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

public class InventoryManager : MonoBehaviour
{
    static InventoryManager instance;
    
    // !!
    public Inventory myBag;
    public GameObject slotGrid;
    // public Slot slotPrefab;
    public GameObject emptySlot;
    public Text itemInfomation;
    public int slotIndex;
    public GameObject bagImage;
    public GameObject SceneChange;
    // public Character maincharacter;

    public List<GameObject> slots = new List<GameObject>();

    GameManager gameManager;
    GameObject[] pieces;
    Character maincharacter;
    Character selected;

    void Awake()
    {
        if (instance != null)
            Destroy(this);
        instance = this;

        gameManager = GameObject.Find("GameManager").GetComponent<GameManager>();
        pieces = GameObject.FindGameObjectsWithTag("Pieces");
        foreach (var piece in pieces)
        {
            if(piece.GetComponent<Character>().id == 0)
            {
                instance.maincharacter = piece.GetComponent<Character>();
                break;
            }
        } 
        instance.selected = gameManager.GetSelected(); 
    }

    void Update()
    {
        instance.selected = gameManager.GetSelected();
    }

    private void OnEnable()
    {
        RefreshItem();
        instance.itemInfomation.text = "这里是物品描述。";
    }

    public static void UpdateItemInfo(string itemDescription)
    {
        instance.itemInfomation.text = itemDescription;
    }

    public static void UpdateItemIndex(int index)
    {
        instance.slotIndex = index;
    }

    public static void RefreshItem()
    {
        // 循环删除slotGrid下的子集物品
        for (int i = 0; i < instance.slotGrid.transform.childCount; i++)
        {
            if(instance.slotGrid.transform.childCount == 0)
                break;
            Destroy(instance.slotGrid.transform.GetChild(i).gameObject);
            instance.slots.Clear(); // 清空slots列表
        }

        // 重新生成对应背包中物品的slot
        for (int i = 0; i < instance.myBag.itemList.Count; i++)
        {
            instance.slots.Add(Instantiate(instance.emptySlot));
            instance.slots[i].transform.SetParent(instance.slotGrid.transform);
            instance.slots[i].GetComponent<Slot>().slotIndex = i;
            instance.slots[i].GetComponent<Slot>().SetupSlot(instance.myBag.itemList[i]);
        }
    }

    public static void UseItem()
    {
        // Debug.Log(instance.myBag.itemList[instance.slotIndex].itemName);
        if(instance.myBag.itemList[instance.slotIndex].usable)
        {
            if(instance.myBag.itemList[instance.slotIndex].itemName == "Crystal")
            {
                if(instance.gameManager.GetExploreMode())
                {
                    instance.SceneChange.SetActive(true);
                    instance.bagImage.SetActive(false);
                }               
            }

            if(instance.myBag.itemList[instance.slotIndex].itemName == "Health")
            {
                instance.selected.ChangeHealth(5);
                
                if(instance.myBag.itemList[instance.slotIndex].itemHeld <= 1)
                {
                    instance.myBag.itemList[instance.slotIndex] = null;
                }
                else
                {
                    instance.myBag.itemList[instance.slotIndex].itemHeld--;
                }
                RefreshItem();
            }
            
            if(instance.myBag.itemList[instance.slotIndex].itemName == "Mana")
            {
                instance.selected.ChangeMana(3);
                
                if(instance.myBag.itemList[instance.slotIndex].itemHeld <= 1)
                {
                    instance.myBag.itemList[instance.slotIndex] = null;
                }
                else
                {
                    instance.myBag.itemList[instance.slotIndex].itemHeld--;
                }
                RefreshItem();
            }
        }
    }
}