import type { DeltaPage, DeltaRecord } from "./delta-client.js";
type ApplyKind = "regular" | "symlink" | "delete";
export interface DurableApplyContent {
    kind: "regular" | "symlink";
    /** Exact bytes returned by the authorized delta content descriptor. */
    bytes: Buffer;
    /** SHA-256 hexadecimal digest authenticated by that descriptor. */
    sha256: string;
}
export interface DurableApplyIntent {
    deltaId: string;
    canonicalPath: string;
    operation: ApplyKind;
    versionId: string | null;
    sha256: string | null;
    mode: number | null;
    symlinkTarget: string | null;
    stageName: string | null;
}
export interface DurableAppliedPath {
    deltaId: string;
    operation: ApplyKind;
    versionId: string | null;
    sha256: string | null;
}
export interface DurableApplyState {
    intents: Record<string, DurableApplyIntent>;
    paths: Record<string, DurableAppliedPath>;
    cursor: string | null;
}
export interface DurableApplyOptions {
    /** Filesystem root for one authorized scope projection. */
    rootDir: string;
    /** Root used by the WAL v3 state store. */
    stateRootDir: string;
    scopeId: string;
    initialCursor?: string | null;
    /** Test-only crash seam, called after each durable boundary. */
    afterStep?: (step: DurableApplyStep) => void;
}
export type DurableApplyStep = "stage-hashed" | "stage-fdatasynced" | "stage-parent-fsynced" | "intent-durable" | "filesystem-applied" | "parent-fsynced" | "path-durable" | "cursor-durable";
export declare class DurableApplyError extends Error {
    constructor(message: string, options?: ErrorOptions);
}
export declare class DurableApplyRecoveryError extends DurableApplyError {
    constructor(message: string, options?: ErrorOptions);
}
/**
 * A page is the cursor unit. All path records are durable before its opaque
 * fixed-H cursor is appended. The caller must serialize calls per scope.
 */
export declare class DurableApplyEngine {
    private readonly rootDir;
    private readonly afterStep;
    private readonly store;
    constructor(options: DurableApplyOptions);
    getState(): DurableApplyState;
    /** Finish every prior filesystem intent, but never invent a page cursor. */
    recover(): void;
    /**
     * Fetching is deliberately outside this module: only the authorized
     * deltaId-to-exact-version transport can provide bytes. Deletes never ask
     * for content.
     */
    applyPage(page: Pick<DeltaPage, "untilCursor" | "nextPageToken" | "deltas">, fetchContent: (delta: DeltaRecord) => Promise<DurableApplyContent>): Promise<void>;
    private beginUpsert;
    private beginDelete;
    private recoverIntent;
    private applyIntentFilesystem;
    private finishIntent;
    private targetPath;
    private step;
    private sweepUnreferencedStages;
}
export {};
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