/**
 * Shared Intl object instances with lazy initialization.
 *
 * Intl constructors are expensive (~0.05-0.1ms each), so we cache instances
 * for reuse across the codebase instead of creating new ones each time.
 * Lazy initialization ensures we only pay the cost when actually needed.
 */

// Segmenters for Unicode text processing (lazily initialized)
let graphemeSegmenter: Intl.Segmenter | null = null

export function getGraphemeSegmenter(): Intl.Segmenter {
	if (!graphemeSegmenter) {
		graphemeSegmenter = new Intl.Segmenter(undefined, {
			granularity: 'grapheme',
		})
	}
	return graphemeSegmenter
}

/**
 * Extract the first grapheme cluster from a string.
 * Returns '' for empty strings.
 */
export function firstGrapheme(text: string): string {
	if (!text) return ''
	const segments = getGraphemeSegmenter().segment(text)
	const first = segments[Symbol.iterator]().next().value
	return first?.segment ?? ''
}

/**
 * Extract the last grapheme cluster from a string.
 * Returns '' for empty strings.
 */
export function lastGrapheme(text: string): string {
	if (!text) return ''
	let last = ''
	for (const { segment } of getGraphemeSegmenter().segment(text)) {
		last = segment
	}
	return last
}