/**
 * Git-based filesystem checkpoints for the /rewind feature.
 *
 * Creates lightweight snapshots via `git stash create` at each agent turn,
 * allowing the user to restore the working tree to a previous state.
 */
/** A filesystem checkpoint associated with a session entry. */
export interface Checkpoint {
    /** Session entry ID this checkpoint is associated with. */
    entryId: string;
    /** Git stash commit ref. Empty string means working tree was clean (HEAD is the checkpoint). */
    stashRef: string;
    /** HEAD commit hash at checkpoint creation time. */
    headRef: string;
    /** ISO timestamp when the checkpoint was created. */
    timestamp: string;
}
/** Result of a filesystem restore operation. */
export interface RestoreResult {
    ok: boolean;
    /** Files that were changed by the restore. */
    filesChanged: string[];
    /** Error message if restore failed. */
    error?: string;
}
/** Check if the cwd is inside a git repository. */
export declare function isGitRepo(cwd: string): boolean;
/** Get the current HEAD commit hash. */
export declare function getHeadRef(cwd: string): string | undefined;
/**
 * Create a stash commit without storing it in the stash list.
 * Returns the commit hash, or empty string if working tree is clean.
 */
export declare function createStashCommit(cwd: string): string;
/** Check if a git object ref is still valid (not garbage-collected). */
export declare function isValidRef(cwd: string, ref: string): boolean;
/**
 * Get the list of files that differ between two refs.
 * If `toRef` is omitted, compares against the current working tree.
 */
export declare function getChangedFilesBetween(cwd: string, fromRef: string, toRef?: string): string[];
/**
 * Get files that will change if we restore to a checkpoint.
 * Compares the checkpoint state against the current working tree.
 */
export declare function getFilesChangedByRewind(cwd: string, checkpoint: Checkpoint): string[];
/**
 * Restore the working tree to match a checkpoint.
 *
 * Strategy:
 * 1. Reset all tracked files to HEAD (`git checkout -- .`)
 * 2. Apply the checkpoint stash on top (`git stash apply <ref>`)
 *
 * If the checkpoint stash ref is empty (working tree was clean at checkpoint time),
 * only step 1 is performed.
 */
export declare function restoreCheckpoint(cwd: string, checkpoint: Checkpoint): RestoreResult;
/**
 * Create a safety stash of the current working tree state.
 * Returns the stash ref (empty if working tree is clean).
 * This allows undoing a rewind operation.
 */
export declare function createSafetyStash(cwd: string): string;
/** Get the checkpoints file path for a session file. */
export declare function getCheckpointsPath(sessionFile: string): string;
/** Load checkpoints from a JSON file. Returns empty map if file doesn't exist. */
export declare function loadCheckpoints(path: string): Map<string, Checkpoint>;
/** Save checkpoints to a JSON file. */
export declare function saveCheckpoints(filePath: string, checkpoints: Map<string, Checkpoint>): void;
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