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

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

        [Header("HUD Elements")]
        [Tooltip("Text element for showing Time of Day (e.g. 08:00)")]
        [SerializeField] private TextMeshProUGUI timeText;
        [Tooltip("Text element for showing current money")]
        [SerializeField] private TextMeshProUGUI moneyText;
        [Tooltip("Text element for showing customer count")]
        [SerializeField] private TextMeshProUGUI customersText;
        [Tooltip("Text element for showing event alerts (e.g. Goblin Raid!)")]
        [SerializeField] private TextMeshProUGUI alertText;

        [Header("Context Menu Panels")]
        [SerializeField] private GameObject shelfMenuPanel;
        [SerializeField] private GameObject npcMenuPanel;
        [SerializeField] private GameObject inventoryMenuPanel;
        [SerializeField] private GameObject tillMenuPanel;

        // Active context tracking
        private Shelf activeShelf;
        private CustomerNPC activeNPC;
        private PlayerController activePlayer;
        private ShopTill activeTill;
        
        [Header("Inventory Test Fields")]
        [Tooltip("Assign an ItemData here to test Buy/Sell/Discard buttons via the Inspector/UI until a full scrolling list is built.")]
        public ItemData testInventoryItem;
        public int testTransactionAmount = 5;

        private void Awake()
        {
            if (Instance != null && Instance != this)
            {
                Destroy(gameObject);
                return;
            }
            Instance = this;

            // Hide all menus initially
            CloseAllMenus();
            if (alertText != null) alertText.gameObject.SetActive(false);
        }

        private void Start()
        {
            // Subscribe to GameManager events
            if (GameManager.Instance != null)
            {
                GameManager.Instance.OnTimeChanged += UpdateTimeUI;
                GameManager.Instance.OnMoneyChanged += UpdateMoneyUI;
                GameManager.Instance.OnCustomerCountChanged += UpdateCustomersUI;
                GameManager.Instance.OnRandomEventTriggered += ShowEventAlert;
            }
            else
            {
                Debug.LogWarning("[UIManager] GameManager.Instance is missing! HUD will not update.");
            }
        }

        private void OnDestroy()
        {
            if (GameManager.Instance != null)
            {
                GameManager.Instance.OnTimeChanged -= UpdateTimeUI;
                GameManager.Instance.OnMoneyChanged -= UpdateMoneyUI;
                GameManager.Instance.OnCustomerCountChanged -= UpdateCustomersUI;
                GameManager.Instance.OnRandomEventTriggered -= ShowEventAlert;
            }
        }

        #region HUD Updates

        private void UpdateTimeUI(int hour, int minute)
        {
            if (timeText != null)
            {
                timeText.text = $"{hour:D2}:{minute:D2}";
            }
        }

        private void UpdateMoneyUI(int money)
        {
            if (moneyText != null)
            {
                moneyText.text = $"{money} G";
            }
        }

        private void UpdateCustomersUI(int customers)
        {
            if (customersText != null)
            {
                customersText.text = $"Customers: {customers}";
            }
        }

        private void ShowEventAlert(GameEvent gameEvent)
        {
            if (alertText == null) return;
            
            StopCoroutine(nameof(FadeAlertText));
            StartCoroutine(FadeAlertText($"EVENT: {gameEvent}!"));
        }

        private IEnumerator FadeAlertText(string message)
        {
            alertText.text = message;
            alertText.gameObject.SetActive(true);
            alertText.alpha = 1f;

            // Wait 3 seconds
            yield return new WaitForSeconds(3f);

            // Fade out
            float fadeTime = 1.5f;
            float t = 0;
            while (t < fadeTime)
            {
                t += Time.deltaTime;
                alertText.alpha = Mathf.Lerp(1f, 0f, t / fadeTime);
                yield return null;
            }

            alertText.gameObject.SetActive(false);
        }

        #endregion

        #region Context Menus

        public void CloseAllMenus()
        {
            if (shelfMenuPanel != null) shelfMenuPanel.SetActive(false);
            if (npcMenuPanel != null) npcMenuPanel.SetActive(false);
            if (inventoryMenuPanel != null) inventoryMenuPanel.SetActive(false);
            if (tillMenuPanel != null) tillMenuPanel.SetActive(false);

            activeShelf = null;
            activeNPC = null;
            activePlayer = null;
            activeTill = null;
        }

