import type { SyntaxNode } from '../types.js';
import type { SupportedLanguage } from '../languages/registry.js';
/** Raw Halstead counts from AST */
export interface HalsteadCounts {
    n1: number;
    n2: number;
    N1: number;
    N2: number;
    operators: Map<string, number>;
    operands: Map<string, number>;
}
/** Calculated Halstead metrics */
export interface HalsteadMetrics {
    vocabulary: number;
    length: number;
    volume: number;
    difficulty: number;
    effort: number;
    time: number;
    bugs: number;
}
/**
 * Count operators and operands in an AST node
 *
 * @param node - AST node to analyze (typically a function/method)
 * @param language - Programming language for language-specific handling
 * @returns HalsteadCounts with raw operator/operand counts
 */
export declare function countHalstead(node: SyntaxNode, language: SupportedLanguage): HalsteadCounts;
/**
 * Calculate derived Halstead metrics from raw counts
 *
 * Formulas based on Maurice Halstead's "Elements of Software Science" (1977):
 * - Vocabulary (n) = n1 + n2
 * - Length (N) = N1 + N2
 * - Volume (V) = N × log₂(n) - size of implementation
 * - Difficulty (D) = (n1/2) × (N2/n2) - error-proneness
 * - Effort (E) = D × V - mental effort required
 * - Time (T) = E / 18 - seconds to understand (Stroud number)
 * - Bugs (B) = E^(2/3) / 3000 - estimated delivered bugs (effort-based variant)
 *
 * @param counts - Raw Halstead counts from countHalstead()
 * @returns Calculated HalsteadMetrics
 */
export declare function calculateHalsteadMetrics(counts: HalsteadCounts): HalsteadMetrics;
/**
 * Calculate Halstead metrics for an AST node in one call
 *
 * Convenience function that combines countHalstead and calculateHalsteadMetrics.
 *
 * @param node - AST node to analyze
 * @param language - Programming language
 * @returns Calculated HalsteadMetrics
 */
export declare function calculateHalstead(node: SyntaxNode, language: SupportedLanguage): HalsteadMetrics;
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