/**
 * Resolves whether the capture layer crosses shadow boundaries, and how deep.
 *
 * {@link ShadowMode} is a union, so `enabled: true` always carries a positive
 * crossing budget and off is a single value ({@link SHADOW_OFF}). Callers branch
 * on `enabled` and read `maxDepth` only in the enabled arm.
 *
 * {@link ShadowGate} holds the mode for the page. It starts off and latches on
 * the first remote-config delivery that enables shadow support, notifying
 * `onArm` subscribers so they can run their one-time discovery scans (attaching
 * MutationObservers to existing shadow roots, registering in-shadow elements for
 * exposure). Subsequent deliveries do not change it — including one that
 * disables shadow support, which takes effect on the next page load.
 *
 * The gate is read on every captured event and on every observer callback.
 * Latching means those reads always agree with each other and with the scans
 * already performed, without threading the mode through every call.
 *
 * Rollout limitations (open roots only, latch-once per page, late
 * `attachShadow` discovery, DFS performance) are documented in
 * `packages/plugin-autocapture-browser/SHADOW-DOM.md`.
 */
import type { ResolvedSelectorConfig } from '@amplitude/element-selector';
/** Shadow piercing on. `maxDepth` is the number of boundaries a walk may cross. */
export type ShadowOn = {
    readonly enabled: true;
    readonly maxDepth: number;
};
/** Shadow piercing off. `maxDepth` is pinned to 0 so no walk can cross. */
export type ShadowOff = {
    readonly enabled: false;
    readonly maxDepth: 0;
};
/** Whether the capture layer crosses shadow boundaries, and how deep. */
export type ShadowMode = ShadowOn | ShadowOff;
/** The off value. Shared rather than reconstructed, so identity checks hold. */
export declare const SHADOW_OFF: ShadowOff;
/**
 * Project a resolved selector config onto a {@link ShadowMode}. A zero or
 * negative budget resolves to off, since an enabled mode that cannot cross a
 * boundary would behave as off while reading as on. The config resolver already
 * clamps into `[1, MAX_SHADOW_DOM_DEPTH]`; this covers a config that bypassed it.
 */
export declare const shadowModeFromConfig: (config: Pick<ResolvedSelectorConfig, 'shadowDomEnabled' | 'maxShadowDomDepth'>) => ShadowMode;
/** Holds the {@link ShadowMode} for a page, transitioning from off to on once. */
export interface ShadowGate {
    /** The current mode: {@link SHADOW_OFF} until armed, then the armed mode. */
    get(): ShadowMode;
    /**
     * Apply a resolved mode. Takes effect only on the first call with an enabled
     * mode, which also notifies `onArm` subscribers. Later calls are ignored,
     * including one carrying {@link SHADOW_OFF}. Returns the current mode.
     */
    arm(mode: ShadowMode): ShadowMode;
    /**
     * Register `cb` to run when the gate arms, or synchronously if it is already
     * armed. Observables use this to run their shadow discovery scan once, whether
     * they subscribed before or after the arming config arrived. Returns an
     * unsubscribe function.
     */
    onArm(cb: (mode: ShadowOn) => void): () => void;
}
export declare const createShadowGate: () => ShadowGate;
export declare const getSharedShadowGate: () => ShadowGate;
/**
 * Test-only. `arm` cannot move the gate back to off, so tests that exercise the
 * enabled path replace the singleton to return to the off mode.
 */
export declare const resetSharedShadowGateForTesting: () => void;
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