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

public class GoldPickupNotifier : MonoBehaviour
{
    public static GoldPickupNotifier Instance;
    
    public GameObject messagePanel;
    public TextMeshProUGUI messageText;
    public float displayDuration = 2f;
    public float fadeSpeed = 1f;
    
    [Header("Queue Settings")]
    [Tooltip("Combine gold amounts if picked up within this time window (seconds)")]
    public float combineWindow = 0.3f;
    [Tooltip("Enable to combine multiple pickups into one message")]
    public bool enableCombining = true;
    
    private float timer;
    private CanvasGroup canvasGroup;
    private Queue<int> messageQueue = new Queue<int>();
    private bool isDisplaying = false;
    private float lastPickupTime;
    private int pendingCombinedAmount;
    
    void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
        }
        else
        {
            Destroy(gameObject);
        }
    }
    
    void Start()
    {
        if (messagePanel)
        {
            canvasGroup = messagePanel.GetComponent<CanvasGroup>();
            if (!canvasGroup) canvasGroup = messagePanel.AddComponent<CanvasGroup>();
            canvasGroup.alpha = 0;
            messagePanel.SetActive(false);
        }
    }
    
    public static void Show(int goldAmount)
    {
        if (Instance) Instance.EnqueueMessage(goldAmount);
    }
    
    void EnqueueMessage(int amount)
    {
        if (!messagePanel || !messageText) return;
        
        // Try to combine with pending amount if within time window
        if (enableCombining && Time.time - lastPickupTime < combineWindow)
        {
            pendingCombinedAmount += amount;
            lastPickupTime = Time.time;
        }
        else
        {
            // If we had a pending combined amount, queue it first
            if (pendingCombinedAmount > 0)
            {
                messageQueue.Enqueue(pendingCombinedAmount);
                pendingCombinedAmount = 0;
            }
            
            // Start new pending amount
            pendingCombinedAmount = amount;
            lastPickupTime = Time.time;
        }
        
        // If not currently displaying, show immediately
        if (!isDisplaying)
        {
            ShowNextMessage();
        }
    }
    
    void ShowNextMessage()
    {
        // Check if we should flush the pending combined amount
        if (pendingCombinedAmount > 0 && Time.time - lastPickupTime >= combineWindow)
        {
            messageQueue.Enqueue(pendingCombinedAmount);
            pendingCombinedAmount = 0;
        }
        
        if (messageQueue.Count == 0)
        {
            isDisplaying = false;
            return;
        }
        
        int amount = messageQueue.Dequeue();
        isDisplaying = true;
        
        messageText.text = $"+{amount} Gold";
        messagePanel.SetActive(true);
        canvasGroup.alpha = 1;
        timer = displayDuration;
    }
    
    void Update()
    {
        // Check if we should flush pending combined amount
        if (pendingCombinedAmount > 0 && Time.time - lastPickupTime >= combineWindow && !isDisplaying)
        {
            messageQueue.Enqueue(pendingCombinedAmount);
            pendingCombinedAmount = 0;
            ShowNextMessage();
        }
        
        if (timer > 0)
        {
            timer -= Time.deltaTime;
            
            if (timer <= fadeSpeed)
            {
                canvasGroup.alpha = timer / fadeSpeed;
            }
            
            if (timer <= 0)
            {
                messagePanel.SetActive(false);
                isDisplaying = false;
                
                // Show next message in queue if any
                if (messageQueue.Count > 0)
                {
                    ShowNextMessage();
                }
            }
        }
    }
}