import { type ControllerLog, type KeyState, type SignedEvent } from '@kokuin/controller';
import type { StoreProvider } from '@kubun/db';
import { type Logger } from '@kubun/logger';
import type { EngineEvents } from './engine-events.js';
import type { EngineEventBus } from './events.js';
export type ControllerHeadState = {
    status: 'ok';
    state: KeyState;
    log: ControllerLog;
    digest: string;
} | {
    status: 'missing';
};
/** A version changes whenever the accepted head moves. */
export declare function controllerHeadVersion(head: ControllerHeadState): string;
export type IngestOutcome = 'unchanged' | 'advanced' | 'rejected';
export type IngestSource = 'network' | 'handoff' | 'service' | 'local';
export type ControllerHeadHistory = {
    log: ControllerLog | null;
};
export type ControllerHeadParams = {
    eventBus: EngineEventBus<EngineEvents>;
    logger?: Logger;
};
/** External evidence must commit independently of a caller's mutation. */
export declare class ControllerHeadTransactionError extends Error {
    constructor(source: IngestSource);
}
export declare class ControllerHeadLockError extends Error {
    constructor();
}
/** Event-wise digest prefix, equal logs included. False for unhashable evidence. */
export declare function isLogPrefixOf(prefix: Array<SignedEvent>, log: Array<SignedEvent>): boolean;
/** Owns controller-log arbitration and answers from the accepted stored log. */
export declare class ControllerHead {
    #private;
    constructor(params: ControllerHeadParams);
    assertStoreSchema(stores: StoreProvider): Promise<void>;
    head(stores: StoreProvider, did: string): Promise<ControllerHeadState>;
    headForUpdate(stores: StoreProvider, did: string): Promise<ControllerHeadState>;
    history(stores: StoreProvider, did: string): Promise<ControllerHeadHistory>;
    ingest(stores: StoreProvider, did: string, candidates: Array<Array<SignedEvent>>, source: IngestSource): Promise<IngestOutcome>;
}