export interface YonexusClientConfig {
  mainHost: string;
  identifier: string;
  /**
   * Optional. The client never sends pairing notifications (the server
   * does); accepted for back-compat but no longer required.
   */
  notifyBotToken?: string;
  adminUserId?: string;
}

export class YonexusClientConfigError extends Error {
  readonly issues: string[];

  constructor(issues: string[]) {
    super(`Invalid Yonexus.Client config: ${issues.join("; ")}`);
    this.name = "YonexusClientConfigError";
    this.issues = issues;
  }
}

function isNonEmptyString(value: unknown): value is string {
  return typeof value === "string" && value.trim().length > 0;
}

function isValidWsUrl(value: string): boolean {
  try {
    const url = new URL(value);
    return url.protocol === "ws:" || url.protocol === "wss:";
  } catch {
    return false;
  }
}

export function validateYonexusClientConfig(raw: unknown): YonexusClientConfig {
  const source = (raw && typeof raw === "object" ? raw : {}) as Record<string, unknown>;
  const issues: string[] = [];

  const rawMainHost = source.mainHost;
  if (!isNonEmptyString(rawMainHost)) {
    issues.push("mainHost is required");
  } else if (!isValidWsUrl(rawMainHost.trim())) {
    issues.push("mainHost must be a valid ws:// or wss:// URL");
  }

  const rawIdentifier = source.identifier;
  if (!isNonEmptyString(rawIdentifier)) {
    issues.push("identifier is required");
  }

  // Optional (back-compat): the client does not send notifications.
  const rawNotifyBotToken = source.notifyBotToken;
  const rawAdminUserId = source.adminUserId;

  if (issues.length > 0) {
    throw new YonexusClientConfigError(issues);
  }

  const mainHost = (rawMainHost as string).trim();
  const identifier = (rawIdentifier as string).trim();

  return {
    mainHost,
    identifier,
    notifyBotToken: isNonEmptyString(rawNotifyBotToken)
      ? rawNotifyBotToken.trim()
      : undefined,
    adminUserId: isNonEmptyString(rawAdminUserId)
      ? rawAdminUserId.trim()
      : undefined
  };
}