using System.Reflection;
using ln.type;

namespace ln.application
{
    public class FieldArgument : IArgument
    {
        public FieldInfo FieldInfo { get; }
        public object Instance { get;}

        public FieldArgument(FieldInfo fieldInfo)
            :this(null, fieldInfo, fieldInfo.GetCustomAttribute<StaticArgumentAttribute>())
        {}
        public FieldArgument(object instance,FieldInfo fieldInfo)
            :this(instance, fieldInfo, fieldInfo.GetCustomAttribute<StaticArgumentAttribute>())
        {}

        public FieldArgument(FieldInfo fieldInfo, StaticArgumentAttribute staticArgumentAttribute)
            :this(null,fieldInfo,staticArgumentAttribute){}
        public FieldArgument(object instance,FieldInfo fieldInfo, StaticArgumentAttribute staticArgumentAttribute)
        {
            FieldInfo = fieldInfo;
            OptionName = staticArgumentAttribute?.Option ?? (char)0;
            LongOptionName = staticArgumentAttribute?.LongOption ?? fieldInfo.Name;
            HelpString = staticArgumentAttribute?.HelpString ?? "";
            HasArgument = fieldInfo.FieldType != typeof(bool);
            Instance = instance;
        }

        public char OptionName { get; }
        public string LongOptionName { get; }
        public bool HasArgument { get; }
        public string HelpString { get; }
        public string Value
        {
            get => FieldInfo.GetValue(Instance)?.ToString();
            set
            {
                if (HasArgument)
                {
                    FieldInfo.SetValue(Instance, Cast.To(value, FieldInfo.FieldType));
                }
                else
                {
                    FieldInfo.SetValue(Instance, true);
                }
            }
        }
    }
}