using Godot;
using SupaLidlGame.Characters;
using Godot.Collections;

namespace SupaLidlGame.Items;

public partial class Inventory : Node2D, IItemCollection<ItemMetadata>
{
    public Character Character { get; private set; }

    [Export]
    public Array<Item> Hotbar { get; private set; }

    public Array<int> HotbarToItemIndexMap { get; set; } = new();

    [Export]
    public Array<ItemMetadata> Items { get; set; }

    [Signal]
    public delegate void UsedItemEventHandler(Item item);

    [Signal]
    public delegate void EquippedItemEventHandler(Item newItem, Item prevItem);

    [Signal]
    public delegate void ItemAddedEventHandler(ItemMetadata newItemMetadata);

    public int Capacity { get; set; } = 30;

    public const int HotbarCapacity = 3;

    private Item _selectedItem;

    public Item SelectedItem
    {
        get => _selectedItem;
        set => EquipItem(value);
    }

    private int _selectedIndex;

    public int SelectedIndex
    {
        get => _selectedIndex;
        set => EquipIndex(value);
    }

    private int _quickSwitchIndex = -1;

    public const int QUICKSWITCH_SIZE = 3;

    public int CurrentQuickSwitchIndex
    {
        get => _quickSwitchIndex;
        set
        {
            const int size = QUICKSWITCH_SIZE;
            _quickSwitchIndex = (value % size + size) % size;
        }
    }

    public bool IsUsingItem => SelectedItem?.IsUsing ?? false;

    public Inventory()
    {
        HotbarToItemIndexMap.Resize(HotbarCapacity);
        HotbarToItemIndexMap.Fill(-1);
    }

    public override void _Ready()
    {
        if (Hotbar is null)
        {
            // instantiating a new array will prevent characters from
            // sharing inventories
            Hotbar = new();
            Hotbar.Resize(HotbarCapacity);
        }

        if (Items is null)
        {
            Items = new();
        }

        Character = GetParent<Character>();
        foreach (Node child in GetChildren())
        {
            if (child is Item item)
            {
                AddItem(item);
            }
        }

        base._Ready();
    }

    public virtual bool EquipIndex(int index)
    {
        if (index >= Hotbar.Count)
        {
            return false;
        }

        Item prevItem = _selectedItem;
        prevItem?.Unequip(Character);
        _selectedIndex = index;

        if (index >= 0)
        {
            _selectedItem = Hotbar[index];
            _selectedItem?.Equip(Character);
        }
        else
        {
            _selectedItem = null;
        }

        EmitSignal(SignalName.EquippedItem, prevItem, _selectedItem);

        return true;
    }

    protected virtual bool EquipItem(Item item)
    {
        if (item is null)
        {
            EquipIndex(-1);
        }

        int index = Hotbar.IndexOf(item);
        if (index < 0)
        {
            GD.PushWarning("Trying to equip item not in the hot inventory.");
        }
        return EquipIndex(index);
    }

    public Item AddToHotbar(ItemMetadata metadata)
    {
        //AddItemMetadata(metadata);
        var item = metadata.Instance.Instantiate<Item>();
        AddItem(item);
        AddChild(item);
        GD.Print("Added " + item.Metadata.Name);
        return item;
    }

    public Item SetHotbarIndexToItemIndex(int hotbarIndex, int itemIndex)
    {
        HotbarToItemIndexMap[hotbarIndex] = itemIndex;

        if (itemIndex >= 0)
        {
            return SetHotbarIndexToItem(hotbarIndex, Items[itemIndex]);
        }

        return null;
    }

    private Item SetHotbarIndexToItem(int index, ItemMetadata metadata)
    {
        var oldItem = Hotbar[index];
        Item newItem = null;

        if (IsInstanceValid(oldItem))
        {
            oldItem?.QueueFree();
        }

        if (metadata is not null)
        {
            newItem = metadata.Instance.Instantiate<Item>();
            AddChild(newItem);
            Hotbar[index] = newItem;
        }

        if (SelectedIndex == index)
        {
            // equip item if the hotbar index we are setting is selected
            EquipIndex(index);
        }

        var bus = Events.EventBus.Instance;
        bus.EmitSignal(Events.EventBus.SignalName.PlayerInventoryUpdate, this);

        return newItem;
    }

    public Item AddItem(Item item)
    {
        if (Hotbar.Count >= HotbarCapacity)
        {
            return null;
        }

        item.CharacterOwner = Character;
        item.Visible = false;
        if (!Hotbar.Contains(item))
        {
            Hotbar.Add(item);
        }

        return item;
    }

    public System.Collections.Generic.IEnumerable<ItemMetadata> GetItems()
    {
        return Items;
    }

    public bool Add(ItemMetadata item)
    {
        if (Items.Count >= Capacity)
        {
            return false;
        }

        Items.Add(item);
        EmitSignal(SignalName.ItemAdded, item);
        return true;
    }

    public bool Remove(ItemMetadata item)
    {
        return Items.Remove(item);
    }

    public Item DropItem(Item item)
    {
        item.CharacterOwner = null;
        item.Visible = true;
        var e = SelectedItem = item;
        throw new System.NotImplementedException();
    }
}