/**
 * Manages SAS tokens for accessing Planetary Computer assets.
 * Implements token caching to minimize API calls.
 */
export declare class SASTokenManager {
    private cache;
    private bufferMs;
    /**
     * Creates a new SAS token manager.
     *
     * @param bufferMs - Buffer time before expiry to refresh token (default: 5 min).
     */
    constructor(bufferMs?: number);
    /**
     * Gets a valid SAS token for the given collection.
     *
     * @param collectionId - Collection identifier.
     * @returns Promise resolving to SAS token string.
     */
    getToken(collectionId: string): Promise<string>;
    /**
     * Signs a URL with a SAS token.
     *
     * @param url - URL to sign.
     * @param collectionId - Collection identifier for token lookup.
     * @returns Promise resolving to signed URL.
     */
    signUrl(url: string, collectionId: string): Promise<string>;
    /**
     * Checks if a token is cached and valid for a collection.
     *
     * @param collectionId - Collection identifier.
     * @returns True if a valid token is cached.
     */
    hasValidToken(collectionId: string): boolean;
    /**
     * Clears the token cache.
     */
    clearCache(): void;
    /**
     * Clears the cached token for a specific collection.
     *
     * @param collectionId - Collection identifier.
     */
    clearToken(collectionId: string): void;
}
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