interface PromptVariant<TResult = string> {
    /** Variant id — matches a feature-flag payload / flag value. */
    id: string;
    /** The prompt value to serve when this variant is picked. */
    prompt: TResult;
    /** Relative weight used by the default sticky-hash resolver. Default 1. */
    weight?: number;
}
interface PromptExperimentContext {
    /**
     * Opaque stable identifier used for sticky assignment — user id,
     * session id, or any business key. Without this, resolution is
     * random-per-call (fine for smoke tests, bad for A/B cohorts).
     */
    subjectId?: string;
    /** Pass-through metadata handed to custom resolvers. */
    metadata?: Record<string, unknown>;
}
type PromptResolver<TResult = string> = (variants: PromptVariant<TResult>[], context: PromptExperimentContext) => PromptVariant<TResult> | Promise<PromptVariant<TResult>> | string | Promise<string>;
interface PromptExperiment<TResult = string> {
    /** Experiment name — used by analytics / flag providers as the key. */
    name: string;
    variants: PromptVariant<TResult>[];
    /**
     * Pick a variant. Plug in your feature-flag client
     * (PostHog / GrowthBook / Unleash / custom) here. If it throws or
     * returns an unknown id, the experiment falls back to the built-in
     * sticky-hash resolver.
     */
    resolve: PromptResolver<TResult>;
    /** Fires on every resolution — feed your analytics pipeline. */
    onExposure?: (decision: {
        name: string;
        variantId: string;
        subjectId?: string;
        fallback: boolean;
    }) => void;
}
interface PromptDecision<TResult = string> {
    name: string;
    variantId: string;
    prompt: TResult;
    fallback: boolean;
}
/**
 * Deterministic sticky assignment: same `subjectId` always maps to
 * the same variant, weighted by `variant.weight`. When `subjectId`
 * is omitted, falls back to `Math.random()` — good enough for
 * smoke tests, not for production cohorts.
 */
declare function stickyResolver<TResult = string>(): PromptResolver<TResult>;
/**
 * Build a prompt experiment. Call `.pick(context)` at the call site
 * to get the variant id + prompt; wire `resolve` to your flag
 * provider's variant-selection API (PostHog's `getFeatureFlagPayload`,
 * GrowthBook's `getFeatureValue`, etc.).
 */
declare function createPromptExperiment<TResult = string>(config: PromptExperiment<TResult>): {
    pick: (context?: PromptExperimentContext) => Promise<PromptDecision<TResult>>;
};
/**
 * Convenience resolver: maps your flag client's `getVariant(name,
 * subjectId) => string | undefined` signature directly into a
 * `PromptResolver`. Works with PostHog, GrowthBook, Unleash — anything
 * that returns a string variant id.
 */
declare function flagResolver<TResult = string>(getVariant: (name: string, context: PromptExperimentContext) => string | undefined | Promise<string | undefined>, experimentName: string): PromptResolver<TResult>;

export { type PromptDecision, type PromptExperiment, type PromptExperimentContext, type PromptResolver, type PromptVariant, createPromptExperiment, flagResolver, stickyResolver };