open class Playlist(val songliste: MutableList<Song>) {

    open fun gesamteSpieldauer() = songliste.sumBy { it.spieldauer }

    fun SpieldauerMitXOderBesser(x: Int): Int {

        var tmp: Int = 0

        for (s in songliste) {
            if(s.bewertung >= x){
                tmp += 1
            }
        }

        return tmp
    }

    open fun alleAbspielen() {

        for (s in songliste) {

            s.abspielen()
        }
    }
}

class DynamicPlaylist (songlisteParam: MutableList<Song>): Playlist(songlisteParam){

    class SongNode(val song : Song, var nextSong : SongNode?)

    private var first: SongNode? = null
    private var last: SongNode? = null

    init {

        reset();

        /*first = SongNode(songliste.get(0), null)

        var runPointer = first

        for( i in 1..songliste.size){

            runPointer?.nextSong = SongNode(songliste.get(i), null)
            runPointer = runPointer?.nextSong ?: runPointer
        }

        last = runPointer*/
    }

    fun add(derSongTM : Song){

        last?.nextSong = SongNode(derSongTM, null)
        last = last?.nextSong
    }

    fun take() : Song?{

        var tmp = first
        first = first?.nextSong

        return tmp?.song
    }

    fun take2(searchSong : Song){

        var test : Boolean = false
        var runTest = first

        while(runTest != null){

            if(runTest.song == searchSong)
                test = true

            runTest = runTest.nextSong
        }

        if(test){

            if(first?.song == searchSong)
            first = first?.nextSong
            else{

                var runPointer = first

                while(runPointer?.nextSong?.song != searchSong){

                    runPointer = runPointer?.nextSong
                }

                if(runPointer.nextSong == last){

                    last = runPointer
                    last?.nextSong = null
                }
                else
                    runPointer.nextSong = runPointer.nextSong?.nextSong
            }
        }
        else
            println("Der zu löschende Song ist nicht vorhanden!")
    }

    fun reset(){

        first = SongNode(songliste.get(0), null)

        var runPointer = first

        for( i in 1..songliste.size-1){

            runPointer?.nextSong = SongNode(songliste.get(i), null)
            runPointer = runPointer?.nextSong ?: runPointer
        }

        last = runPointer
    }

    override fun gesamteSpieldauer() : Int{

        var runPointer = first
        var tmp : Int = 0

        while (runPointer != null){

            tmp += runPointer.song.spieldauer
            runPointer = runPointer.nextSong
        }

        return tmp
    }

    override fun alleAbspielen() {

        var runPointer = first

        while (runPointer != null){

            runPointer.song.abspielen()
            runPointer = runPointer.nextSong
        }
    }

}