HV Test 2

namespace HVTest
{
    using System;
    using System.Collections.Generic;
    using System.Linq;

    class Program
    {
        static void Main(string[] args)
        {
            var manipulator = new WeatherManipulator();
            manipulator.Run();
        }
    }

    class WeatherManipulator
    {
        private IEnumerable<Weather> collection;

        public void Run()
        {
            collection = this.GenerateData();
            collection = collection.DateIs(DateTime.Now).CityIs("Tartu").ToList();
            foreach(var item in collection)
                Console.WriteLine(item.ToString());

            Console.ReadKey();
        }

        private List<Weather> GenerateData()
        {
            Random random = new Random();
            DateTime start = new DateTime(2012, 1, 1);
            DateTime end = new DateTime(2012, 4, 1).AddDays(-1);
            IEnumerable<City> cities = Enum.GetValues(typeof(City)).Cast<City>();

            List<Weather> result = new List<Weather>();

            foreach(var city in cities)
            {
                for (DateTime date = start; date <= end; date = date.AddDays(1)) result.Add(new Weather() { City = city, Date = date, Temperature = random.Next(-16, 3) });
            }
            return result;
        }
    }

    static class WeatherExtensions
    {
        public static IEnumerable<Weather> DateIs(this IEnumerable<Weather> collection, DateTime date)
        {
            foreach(var item in collection)
            {
                if (item.Date.Date == date.Date) yield return item;
            }
        }

        public static IEnumerable<Weather> DateIsLINQ(this IEnumerable<Weather> collection, DateTime date)
        {
            return collection.Where(item => item.Date.Date == date.Date);
        }

        public static IEnumerable<Weather> CityIs(this IEnumerable<Weather> collection, string city)
        {
            foreach(var item in collection)
            {
                if (item.City == (City)Enum.Parse(typeof(City), city, true)) yield return item;
            }
        }

        public static IEnumerable<Weather> CityIsLINQ(this IEnumerable<Weather> collection, string city)
        {
            return collection.Where(item => item.City == (City)Enum.Parse(typeof(City), city, true));
        }
    }


    class Weather
    {
        public DateTime Date { get; set; }
        public City City { get; set; }
        public int Temperature { get; set; }

        public override string ToString()
        {
            return String.Format("City: {0}, Date: {1}, Temperature: {2}", City, Date, Temperature);
        }
    }

    public enum City { Jõhvi, Narva, Tartu, Tallinn }

}