Add a Play Next Song And A shuffle Option To Music Player C#

I have this music player script that I would really like to be able to add a couple more options too: 1) a button for shuffle songs. 2) Play next song automatically. this is an awesome music player only it's currently lacking the ability to play the next song in the array.

here is the music player Script. With help from some other postings it now currently has the ability to display using UI text the current song playing. So it's getting there. :)

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using UnityEngine.UI;
 
 public class AltMusicPlayer : MonoBehaviour
 {
 
     public Text MusicListText;// Reference to my UI Display Text for Songs
     private string display = "";//NEW Delete if does not work!!
     public enum SeekDirection { Forward, Backward }
     
     public AudioSource source;
     public List<AudioClip> clips = new List<AudioClip>();
     
     [SerializeField] [HideInInspector] private int currentIndex = 0;
     
     private FileInfo[] soundFiles;
     private List<string> validExtensions = new List<string> { ".ogg", ".wav" }; // Don't forget the "." i.e. "ogg" won't work - cause Path.GetExtension(filePath) will return .ext, not just ext.
     private string absolutePath = "./Audio/Music"; // relative path to where the app is running - change this to "./music" in your case
 
     void Start()
     {
         //being able to test in unity
         if (Application.isEditor) absolutePath = "Assets/Audio/Music";
         
         if (source == null) source = gameObject.AddComponent<AudioSource>();
         ReloadSounds();
     }
 
     //My New UI Buttons Added
     public void PlayPrevious (){
         Seek(SeekDirection.Backward);
         PlayCurrent();
     }
 
     public void PlayCurrentClip () {
         PlayCurrent();
     }
 
     public void PlayNext () {
         Seek(SeekDirection.Forward);
         PlayCurrent();
     }
 
     public void ReloadAudio () {
         ReloadSounds();
     }
 
 
     //End My New UI Buttons Added
     
     void Seek(SeekDirection d)
     {
         if (d == SeekDirection.Forward)
             currentIndex = (currentIndex + 1) % clips.Count;
         else {
             currentIndex--;
             if (currentIndex < 0) currentIndex = clips.Count - 1;
         }
     }
     
     void PlayCurrent()
     {
         source.clip = clips[currentIndex];
         source.Play();
         Debug.Log (source.clip);
         MusicListText.text = clips[currentIndex].name;
     }
     
     void ReloadSounds()
     {
         clips.Clear();
         
         // get all valid files
         var info = new DirectoryInfo(absolutePath);
         soundFiles = info.GetFiles()
             .Where(f => IsValidFileType(f.Name))
                 .ToArray();
         
         // and load them
         foreach (var s in soundFiles)
             StartCoroutine(LoadFile(s.FullName));
     }
     
     bool IsValidFileType(string fileName)
     {
         return validExtensions.Contains(Path.GetExtension(fileName));
         // Alternatively, you could go fileName.SubString(fileName.LastIndexOf('.') + 1); that way you don't need the '.' when you add your extensions
     }
     
     IEnumerator LoadFile(string path)
     {
         WWW www = new WWW("file://" + path);
         print("loading " + path);
         
         AudioClip clip = www.GetAudioClip(false);
         while(!clip.isReadyToPlay)
             yield return www;
         
         print("done loading");
         clip.name = Path.GetFileName(path);
         clips.Add(clip);
 
 
         //Count Array List Length
         //source.clip = clips[currentIndex];
         Debug.Log (clip);
         //int List = clips.Count;
         //Debug.Log (List);
     }
 
     //NEW
     void AddText()
     {
         display = currentIndex + " : " + clips[currentIndex].name;
         MusicListText.text = display;
     }
     //END NEW
 
     //Quit Button
     public void  GoQuit(){
         StartCoroutine(LoadQuit("ThreeD_Overview"));
     }
     
     IEnumerator LoadQuit(string levelMain){
         yield return new WaitForSeconds(0.5f); // wait time
         Application.LoadLevel(levelMain);
         
     }
 
 
 }