import type { DatabaseConnection } from '../../driver/database-connection.js';
/**
 * Config for the PostgreSQL dialect.
 */
export interface PostgresDialectConfig {
    /**
     * A postgres Pool instance or a function that returns one.
     *
     * If a function is provided, it's called once when the first query is executed.
     *
     * https://node-postgres.com/apis/pool
     */
    pool: PostgresPool | (() => Promise<PostgresPool>);
    /**
     * https://github.com/brianc/node-postgres/tree/master/packages/pg-cursor
     *
     * ```ts
     * import { PostgresDialect } from 'kysely'
     * import { Pool } from 'pg'
     * import Cursor from 'pg-cursor'
     * // or import * as Cursor from 'pg-cursor'
     *
     * new PostgresDialect({
     *  cursor: Cursor,
     *  pool: new Pool('postgres://localhost:5432/mydb')
     * })
     * ```
     */
    cursor?: PostgresCursorConstructor;
    /**
     * Called once for each created connection.
     */
    onCreateConnection?: (connection: DatabaseConnection) => Promise<void>;
    /**
     * Called every time a connection is acquired from the pool.
     */
    onReserveConnection?: (connection: DatabaseConnection) => Promise<void>;
}
/**
 * This interface is the subset of pg driver's `Pool` class that
 * kysely needs.
 *
 * We don't use the type from `pg` here to not have a dependency to it.
 *
 * https://node-postgres.com/apis/pool
 */
export interface PostgresPool {
    connect(): Promise<PostgresPoolClient>;
    end(): Promise<void>;
}
export interface PostgresPoolClient {
    query<R>(sql: string, parameters: ReadonlyArray<unknown>): Promise<PostgresQueryResult<R>>;
    query<R>(cursor: PostgresCursor<R>): PostgresCursor<R>;
    release(): void;
}
export interface PostgresCursor<T> {
    read(rowsCount: number): Promise<T[]>;
    close(): Promise<void>;
}
export type PostgresCursorConstructor = new <T>(sql: string, parameters: unknown[]) => PostgresCursor<T>;
export interface PostgresQueryResult<R> {
    command: 'UPDATE' | 'DELETE' | 'INSERT' | 'SELECT' | 'MERGE';
    rowCount: number;
    rows: R[];
}
export interface PostgresStream<T> {
    [Symbol.asyncIterator](): AsyncIterableIterator<T>;
}
