export { DatabaseError } from "./lowlevel.js";
/**
 * Union type representing the supported data formats for keys and values.
 * Can be a Uint8Array, ArrayBuffer, or string.
 */
export type Data = Uint8Array | ArrayBuffer | string;
/**
 * When returned from a transaction function, indicates that the caller wants
 * to receive the commit sequence number as the resolved value of the transact() promise.
 * This can be useful for applications that need a globally unique, monotonically increasing
 * identifier for each committed transaction.
 */
export declare const RETURN_COMMIT_SEQ: unique symbol;
/**
 * Attach some arbitrary user data to the current transaction context, which is
 * attached to the currently running (async) task.
 * @param key - A symbol key to store data in the current transaction context.
 * @param value - The value to store.
 * @throws {TypeError} If called outside of a transaction context.
 * @example
 * ```typescript
 * const MY_SYMBOL = Symbol("myKey");
 * await transact(async () => {
 *   setTransactionData(MY_SYMBOL, "myValue");
 *   await somethingAsync(); // Can be interleaved with other transactions
 *   const value = getTransactionData(MY_SYMBOL);
 *   console.log(value); // "myValue"
 * });
 * ```
 */
export declare function setTransactionData(key: symbol, value: any): void;
/**
 * Retrieves data from the current transaction context.
 * @param key - A symbol key to retrieve data from the current transaction context.
 * @returns - The value associated with the key, or undefined if not set.
 * @throws {TypeError} If called outside of a transaction context.
 */
export declare function getTransactionData(key: symbol): any;
/**
 * Retrieves a value from the database by key within the current transaction.
 *
 * @param key - The key to look up as a Uint8Array, ArrayBuffer, or string.
 * @returns The value associated with the key as a Uint8Array, or undefined if not found.
 * @throws {TypeError} If called outside of a transaction context.
 * @throws {DatabaseError} With code "INVALID_TRANSACTION" if transaction is invalid or already closed.
 * @throws {DatabaseError} With code "KEY_TOO_LONG" if key exceeds maximum allowed length.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 */
export declare function get(key: Data): Readonly<Uint8Array> | undefined;
/**
 * Retrieves a value from the database by key within the current transaction.
 *
 * @param key - The key to look up as a Uint8Array, ArrayBuffer, or string.
 * @returns The value associated with the key as an ArrayBuffer, or undefined if not found.
 * @throws {TypeError} If called outside of a transaction context.
 * @throws {DatabaseError} With code "INVALID_TRANSACTION" if transaction is invalid or already closed.
 * @throws {DatabaseError} With code "KEY_TOO_LONG" if key exceeds maximum allowed length.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 */
export declare function getBuffer(key: Data): Readonly<ArrayBuffer> | undefined;
/**
 * Retrieves a value from the database by key within the current transaction and decodes it as a string.
 *
 * @param key - The key to look up as a Uint8Array, ArrayBuffer, or string.
 * @returns The value associated with the key as a UTF-8 decoded string, or undefined if not found.
 * @throws {TypeError} If called outside of a transaction context.
 * @throws {DatabaseError} With code "INVALID_TRANSACTION" if transaction is invalid or already closed.
 * @throws {DatabaseError} With code "KEY_TOO_LONG" if key exceeds maximum allowed length.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 */
export declare function getString(key: Data): string | undefined;
/**
 * Stores a key-value pair in the database within the current transaction.
 *
 * @param key - The key to store as a Uint8Array, ArrayBuffer, or string.
 * @param val - The value to associate with the key as a Uint8Array, ArrayBuffer, or string.
 * @throws {TypeError} If called outside of a transaction context.
 * @throws {DatabaseError} With code "INVALID_TRANSACTION" if transaction is invalid or already closed.
 * @throws {DatabaseError} With code "KEY_TOO_LONG" if key exceeds maximum allowed length.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 */
export declare function put(key: Data, val: Data): void;
/**
 * Deletes a key-value pair from the database within the current transaction.
 *
 * @param key - The key to delete as a Uint8Array, ArrayBuffer, or string.
 * @throws {TypeError} If called outside of a transaction context.
 * @throws {DatabaseError} With code "INVALID_TRANSACTION" if transaction is invalid or already closed.
