using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;
using System.Text;

namespace VLB
{
    public static class ReflectionUtils
    {
        public static string GetFieldPath<T, TValue>(Expression<Func<T, TValue>> expr)
        {
            MemberExpression me;
            switch (expr.Body.NodeType)
            {
                case ExpressionType.Convert:
                case ExpressionType.ConvertChecked:
                    var ue = expr.Body as UnaryExpression;
                    me = (ue != null ? ue.Operand : null) as MemberExpression;
                    break;
                default:
                    me = expr.Body as MemberExpression;
                    break;
            }

            var members = new List<string>();
            while (me != null)
            {
                members.Add(me.Member.Name);
                me = me.Expression as MemberExpression;
            }

            var sb = new StringBuilder();
            for (int i = members.Count - 1; i >= 0; i--)
            {
                sb.Append(members[i]);
                if (i > 0) sb.Append('.');
            }

            return sb.ToString();
        }
    }
}