Babushka/scripts/CSharp/Common/Inventory/InventoryUi.cs

using Godot;

namespace Babushka.scripts.CSharp.Common.Inventory;

public partial class InventoryUi : Control
{
    [Export] private Control _slotsParent;
    [Export] private Control _slotsMover;
    [Export] private Control[] _headerSlots;
    [Export] private Control _slotSelect;

    private InventoryInstance _playerInventory;
    private int? _slotOnMouse;
    private bool _inventoryExtended = false;
    private Tween? _inventoryExtensionTween;
    private float _inventoryClosedOffset = 0f;
    private float _inventoryOpenedOffset = 200f;

    public override void _Ready()
    {
        _playerInventory = InventoryManager.Instance.playerInventory;
        //PopulateSlots();
        SubscribeSlots();
        SetSlotContent();
        SetSlotSelectPosition();
        InventoryManager.Instance.playerInventory.InventoryContentsChanged += SetSlotContent;
    }

    public override void _ExitTree()
    {
        UnsubscribeSlots();
    }

    private void SetSlotContent()
    {
        for (var i = 0; i < _playerInventory.Slots.Count; i++)
        {
            var inventorySlot = _playerInventory.Slots[i];
            var uiSlot = _slotsParent.GetChild(i) as SlotUi;

            if (inventorySlot.itemInstance != null)
            {
                var blueprint = inventorySlot.itemInstance.blueprint;
                var amount = inventorySlot.itemInstance.amount;

                if (blueprint.icon != null)
                {
                    // show icon
                    uiSlot!.nameLabel.Text = "";

                    uiSlot.icon.Texture = blueprint.icon;
                }
                else
                {
                    // show name label
                    uiSlot!.nameLabel.Text = inventorySlot.itemInstance.blueprint.name;
                    uiSlot!.nameLabel.LabelSettings = uiSlot!.nameLabel.LabelSettings.Duplicate() as LabelSettings;
                    uiSlot!.nameLabel.LabelSettings!.FontColor = inventorySlot.itemInstance?.blueprint.color ?? Colors.White;

                    uiSlot.icon.Texture = null;
                }

                // amount
                uiSlot!.amountLabel.Text = amount != 1 ? amount.ToString() : "";
            }
            else
            {
                uiSlot!.nameLabel.Text = "";
                uiSlot!.icon.Texture = null;
                uiSlot!.amountLabel.Text = "";
            }
        }
    }

    private void SetSlotSelectPosition()
    {
        _slotSelect.GlobalPosition = _headerSlots[InventoryManager.Instance.CurrentSelectedSlotIndex].GlobalPosition;
    }

    private void PopulateSlots()
    {
        var slotPackedScene = GD.Load<PackedScene>("res://prefabs/UI/Inventory/Slot.tscn");
        for (var index = 0; index < _playerInventory.Slots.Count; index++)
        {
            var slotInstance = slotPackedScene.Instantiate<SlotUi>();
            slotInstance.index = index;
            slotInstance.Clicked += SlotClicked;
            _slotsParent.AddChild(slotInstance);
        }
    }

    private void SubscribeSlots()
    {
        for (var index = 0; index < _playerInventory.Slots.Count; index++)
        {
            var slotInstance = _slotsParent.GetChild<SlotUi>(index);
            slotInstance.index = index;
            slotInstance.Clicked += SlotClicked;
        }
    }

    private void UnsubscribeSlots()
    {
        for (var index = 0; index < _playerInventory.Slots.Count; index++)
        {
            var slotInstance = _slotsParent.GetChild(index) as SlotUi;
            slotInstance!.Clicked -= SlotClicked;
        }
    }

    private void SlotClicked(int index)
    {
        if (!_inventoryExtended) return;

        GD.Print($"Clicked slot {index}");
        if (_slotOnMouse == null)
        {
            if (_playerInventory.Slots[index].IsEmpty()) return;
            _slotOnMouse = index;
            GD.Print($"Slot on mouse: {_slotOnMouse}");
        }
        else
        {
            var sourceSlot = _slotOnMouse.Value;
            var destinationSlot = index;
            InventoryManager.Instance.MoveItem(_playerInventory, sourceSlot, _playerInventory, destinationSlot);
            _slotOnMouse = null;
            //SetSlotContent();
        }
    }

    public override void _Process(double delta)
    {
        if (Input.IsActionJustPressed("ui_inventory_open_close"))
        {
            // We adjust the offset value in accordance with the screen height to make sure that the inventory is always in the middle of the screen.
            _inventoryOpenedOffset = (GetViewportRect().Size.Y / 2 + 400) * (-1);
            InputInventoryOpenClose();
        }
        
        if (Input.IsActionJustPressed("ui_inventory_close"))
        {
            if(_inventoryExtended)
                InputInventoryOpenClose();
        }

        if (Input.IsActionJustPressed("ui_inventory_disadvance"))
        {
            InventoryManager.Instance.CurrentSelectedSlotIndex++;
            if (InventoryManager.Instance.CurrentSelectedSlotIndex > 8)
                InventoryManager.Instance.CurrentSelectedSlotIndex = 0;
            SetSlotSelectPosition();
        }

        if (Input.IsActionJustPressed("ui_inventory_advance"))
        {
            InventoryManager.Instance.CurrentSelectedSlotIndex--;
            if (InventoryManager.Instance.CurrentSelectedSlotIndex < 0)
                InventoryManager.Instance.CurrentSelectedSlotIndex = 8;
            SetSlotSelectPosition();
        }
    }

    private void InputInventoryOpenClose()
    {
        _inventoryExtensionTween?.Kill();

        _inventoryExtended = !_inventoryExtended;
        if (_inventoryExtended)
        {
            GD.Print("Open inventory");
            _inventoryExtensionTween = GetTree().CreateTween();
            _slotSelect.Hide();
            _inventoryExtensionTween
                .TweenProperty(_slotsMover, "offset_bottom", _inventoryOpenedOffset, 0.4)
                .SetTrans(Tween.TransitionType.Quad)
                .SetEase(Tween.EaseType.Out);
        }
        else
        {
            GD.Print("Close inventory");
            _inventoryExtensionTween = GetTree().CreateTween();
            _slotSelect.Show();
            _inventoryExtensionTween
                .TweenProperty(_slotsMover, "offset_bottom", _inventoryClosedOffset, 0.4)
                .SetTrans(Tween.TransitionType.Quad)
                .SetEase(Tween.EaseType.Out);

            _slotOnMouse = null;
        }
    }
}