 * @throws {DatabaseError} With code "KEY_TOO_LONG" if key exceeds maximum allowed length.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 */
export declare function del(key: Data): void;
/**
 * Initialize the database with the specified directory path.
 * This function may be called multiple times with the same parameters. If it is not called before the first transact(),
 * the database will be automatically initialized with the default directory.
 *
 * @param dbDir - Optional directory path for the database (defaults to environment variable $OLMDB_DIR or "./.olmdb").
 * @throws {DatabaseError} With code "INCONSISTENT_INIT" if database is already initialized with different parameters.
 * @throws {DatabaseError} With code "CREATE_DIR_FAILED" if directory creation fails.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 *
 * @example
 * ```typescript
 * init("./my-database");
 * ```
 */
export declare function init(dbDir?: string): void;
/**
 * Registers a callback to be executed when the current transaction is reverted (aborted due to error).
 * The callback will be executed outside of transaction context.
 *
 * @param callback - Function to execute when transaction is reverted. It receives the dummy (always 0) commit sequence indicating failure as an argument.
 * @throws {TypeError} If called outside of a transaction context
 */
export declare function onRevert(callback: (commitSeq: number) => void): void;
/**
 * Registers a callback to be executed when the current transaction commits successfully.
 * The callback will be executed outside of transaction context.
 *
 * @param callback - Function to execute when transaction commits. It receives the commit sequence, which is an always-increasing number that provides a global ordering of commits, as an argument.
 * @throws {TypeError} If called outside of a transaction context
 */
export declare function onCommit(callback: (commitSeq: number) => void): void;
/**
 * Executes a function within a database transaction context.
 *
 * All database operations (get, put, del) must be performed within a transaction.
 * Transactions are automatically committed if the function completes successfully,
 * or aborted if an error occurs. Failed transactions may be automatically retried
 * up to 6 times in case of validation conflicts.
 *
 * @template T - The return type of the transaction function.
 * @param fn - The (optionally asynchronous) function to execute within the transaction context.
 * @returns A promise that resolves with the function's return value. If the function returns the special symbol `RETURN_COMMIT_SEQ`, the promise resolves with the commit sequence number instead.
 * @throws {TypeError} If nested transactions are attempted.
 * @throws {DatabaseError} With code "RACING_TRANSACTION" if the transaction fails after retries due to conflicts.
 * @throws {DatabaseError} With code "TRANSACTION_FAILED" if the transaction fails for other reasons.
 * @throws {DatabaseError} With code "TXN_LIMIT" if maximum number of transactions is reached.
 * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
 *
 * @example
 * ```typescript
 * const result = await transact(() => {
 *   const value = get(keyBytes);
 *   if (value) {
 *     put(keyBytes, newValueBytes);
 *   }
 *   return value;
 * });
 * ```
 */
export declare function transact<T>(fn: () => Promise<typeof RETURN_COMMIT_SEQ>): Promise<number>;
export declare function transact<T>(fn: () => typeof RETURN_COMMIT_SEQ): Promise<number>;
export declare function transact<T>(fn: () => Promise<T>): Promise<T>;
export declare function transact<T>(fn: () => T): Promise<T>;
/**
 * Represents a key-value pair returned by the iterator
 */
export interface DbEntry<K, V> {
    key: K;
    value: V;
}
/**
 * Database iterator that implements the standard TypeScript iterator protocol
 */
export declare class DbIterator<K, V> extends Iterator<DbEntry<K, V>, undefined> implements Iterator<DbEntry<K, V>, undefined> {
    private iteratorId;
    private convertKey;
    private convertValue;
    constructor(iteratorId: number, convertKey: (buffer: Readonly<ArrayBuffer>) => K, convertValue: (buffer: Readonly<ArrayBuffer>) => V);
    [Symbol.iterator](): DbIterator<K, V>;
    /**
     * Advances the iterator to the next key-value pair.
     *
     * @returns An IteratorResult with the next DbEntry or done: true if no more entries.
     * @throws {DatabaseError} With code "INVALID_ITERATOR" if iterator is invalid or already closed.
     * @throws {DatabaseError} With code "LMDB-{code}" for LMDB-specific errors.
     */
    next(): IteratorResult<DbEntry<K, V>>;
    /**
     * Closes the iterator and frees its resources.
