Zazama / node-id3

import { Tags, TagAliases, RawTags, WriteTags  } from "./Tags"

import { FrameOptions, FRAME_IDENTIFIERS, FRAME_ALIASES } from "./ID3Definitions"

const ID3Util = require('./ID3Util')

export function updateTags(newTags: WriteTags, currentTags: Tags): RawTags {

    const newRawTags = makeRawTags(newTags)

    const currentRawTags = currentTags.raw ?? {}

    let updatedRawTags = {... currentRawTags}

    Object.entries(newRawTags).forEach(([identifier, newValue]) => {

        const identifierKey = identifier as keyof RawTags

        const options: FrameOptions = ID3Util.getSpecOptions(identifier)

        const currentValue =

            currentRawTags[identifierKey] as RawTags[typeof identifierKey]

        if(!currentValue || !options.multiple || !options.updateCompareKey) {

            updatedRawTags[identifierKey] = newValue

            return

        }

        newValue = newValue instanceof Array ? newValue : [newValue]

        updatedRawTags[identifierKey] = replaceMatchingTags(

            currentValue instanceof Array ? currentValue : [currentValue],

            newValue,

            options.updateCompareKey

        )

    })

    return updatedRawTags

}

function replaceMatchingTags(

    oldFrames: Array<any>,

    newFrames: Array<any>,

    replaceKey: string): any

{

    for(let newFrame of newFrames) {

        oldFrames = replaceMatchingTag(

            oldFrames,

            replaceKey,

            newFrame[replaceKey],

            newFrame

        )

    }

    return oldFrames

}

function replaceMatchingTag(

    frames: Array<any>,

    replaceKey: string,

    searchString: string,

    replaceValue: any): any

{

    let newFrames = frames.filter(

        (frame) => !frame[replaceKey] || frame[replaceKey] !== searchString)

    newFrames.push(replaceValue)

    return newFrames

}

function makeRawTags(tags: WriteTags): RawTags {

    return Object.entries(tags).reduce<RawTags>((rawTags, [key, value]) => {

        const identifiers = FRAME_IDENTIFIERS.v34

        const aliases = FRAME_ALIASES.v34

        if (key in identifiers) {

            rawTags[identifiers[key as keyof TagAliases]] = value

        }

        if (key in aliases) {

            rawTags[key as keyof RawTags] = value

        }

        return rawTags

    }, {})

}