using System.Collections.Generic;
using UnityEngine;

public class TillSystem : MonoBehaviour
{

    public static TillSystem Instance;
    void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
        }
        else
        {
            Destroy(gameObject);
        }
    }
    public GameObject tillUIPanel;
    private bool isTillOpen = false;
    private float enteredPrice = 0f;
    private CustomerAI currentCustomer;
    private Queue<ShopItemData> itemsToScan = new Queue<ShopItemData>();
    private float runningTotal = 0f;
    private float customerTendered = 0f;

    void Start()
    {
        tillUIPanel.SetActive(false);
        LockCursor(true);
    }

    void Update()
    {

    }

    public void OpenTill(CustomerAI customer)
    {
        isTillOpen = true;
        tillUIPanel.SetActive(true);
        LockCursor(false);
        currentCustomer = customer;
        itemsToScan.Clear();
        foreach (var entry in customer.itemsToBuy)
        {
            for (int i = 0; i < entry.quantity; i++)
            {
                ShopItemData shopItem = entry.item;
                itemsToScan.Enqueue(shopItem);
            }
        }
        runningTotal = 0f;
        // Update UI for new transaction
    }
    public void ScanNextItem()
    {
        if (itemsToScan.Count > 0)
        {
            var item = itemsToScan.Dequeue();
            runningTotal += item.price;
            // Update UI: show item and price
        }
        // If no items left, enable "Total" button
    }
    public void PressTotal()
    {
        // Show total on UI
        // Simulate customer payment
        customerTendered = currentCustomer.Pay(runningTotal);
        // Show tendered amount on UI
    }
    public void HandOverChange(float changeGiven)
    {
        float correctChange = customerTendered - runningTotal;
        bool correct = Mathf.Approximately(changeGiven, correctChange);
        // Show green/red on UI
        // Proceed to next customer
        _ = currentCustomer.LeaveShop();
        currentCustomer = null;
        // Reset UI for next customer
    }

    public void CloseTill()
    {
        isTillOpen = false;
        tillUIPanel.SetActive(false);
        LockCursor(true); // Lock cursor when till is closed
    }

    void LockCursor(bool locked)
    {
        Cursor.lockState = locked ? CursorLockMode.Locked : CursorLockMode.None;
        Cursor.visible = !locked;
    }

    public void EnterPrice(float price)
    {
        enteredPrice = price;
        Debug.Log($"📌 Entered Price: £{enteredPrice:0.00}");
    }
public void ProcessTransaction(float customerTendered)
{
    if (customerTendered >= enteredPrice)
    {
        FinanceManager.Instance.AddRevenue(enteredPrice);
        GeneralUIController.Instance.ShowMessage($"✅ Sale Complete! Change: £{customerTendered - enteredPrice:0.00}");
    }
    else
    {
        GeneralUIController.Instance.ShowMessage("🚨 Price too high! Customer walks away.");
    }
}

    public bool IsTillOpen => isTillOpen;
}