using System;
using System.Reflection;
using FluentNHibernate.Conventions;
using FluentNHibernate.Conventions.Inspections;
using FluentNHibernate.Conventions.Instances;

namespace Tanshu.Accounts.Conventions
{
    public class PropertyAccessConvention : IPropertyConvention
    {
        public void Apply(IPropertyInstance instance)
        {
            var entityType = instance.EntityType;
            var camelCaseUnderscoreName = ConvertToCamelCaseUnderscore(instance.Name);

            // Default is to use property setter, so only modify mapping
            // if there is a backing field

            if (HasField(entityType, camelCaseUnderscoreName))
                instance.Access.CamelCaseField(CamelCasePrefix.Underscore);
        }

        private static string ConvertToCamelCaseUnderscore(string propertyName)
        {
            return "_" + propertyName[0].ToString().ToLower() + propertyName.Substring(1);
        }

        private static bool HasField(Type type, string fieldName)
        {
            var backingField = type.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Instance);
            return backingField != null;
        }
    }
}