using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // movie collection

        Movie[] movies = new Movie[] { new Movie("Xenogenesis", 1978, "James Cameron"),

                                    new Movie("E.T. The Extra-Terrestrial", 1982, "Steven Speilberg"),                                  

                                    new Movie("Twilight Zone: The Movie", 1983, "Steven Speilberg"),

                                    new Movie("The Terminator", 1984, "James Cameron"),

                                    new Movie("Empire of the Sun", 1987, "Steven Speilberg"),

                                    new Movie("Ghosts of the Abyss", 2003, "James Cameron"),

                                    new Movie("Shutter Island", 2010, "Martin Scorcese")};

        // Linq query syntax        

        var result = (from ag in 

                          (from m in movies // sub-query to do groupby on Producer

                            group m by m.Producer into grp 

                            where grp.Count() == (from q in movies // limit by the max of count by another subquery

                                group q by q.Producer into grp2 

                                orderby grp2.Count() descending 

                                select grp2.Count()).FirstOrDefault()

                            select new { // create a new result object including the count

                              Producer = grp.Key,

                              Count = grp.Count()                           

                          })                  

                      group ag by 1 into tot // fake group by so we can use aggregate functions

                      select new {

                          Producers = string.Join(", ", tot.Select(x => x.Producer)), // concatenate the top producers

                          Count = tot.Max(x => x.Count) // grab a count

                      }

                     ).FirstOrDefault();

        // Linq method syntax - same as query syntax but coded like c# methods with lambda

        var altResult = movies

            .GroupBy(x => x.Producer) // group by the producer

            .Where(x => x.Count() == // limit by the max of count by another subquery

                movies.GroupBy(y => y.Producer)

                .OrderByDescending(y => y.Count())

                .Select(y => y.Count())

                .FirstOrDefault())

            .Select(x => new { // create a new result object including the count

                Producer = x.Key, 

                Count = x.Count()})

            .GroupBy(x => 1) // fake group by so we can use aggregate functions

            .Select(tot => new {

                Producers = tot.Aggregate(string.Empty, (curr, next) => curr + ((curr.Equals(string.Empty)) ? "" : ", ") + next.Producer), // concatenate the top producers

                Count = tot.Max(y => y.Count) // grab a count

            }).FirstOrDefault();

        // output result

        if (result != null)

        {

            Console.WriteLine("The most common producer(s) are {0} with {1} movies"

                              , result.Producers // concatenate the string getting just the producer field and string joining them

                              , result.Count); // just output the first count in the list

        }

        if (altResult != null)

        {

            Console.WriteLine("The most common producer(s) are {0} with {1} movies"

                              , altResult.Producers

                              , altResult.Count); // just output the first count in the list

        }

    }

    private class Movie {

        public string Name { get; set; }

        public int Year {get; set; }

        public string Producer {get; set; }

        public Movie (string name, int year, string producer) {

            Name = name;

            Year = year;

            Producer = producer;

        }

    }

}