import type { AuditEntry } from './types.js';
export declare class AuditLog {
    private readonly filePath;
    private lastHash;
    constructor(filePath: string);
    /**
     * Append an audit entry to the NDJSON log.
     * Each entry includes the SHA-256 hash of the previous entry
     * to create a tamper-evident hash chain.
     */
    append(entry: AuditEntry): Promise<void>;
    /**
     * Verify the integrity of the entire hash chain.
     * Returns { valid, entries, brokenAt } — brokenAt is the index
     * of the first entry with a hash mismatch, or -1 if all valid.
     */
    verifyIntegrity(): Promise<{
        valid: boolean;
        entries: number;
        brokenAt: number;
    }>;
    /**
     * Read all audit entries from the log file.
     */
    private readAll;
    /**
     * Get the hash of the last entry in the log file.
     * Returns empty string if the file is empty or doesn't exist.
     */
    private getLastHash;
    /**
     * Ensure the log file and parent directories exist.
     */
    private ensureFileExists;
}