Generate Random Phone Numbers in C#

using System;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

public class PhoneNumberGenerator
{
    private static readonly Random random = new Random();

    // Generate random US phone number (xxx) xxx-xxxx
    public static string RandomUsPhoneNumber()
    {
        int areaCode = random.Next(200, 1000);
        int exchange = random.Next(200, 1000);
        int lineNumber = random.Next(1000, 10000);
        return $"({areaCode:D3}) {exchange:D3}-{lineNumber:D4}";
    }

    // Generate random phone number with country code
    public static string RandomInternationalPhone(string countryCode = "+1")
    {
        int areaCode = random.Next(200, 1000);
        int exchange = random.Next(200, 1000);
        int lineNumber = random.Next(1000, 10000);
        return $"{countryCode} ({areaCode:D3}) {exchange:D3}-{lineNumber:D4}";
    }

    // Generate phone number without formatting
    public static string RandomPhoneDigits(int length = 10)
    {
        var sb = new StringBuilder();
        for (int i = 0; i < length; i++)
        {
            sb.Append(random.Next(10));
        }
        return sb.ToString();
    }

    // Validate US phone number format
    public static bool IsValidUsPhone(string phone)
    {
        return Regex.IsMatch(phone, @"^\(\d{3}\) \d{3}-\d{4}$");
    }

    // Generate multiple phone numbers
    public static string[] GeneratePhoneNumbers(int count = 10)
    {
        return Enumerable.Range(0, count)
            .Select(_ => RandomUsPhoneNumber())
            .ToArray();
    }

    // Using Bogus library (Install-Package Bogus)
    // using Bogus;
    // var faker = new Faker();
    // string phone = faker.Phone.PhoneNumber("(###) ###-####"); // (555) 123-4567
    // string phoneE164 = faker.Phone.PhoneNumber("+1##########"); // +15551234567

    public static void Main()
    {
        Console.WriteLine($"US Phone: {RandomUsPhoneNumber()}");
        Console.WriteLine($"International: {RandomInternationalPhone(\"+44\")}");
        Console.WriteLine($"Digits only: {RandomPhoneDigits(10)}");
        Console.WriteLine($"Valid: {IsValidUsPhone(\"(555) 123-4567\")}");
        Console.WriteLine($"Batch: {string.Join(\", \", GeneratePhoneNumbers(3))}");
    }
}