using System;

using Newtonsoft.Json;

using System.Collections.Generic;

using Dapper;

using System.ComponentModel.DataAnnotations.Schema;

public class Program

{

    public static void Main()

    {

        var phone1 = new Phone

        {

            PhoneArea = "null",

            PhoneNumber = "2370000"

        };

        Console.WriteLine($"Phone1: {phone1.FormattedNumber}");

        var phone2 = new Phone

        {

            PhoneArea = "434",

            PhoneNumber = "2370000"

        };

        Console.WriteLine($"Phone2: {phone2.FormattedNumber}");

        // now in json

        var phones = new List<Phone>

        {

            phone1, 

            phone2

        };

        string json = JsonConvert.SerializeObject(phones);

        Console.WriteLine(json);

    }

    public class Phone

    {

        // this automatically creates code for get and set

        [JsonIgnore]

        [Column("sprtele_phone_area")]

        public string PhoneArea { get; set; }

        [JsonIgnore]

        [Column("sprtele_phone_number")]

        public string PhoneNumber { get; set; }

        // we're making our own code just for a getter

        public string FormattedNumber 

        {

            get

            {

                if (string.IsNullOrEmpty(PhoneArea) || PhoneArea == "null")

                {

                    return FormatNumber(PhoneNumber);

                }

                return $"({PhoneArea}) {FormatNumber(PhoneNumber)}";

            }

        }

        private static string FormatNumber(string number)

        {

          if (string.IsNullOrEmpty(number))

            return "";

          if (number.Length < 7)

            return number;

          return number.Substring(0, 3) + "-" + number.Substring(3);

        }

    }

}