using System;
using Godot;

namespace Babushka.scripts.CSharp.Common.Inventory;

public partial class InventoryManager : Node
{
    [Signal]
    public delegate void SlotIndexChangedEventHandler(int newIndex);
    
    
    public static InventoryManager Instance { get; private set; } = null!;
    public int CurrentSelectedSlotIndex
    {
        get => _currentSelectedSlotIndex;
        set
        {
            if (value >= 0 && value <= 8)
            {
                _currentSelectedSlotIndex = value;
                EmitSignalSlotIndexChanged(_currentSelectedSlotIndex);
            }
        }
    }

    public InventoryInstance? playerInventory;

    private int _currentSelectedSlotIndex = 0;

    public override void _EnterTree()
    {
        Instance = this;
    }

    public override void _Ready()
    {
        playerInventory = new InventoryInstance();
        playerInventory.SlotAmount = 37;
        AddChild(playerInventory);
    }

    public InventoryActionResult CreateItem(
        ItemResource itemBlueprint,
        InventoryInstance inventory,
        int amount = 1,
        int inventorySlot = -1)
    {
        var newItem = new ItemInstance { blueprint = itemBlueprint, amount = amount };
        return inventorySlot < 0
            ? inventory.AddItem(newItem)
            : inventory.AddItemToSlot(newItem, inventorySlot);
    }

    public InventoryActionResult MoveItem(
        InventoryInstance sourceInventory,
        int sourceSlot,
        InventoryInstance destinationInventory,
        int destinationSlot)
    {
        var remResult = sourceInventory.RemoveItem(sourceSlot, out var item);
        if (remResult != InventoryActionResult.Success) return remResult;

        var addResult = destinationInventory.AddItemToSlot(item!, destinationSlot);
        if (addResult == InventoryActionResult.Success) return InventoryActionResult.Success;

        // if adding in the destination failed, re-add the item into the source
        sourceInventory.AddItemToSlot(item!, sourceSlot); // can not fail ... in theory
        return addResult;
    }

    public InventoryActionResult RemoveItem(
        InventoryInstance inventory,
        int inventorySlot,
        out ItemInstance? itemInstance)
    {
        return inventory.RemoveItem(inventorySlot, out itemInstance);
    }

    public InventoryActionResult RemoveItem(
        InventoryInstance inventory,
        int inventorySlot)
    {
        return inventory.RemoveItem(inventorySlot);
    }

    public InventoryActionResult CollectItem(ItemInstance itemInstance)
    {
        return playerInventory.AddItem(itemInstance);
    }

    public InventorySlot GetCurrentSelectedSlot()
    {
        if (CurrentSelectedSlotIndex < 0 || CurrentSelectedSlotIndex > 8)
            throw new ArgumentOutOfRangeException(
                nameof(CurrentSelectedSlotIndex),
                "currentInventoryBarIndex must be between 0 and 8 (inclusively)");

        return playerInventory.Slots[CurrentSelectedSlotIndex];
    }
}