import { IKaraokeWord, ILyric, ILyricLine, LyricType } from './declare'
import { genLyricTag, parseLyricTag } from './common'

/**
 * 解析nrc歌词
 * @param nrcxText nrc歌词文本内容
 */
export function parse(nrcxText: string) {
	//结果
	const result: ILyric = { type: LyricType.KARA, content: [] }

	//逐行处理
	nrcxText.split(/\r?\n/).forEach(line => {
		line = line.trim()
		const match = line.match(/^\[(\d+),(\d+)\]/)
		if (match) {
			const lyricLine: ILyricLine<IKaraokeWord[]> = {
				start: parseInt(match[1]),
				duration: parseInt(match[2]),
				content: [],
			}
			line = line.substring(match[0].length)
			while (line.length) {
				const match = line.match(/^\((\d+),(\d+)(,(\d+))?\)([^\(]+)/)
				if (!match) break
				const start = parseInt(match[1])
				const dur = parseInt(match[2])
				const txt = match[5]
				lyricLine.content.push({
					start: start - lyricLine.start,
					duration: dur,
					content: txt,
				})
				line = line.substring(match[0].length)
			}
			if (lyricLine.content.length) result.content.push(lyricLine)
		}
		else parseLyricTag(result, line)
	})

	return result
}

/**
 * 将nrc歌词转换为文本
 * 
 * @param lyric 歌词(只能是卡拉OK歌词)
 */
export function stringify(lyric: ILyric) {
	if (lyric.type != LyricType.KARA) throw new Error(`lrc cannot stringify to nrc`)

	const buffer: string[] = [...genLyricTag(lyric)]


	lyric.content.forEach(line => {
		if (typeof line.content === 'string') return

		const text = line.content.map(word => {
			return `(${word.start + line.start},${word.duration},${0})${word.content}`
		}).join('')
		buffer.push(`[${line.start},${line.duration}]${text}`)
	})

	return buffer.join('\n')
}