/**
 * Utility functions for calculating accurate lyric progress
 * based on word timing in parts
 */
import type { LyricPart } from '../types';
/**
 * Calculate accurate progress for line-level wipe effect
 * Based on character position according to actual word timings
 *
 * Progress is calculated by finding how many characters should be highlighted
 * based on the current time and the timing of each part (word).
 *
 * @param parts - Array of lyric parts with timing
 * @param currentTime - Current playback time (in milliseconds)
 * @returns Progress value between 0 and 1
 */
export declare function calculateLineProgress(parts: LyricPart[], currentTime: number): number;
/**
 * Calculate accurate progress with word-by-word precision
 * This version counts complete words only (no partial word highlighting)
 *
 * @param parts - Array of lyric parts with timing
 * @param currentTime - Current playback time (in milliseconds)
 * @returns Progress value between 0 and 1
 */
export declare function calculateLineProgressWordByWord(parts: LyricPart[], currentTime: number): number;
/**
 * Get debug information about current progress calculation
 * Useful for troubleshooting timing issues
 */
export declare function getProgressDebugInfo(parts: LyricPart[], currentTime: number): {
    currentTime: number;
    totalChars: number;
    charsHighlighted: number;
    progress: number;
    currentPartIndex: number;
    currentPartText: string;
    currentPartTime: number;
};