using System;
using System.Reflection;

namespace xCommons.Helpers {
    public static class XReflectionHelper {
        public static object GetFieldValue (this object obj, string fieldName) {
            if (obj == null)
                throw new ArgumentNullException (nameof (obj));
            Type objType = obj.GetType ();
            var fieldInfo = GetFieldInfo (objType, fieldName);
            if (fieldInfo == null)
                throw new ArgumentOutOfRangeException (fieldName,
                    $"Couldn't find field {fieldName} in type {objType.FullName}");
            return fieldInfo.GetValue (obj);
        }

        public static void SetFieldValue (this object obj, string fieldName, object val) {
            if (obj == null)
                throw new ArgumentNullException (nameof (obj));
            Type objType = obj.GetType ();
            var fieldInfo = GetFieldInfo (objType, fieldName);
            if (fieldInfo == null)
                throw new ArgumentOutOfRangeException (fieldName,
                    $"Couldn't find field {fieldName} in type {objType.FullName}");
            fieldInfo.SetValue (obj, val);
        }

        private static FieldInfo GetFieldInfo (Type type, string fieldName) {
            FieldInfo fieldInfo = null;
            do {
                fieldInfo = type.GetField (fieldName, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
                type = type.BaseType;
            } while (fieldInfo == null && type != null);

            return fieldInfo;
        }

        public static object GetPropertyValue (this object obj, string propertyName) {
            if (obj == null)
                throw new ArgumentNullException (nameof (obj));
            Type objType = obj.GetType ();
            var propertyInfo = GetPropertyInfo (objType, propertyName);
            if (propertyInfo == null)
                throw new ArgumentOutOfRangeException (propertyName,
                    $"Couldn't find property {propertyName} in type {objType.FullName}");
            return propertyInfo.GetValue (obj, null);
        }

        public static void SetPropertyValue (this object obj, string propertyName, object val) {
            if (obj == null)
                throw new ArgumentNullException (nameof (obj));
            Type objType = obj.GetType ();
            var propertyInfo = GetPropertyInfo (objType, propertyName);
            if (propertyInfo == null)
                throw new ArgumentOutOfRangeException (propertyName,
                    $"Couldn't find property {propertyName} in type {objType.FullName}");
            propertyInfo.SetValue (obj, val, null);
        }

        private static PropertyInfo GetPropertyInfo (Type type, string propertyName) {
            PropertyInfo propertyInfo = null;
            do {
                propertyInfo = type.GetProperty (propertyName, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
                type = type.BaseType;
            } while (propertyInfo == null && type != null);

            return propertyInfo;
        }
    }
}