Test-Multiplayer/Assets/Scripts/Chat/ChatUI.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
using TMPro;

// Client-only UI. DO NOT add a NetworkIdentity to this prefab.
public class ChatUI : MonoBehaviour
{
    [Header("UI Elements")]
    [SerializeField] private TextMeshProUGUI chatHistory;
    [SerializeField] private Scrollbar scrollbar;
    [SerializeField] private TMP_InputField chatMessage;
    [SerializeField] private Button sendButton;

    internal static string localPlayerName;

    // Instance reference so static callers can check focus state safely
    internal static ChatUI Instance;

    private readonly List<string> lines = new();
    private Player localPlayer;

    void Awake()
    {
        Instance = this;

        if (chatMessage != null)
        {
            chatMessage.onValueChanged.AddListener(ToggleButton);
            chatMessage.onSubmit.AddListener(OnInputSubmit);
        }
    }

    // Expose whether the chat input is focused so other systems can disable input/movement
    public static bool IsInputFieldFocused => Instance != null && Instance.chatMessage != null && Instance.chatMessage.isFocused;

    // Called by PlayerScript when Escape is pressed while chat is focused, so mouse-look/
    // cursor lock can resume immediately instead of waiting for a manual click-away.
    public void ExitChatFocus()
    {
        if (chatMessage != null)
            chatMessage.DeactivateInputField();

        if (EventSystem.current != null)
            EventSystem.current.SetSelectedGameObject(null);
    }

    // Called by Player.OnStartLocalPlayer to connect the UI to the player's network methods.
    public void Initialize(Player player)
    {
        localPlayer = player;
    }

    public void SetHistory(string[] history)
    {
        lines.Clear();
        if (history != null && history.Length > 0)
            lines.AddRange(history);

        RefreshVisual();
    }

    // Called by Player.RpcReceiveChat / Player.TargetReceiveHistory
    public void AddMessage(string message)
    {
        lines.Add(message);
        if (chatHistory != null)
            chatHistory.text += message + "\n";

        StartCoroutine(ScrollNextFrame());
    }

    IEnumerator ScrollNextFrame()
    {
        yield return null;
        yield return null;
        if (scrollbar != null)
            scrollbar.value = 0;
    }

    void RefreshVisual()
    {
        if (chatHistory == null) return;

        chatHistory.text = string.Empty;
        foreach (var l in lines)
            chatHistory.text += l + "\n";

        StartCoroutine(ScrollNextFrame());
    }

    public void ToggleButton(string input)
    {
        if (sendButton != null)
            sendButton.interactable = !string.IsNullOrWhiteSpace(input);
    }

    private void OnInputSubmit(string input)
    {
        if (!string.IsNullOrWhiteSpace(input))
            SendMessage();
    }

    public void SendMessage()
    {
        if (localPlayer == null)
        {
            Debug.LogWarning("ChatUI: local player not set; cannot send chat.");
            return;
        }

        if (string.IsNullOrWhiteSpace(chatMessage?.text)) return;

        localPlayer.SendChatToServer(chatMessage.text.Trim());

        chatMessage.text = string.Empty;
        chatMessage.ActivateInputField();
    }

    void OnDestroy()
    {
        if (chatMessage != null)
        {
            chatMessage.onValueChanged.RemoveListener(ToggleButton);
            chatMessage.onSubmit.RemoveListener(OnInputSubmit);
        }

        // Clear static instance reference
        if (Instance == this) Instance = null;
    }
}