// Copyright (C) Stichting Deltares 2018. All rights reserved.
//
// This file is part of the Dam Engine.
//
// The Dam Engine is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// All names, logos, and references to "Deltares" are registered trademarks of
// Stichting Deltares and remain full property of Stichting Deltares at all times.
// All rights reserved.

using System;
using System.Linq.Expressions;
using System.Text;

namespace Deltares.DamEngine.Data.Standard
{
    /// <summary>
    /// static class StaticReflection
    /// </summary>
    public static class StaticReflection
    {
        /// <summary>
        /// Gets the name of the member.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="instance">The instance.</param>
        /// <param name="expression">The expression.</param>
        /// <returns></returns>
        public static string GetMemberName<T>(this T instance, Expression<Func<T, object>> expression)
        {
            return GetMemberName(expression);
        }

        public static string GetMemberName<T>(Expression<Func<T, object>> expression)
        {
            return GetMemberName<T, object>(expression);
        }

        private static string GetMemberName<T, TV>(Expression<Func<T, TV>> expression)
        {
            if (expression == null)
            {
                throw new ArgumentException("The expression cannot be null.");
            }

            return GetMemberName(expression.Body);
        }

        private static string GetMemberName(Expression expression)
        {
            if (expression == null)
            {
                throw new ArgumentException("The expression cannot be null.");
            }

            var memberExpression = expression as MemberExpression;
            if (memberExpression != null)
            {
                return GetMemberName(memberExpression);
            }

            var methodCallExpression = expression as MethodCallExpression;
            if (methodCallExpression != null)
            {
                // Reference type method
                return GetMemberName(methodCallExpression);
            }

            var unaryExpression = expression as UnaryExpression;
            if (unaryExpression != null)
            {
                // Property, field of method returning value type
                return GetMemberName(unaryExpression);
            }

            throw new ArgumentException("Invalid expression, type is \"" + expression.Type + "\"");
        }

        private static string GetFullMemberName(string startingMember, string separator, Expression expression)
        {
            var fullMemberNameBuilder = new StringBuilder(startingMember);
            var memberExpression = expression as MemberExpression;

            while (null != memberExpression)
            {
                if (fullMemberNameBuilder.Length > 0)
                {
                    fullMemberNameBuilder.Insert(0, separator);
                }
                fullMemberNameBuilder.Insert(0, memberExpression.Member.Name);
                memberExpression = memberExpression.Expression as MemberExpression;
            }

            return fullMemberNameBuilder.ToString();
        }

        private static string GetMemberName(MemberExpression memberExpression)
        {
            return GetFullMemberName(memberExpression.Member.Name, ".", memberExpression.Expression);
        }

        private static string GetMemberName(MethodCallExpression methodCallExpression)
        {
            return GetFullMemberName(methodCallExpression.Method.Name, ".", methodCallExpression.Object);
        }

        private static string GetMemberName(UnaryExpression unaryExpression)
        {
            var methodExpression = unaryExpression.Operand as MethodCallExpression;
            if (methodExpression != null)
            {
                return methodExpression.Method.Name;
            }

            return GetFullMemberName("", ".", unaryExpression.Operand);
        }        
    }
}