, string[]>;
}

export function handleApiError(error: unknown): ApiError {
  if (error instanceof AxiosError) {
    const status = error.response?.status || 500;
    const data = error.response?.data;

    // Django validation errors
    if (status === 400 && data) {
      return {
        message: 'Validation failed',
        code: 'VALIDATION_ERROR',
        status,
        details: data,
      };
    }

    // Authentication errors
    if (status === 401) {
      return {
        message: 'Authentication required',
        code: 'UNAUTHORIZED',
        status,
      };
    }

    // Permission errors
    if (status === 403) {
      return {
        message: 'Permission denied',
        code: 'FORBIDDEN',
        status,
      };
    }

    // Not found
    if (status === 404) {
      return {
        message: 'Resource not found',
        code: 'NOT_FOUND',
        status,
      };
    }

    // Rate limiting
    if (status === 429) {
      return {
        message: 'Too many requests',
        code: 'RATE_LIMITED',
        status,
      };
    }

    // Server errors
    if (status >= 500) {
      return {
        message: 'Server error occurred',
        code: 'SERVER_ERROR',
        status,
      };
    }

    return {
      message: data?.message || error.message || 'An error occurred',
      code: 'API_ERROR',
      status,
    };
  }

  // Network errors
  return {
    message: 'Network error occurred',
    code: 'NETWORK_ERROR',
    status: 0,
  };
}

export function formatErrorForUser(error: ApiError): string {
  if (error.details) {
    const messages = Object.entries(error.details)
      .map(([field, errors]) => `${field}: ${errors.join(', ')}`)
      .join('\n');
    return messages;
  }
  return error.message;
}