Zazama / node-id3

import { FrameBuilder } from "../FrameBuilder"

import { FrameReader } from "../FrameReader"

import type { Data } from "./type"

export const ETCO = {

    create: (data: Data) => {

        const builder = new FrameBuilder("ETCO")

            .appendNumber(data.timeStampFormat, 1)

        data.keyEvents.forEach((keyEvent: Data) => {

            builder

                .appendNumber(keyEvent.type, 1)

                .appendNumber(keyEvent.timeStamp, 4)

        })

        return builder.getBuffer()

    },

    read: (buffer: Buffer) => {

        const reader = new FrameReader(buffer)

        return {

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

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

                while(true) {

                    const type = reader.consumeStaticValue('number', 1)

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

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

                        break

                    }

                    yield {type, timeStamp}

                }

            })())

        }

    }

}