using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

using System.Threading;

​

namespace ContactBook

{

    internal class Program

    {

       // static  Contact[] contacts = new Contact[100];

       // private static int _contactCounter = 0;

​

       static List<Contact> contacts = new List<Contacts>();

​

       public static void Main(string[] args)

        {

            while (true)

            {

                Console.WriteLine("1.Register new Person data .");

                Console.WriteLine("2.Show person table by alphabet .");

​

                var key = Console.ReadKey();

​

                switch (key.Key)

                {

                    case ConsoleKey.D1:

                        contacts.Add(MakeContact());

                        Console.Clear();

                        break;

                    case ConsoleKey.D2:

                        SearchContact();

                        break;

                }

                Thread.Sleep(500);

                Console.Clear();

            }

        }

​

        private static Contact MakeContact()

        {

            Console.Clear();

            var contact = new Contact();

​

            //firstName

            Console.WriteLine("please enter contact firstName :");

            var firstName = Console.ReadLine();

            while (string.IsNullOrWhiteSpace(firstName))

            {

                Console.WriteLine("firstName must not be empty!");

                firstName = Console.ReadLine();

            }

            contact.FirstName = firstName;

            //lastName

            Console.WriteLine("please enter contact lastName :");

            var lastName = Console.ReadLine();

            while (string.IsNullOrWhiteSpace(lastName))

            {

                Console.WriteLine("lastName must not be empty!");

                lastName = Console.ReadLine();

            }

            contact.LastName = lastName;

            //address

            Console.WriteLine("please enter contact address :");

            var address = Console.ReadLine();

            while (string.IsNullOrWhiteSpace(address))

            {

                Console.WriteLine("address must not be empty!");

                address = Console.ReadLine();

            }

            contact.Address = address;

            //phoneNumber

            Console.WriteLine("please enter contact phoneNumber :");

            var phoneNumber = Console.ReadLine();

            while (string.IsNullOrWhiteSpace(phoneNumber))

            {

                Console.WriteLine("phoneNumber must not be empty!");

                phoneNumber = Console.ReadLine();

            }

​

            var rgx = new Regex(@"^[+]*[(]{0,1}[0-9]{1,4}[)]{0,1}[-\s\./0-9]*$");

            if (rgx.IsMatch(phoneNumber))

            {

                contact.PhoneNumber = phoneNumber; 

            }

            else

            {

                throw new Exception("Invalid PhoneNumber input");

            }

            contact.CreatedTime =DateTime.Now;

            return contact;

        }

​

        private static void SearchContact()

        {

​

            Console.Clear();

            Console.WriteLine("please enter one character to search or type (all) to show all contact :");

​

            var input = Console.ReadLine();

​

            if (input != null)

            {

                if (input.Equals("all".ToLower()))

                {

                    ShowAllContacts();

                }

                else

                {

                    if (input.Length == 1)

                    {

                        ShowSearchedContact(input);

                    }

                }

            }

            //close section

            Console.WriteLine("please press  \"Enter\" to go to main menu ");

            if (Console.ReadKey().Key == ConsoleKey.Enter)

            {

                Console.Clear();

            }

        }

​

        private static void ShowAllContacts()

        {

            Console.Clear();

            if (contacts.Count == 0)

            {

                Console.WriteLine("there is no contact !");

            }

            foreach (var contact in contacts)

            {

                PrintContact(contact);

            }

        }

​

        private static void ShowSearchedContact(string input)

        {

            var isThereContact = false; 

            var rgx = new Regex($"^{input.ToLower()}|{input.ToUpper()}");

            foreach (var contact in contacts)

            {

                if (rgx.IsMatch(contact.LastName))

                {

                    isThereContact = true;

                    PrintContact(contact);

                }

            }

​

            if (!isThereContact)

            {

                Console.WriteLine("there is no contact !");

            }

        }

​

        private static void PrintContact(Contact contact)

        {

            Console.WriteLine($"Name:{contact.FirstName}\t Family:{contact.LastName}\t Tel:{contact.PhoneNumber}\t Address:{contact.Address}\t RegisterYear:{contact.CreatedTime.Date}");

​

        }

    }

}

​