import axios, { AxiosError, Method } from "axios";

export interface SapB1ErrorDetails {
  status?: number;
  code?: string;
  message?: string;
  method?: string;
  url?: string;
  retryable?: boolean;
  cause?: unknown;
}

export class SapB1Error extends Error {
  public readonly status?: number;
  public readonly code?: string;
  public readonly method?: string;
  public readonly url?: string;
  public readonly retryable: boolean;
  public override readonly cause?: unknown;

  public constructor(details: SapB1ErrorDetails) {
    super(details.message || "SAP Business One Service Layer request failed");
    this.name = "SapB1Error";
    this.status = details.status;
    this.code = details.code;
    this.method = details.method;
    this.url = details.url;
    this.retryable = details.retryable ?? false;
    this.cause = details.cause;
  }
}

// Shared normalizer so every SAP call (including login) surfaces the SAP status/code
// and message when the Service Layer actively rejected the request, and falls back to
// the transport-level message (ECONNREFUSED, timeout, TLS, ...) otherwise. This is what
// lets a caller tell "SAP rejected it" apart from "we never reached SAP".
export function toSapB1Error(
  error: unknown,
  method?: Method,
  path?: string,
  fallbackMessage = "SAP B1 request failed"
): SapB1Error {
  if (error instanceof SapB1Error) {
    return error;
  }

  if (axios.isAxiosError(error)) {
    const axiosError = error as AxiosError<{ error?: { code?: string; message?: { value?: string } | string } }>;
    const status = axiosError.response?.status;
    const sapError = axiosError.response?.data?.error;
    const message =
      typeof sapError?.message === "string"
        ? sapError.message
        : sapError?.message?.value || axiosError.message || fallbackMessage;

    return new SapB1Error({
      status,
      code: sapError?.code,
      message,
      method,
      url: path,
      retryable: status === 408 || status === 429 || (status !== undefined && status >= 500),
      cause: error
    });
  }

  return new SapB1Error({ message: fallbackMessage, method, url: path, cause: error });
}