UIManager - Part 3 & 4

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

public class UIManager : MonoBehaviour
{
    public static UIManager Instance { get; private set; }

    public GameObject inventoryPanel;
    public GameObject inventoryPrompt;
    public Text promptText;
    public Button yesButton;
    public Button noButton;
    public Button okButton;
    public Button closeButton;
    public Button inventoryDoneButton;
    public Transform inventorySlotParent;
    public Transform storageHolder;
    public GameObject moneyDisplay;
    public GameObject doneButton;
    public GameObject itemDetailsPanel;
    public TextMeshProUGUI itemTitleText;
    public TextMeshProUGUI itemDescriptionText;
    public TextMeshProUGUI itemUsesText;

    [SerializeField] private GameObject itemIconPrefab;

    private InventorySystem inventorySystem;
    private StorageSystem storageSystem;
    private InteractionSystem interactionSystem;
    private PlayerMovement playerMovement;
    private Item currentStorageItem;
    private Item draggedItem;
    private Transform originalSlot;

    public bool isInventoryOpen = false;

    private void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
        }
        else
        {
            Destroy(gameObject);
        }
    }

    private void Start()
    {
        inventorySystem = InventorySystem.Instance;
        storageSystem = StorageSystem.Instance;
        interactionSystem = FindObjectOfType<InteractionSystem>();
        playerMovement = FindObjectOfType<PlayerMovement>();

        if (closeButton != null) closeButton.onClick.AddListener(CloseInventory);
        if (okButton != null)
        {
            okButton.onClick.AddListener(ResetPrompt);
            okButton.gameObject.SetActive(false);
        }
        if (yesButton != null) yesButton.onClick.AddListener(() => OpenInventory(currentStorageItem));
        if (noButton != null) noButton.onClick.AddListener(ClosePrompt);
        if (inventoryDoneButton != null) inventoryDoneButton.onClick.AddListener(CloseInventory);
    }

    public void ShowInventoryPrompt(Item storageItem)
    {
        if (storageItem == null) return;

        currentStorageItem = storageItem;
        inventoryPrompt.SetActive(true);
        promptText.text = $"Open {storageItem.itemName}?";
        TogglePlayerControls(false);
    }

    public void OpenInventory(Item storageItem)
    {
        inventoryPrompt.SetActive(false);
        inventoryPanel.SetActive(true);
        currentStorageItem = storageItem;
        isInventoryOpen = true;

        TransferHeldItemsToStorage();
        PopulateInventoryUI(storageItem);
        TogglePlayerControls(false);
    }

    private void TransferHeldItemsToStorage()
    {
        if (inventorySystem.leftHandItem != null)
        {
            bool added = storageSystem.AddToStorage(currentStorageItem, inventorySystem.leftHandItem);
            if (added)
            {
                inventorySystem.UnequipItem(true);
                playerMovement.UpdateCarryingAnimations();
            }
        }
        if (inventorySystem.rightHandItem != null)
        {
            bool added = storageSystem.AddToStorage(currentStorageItem, inventorySystem.rightHandItem);
            if (added)
            {
                inventorySystem.UnequipItem(false);
                playerMovement.UpdateCarryingAnimations();
            }
        }
    }

    private void PopulateInventoryUI(Item storageItem)
    {
        ClearInventoryUI();
        List<Item> storageInventory = storageSystem.GetStorageInventory(storageItem);

        for (int i = 0; i < inventorySlotParent.childCount - 3; i++)
        {
            Transform slot = inventorySlotParent.GetChild(i);
            if (i < storageInventory.Count)
            {
                UpdateInventorySlot(slot.gameObject, storageInventory[i]);
            }
            else
            {
                ClearInventorySlot(slot.gameObject);
            }
        }
    }

    private void ClearInventoryUI()
    {
        for (int i = 0; i < inventorySlotParent.childCount - 3; i++)
        {
            Transform slot = inventorySlotParent.GetChild(i);
            ClearInventorySlot(slot.gameObject);
        }
    }

    private void UpdateInventorySlot(GameObject slotObject, Item item)
    {
        ClearInventorySlot(slotObject);

        GameObject iconObject = Instantiate(itemIconPrefab, slotObject.transform);
        Image iconImage = iconObject.GetComponent<Image>();
        if (iconImage != null)
        {
            iconImage.sprite = item.icon;
            iconImage.enabled = true;
        }

        iconObject.AddComponent<ItemReference>().item = item;

        EventTrigger trigger = iconObject.GetComponent<EventTrigger>();
        if (trigger == null) trigger = iconObject.AddComponent<EventTrigger>();

        trigger.triggers.Clear();

        EventTrigger.Entry rightClickEntry = new EventTrigger.Entry();
        rightClickEntry.eventID = EventTriggerType.PointerClick;
        rightClickEntry.callback.AddListener((data) => {
            if (((PointerEventData)data).button == PointerEventData.InputButton.Right)
                TryEquipItem(item);
        });

        EventTrigger.Entry dragEntry = new EventTrigger.Entry();
        dragEntry.eventID = EventTriggerType.BeginDrag;
        dragEntry.callback.AddListener((data) => BeginDrag(iconObject.transform));

