using Godot;
using Rokojori;
 
namespace Rokojori
{ 

  [Tool]
  [GlobalClass] 
  public partial class UINumber : Resource
  { 
    [Export]
    public float value = 0;

    [Export]
    public string unit = "";
    

    public bool IsNone =>  unit == "none";

    public float Compute( Control control, float alternative )
    {
      return UINumber.Compute( control, this, alternative );
    }
    

    public static bool IsNullOrNone( UINumber number )
    {
      if ( number == null )
      {
        return true;
      }

      return number.IsNone;
    }

    
    public static float Compute( Control control, UINumber number, float alternative = 0, float relative = 100 )
    {
      if ( number == null || control == null || number.IsNone )
      {
        return alternative;
      }

      var width  = UI.GetWindowWidth( control );
      var height = UI.GetWindowHeight( control );


      return Compute( control, number, width, height, relative );
      
    }

    static UI _ui;

    static float em()
    {
      return _ui == null ? 12 : _ui.X_computedFontSizePixels;
    }

    public static float Compute( Control control, UINumber number, float width, float height, float relative )
    {
      if ( number == null )
      {
        return 0;
      }

      if ( _ui == null )
      {
        _ui = NodesWalker.Get().GetInParents( control, n => n is UI ) as UI;
      }

      switch ( number.unit )
      {
        case "em":
        {
          return number.value * em();
        }

        case "vw":
        {
          return number.value * width / 100f;
        }

        case "vh":
        {
          return number.value * height / 100f;
        }

        case "pw":
        {
          var parent = control.GetParent<Control>();
          return number.value / 100f * ( parent == null ?  width : parent.Size.X );
        }

        case "ph":
        {
          var parent = control.GetParent<Control>();
          return number.value / 100f * ( parent == null ?  height : parent.Size.Y );
        }

        case "px": case "":
        {
          return number.value;
        }

        case "%":
        {
          return number.value * relative / 100f;
        }
      }

      var expression = new Expression();


      var expressionText = number.unit == null ? "" : RegexUtility.Replace( number.unit, "%", " * relative " ); 
      var parseResult = expression.Parse( expressionText, 
        new string[]
        { 
          "em","vw", "vh", "pw", "ph", "px", "relative", "value" } 
        );

      if ( Error.Ok != parseResult )
      {
        return 0;
      }

      var parentControl = control.GetParent<Control>();

      var inputs = new Godot.Collections.Array();
      inputs.Add( em() );
      inputs.Add( width / 100f );
      inputs.Add( height / 100f );
      inputs.Add( ( parentControl == null ? width : parentControl.Size.X ) / 100f );
      inputs.Add( ( parentControl == null ? height : parentControl.Size.Y ) / 100f );
      inputs.Add( 1 );      
      inputs.Add( relative / 100f );


      if ( number.unit.IndexOf( "value" ) == -1 )
      {  
        inputs.Add( 0 );
        return number.value * (float)  expression.Execute( inputs ).AsDouble() ;
      }

      inputs.Add( number.value );

      return (float) expression.Execute( inputs ).AsDouble() ;
    }

  }

}