        // --- SHELF MENU ---
        
        public void OpenShelfMenu(Shelf shelf, PlayerController player)
        {
            CloseAllMenus();
            activeShelf = shelf;
            activePlayer = player;
            
            if (shelfMenuPanel != null) 
            {
                shelfMenuPanel.SetActive(true);
            }
            else
            {
                Debug.LogWarning("[UIManager] Shelf Menu Panel is not assigned!");
            }
        }

        public void UI_StockShelf()
        {
            if (activeShelf != null && activePlayer != null)
            {
                activeShelf.StockFromPlayer(activePlayer);
            }
            CloseAllMenus();
        }

        public void UI_EmptyShelf()
        {
            if (activeShelf != null)
            {
                activeShelf.EmptyShelf();
            }
            CloseAllMenus();
        }
        
        public void UI_CheckShelf()
        {
            if (activeShelf != null)
            {
                string itemName = activeShelf.AssignedItem != null ? activeShelf.AssignedItem.itemName : "Empty";
                Debug.Log($"[Shelf Status] Item: {itemName}, Stock: {activeShelf.CurrentStock}");
            }
        }

        // --- NPC MENU ---

        public void OpenNPCMenu(CustomerNPC npc, PlayerController player)
        {
            CloseAllMenus();
            activeNPC = npc;
            activePlayer = player;

            if (npcMenuPanel != null)
            {
                npcMenuPanel.SetActive(true);
            }
            else
            {
                Debug.LogWarning("[UIManager] NPC Menu Panel is not assigned!");
            }
        }

        public void UI_TalkToNPC()
        {
            if (activeNPC != null)
            {
                activeNPC.TalkTo();
            }
            CloseAllMenus();
        }

        public void UI_KickOutNPC()
        {
            if (activeNPC != null)
            {
                activeNPC.KickOut();
            }
            CloseAllMenus();
        }
        
        public void UI_CheckNPC()
        {
            if (activeNPC != null)
            {
                Debug.Log($"[NPC Info] Name: {activeNPC.npcName}");
            }
        }

        // --- TILL MENU ---

        public void OpenTillMenu(ShopTill till, System.Collections.Generic.List<ItemData> basket)
        {
            CloseAllMenus();
            activeTill = till;

            if (tillMenuPanel != null)
            {
                tillMenuPanel.SetActive(true);
                
                // Here is where you would populate a dynamic UI list of icons.
                // Example debug output of what the UI should show:
                string basketContents = "Customer Basket: ";
                int total = 0;
                foreach(var item in basket)
                {
                    if (item != null)
                    {
                        basketContents += $"[{item.itemName} ({item.sellPrice}G)] ";
                        total += item.sellPrice;
                    }
                }
                Debug.Log($"[UIManager] Till Opened. {basketContents} | Total: {total}G");
            }
            else
            {
                Debug.LogWarning("[UIManager] Till Menu Panel is not assigned! Defaulting to auto-charge.");
                // Fallback if no UI panel
                if (activeTill != null) activeTill.ChargeCustomer();
            }
        }

        public void UI_ChargeCustomer()
        {
            if (activeTill != null)
            {
                activeTill.ChargeCustomer();
            }
            CloseAllMenus();
        }

        // --- INVENTORY MENU ---

        public void OpenInventoryMenu(PlayerController player = null)
        {
            CloseAllMenus();
            activePlayer = player;
            if (inventoryMenuPanel != null)
            {
                inventoryMenuPanel.SetActive(true);
            }
            else
            {
                Debug.LogWarning("[UIManager] Inventory Menu Panel is not assigned!");
            }
        }

        public void UI_BuyTestItem()
        {
            if (testInventoryItem != null && ShopInventory.Instance != null)
            {
                bool success = ShopInventory.Instance.BuyStock(testInventoryItem, testTransactionAmount);
                if (success)
                {
                    PlayerController targetPlayer = activePlayer != null ? activePlayer : FindObjectOfType<PlayerController>();
                    if (targetPlayer != null)
                    {
                        ShopInventory.Instance.WithdrawToPlayer(testInventoryItem, testTransactionAmount, targetPlayer);
                        CloseAllMenus();
                    }
                }
            }
        }

        public void UI_SellTestItem()
        {
            // Sell logic usually requires NPC interaction, but if selling back to supplier:
            if (testInventoryItem != null && ShopInventory.Instance != null)
            {
                if (ShopInventory.Instance.RemoveStock(testInventoryItem, testTransactionAmount))
                {
                    int totalSale = testInventoryItem.sellPrice * testTransactionAmount;
                    GameManager.Instance.AddMoney(totalSale);
                    Debug.Log($"[UIManager] Sold {testTransactionAmount}x {testInventoryItem.itemName} for {totalSale} G.");
                }
            }
        }

        public void UI_DiscardTestItem()
        {
            if (testInventoryItem != null && ShopInventory.Instance != null)
            {
                if (ShopInventory.Instance.RemoveStock(testInventoryItem, testTransactionAmount))
                {
                    Debug.Log($"[UIManager] Discarded {testTransactionAmount}x {testInventoryItem.itemName}.");
                }
            }
        }

        #endregion
    }
}