import { type LeafEntry, type SessionMetadata, type SessionStorage, type SessionTreeEntry, type SessionWriteOptions } from "../harness/types.js";
/** Return the effective branch leaf after applying a session tree entry. */
export declare function leafIdAfterEntry(entry: SessionTreeEntry): string | null;
export declare abstract class BaseSessionStorage<TMetadata extends SessionMetadata = SessionMetadata> implements SessionStorage<TMetadata> {
    private readonly metadata;
    private readonly entries;
    private readonly byId;
    private readonly labelsById;
    private leafId;
    private readonly floorId;
    protected constructor(metadata: TMetadata, entries: SessionTreeEntry[], leafId?: string | null, opts?: {
        floorEntryId?: string | null;
    });
    /** The bounded-window root this storage was woken with, or null for a full-tree load (F3). */
    getFloorId(): string | null;
    getMetadata(): Promise<TMetadata>;
    getLeafId(): Promise<string | null>;
    protected createLeafEntry(leafId: string | null): LeafEntry;
    createEntryId(): Promise<string>;
    /**
     * Optimistic-lock check (F2). Throws `SessionError("conflict")` when `opts.expectedLeafId` is
     * provided and does not match the current in-memory leaf. Concrete `appendEntry`/`setLeafId`
     * implementations call this before persisting; durable backends should instead perform the same
     * check atomically against shared state (a conditional write) so concurrent instances can't fork.
     */
    protected assertExpectedLeaf(opts?: SessionWriteOptions): void;
    protected recordEntry(entry: SessionTreeEntry): void;
    getEntry(id: string): Promise<SessionTreeEntry | undefined>;
    findEntries<TType extends SessionTreeEntry["type"]>(type: TType): Promise<Array<Extract<SessionTreeEntry, {
        type: TType;
    }>>>;
    getLabel(id: string): Promise<string | undefined>;
    getPathToRoot(leafId: string | null): Promise<SessionTreeEntry[]>;
    getEntries(): Promise<SessionTreeEntry[]>;
    abstract setLeafId(leafId: string | null, opts?: SessionWriteOptions): Promise<void>;
    abstract appendEntry(entry: SessionTreeEntry, opts?: SessionWriteOptions): Promise<void>;
}