using System;
using System.Reflection;

namespace BITKit
{
    [AttributeUsage(AttributeTargets.Method)]
    public class BITCommandAttribute : Attribute
    {
    }

    /// <summary>
    /// 自动注入依赖
    /// </summary>
    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
    public class InjectAttribute : Attribute
    {
        public static void Clear(object obj)
        {
            var fields = obj.GetType().GetFields(ReflectionHelper.Flags);
            foreach (var field in fields)
            {
                if (field.GetCustomAttributes(typeof(InjectAttribute), true).Length > 0)
                {
                    field.SetValue(obj, null);
                }
            }
        }
        public readonly bool CanBeNull;
        public InjectAttribute()
        {
        }
        public InjectAttribute(bool canBeNull)
        {
            CanBeNull = canBeNull;
        }
    }

    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface, AllowMultiple = true, Inherited = true)]
    public class CustomTypeAttribute : System.Attribute
    {
        public readonly Type Type;
        public readonly bool AsGlobal;
        public CustomTypeAttribute(Type type)
        {
            Type = type;
        }
        public CustomTypeAttribute(Type type, bool asGlobal)
        {
            Type = type;
            AsGlobal = asGlobal;
        }
        public CustomTypeAttribute(bool asGlobal)
        {
            AsGlobal = asGlobal;
        }
    }
    #if !Godot
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Field | AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
    public class ExportAttribute : System.Attribute
    {
        public static string GetName(object obj)
        {
            var att = obj.GetType().GetCustomAttribute<ExportAttribute>();
            att = obj switch
            {
                FieldInfo field => field.GetCustomAttribute<ExportAttribute>(),
                MethodInfo method => method.GetCustomAttribute<ExportAttribute>(),
                PropertyInfo property => property.GetCustomAttribute<ExportAttribute>(),
                _ => att
            };
            if (att is null) return obj.GetType().Name;
            if (string.IsNullOrEmpty(att.Name))
            {
                return obj switch
                {
                    FieldInfo field => field.Name,
                    MethodInfo method => method.Name,
                    PropertyInfo property => property.Name,
                    _ => att.Name
                };
            }
            return att.Name;
        }
        public readonly string Name;
        public readonly IExportSetting Settings;
        public ExportAttribute(){}
        public ExportAttribute(IExportSetting settings)
        {
            Settings = settings;
        }
        public ExportAttribute(string name)
        {
            Name = name;
        }
    }
    public interface IExportSetting{}
    #endif
}