/**
 * Core Metrics Analysis Engine
 *
 * Implements the main BFS traversal algorithm from the Ruby aac-metrics tool.
 * Calculates effort scores for all buttons in an AAC board set.
 *
 * Based on: aac-metrics/lib/aac-metrics/metrics.rb
 */
import { AACTree } from '../../../core/treeStructure';
import { MetricsOptions, MetricsResult } from './types';
export declare class MetricsCalculator {
    private locale;
    /**
     * Main analysis function - calculates metrics for an AAC tree
     *
     * @param tree - The AAC tree to analyze
     * @param options - Optional configuration for metrics calculation
     * @returns Complete metrics result
     */
    analyze(tree: AACTree, options?: MetricsOptions): MetricsResult;
    /**
     * Identify keyboard/spelling page and calculate base/avg effort
     */
    private identifySpellingMetrics;
    /**
     * Build reference maps for semantic_id and clone_id frequencies
     */
    private buildReferenceMaps;
    /**
     * Count scan items for visual scanning effort
     * When block scanning is enabled, count unique scan blocks instead of individual buttons
     */
    private countScanBlocks;
    /**
     * Analyze starting from a specific board
     */
    private analyzeFrom;
    /**
     * Calculate what percentage of links to this board match semantic_id/clone_id
     */
    private calculateBoardLinkPercentages;
    /**
     * Quick check whether any button in the tree has a POS tag.
     * Used to auto-enable smart grammar without requiring explicit opt-in.
     *
     * IMPORTANT: Only counts POS from non-Inflector and non-Suffix buttons.
     * TDSnap Inflector buttons and Grid3 Suffix buttons are grammar controls,
     * not content words — they should NOT auto-enable morphology.
     */
    private treeHasPosTags;
    /**
     * Expand morphological predictions from POS tags on buttons
     *
     * For each button that has a POS tag (e.g., 'Verb', 'Noun'), use the
     * MorphologyEngine to generate inflected word forms and populate the
     * button's predictions array. This is done as a pre-processing step
     * before calculateWordFormMetrics assigns effort to each form.
     */
    private expandMorphologicalPredictions;
    /**
     * Expand morphological predictions for Grid3 pagesets.
     *
     * Grid3 uses suffix buttons (pos='Suffix') on the same page as content words.
     * Different pages have different suffix buttons — e.g., topic pages may only
     * have -s (plural), while the Magic Wand page has -s, -er, -est, -ly, -y, -'s.
     *
     * Rules:
     * 1. Build a suffix→formSlot map (-s → plural, -er → comparative, etc.)
     * 2. For each page, collect available suffix buttons
     * 3. Only generate forms for slots that have matching suffix buttons on that page
     * 4. POS inference is used for untagged content words (Grid3 grids often lack POS)
     */
    private expandGrid3Predictions;
    /**
     * Expand morphological predictions for TDSnap pagesets.
     *
     * TDSnap uses Inflector buttons (ContentType=3) on "Word Forms" pages to
     * provide morphology. These pages are loaded dynamically by the runtime,
     * NOT via navigation buttons, so they are unreachable in our tree model.
     *
     * Rules:
     * 1. If the pageset has NO Inflector buttons → no morphology at all
     * 2. Only generate forms whose grammar tag matches an available Inflector
     *    (e.g., if there's no -ly Inflector, don't generate "happily")
     * 3. No POS inference — only the lexicon determines which words get forms
     */
    private expandTDSnapPredictions;
    private filterFormsByAvailableTags;
    /**
     * Calculate metrics for word forms (smart grammar predictions)
     *
     * Word forms are dynamically generated and not part of the tree structure.
     * Their effort is calculated as:
     * - Parent button's cumulative effort (to reach the button)
     * - + Effort to select the word form from its position in predictions grid
     *
     * If a word exists as both a regular button and a word form, the version
     * with lower effort is kept.
     *
     * @param tree - The AAC tree
     * @param buttons - Already calculated button metrics
     * @param options - Metrics options
     * @returns Object containing word form metrics and labels that were replaced
     */
    private calculateWordFormMetrics;
    /**
     * Calculate grid dimensions from the tree
     */
    private calculateGridDimensions;
    /**
     * Calculate scanning steps and selections for a button based on access method
     */
    private calculateScanSteps;
}