using System.Reflection;
using static System.Reflection.BindingFlags;

namespace InnovEnergy.Lib.Utils.Reflection;

public class Field : DataMember
{
    private readonly Object?   _Instance;
    private readonly FieldInfo _FieldInfo;

    public override String Name => _FieldInfo.Name;
    public override Type   Type => _FieldInfo.FieldType;
    
    public override Boolean IsPublic   => _FieldInfo.IsPublic;
    public override Boolean IsPrivate  => _FieldInfo.IsPrivate;
    public override Boolean IsStatic   => _FieldInfo.IsStatic;
    
    public override Boolean IsWriteable => true;
    public override Boolean IsReadable  => true;

    public override IEnumerable<Attribute> Attributes => _FieldInfo
                                                         .GetCustomAttributes(inherit: false)
                                                         .OfType<Attribute>();

    internal Field(Object? instance, FieldInfo fieldInfo)
    {
        _Instance  = instance;
        _FieldInfo = fieldInfo;
    }

    public override Object? Get() => _FieldInfo.GetValue(_Instance) ;
    public override void    Set(Object value) => _FieldInfo.SetValue(_Instance, value);
}

public static class Fields
{
    public static IEnumerable<Field> GetFields<T>(this T instance) where T : notnull
    {
        return instance
              .GetType()
              .GetFields(Instance | Static | Public | NonPublic)
              .Select(fi => new Field(fi.IsStatic ? null : instance, fi));
    }
    
    public static IEnumerable<Field> OfInstance<T>(T instance) where T : notnull
    {
        return instance.GetFields();
    }
}