/**
 * Pure utility functions for ClickHouse HTTP interface communication.
 * Uses ONLY Node.js built-ins — no npm imports.
 */
export interface ClickHouseCredentials {
    host: string;
    port: number;
    database: string;
    username: string;
    password: string;
    protocol: string;
    authMethod?: string;
    jwtToken?: string;
}
export interface QueryParam {
    name: string;
    value: string;
}
export interface ColumnMapping {
    sourceField: string;
    targetColumn: string;
}
export interface QueryStats {
    read_rows: string;
    read_bytes: string;
    written_rows: string;
    written_bytes: string;
    total_rows_to_read: string;
    elapsed_ns: string;
}
export interface SchemaColumn {
    name: string;
    type: string;
    default_kind?: string;
    default_expression?: string;
    comment?: string;
    is_in_sorting_key?: number;
    is_in_primary_key?: number;
    is_in_partition_key?: number;
}
export interface SchemaTable {
    name: string;
    engine: string;
    total_rows: number | string;
    total_bytes: number | string;
    sorting_key?: string;
    partition_key?: string;
    primary_key?: string;
    comment?: string;
    columns: SchemaColumn[];
    sampleData?: Record<string, unknown>[];
}
/**
 * Validates a ClickHouse identifier (database name, table name).
 * Throws if the identifier contains invalid characters that could enable injection.
 */
export declare function validateIdentifier(value: string, label: string): void;
/**
 * Validates that a port number is within the valid TCP range.
 */
export declare function validatePort(port: number): void;
export declare function buildBaseUrl(credentials: ClickHouseCredentials): string;
export declare function buildAuthHeader(credentials: ClickHouseCredentials): string;
export declare function buildUrlParams(database: string, settings?: string, queryParams?: QueryParam[]): string;
export declare function chunkArray<T>(arr: T[], size: number): T[][];
export declare function parseClickHouseResponse(body: string): Record<string, unknown>[];
/**
 * Extracts a user-safe error message from a ClickHouse HTTP error response.
 * Strips potential credential/connection details and keeps only the
 * ClickHouse error code and message.
 */
export declare function extractClickHouseError(error: unknown): string;
/**
 * Applies column mapping to a row object.
 * Renames source fields to target columns, optionally filtering to only mapped fields.
 */
export declare function applyColumnMapping(row: Record<string, unknown>, mappings: ColumnMapping[], onlyMapped: boolean): Record<string, unknown>;
/**
 * Parses the X-ClickHouse-Summary header into a structured stats object.
 */
export declare function parseQueryStats(summaryHeader: string | undefined): QueryStats | null;
/**
 * Infers a ClickHouse type from a JavaScript value.
 */
export declare function inferClickHouseType(value: unknown): string;
/**
 * Builds a CREATE TABLE DDL from column definitions and options.
 */
export declare function buildCreateTableDDL(params: {
    table: string;
    database: string;
    columns: Array<{
        name: string;
        type: string;
    }>;
    engine: string;
    orderBy: string;
    ifNotExists: boolean;
    partitionBy?: string;
    ttl?: string;
}): string;
export declare function formatRowCount(count: number | string): string;
export declare function formatBytes(bytes: number | string): string;
export declare function formatSchemaForAgent(database: string, tables: SchemaTable[]): string;
/**
 * Validates a WHERE clause for SQL injection.
 * Uses strict allowlist approach - only permits safe operators.
 * @throws Error if dangerous patterns are detected
 */
export declare function validateWhereClause(whereClause: string): void;
/**
 * Escapes a string value for safe use in SQL.
 * Escapes single quotes and backslashes.
 */
export declare function escapeStringValue(value: string): string;
/**
 * Validates and sanitizes a SET expression for UPDATE operations.
 * Expects format: column1 = value1, column2 = value2
 * @throws Error if the expression contains dangerous patterns
 */
export declare function validateSetExpression(setExpression: string): void;
/**
 * Validates an array of column update specifications.
 * Each entry should have a column name and a value.
 */
export declare function validateColumnUpdates(updates: Array<{
    column: string;
    value: string;
}>): void;
/**
 * Builds a safe SET clause from validated column updates.
 * Returns format: column1 = value1, column2 = value2
 */
export declare function buildSafeSetClause(updates: Array<{
    column: string;
    value: string;
    quoted?: boolean;
}>): string;