using System.Collections.Generic;
using UnityEngine;

namespace MedievalShopkeeper
{
    public class ShopTill : Interactable
    {
        [Header("Queue Settings")]
        [Tooltip("Where the first customer stands (typically directly in front of the counter).")]
        public Transform queueStartPoint;
        [Tooltip("How far apart customers stand in line.")]
        public float queueSpacing = 1.5f;

        [Header("Counter Settings")]
        [Tooltip("Where the physical item models will spawn when a customer is checking out.")]
        public Transform counterTopSpot;

        // Queue Management
        private List<CustomerNPC> line = new List<CustomerNPC>();
        private CustomerNPC customerAtTill;
        private List<GameObject> spawnedItems = new List<GameObject>();

        public override string InteractionPrompt 
        {
            get
            {
                if (customerAtTill != null) return "Serve Customer";
                return "Till (No customers waiting)";
            }
        }

        public void JoinQueue(CustomerNPC npc)
        {
            if (!line.Contains(npc))
            {
                line.Add(npc);
            }
        }

        public void LeaveQueue(CustomerNPC npc)
        {
            line.Remove(npc);
            if (customerAtTill == npc)
            {
                ClearCounter();
                customerAtTill = null;
            }
        }

        public bool IsFrontOfQueue(CustomerNPC npc)
        {
            return line.Count > 0 && line[0] == npc;
        }

        public Vector3 GetQueuePosition(CustomerNPC npc)
        {
            int index = line.IndexOf(npc);
            if (index == -1) index = 0; // Fallback

            if (queueStartPoint != null)
            {
                // Queue extends backwards along the local Z axis
                return queueStartPoint.position - (queueStartPoint.forward * (index * queueSpacing));
            }
            
            return transform.position - (transform.forward * (1f + (index * queueSpacing)));
        }

        public void PlaceItemsOnCounter(CustomerNPC npc, List<ItemData> items)
        {
            customerAtTill = npc;
            ClearCounter();

            if (counterTopSpot == null) return;

            foreach (var item in items)
            {
                if (item != null && item.displayPrefab != null)
                {
                    // Add a tiny random offset so items pile up naturally
                    Vector3 randomOffset = new Vector3(
                        Random.Range(-0.2f, 0.2f), 
                        0, 
                        Random.Range(-0.2f, 0.2f)
                    );
                    
                    GameObject vis = Instantiate(item.displayPrefab, counterTopSpot.position + randomOffset, Quaternion.identity);
                    
                    // Strip colliders from the spawned visuals
                    foreach (var col in vis.GetComponentsInChildren<Collider>()) Destroy(col);
                    
                    spawnedItems.Add(vis);
                }
            }
        }

        private void ClearCounter()
        {
            foreach (var vis in spawnedItems)
            {
                if (vis != null) Destroy(vis);
            }
            spawnedItems.Clear();
        }

        public override void Interact(PlayerController player)
        {
            base.Interact(player);

            if (customerAtTill != null && customerAtTill.GetBasket().Count > 0)
            {
                if (UIManager.Instance != null)
                {
                    UIManager.Instance.OpenTillMenu(this, customerAtTill.GetBasket());
                }
                else
                {
                    // Fallback if no UI
                    ChargeCustomer();
                }
            }
            else
            {
                Debug.Log("[ShopTill] No customer is ready at the till.");
            }
        }

        public void ChargeCustomer()
        {
            if (customerAtTill == null) return;

            int totalCost = 0;
            foreach (var item in customerAtTill.GetBasket())
            {
                if (item != null) totalCost += item.sellPrice;
            }

            if (GameManager.Instance != null)
            {
                GameManager.Instance.AddMoney(totalCost);
                Debug.Log($"[ShopTill] Charged customer {totalCost} G.");
            }
            
            if (AudioManager.Instance != null)
            {
                AudioManager.Instance.PlaySale();
            }

            ClearCounter();

            // Customer leaves
            line.Remove(customerAtTill);
            customerAtTill.FinishCheckoutAndLeave();
            customerAtTill = null;

            if (UIManager.Instance != null)
            {
                UIManager.Instance.CloseAllMenus();
            }
        }
    }
}