using System;

using System.Collections.Generic;

using System.Linq;

using System.Net.Http;

using System.Net.Http.Json;

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Threading.Tasks;

public class Program

{

    static readonly HttpClient httpClient = new HttpClient();

    static readonly string baseUrl = "https://jsonmock.hackerrank.com/api/articles?page=";

    public static async Task Main()

    {

        var limit = 41;

        var articles = await GetFilteredArticles(limit);

        string jsonString = JsonSerializer.Serialize(articles);

        Console.WriteLine("Filtered Articles");

        Console.WriteLine(articles.Count());

        Console.WriteLine(jsonString);

        return;

    }

    // this doesn't need to be static in test

    public static async Task<string[]> GetFilteredArticles(int limit)

    {

        var articles = await GetAllArticles();

        var filteredArticles = articles.Where(a => a.NumComments != null && a.ArticleName != null).Take(limit);

        var hasTiedComments =  filteredArticles.GroupBy(a => a.NumComments).Any(g => g.Count() > 1);

        if(hasTiedComments)

        {

            return filteredArticles.OrderByDescending(a => a.NumComments).ThenByDescending(a => a.ArticleName).Select(a => a.ArticleName).ToArray();

        }

        else 

        {

            return filteredArticles.OrderByDescending(a => a.NumComments).Select(a => a.ArticleName).ToArray();

        }

    }

    // this doesn't need to be static in test

    private static async Task<List<Article>> GetAllArticles()

    {

        int pageNumber = 1;

        int totalPages = 1;

        List<Article> articles = new List<Article>();

        while (pageNumber <= totalPages)

        {

            var page = await httpClient.GetFromJsonAsync<Page>(baseUrl + pageNumber) 

                ?? throw new Exception("Oops... Something went wrong");

            articles.AddRange(page.Data);

            totalPages = page.TotalPages;

            pageNumber++;

        }

        var articleNames = articles.Select(a => a.ArticleName).ToArray();

        string jsonString = JsonSerializer.Serialize(articles);

        Console.WriteLine("All Articles");

        Console.WriteLine(articles.Count());

        Console.WriteLine(JsonSerializer.Serialize(articleNames));

        //Console.WriteLine(jsonString);

        return articles;

    }

}

​

public class Page

{

    [JsonPropertyName("total_pages")]

    public int TotalPages { get; set; }

    public List<Article> Data { get; set; }

}

​

public class Article

{

    public string Title { get; set; }

    public string StoryTitle { get; set; }

    public string ArticleName     {

        get { return Title != null ? Title : StoryTitle; }

    }

    [JsonPropertyName("num_comments")]

    public int? NumComments { get; set; }

}