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

public class Inventory : MonoBehaviour
{
    int inventorySize = 69;

    public short[,] PlayerInventory = new short[69, 2];

    public static Inventory instance;

    public GameObject inventoryDisplay;

    public delegate void OnItemChanged();
    public OnItemChanged onItemChangedCallback;

    void Awake()
    {
        if (instance != null)
            return;

        instance = this;
    }

    void Start()
    {
        CleanInventory();
    }

    public void AddItem(short id, short amount)
    {
        bool hasItem = false;

        for (int i = 0; i < inventorySize; i++)
        {
            if (PlayerInventory[i, 0] == id)
            {
                PlayerInventory[i, 0] = id;
                PlayerInventory[i, 1] += amount;
                Debug.Log("Added item ID: " + PlayerInventory[i, 0] + " (" + PlayerInventory[i, 1] + " total).");
                hasItem = true;
                break;
            }
        }
        if (!hasItem)
        {
            for (int i = 0; i < inventorySize; i++)
            {
                if (PlayerInventory[i, 0] == -1)
                {
                    PlayerInventory[i, 0] = id;
                    PlayerInventory[i, 1] += amount;
                    Debug.Log("Added item ID: " + PlayerInventory[i, 0] + " (" + PlayerInventory[i, 1] + " total).");
                    break;
                }
            }
        }

        if (onItemChangedCallback != null)
            onItemChangedCallback.Invoke();
    }

    public void RemoveItem(int slot, short amount)
    {
        //Check if they're trying to remove too many items
        if(amount > PlayerInventory[slot, 1] || PlayerInventory[slot, 0] == -1)
        {
            Debug.Log("Nothing to remove.");
            return;
        }
        //Check if it is their last item
        else if(PlayerInventory[slot, 1] == 1)
        {
            Debug.Log("Removed " + amount + " item ID " +
                PlayerInventory[slot, 0] + " from inventory. (" + (PlayerInventory[slot, 1] - (short)1) + " remaining.)");
            PlayerInventory[slot, 0] = -1;
            PlayerInventory[slot, 1] = 0;
        }
        else
        {
            Debug.Log("Removed " + amount + " item ID " +
                PlayerInventory[slot, 0] + " from inventory. (" + (PlayerInventory[slot, 1] - (short)1) + " remaining.)");
            PlayerInventory[slot, 1] -= amount;
        }

        if (onItemChangedCallback != null)
            onItemChangedCallback.Invoke();
    }

    public void MoveItem(int slotA, int slotB)
    {
        //Temp values
        short slotItemA = PlayerInventory[slotA, 0];
        short slotAmountA = PlayerInventory[slotA, 1];

        short slotItemB = PlayerInventory[slotB, 0];
        short slotAmountB = PlayerInventory[slotB, 1];

        //Swap the items
        PlayerInventory[slotA, 0] = slotItemB;
        PlayerInventory[slotA, 1] = slotAmountB;

        PlayerInventory[slotB, 0] = slotItemA;
        PlayerInventory[slotB, 1] = slotAmountA;


        Debug.Log("Swapped slot " + slotA + " with slot " + slotB + ".");

        if (onItemChangedCallback != null)
            onItemChangedCallback.Invoke();
    }

    public void PrintInventory()
    {
        for (int i = 0; i < inventorySize; i++)
        {
            Debug.Log("Slot " + i + ": item ID: " + PlayerInventory[i, 0] + " (" + PlayerInventory[i, 1] + ").");
        }

        if (onItemChangedCallback != null)
            onItemChangedCallback.Invoke();
    }

    public void CleanInventory()
    {
        for (int i = 0; i < inventorySize; i++)
        {
            //Set item ID to -1
            PlayerInventory[i, 0] = -1;

            //Set the item amount to 0
            PlayerInventory[i, 1] = 0;
        }

        if(onItemChangedCallback != null)
            onItemChangedCallback.Invoke();
    }
}