/**
 * LyricHighlighter - Headless lyric highlighting logic
 *
 * This is a framework-agnostic implementation that provides
 * the core logic for lyric highlighting without any UI dependencies.
 */
import type { LyricLine, LyricHighlightState, LyricDisplayOptions } from '../types/components';
export declare class LyricHighlighter {
    private lyrics;
    private options;
    constructor(options?: Partial<LyricDisplayOptions>);
    /**
     * Set lyrics data
     */
    setLyrics(lyrics: LyricLine[]): void;
    /**
     * Update display options
     */
    setOptions(options: Partial<LyricDisplayOptions>): void;
    /**
     * Get current lyric state at given time
     */
    getState(currentTime: number): LyricHighlightState;
    /**
     * Find current line index using binary search
     */
    private getCurrentLineIndex;
    /**
     * Get lines to display based on display mode
     */
    private getDisplayLines;
    /**
     * Get highlighted words for current line with progress
     * Supports wipe effect (gradient progress per word)
     */
    private getHighlightedWords;
    /**
     * Get word progress for wipe effect (0-1)
     * Returns progress for each word to create smooth gradient wipe
     */
    getWordProgress(lineIndex: number, wordIndex: number, currentMs: number): number;
    /**
     * Calculate progress through current line (0-1)
     */
    private getProgress;
    /**
     * Check if Thai vowel or diacritic (for Thai language support)
     */
    isThaiVowelOrDiacritic(char: string): boolean;
    /**
     * Check if text contains only Thai vowels
     */
    isOnlyThaiVowels(text: string): boolean;
}
/**
 * Utility functions for lyric manipulation
 */
/**
 * Get lyric line at specific time
 */
export declare function getLyricAtTime(lyrics: LyricLine[], time: number): LyricLine | null;
/**
 * Get all lyrics within time range
 */
export declare function getLyricsInRange(lyrics: LyricLine[], startTime: number, endTime: number): LyricLine[];
/**
 * Calculate total duration of lyrics
 */
export declare function getLyricsDuration(lyrics: LyricLine[]): number;
/**
 * Search lyrics by text
 */
export declare function searchLyrics(lyrics: LyricLine[], query: string): LyricLine[];