/**
 * @license
 * Copyright (c) 2025 Handsoncode. All rights reserved.
 */
import { ArraySize } from '../../ArraySize';
import { ProcedureAst } from '../../parser';
import { InterpreterState } from '../InterpreterState';
import { InterpreterValue } from '../InterpreterValue';
import { FunctionPlugin, FunctionPluginTypecheck, ImplementedFunctions } from './FunctionPlugin';
/**
 * Plugin implementing the UNIQUE spreadsheet function.
 *
 * UNIQUE(array, [by_col], [exactly_once]) returns the distinct rows (or columns
 * when by_col is TRUE) of `array`, preserving first-occurrence order. When
 * exactly_once is TRUE, only rows/columns that occur exactly once are returned.
 * Equality delegates to {@link ArithmeticHelper}, so comparison honors the
 * caseSensitive/accentSensitive configuration (case-insensitive by default).
 */
export declare class UniquePlugin extends FunctionPlugin implements FunctionPluginTypecheck<UniquePlugin> {
    static implementedFunctions: ImplementedFunctions;
    /**
     * Corresponds to UNIQUE(array, [by_col], [exactly_once]).
     *
     * Errors found anywhere in the input range are propagated. An empty result
     * (only reachable via exactly_once when nothing occurs exactly once) yields
     * #N/A, mirroring FILTER's empty-result handling.
     *
     * @param {ProcedureAst} ast - the parsed function-call AST node.
     * @param {InterpreterState} state - current interpreter evaluation state.
     */
    unique(ast: ProcedureAst, state: InterpreterState): InterpreterValue;
    /**
     * Predicts the output array size for UNIQUE at parse time.
     * The size is data-dependent, so we predict the input size as an upper bound
     * (mirroring FILTER) and return the smaller actual result at runtime. A fresh
     * ArraySize is returned so the input's `isRef` flag is not propagated (an
     * ArraySize flagged as a ref is treated as scalar, which would collapse the
     * spilled result into a single cell).
     *
     * @param {ProcedureAst} ast - the parsed function-call AST node.
     * @param {InterpreterState} state - current interpreter evaluation state.
     */
    uniqueArraySize(ast: ProcedureAst, state: InterpreterState): ArraySize;
    /** Returns the first {@link CellError} found in a 2-D array, or undefined. */
    private static findFirstError;
    /** Transposes a 2-D array (rows <-> columns). */
    private static transpose;
}