import { type StorageOperation } from './storage-operation.js';
/**
 * The storage backend implementations provide the logic to read and write configuration and other persistent data layer
 * elements to and from various storage mediums.
 *
 * The Data Layer API must provide the following minimal set of implementations:
 * <ul>
 *   <li>Local File System</li>
 *   <li>Kubernetes ConfigMap</li>
 *   <li>Kubernetes Secret (for future use)</li>
 *   <li>Environment Variables</li>
 * </ul>
 *
 * Storage backends should not attempt to interpret or validate the data being read or written, but should handle the
 * conversion of plain javascript objects to the underlying data format and vice versa.
 */
export interface StorageBackend {
    /**
     * List all keys in the storage backend. Not all storage backends support listing keys.
     *
     * @returns A list of keys in the storage backend.
     */
    list(): Promise<string[]>;
    /**
     * Reads the persisted data from the storage backend and marshals it into bytes.
     *
     * @param key - The key to use to read the data from the storage backend. The key is implementation specific and might
     *              be a file path, a config map name, or an environment variable prefix.
     * @returns The persisted data represented as a byte array.
     */
    readBytes(key: string): Promise<Buffer>;
    /**
     * Write the configuration data to the storage backend by marshalling the bytes into the underlying
     * persistent data format.
     *
     * @param key - The key to use to write the data to the storage backend. The key is implementation specific and might
     *              be a file path, a config map name, or an environment variable prefix.
     * @param data - The persistent data represented as a byte array.
     */
    writeBytes(key: string, data: Buffer): Promise<void>;
    /**
     * Deletes the persisted data from the storage backend. Not all storage backends support deletion.
     *
     * @param key - The key to use to delete the data from the storage backend. The key is implementation specific and might
     *              be a file path, a config map name, or an environment variable prefix.
     */
    delete(key: string): Promise<void>;
    /**
     * Checks if the storage backend supports the given operation.
     * Implementations must provide a valid definition which responds appropriately for the requested operation.
     *
     * @param op - The desired storage operation to check.
     * @returns True if the operation is supported, false otherwise.
     */
    isSupported(op: StorageOperation): boolean;
}