Zazama / node-id3

import { FrameBuilder } from "../FrameBuilder"

import { FrameReader } from "../FrameReader"

import type { Data } from "./type"

export const SYLT = {

    create: (data: Data) => {

        if(!(data instanceof Array)) {

            data = [data]

        }

        const encoding = 1 // 16 bit unicode

        return Buffer.concat(data.map((lycics: Data) => {

            const frameBuilder = new FrameBuilder("SYLT")

                .appendNumber(encoding, 1)

                .appendValue(lycics.language, 3)

                .appendNumber(lycics.timeStampFormat, 1)

                .appendNumber(lycics.contentType, 1)

                .appendNullTerminatedValue(lycics.shortText, encoding)

            lycics.synchronisedText.forEach((part: Data) => {

                frameBuilder.appendNullTerminatedValue(part.text, encoding)

                frameBuilder.appendNumber(part.timeStamp, 4)

            })

            return frameBuilder.getBuffer()

        }))

    },

    read: (buffer: Buffer) => {

        const reader = new FrameReader(buffer, 0)

        return {

            language: reader.consumeStaticValue('string', 3, 0x00),

            timeStampFormat: reader.consumeStaticValue('number', 1),

            contentType: reader.consumeStaticValue('number', 1),

            shortText: reader.consumeNullTerminatedValue('string'),

            synchronisedText: Array.from((function*() {

                while(true) {

                    const text = reader.consumeNullTerminatedValue('string')

                    const timeStamp = reader.consumeStaticValue('number', 4)

                    if (text === undefined || timeStamp === undefined) {

                        break

                    }

                    yield {text, timeStamp}

                }

            })())

        }

    }

}