Unable to stop excess input and unable to call the entered combo from the combo system

Hi my name is Tim and I am currently trying to emplace a combo system in my game. However I have encountered a few problems with it, including:

1. There are excess input of down(S) and right(E) when I pressed the corresponding button, which overflows the combo array I have set;

2. Sometimes the key presses does not register;

3. Even if the combo is entered correctly, the combo won't be recognized and show up in the console as activated.

4. How do I make a combo system which can contain different number of key presses with my combo system? Right now I can only make a combo with 3 presses.

My code for the combo system is here: using UnityEngine; using System.Linq; using System.Collections; using System.Collections.Generic;

 [System.Serializable]
 public class Combo
 {
     public string name;
     public string[] comboSequence;
 }
 
 public class ComboHandler : MonoBehaviour {
     
     public Combo[] combos;
     
     public int comboLimit = 3; // Buffer Size
     public int clearBufferTime = 1; // 
     private string comboActivated;
     private List<string> comboToAdd; // Buffer
     
     private float inputBufferTime = 0.1f;
     private float bufTime = 0; // Seconds
     private float dpadfreezetime = 0.2f;
     
     // Use this for initialization
     void Start () {
         comboToAdd = new List<string>();
     }
     
     // Update is called once per frame
     void FixedUpdate () {
         float inputX = Input.GetAxis("Horizontal");
         float inputY = Input.GetAxis("Vertical");
         string direction = "";
         if( inputY > 0.2f ) {
             direction = "N";
         }else if( inputY < -0.2f ) {
             direction = "S";
         }
         
         if( inputX > 0.2f ) {
             direction += "E";
         }else if( inputX < -0.2f ) {
             direction += "W";
         }
         
         // Time span for capturing input key
         if(inputBufferTime > 0.1){
             if( direction != "" ){
                 comboToAdd.Add(direction);
                 print("Key Pressed: "+direction);
             }
             
             if( Input.GetButtonDown("Fire") ){
                 comboToAdd.Add("Fire");
                 print("Key Pressed: Fire");
             }
             
             inputBufferTime = 0;
         }else{
             inputBufferTime += Time.fixedDeltaTime;
         }
         //    print ("Combo Limit: "+comboLimit);
         //    print ("Key Count: "+comboToAdd.Count);
         
         if (comboToAdd.Count >= comboLimit)
         {
             //    print (comboToAdd.ToString());
             for (int i=0; i<combos.Length; i++)
             {
                 if (comboToAdd.SequenceEqual(combos[i].comboSequence))
                 {
                     comboActivated = combos[i].name;
                     print ("Combo: "+comboActivated);
                 }
             }
             comboToAdd.Clear();
         }
         
         if( bufTime > clearBufferTime ) {
             comboToAdd.Clear();
             bufTime = 0;
         }
         else{
             bufTime += Time.fixedDeltaTime;
         }
     }
 }
 

I would be grateful if anyone can give me advice.