using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class DebugUIMessage : MonoBehaviour
{
    private static DebugUIMessage instance;
    private Text messageText;
    private Canvas canvas;
    private Coroutine hideCoroutine;

    /// <summary>
    /// Show a debug message on the UI for a set duration.
    /// </summary>
    /// <param name="message">The message to display.</param>
    /// <param name="duration">How long to display the message (seconds).</param>
    /// <param name="displayColor"></param>
    public static void Show(string message, Color displayColor, float duration = 2f)
    {
        if (instance == null)
        {
            var go = new GameObject("DebugUIMessage");
            instance = go.AddComponent<DebugUIMessage>();
            instance.SetupUI();
            DontDestroyOnLoad(go);
        }
        instance.ShowMessage(message, duration, displayColor);
    }

    /// <summary>
    /// Sets up the UI canvas and text for debug messages.
    /// </summary>
    private void SetupUI()
    {
        canvas = new GameObject("DebugUICanvas").AddComponent<Canvas>();
        canvas.renderMode = RenderMode.ScreenSpaceOverlay;
        canvas.sortingOrder = 9999;
        canvas.gameObject.transform.SetParent(transform);
        var textGO = new GameObject("DebugUIText");
        textGO.transform.SetParent(canvas.transform);
        messageText = textGO.AddComponent<Text>();
        messageText.alignment = TextAnchor.MiddleCenter;
        // Try to load a custom font from Resources/Fonts/DebugFont.ttf
        Font customFont = Resources.Load<Font>("Fonts/DebugFont");
        if (customFont != null)
            messageText.font = customFont;
        else
            messageText.font = Resources.GetBuiltinResource<Font>("LegacyRuntime.ttf");
        messageText.fontSize = 32;
        messageText.color = Color.yellow;
        var outline = textGO.AddComponent<Outline>();
        outline.effectColor = Color.black;
        outline.effectDistance = new Vector2(2, -2);
        var rect = messageText.GetComponent<RectTransform>();
        rect.anchorMin = new Vector2(0.5f, 0.5f);
        rect.anchorMax = new Vector2(0.5f, 0.5f);
        rect.pivot = new Vector2(0.5f, 0.5f);
        rect.anchoredPosition = Vector2.zero;
        rect.sizeDelta = new Vector2(800, 40);
        messageText.text = "";
    }

    /// <summary>
    /// Internal method to show a message and start the hide coroutine.
    /// </summary>
    private void ShowMessage(string message, float duration, Color fontColor)
    {
        messageText.text = message;
        messageText.color = fontColor;
        messageText.enabled = true;
        if (hideCoroutine != null)
            StopCoroutine(hideCoroutine);
        hideCoroutine = StartCoroutine(HideAfterSeconds(duration));
    }

    /// <summary>
    /// Coroutine to hide the message after a delay.
    /// </summary>
    private IEnumerator HideAfterSeconds(float seconds)
    {
        yield return new WaitForSeconds(seconds);
        messageText.text = "";
        messageText.enabled = false;
    }
}