export const DEFAULT_VARIATION = 'A';

export type VariationKey = string;

export interface LoadableResult<T> {
  loaded: boolean;
  result: T;
}

/**
 * Session persist condition
 * - 'alwaysNewSession': Always start a new session
 * - 'nullToUserId': Start a new session when userId changes from null to a value
 */
export type SessionPersistCondition = 'alwaysNewSession' | 'nullToUserId';

export interface SessionTimeoutCondition {
  /** Session timeout interval in milliseconds */
  timeoutIntervalMillis?: number;
  /** Whether to check session timeout while the app is in foreground */
  onForeground?: boolean;
  /** Whether to check session timeout while the app is in background */
  onBackground?: boolean;
  /** Whether to check session timeout on application state changes */
  onApplicationStateChange?: boolean;
}

export interface SessionPolicy {
  persistCondition?: SessionPersistCondition;
  timeoutCondition?: SessionTimeoutCondition;
}

/**
 * Evaluation mode
 * - 'local': Evaluates locally with the workspace configuration fetched by the client. (default)
 * - 'remote': Reads the evaluation results that the server has pre-evaluated.
 */
export type EvaluationMode = 'local' | 'remote';

export interface SdkConfig {
  debug?: boolean;
  /** @deprecated Use sessionPolicy instead */
  sessionTimeoutMillis?: number;
  pollingIntervalMillis?: number;
  eventFlushIntervalMillis?: number;
  eventFlushThreshold?: number;
  exposureEventDedupIntervalMillis?: number;
  automaticAppLifecycleTracking?: boolean;
  automaticScreenTracking?: boolean;
  optOutTracking?: boolean;
  sessionPolicy?: SessionPolicy;
  /** Evaluation mode. Defaults to 'local'. */
  evaluationMode?: EvaluationMode;
  [key: string]: any;
}

export type PropertyValue =
  | string
  | boolean
  | number
  | Array<string | number>
  | undefined
  | null;