using System;
using System.Linq;
using Godot;

namespace GodotHostTest.GodotDI;

public partial class ScopePickerEditor : EditorProperty
{
    /// <summary>
    /// The "combo box" that picks a choice from the scopes.
    /// </summary>
    private OptionButton _optionButton = new();

    /// <summary>
    /// The currently chosen type.
    /// </summary>
    private string _currentType;

    /// <summary>
    /// All the known fully qualified names for scopes.
    /// </summary>
    private string[] _fullyQualifiedNames;

    /// <summary>
    /// A guard against internal changes while the property is being updated.
    /// </summary>
    private bool _updating;

    public ScopePickerEditor()
    {
        // save all the known fully qualified names
        _fullyQualifiedNames = ScopeTypesAndNames.GetQualifiedNames().ToArray();

        // fill the options button
        for (var i = 0; i < _fullyQualifiedNames.Length; i++)
        {
            // root scope is always the first, and root scope = not scoped
            _optionButton.AddItem(
                i == 0
                    ? "not a scope boundary"
                    : ScopeTypesAndNames.GetSimpleNameFromQualifiedName(_fullyQualifiedNames[i]), i);
        }

        // add the control as a direct child of EditorProperty node.
        AddChild(_optionButton);

        // make sure the control is able to retain the focus.
        AddFocusable(_optionButton);

        // initialize the starting value
        _currentType = _fullyQualifiedNames[0];

        // update the property when the button value changes
        _optionButton.ItemSelected += OnOptionButtonItemSelected;
    }

    public override void _UpdateProperty()
    {
        // get the new value and immediately return if it's already the selected one.
        var newValue = GetEditedObject().Get(GetEditedProperty()).AsString();
        if (newValue == _currentType) return;

        _updating = true;
        try
        {
            var nameIndex = Array.IndexOf(_fullyQualifiedNames, newValue);
            if (nameIndex < 0)
            {
                GD.PushWarning($"Could not find name {newValue} in the list of scope names, resetting to root scope");
                _currentType = _fullyQualifiedNames[0];
                EmitChanged(GetEditedProperty(), _currentType);
                return;
            }

            _currentType = newValue;
            UpdateControl();
        }
        finally
        {
            _updating = false;
        }
    }

    private void OnOptionButtonItemSelected(long index)
    {
        _currentType = _fullyQualifiedNames[index];
        UpdateControl();
        EmitChanged(GetEditedProperty(), _currentType);
    }

    private void UpdateControl()
    {
        _optionButton.Selected = Array.IndexOf(_fullyQualifiedNames, _currentType);
    }
}