        EventTrigger.Entry dragEndEntry = new EventTrigger.Entry();
        dragEndEntry.eventID = EventTriggerType.EndDrag;
        dragEndEntry.callback.AddListener((data) => EndDrag(iconObject.transform));

        EventTrigger.Entry pointerEnterEntry = new EventTrigger.Entry();
        pointerEnterEntry.eventID = EventTriggerType.PointerEnter;
        pointerEnterEntry.callback.AddListener((data) => ShowItemDetails(item));

        EventTrigger.Entry pointerExitEntry = new EventTrigger.Entry();
        pointerExitEntry.eventID = EventTriggerType.PointerExit;
        pointerExitEntry.callback.AddListener((data) => HideItemDetails());

        trigger.triggers.Add(rightClickEntry);
        trigger.triggers.Add(dragEntry);
        trigger.triggers.Add(dragEndEntry);
        trigger.triggers.Add(pointerEnterEntry);
        trigger.triggers.Add(pointerExitEntry);
    }

    private void ClearInventorySlot(GameObject slotObject)
    {
        foreach (Transform child in slotObject.transform)
        {
            Destroy(child.gameObject);
        }
    }

    private void ShowItemDetails(Item item)
    {
        if (item != null && itemDetailsPanel != null)
        {
            itemDetailsPanel.SetActive(true);
            if (itemTitleText != null) itemTitleText.text = item.itemName;
            if (itemDescriptionText != null) itemDescriptionText.text = item.description;
            if (itemUsesText != null) itemUsesText.text = item.itemUses;
        }
    }

    private void HideItemDetails()
    {
        if (itemDetailsPanel != null)
        {
            itemDetailsPanel.SetActive(false);
        }
    }

    private void TryEquipItem(Item item)
    {
        if (inventorySystem.leftHandItem != null && inventorySystem.rightHandItem != null)
        {
            ShowError("Hands are full!");
            return;
        }

        storageSystem.RemoveItemFromStorage(currentStorageItem, item);
        bool isLeftHand = inventorySystem.leftHandItem == null;
        inventorySystem.EquipItem(item, isLeftHand, item.isTwoHanded);
        interactionSystem.UpdateItemPosition(item.gameObject, isLeftHand);
        playerMovement.UpdateCarryingAnimations();
        PopulateInventoryUI(currentStorageItem);
        HideItemDetails();
    }

    private void BeginDrag(Transform iconTransform)
    {
        ItemReference itemRef = iconTransform.GetComponent<ItemReference>();
        if (itemRef != null && itemRef.item != null)
        {
            draggedItem = itemRef.item;
            originalSlot = iconTransform.parent;
            iconTransform.SetParent(inventoryPanel.transform);
        }
    }

    private void EndDrag(Transform iconTransform)
    {
        if (draggedItem == null) return;

        Transform closestSlot = FindClosestSlot();

        if (closestSlot != null)
        {
            SwapItems(closestSlot, iconTransform);
        }
        else
        {
            ReturnItemToOriginalSlot(iconTransform);
        }

        draggedItem = null;
    }

    private Transform FindClosestSlot()
    {
        Transform closestSlot = null;
        float minDistance = Mathf.Infinity;

        foreach (Transform slot in inventorySlotParent)
        {
            float dist = Vector3.Distance(slot.position, Input.mousePosition);
            if (dist < minDistance)
            {
                minDistance = dist;
                closestSlot = slot;
            }
        }

        return closestSlot;
    }

    private void SwapItems(Transform newSlot, Transform draggedIcon)
    {
        if (newSlot.childCount > 0)
        {
            Transform existingIcon = newSlot.GetChild(0);
            existingIcon.SetParent(originalSlot);
            existingIcon.localPosition = Vector3.zero;
        }

        draggedIcon.SetParent(newSlot);
        draggedIcon.localPosition = Vector3.zero;
    }

    private void ReturnItemToOriginalSlot(Transform draggedIcon)
    {
        draggedIcon.SetParent(originalSlot);
        draggedIcon.localPosition = Vector3.zero;
    }

    public void ShowError(string message)
    {
        promptText.text = message;
        yesButton.gameObject.SetActive(false);
        noButton.gameObject.SetActive(false);
        okButton.gameObject.SetActive(true);
    }

    private void ResetPrompt()
    {
        promptText.text = $"Open {currentStorageItem.itemName}?";
        yesButton.gameObject.SetActive(true);
        noButton.gameObject.SetActive(true);
        okButton.gameObject.SetActive(false);
        inventoryPrompt.SetActive(false);
        TogglePlayerControls(true);
    }

    private void ClosePrompt()
    {
        inventoryPrompt.SetActive(false);
        TogglePlayerControls(true);
    }

    public void CloseInventory()
    {
        inventoryPanel.SetActive(false);
        isInventoryOpen = false;
        TogglePlayerControls(true);
    }

    private void TogglePlayerControls(bool enable)
    {
        if (playerMovement != null)
        {
            playerMovement.enabled = enable;
            playerMovement.GetComponent<MouseMovement>().enabled = enable;
        }

        Cursor.lockState = enable ? CursorLockMode.Locked : CursorLockMode.None;
        Cursor.visible = !enable;
    }
}

public class ItemReference : MonoBehaviour
{
    public Item item;
}