type ErrorConfig = {
  getDocsUrl?: ((args: BaseErrorParameters) => string | undefined) | undefined;
};

let errorConfig: ErrorConfig = {
  getDocsUrl: ({
    docsBaseUrl,
    docsPath = "",
    docsSlug,
  }: BaseErrorParameters) =>
    docsPath
      ? `${docsBaseUrl ?? "https://viem.sh"}${docsPath}${
          docsSlug ? `#${docsSlug}` : ""
        }`
      : undefined,
};

export function setErrorConfig(config: ErrorConfig): void {
  errorConfig = config;
}

type BaseErrorParameters = {
  cause?: BaseError | Error | undefined;
  details?: string | undefined;
  docsBaseUrl?: string | undefined;
  docsPath?: string | undefined;
  docsSlug?: string | undefined;
  metaMessages?: string[] | undefined;
  name?: string | undefined;
};

export type BaseErrorType = BaseError & { name: "BaseError" };
export class BaseError extends Error {
  details: string;
  docsPath?: string | undefined;
  metaMessages?: string[] | undefined;
  shortMessage: string;

  override name = "BaseError";

  constructor(shortMessage: string, args: BaseErrorParameters = {}) {
    const details = (() => {
      if (args.cause instanceof BaseError) return args.cause.details;
      if (args.cause?.message) return args.cause.message;
      return args.details!;
    })();
    const docsPath = (() => {
      if (args.cause instanceof BaseError)
        return args.cause.docsPath || args.docsPath;
      return args.docsPath;
    })();
    const docsUrl = errorConfig.getDocsUrl?.({ ...args, docsPath });

    const message = [
      shortMessage || "An error occurred.",
      "",
      ...(args.metaMessages ? [...args.metaMessages, ""] : []),
      ...(docsUrl ? [`Docs: ${docsUrl}`] : []),
      ...(details ? [`Details: ${details}`] : []),
    ]
      .filter((data) => data !== "")
      .join("\n")
      .replace(/\n$/, "");

    super(message, args.cause ? { cause: args.cause } : undefined);

    this.details = details;
    this.docsPath = docsPath;
    this.metaMessages = args.metaMessages;
    this.name = args.name ?? this.name;
    this.shortMessage = shortMessage;
  }

  walk(): Error;
  walk(fn: (err: unknown) => boolean): Error | null;
  // biome-ignore lint/suspicious/noExplicitAny: <explanation>
  walk(fn?: any): any {
    return walk(this, fn);
  }
}

function walk(
  err: unknown,
  fn?: ((err: unknown) => boolean) | undefined,
): unknown {
  if (fn?.(err)) return err;
  if (
    err &&
    typeof err === "object" &&
    "cause" in err &&
    err.cause !== undefined
  )
    return walk(err.cause, fn);
  return fn ? null : err;
}