     * Should be called when done iterating to prevent resource leaks.
     *
     * @throws {DatabaseError} With code "INVALID_ITERATOR" if iterator is invalid or already closed.
     */
    close(): void;
}
/**
 * Creates an iterator to scan through database entries within the current transaction.
 *
 * The iterator implements the standard TypeScript iterator protocol and can be used with for...of loops.
 *
 * The scan covers the half-open range `[start, end)` — `start` is the inclusive
 * lower bound and `end` the exclusive upper bound. This holds regardless of
 * direction: `reverse` only changes the order in which entries are emitted, not
 * which bound is inclusive (so a reverse scan of `[start, end)` begins at the
 * largest key below `end` and ends at `start`).
 *
 * @template K - The type to convert keys to (defaults to Uint8Array).
 * @template V - The type to convert values to (defaults to Uint8Array).
 * @param opts - Configuration options for the scan operation.
 * @param opts.start - Optional inclusive lower bound. If omitted, the range is open at the bottom.
 * @param opts.end - Optional exclusive upper bound. If omitted, the range is open at the top.
 * @param opts.reverse - Whether to iterate in reverse order (defaults to false).
 * @param opts.keyConvert - Function to convert key ArrayBuffers to type K (defaults to asArray).
 * @param opts.valueConvert - Function to convert value ArrayBuffers to type V (defaults to asArray).
 * @returns A DbIterator instance.
 * @throws {TypeError} If called outside of a transaction context.
 * @throws {DatabaseError} With code "INVALID_TRANSACTION" if transaction is invalid or already closed.
 * @throws {DatabaseError} With code "KEY_TOO_LONG" if start or end key exceeds maximum allowed length.
 * @throws {DatabaseError} With code "ITERATOR_LIMIT" if maximum number of iterators is reached.
 * @throws {DatabaseError} With code "OUT_OF_MEMORY" if memory allocation fails.
 *
 * @example
 * ```typescript
 * await transact(() => {
 *   // Iterate over all entries
 *   for (const { key, value } of scan()) {
 *     console.log('Key:', key, 'Value:', value);
 *   }
 *
 *   // Iterate with string conversion
 *   for (const { key, value } of scan({
 *     keyConvert: asString,
 *     valueConvert: asString
 *   })) {
 *     console.log('Key:', key, 'Value:', value);
 *   }
 *
 *   // Iterate with boundaries
 *   for (const { key, value } of scan({
 *     start: "prefix_",
 *     end: "prefix~"
 *   })) {
 *     console.log('Key:', key, 'Value:', value);
 *   }
 *
 *   // Manual iteration control
 *   const iter = scan({ reverse: true });
 *   const first = iter.next();
 *   iter.close(); // Always close when done early
 * });
 * ```
 */
export declare function scan<K = Uint8Array, V = Uint8Array>(opts?: ScanOptions<K, V>): DbIterator<K, V>;
interface ScanOptions<K = Uint8Array, V = Uint8Array> {
    start?: Data;
    end?: Data;
    reverse?: boolean;
    keyConvert?: (buffer: Readonly<ArrayBuffer>) => K;
    valueConvert?: (buffer: Readonly<ArrayBuffer>) => V;
}
/**
 * Converts an ArrayBuffer to a Uint8Array.
 * Helper function for use with scan() keyConvert and valueConvert options.
 *
 * @param buffer - The ArrayBuffer to convert.
 * @returns A new Uint8Array view of the buffer.
 */
export declare function asArray(buffer: Readonly<ArrayBuffer>): Readonly<Uint8Array>;
/**
 * Returns the ArrayBuffer as-is.
 * Helper function for use with scan() keyConvert and valueConvert options.
 *
 * @param buffer - The ArrayBuffer to return.
 * @returns The same ArrayBuffer.
 */
export declare function asBuffer(buffer: Readonly<ArrayBuffer>): Readonly<ArrayBuffer>;
/**
 * Converts an ArrayBuffer to a UTF-8 decoded string.
 * Helper function for use with scan() keyConvert and valueConvert options.
 *
 * @param buffer - The ArrayBuffer to decode.
 * @returns A UTF-8 decoded string.
 */
export declare function asString(buffer: Readonly<ArrayBuffer>): string;