Only activate chat if T is pressed

Hi, I customized a youtube tutorial script for a multiplayer chat. I just need some help with some features with it.

1. You can only write if T is pressed

2. You can send messages by pressing enter

3. Messages gets removed after a certain time

Here's the two codes:

using UnityEngine; using System.Collections;

public class ChatBase : MonoBehaviour { public enum Clean { Full = 0, Semi = 1, none = 0 }; public static Clean cleaning = Clean.Semi; public static ArrayList messages = new ArrayList(); public static string user = "";

 public string[] Swares;

 private string messageToSend = "";

 private void Start()
 {
     DontDestroyOnLoad(gameObject);
 }

 public static void CleanChat()
 {
     ArrayList temp = new ArrayList();
     for (int x = 1; x < messages.Count; x++)
     {
         temp.Add(messages[x]);
     }
     messages = temp;
 }

 public void sendMessage(string mess)
 {
     messageToSend = mess;
     if (mess != "")
     {

         for (int c = 0; c < mess.Length; c++)
         {
             foreach (string s in Swares)
             {
                 if (mess[c].ToString().ToUpper() == s[0].ToString().ToUpper())
                 {
                     string temp = "";
                     int extra = 0;
                     for (int x = c; x < messageToSend.Length; x++)
                     {
                         if (messageToSend[x].ToString().ToUpper() != messageToSend[0].ToString().ToUpper())
                         {
                             if (messageToSend[(x - 1)] == messageToSend[x])
                             {
                                 extra++;
                                 continue;
                             }
                         }

                         if (messageToSend[x].ToString().ToUpper() != s[s.Length - 1].ToString().ToUpper())
                         {

                             temp += messageToSend[x].ToString().ToUpper();
                         }
                         else
                         {
                             string reg = temp + messageToSend.Substring(x, 1).ToString().ToUpper();
                             if (reg.ToUpper() == s.ToUpper())
                             {
                                 string firstHalf = messageToSend.Substring(0, c);
                                 string secondHalf = messageToSend.Substring(c + s.Length + extra, messageToSend.Length - s.Length - c - extra);
                                 string stars = new string('*', s.Length);
                                 messageToSend = firstHalf + stars + secondHalf;
                             }
                             break;
                         }
                     }
                 }
             }
             if (c == (mess.Length - 1))
                 networkView.RPC("ReciveMessage", RPCMode.All, user + ": " + messageToSend);
         }
     }
 }

 [RPC]
 private void ReciveMessage(string sentMess)
 {
     messages.Add(sentMess);
     Invoke("Recheck", 5);
 }

 private void Recheck()
 {
     if (cleaning == Clean.Semi)
         CleanChat();
 }

}

using UnityEngine; using System.Collections;

public class Chat : MonoBehaviour { private string message = ""; private Vector2 scrollView = Vector2.zero;

 private MultiplayerManager MpManager;
 
 public bool IsTyping = false;

 private void Start()
 {
     ChatBase.user = "";
     ChatBase.messages = new ArrayList();
     ChatBase.user = MultiplayerManager.instance.PlayerName;
 }

 private void OnGUI()
 {
     GUILayout.BeginArea(new Rect(Screen.width - 200, Screen.height - 250, 200 ,200));
     scrollView = GUILayout.BeginScrollView(scrollView);
     foreach(string c in ChatBase.messages)
     {
         GUILayout.Label(c);
     }
     GUILayout.EndArea();
     GUILayout.EndScrollView();
     scrollView.y++;
     
     if (IsTyping == false & Input.GetButton("Chat"))
     {
     message = GUI.TextField(new Rect(Screen.width - 200, Screen.height - 25, 150, 25), message);
     if (GUI.Button(new Rect(Screen.width - 50, Screen.height - 25, 50, 25), "Send"))
     {
         ChatBase.cleaning = ChatBase.Clean.none;
         GameObject.Find("Chat").GetComponent<ChatBase>().sendMessage(message);
         message = "";
     }
     }
 }

}

I would really appreciate help with this.