COA.EnterpriseServices/COA.EnterpriseServices.DataAccess.QuickBase/FieldMapRegistry.cs

using COA.EnterpriseServices.DataAccess.Entities;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;

namespace COA.EnterpriseServices.DataAccess.QuickBase
{
    internal static class FieldMapRegistry
    {
        private static readonly ICollection<FieldMap> registry = new List<FieldMap>();

        static FieldMapRegistry()
        {
            AddFieldMap<Creditor>(c => c.Id, 1);
            AddFieldMap<Creditor>(c => c.Created, 2);
            AddFieldMap<Creditor>(c => c.Modified, 3);
            AddFieldMap<Creditor>(c => c.Status, 10);
            AddFieldMap<Creditor>(c => c.ClientFirstName, 20);
            AddFieldMap<Creditor>(c => c.ClientLastName, 21);
        }

        internal static void AddFieldMap<TEntity>(Expression<Func<TEntity, object>> property, int fieldId)
        {
            if (property.Body is MemberExpression memberExpression)
            {
                registry.Add(new FieldMap
                {
                    DeclaringTypeName = memberExpression.Member.DeclaringType.FullName,
                    PropertyName = memberExpression.Member.Name,
                    FieldId = fieldId
                });
            }
            else if (property.Body is UnaryExpression unaryExpression && unaryExpression.Operand is MemberExpression unaryMemberExpression)
            {
                registry.Add(new FieldMap
                {
                    DeclaringTypeName = unaryMemberExpression.Member.DeclaringType.FullName,
                    PropertyName = unaryMemberExpression.Member.Name,
                    FieldId = fieldId
                });
            }
        }

        internal static int? GetFieldId(PropertyInfo info)
        {
            var map = registry.FirstOrDefault(m => m.DeclaringTypeName == info.DeclaringType.FullName && m.PropertyName == info.Name);

            return map != null ? map.FieldId : default;
        }
    }
}