import type { SessionEntry, SessionManager } from "@caupulican/pi-agent-core/node";
export type SessionSnapshotPayload<ValueKey extends string, Value extends object> = {
    version: 1;
} & {
    [Key in ValueKey]: Value;
};
export interface SessionSnapshotCodec<Value extends object, ValueKey extends string> {
    customType: string;
    valueKey: ValueKey;
    isValue(value: unknown): value is Value;
    clone(value: Value): Value;
}
export interface SessionBranchEntrySource {
    getBranch?: () => readonly SessionEntry[];
    getEntries?: () => readonly SessionEntry[];
}
type VersionOneSnapshotPayload = Record<string, unknown> & {
    version: 1;
};
/** Active branch when available; linear entry history only for narrow stores that expose no branch API. */
export declare function getActiveSessionBranchEntries(source: SessionBranchEntrySource): readonly SessionEntry[];
export declare function isVersionOneSessionSnapshotPayload(data: unknown): data is VersionOneSnapshotPayload;
export declare function createSessionSnapshotPayload<Value extends object, ValueKey extends string>(codec: SessionSnapshotCodec<Value, ValueKey>, value: Value): SessionSnapshotPayload<ValueKey, Value>;
export declare function appendSessionSnapshot<Value extends object, ValueKey extends string>(sessionManager: Pick<SessionManager, "appendCustomEntry">, codec: SessionSnapshotCodec<Value, ValueKey>, value: Value): string;
export declare function decodeSessionSnapshotPayload<Value extends object, ValueKey extends string>(data: unknown, codec: SessionSnapshotCodec<Value, ValueKey>): Value | undefined;
export declare function getSessionSnapshots<Value extends object, ValueKey extends string>(entries: readonly SessionEntry[], codec: SessionSnapshotCodec<Value, ValueKey>): Value[];
export declare function getLatestSessionSnapshot<Value extends object, ValueKey extends string>(entries: readonly SessionEntry[], codec: SessionSnapshotCodec<Value, ValueKey>): Value | undefined;
/**
 * Resolves the newest valid snapshot on the active branch. Malformed entries are skipped while
 * walking leaf to root so they cannot hide an older valid checkpoint.
 */
export declare function getLatestSessionSnapshotOnBranch<Value extends object, ValueKey extends string>(sessionManager: Pick<SessionManager, "getLatestCustomEntryOnBranch">, codec: SessionSnapshotCodec<Value, ValueKey>): Value | undefined;
export {};
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