using System;

using System.Collections.Generic;

using System.Linq;

using System.Globalization;

public class Program

{

    public record Animal(bool isMammal, string name) {}

    public enum Location { Europe, Africa, America, Asia, NorthPole }

    public record AnimalObservation(DateTime time, Location location, Animal animal) {}

    public static void Main()

    {

        var observations = new List<AnimalObservation> {

            new AnimalObservation(DateTime.Parse("2008-11-01T19:35:00.0000000Z"), Location.Europe, new Animal(true, "beaver")),

            new AnimalObservation(DateTime.Parse("2008-11-01T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

            new AnimalObservation(DateTime.Parse("2008-11-01T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

            new AnimalObservation(DateTime.Parse("2008-11-01T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

            new AnimalObservation(DateTime.Parse("2008-11-02T19:35:00.0000000Z"), Location.Europe, new Animal(true, "beaver")),

            new AnimalObservation(DateTime.Parse("2008-11-02T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

            new AnimalObservation(DateTime.Parse("2008-11-02T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

            new AnimalObservation(DateTime.Parse("2008-11-03T19:35:00.0000000Z"), Location.Europe, new Animal(true, "beaver")),

            new AnimalObservation(DateTime.Parse("2008-11-03T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

            new AnimalObservation(DateTime.Parse("2008-11-04T19:35:00.0000000Z"), Location.Europe, new Animal(true, "beaver")),

            new AnimalObservation(DateTime.Parse("2008-11-04T19:35:00.0000000Z"), Location.Europe, new Animal(false, "bird")),

        };

        mammalPercentages(observations);

    }

    public static void mammalPercentages(IEnumerable<AnimalObservation> observations) {

        var percentageInfos = observations

            .GroupBy(x => new { 

                x.location, 

                time = NormalizeTime(x.time)

            })

            .Select(g => new {

                g.Key.location,

                g.Key.time,

                mammalPercentage = (double)g.Count(x => x.animal.isMammal) / g.Count()

            });

        foreach (var percentageInfo in percentageInfos) {

            Console.WriteLine($"In {percentageInfo.location} at {percentageInfo.time.ToString("d", CultureInfo.InvariantCulture)} there was {percentageInfo.mammalPercentage.ToString("p", CultureInfo.InvariantCulture)} of mammals");         

        }

        DateTime NormalizeTime(DateTime time) {

            return time.Date;

        }

    }   

}