using System;
using System.Reflection;

namespace BITKit
{
    public interface IWrapper
    {
        public object Obj { get; set; }
    }
    public interface IWrapper<T>:IWrapper
    {
        public  Action<T, T> OnValueChanged  { get; set; }
        public T Value { get; set; }
    }
    public class ValueWrapper<T> : IWrapper<T>
    {
        public ValueWrapper()
        {
            var type = typeof(T);
            if (type == typeof(string))
            {
                _value = string.Empty.As<T>();
                return;
            }
            if(type.IsAbstract || type.IsInterface)return;
            // 检查类型是否具有公共无参数构造函数
            var constructor = type.GetConstructor(BindingFlags.Public | BindingFlags.Instance, null, Type.EmptyTypes, null);
            if (constructor is not null)
            {
                _value = Activator.CreateInstance<T>();
            }
        }
        public Action<T, T> OnValueChanged { get; set; }

        public T Value
        {
            get => _value;
            set
            {
                var prev = _value;
                _value = value;
                OnValueChanged?.Invoke(prev,value);
            }
        }

        private T _value;
        public object Obj
        {
            get => Value;
            set => Value = (T)value;
        }
    }

    public class PropertyWrapper<T> : IWrapper<T>
    {
        private readonly PropertyInfo _field;
        private readonly object _target;
        public Action<T, T> OnValueChanged  { get; set; }
        public PropertyWrapper(PropertyInfo field, object target)
        {
            _field = field;
            _target = target ?? throw new ArgumentNullException(nameof(target));
        }
        public T Value
        {
            get => (T)_field.GetValue(_target);
            set
            {
                var prev = Value;
                _field.SetValue(_target, value);
                OnValueChanged?.Invoke(prev, value);
            }
        }

        public object Obj
        {
            get => Value;
            set => Value = (T)value;
        }
    }
    public class FieldWrapper<T> : IWrapper<T>
    {
        private readonly FieldInfo _field;
        private readonly object _target;
        public FieldWrapper(FieldInfo field, object target)
        {
            _field = field;
            _target = target ?? throw new ArgumentNullException(nameof(target));
        }

        public Action<T, T> OnValueChanged  { get; set; }

        public T Value
        {
            get => (T)_field.GetValue(_target);
            set
            {
                OnValueChanged?.Invoke(Value, value);
                _field.SetValue(_target, value);
            }
        }

        public object Obj
        {
            get => Value;
            set => Value = (T)value;
        }
    }
    public class FuncWrapper<T> : IWrapper<T>
    {
        private readonly Func<T> _get;
        private readonly Action<T> _set;
        public FuncWrapper(Func<T> get, Action<T> set)
        {
            _get = get;
            _set = set;
        }

        public Action<T, T> OnValueChanged  { get; set; }

        public T Value
        {
            get => _get();
            set => _set(value);
        }

        public object Obj
        {
            get => Value;
            set => Value = (T)value;
        }
    }
}