import { Initializer } from './Initializer';
import { Synchronizer } from './Synchronizer';
/**
 * Factory function that creates an {@link Initializer} instance.
 *
 * @param selectorGetter Returns the current selector (basis) string, or
 *   `undefined` if no selector is available.
 */
export type InitializerFactory = (selectorGetter: () => string | undefined) => Initializer;
/**
 * Factory function that creates a {@link Synchronizer} instance.
 *
 * @param selectorGetter Returns the current selector (basis) string, or
 *   `undefined` if no selector is available.
 */
export type SynchronizerFactory = (selectorGetter: () => string | undefined) => Synchronizer;
/**
 * State of a synchronizer slot.
 * - `'available'`: can be selected for use.
 * - `'blocked'`: has been blocked (e.g., terminal error or not yet activated).
 */
export type SynchronizerSlotState = 'available' | 'blocked';
/**
 * A slot in the synchronizer list, wrapping a factory with state metadata.
 */
export interface SynchronizerSlot {
    readonly factory: SynchronizerFactory;
    readonly isFDv1Fallback: boolean;
    state: SynchronizerSlotState;
}
/**
 * Creates a {@link SynchronizerSlot}.
 *
 * @param factory The synchronizer factory function.
 * @param options Optional configuration.
 * @param options.isFDv1Fallback Whether this slot is the FDv1 fallback adapter.
 *   FDv1 slots start `'blocked'` by default.
 * @param options.initialState Override the initial state (defaults to
 *   `'blocked'` for FDv1 slots, `'available'` otherwise).
 */
export declare function createSynchronizerSlot(factory: SynchronizerFactory, options?: {
    isFDv1Fallback?: boolean;
    initialState?: SynchronizerSlotState;
}): SynchronizerSlot;
/**
 * Manages the state of initializers and synchronizers, tracks which source
 * is active, and handles source transitions.
 */
export interface SourceManager {
    /**
     * Get the next initializer and set it as the active source.
     * Closes the previous active source. Returns `undefined` when all
     * initializers are exhausted.
     */
    getNextInitializerAndSetActive(): Initializer | undefined;
    /**
     * Get the next available (non-blocked) synchronizer and set it as the
     * active source. Closes the previous active source. Returns `undefined`
     * when all available synchronizers have been visited.
     */
    getNextAvailableSynchronizerAndSetActive(): Synchronizer | undefined;
    /** Mark the current synchronizer as blocked (e.g., after terminal error). */
    blockCurrentSynchronizer(): void;
    /** Reset the synchronizer index to -1 so the next call starts from the beginning. */
    resetSourceIndex(): void;
    /** Block all non-FDv1 synchronizers and unblock FDv1 synchronizers. */
    fdv1Fallback(): void;
    /** True if the current synchronizer is the first available (primary). */
    isPrimeSynchronizer(): boolean;
    /** Count of synchronizers in `'available'` state. */
    getAvailableSynchronizerCount(): number;
    /** True if any synchronizer slot is marked as an FDv1 fallback. */
    hasFDv1Fallback(): boolean;
    /** Close the active source and mark the manager as shut down. */
    close(): void;
    /** True if {@link close} has been called. */
    readonly isShutdown: boolean;
}
/**
 * Creates a {@link SourceManager} that coordinates initializer and
 * synchronizer lifecycle.
 *
 * @param initializerFactories Ordered list of initializer factories.
 * @param synchronizerSlots Ordered list of synchronizer slots with state.
 * @param selectorGetter Closure that returns the current selector string.
 */
export declare function createSourceManager(initializerFactories: InitializerFactory[], synchronizerSlots: SynchronizerSlot[], selectorGetter: () => string | undefined): SourceManager;
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