export interface DispatcherOptions {
    /** Max attempts per task. Default 3. */
    maxAttempts?: number;
    /** Backoff base in ms. backoff = base * 2^failCount. Default 1000. */
    backoffBaseMs?: number;
}
export type WorkerSnapshot<F extends (...args: any[]) => Promise<any>> = {
    index: number;
    status: 'active';
    fn: F;
    running: boolean;
    failCount: number;
    totalRuns: number;
    blockedMs: number;
    specificQueue: number;
} | {
    index: number;
    status: 'pending';
    promise: Promise<F>;
    specificQueue: number;
} | {
    index: number;
    status: 'rejected';
    error: string;
    specificQueue: number;
};
export declare class WorkflowDispatcher<F extends (...args: any[]) => Promise<any>> {
    private readonly maxAttempts;
    private readonly backoffBaseMs;
    private readonly slots;
    private readonly globalQueue;
    private pendingInits;
    private everActivated;
    private drainScheduled;
    constructor(workersOrPromises: Array<F | Promise<F>>, options?: DispatcherOptions);
    /** Dispatch: choose eligible active with least totalRuns; retry across workers on failure. */
    dispatch(...args: Parameters<F>): Promise<Awaited<ReturnType<F>>>;
    /** Dispatch to a specific worker (ignore backoff), wait until it is free; retry on the same worker. */
    dispatchSpecific(index: number, ...args: Parameters<F>): Promise<Awaited<ReturnType<F>>>;
    /** Replace a worker at index with a new active worker function. */
    replaceWorker(index: number, fn: F): void;
    /** Add a new active worker at the tail; return its index. */
    addWorker(fn: F): number;
    /**
     * Remove a worker completely (splice). It becomes unavailable immediately.
     * Returns a Promise that resolves when its last running task (if any) finishes.
     */
    removeWorker(index: number): Promise<void>;
    snapshot(): WorkerSnapshot<F>[];
    get pending(): number;
    private drain;
    private _drainLoop;
    private hasAnyActive;
    private rejectAllQueued;
    private isEligibleActive;
    private pickBestActiveForGlobal;
    private startTaskOnActiveSlot;
}