using System;
using System.Data;
using System.Linq;
using System.Data.DataSetExtensions;

public class Program
{
    public static void Main()
    {
        Console.WriteLine("Hello World");

        var user = GetUserById(1);

        Console.WriteLine(user.Name);

        var user1 = GetUserByUsername("user3");

        Console.WriteLine(user1.Name);

        var user2 = GetUserByEmail("user5@gmail.com");

        Console.WriteLine(user2.Name);

    }

    public static User GetUserById(int id)
    {
        var users = GetUsers().AsEnumerable().Where(row => row.Field<int>("Id") == id);

        var userInfo = users.Select(s => new User{
            Id = s.Field<int>("Id"),
            Username = s.Field<string>("Username"),
            Name = s.Field<string>("Name"),
            Email = s.Field<string>("Email"),
            CreatedDate = s.Field<DateTime>("CreatedDate"),
            Phone = s.Field<string>("Phone"),
            City = s.Field<string>("City"),
            State = s.Field<string>("State"),
            Country = s.Field<string>("Country")
        }).FirstOrDefault();

        return userInfo;

    }

    public static User GetUserByUsername(string username)
    {
        var users = GetUsers().AsEnumerable().Where(row => row.Field<string>("Username") == username);

        var userInfo = users.Select(s => new User{
            Id = s.Field<int>("Id"),
            Username = s.Field<string>("Username"),
            Name = s.Field<string>("Name"),
            Email = s.Field<string>("Email"),
            CreatedDate = s.Field<DateTime>("CreatedDate"),
            Phone = s.Field<string>("Phone"),
            City = s.Field<string>("City"),
            State = s.Field<string>("State"),
            Country = s.Field<string>("Country")
        }).FirstOrDefault();

        return userInfo;
    }

    public static User GetUserByEmail(string email)
    {
        var users = GetUsers().AsEnumerable().Where(row => row.Field<string>("Email") == email);

        var userInfo = users.Select(s => new User{
            Id = s.Field<int>("Id"),
            Username = s.Field<string>("Username"),
            Name = s.Field<string>("Name"),
            Email = s.Field<string>("Email"),
            CreatedDate = s.Field<DateTime>("CreatedDate"),
            Phone = s.Field<string>("Phone"),
            City = s.Field<string>("City"),
            State = s.Field<string>("State"),
            Country = s.Field<string>("Country")
        }).FirstOrDefault();

        return userInfo;
    }

    static DataTable GetUsers()
    {
        // Consider these are the data from the SQL table.
        DataTable table = new DataTable();
        table.Columns.Add("Id", typeof(int));
        table.Columns.Add("Username", typeof(string));
        table.Columns.Add("Name", typeof(string));
        table.Columns.Add("Email", typeof(string));
        table.Columns.Add("CreatedDate", typeof(DateTime));
        table.Columns.Add("Phone", typeof(string));
        table.Columns.Add("City", typeof(string));
        table.Columns.Add("State", typeof(string));
        table.Columns.Add("Country", typeof(string));

        // Here we add five DataRows.
        table.Rows.Add(1, "user1", "David", "user1@gmail.com",  DateTime.Now, "9999999999", "City 1", "State 1", "India");
        table.Rows.Add(2, "user2", "Sam", "user2@gmail.com", DateTime.Now, "8888888888", "City 2", "State 2", "USA");
        table.Rows.Add(3, "user3", "Christoff", "user3@gmail.com", DateTime.Now, "7777777777", "City 3", "State 3", "UK");
        table.Rows.Add(4, "user4", "Janet", "user4@gmail.com", DateTime.Now, "6666666666", "City 4", "State 4", "Germany");
        table.Rows.Add(5, "user5", "Melanie", "user5@gmail.com", DateTime.Now, "5555555555", "City 5", "State 5", "France");
        return table;
    }
}

public class User
{
    public int Id {get;set;}
    public string Username {get;set;}
    public string Name {get;set;}
    public string Email {get;set;}
    public DateTime CreatedDate {get;set;}
    public string Phone {get;set;}
    public string City {get;set;}
    public string State {get;set;}
    public string Country {get;set;}
}

new User{
            Id = s.Field<int>("Id"),
            Username = s.Field<string>("Username"),
            Name = s.Field<string>("Name"),
            Email = s.Field<string>("Email"),
            CreatedDate = s.Field<DateTime>("CreatedDate"),
            Phone = s.Field<string>("Phone"),
            City = s.Field<string>("City"),
            State = s.Field<string>("State"),
            Country = s.Field<string>("Country")
        }