// See https://aka.ms/new-console-template for more information
using System;
using System.Net.Http;
using System.Threading.Tasks;
using HtmlAgilityPack;
using System.Linq;


var CHALLENGE_URL = "https://tns4lpgmziiypnxxzel5ss5nyu0nftol.lambda-url.us-east-1.on.aws/challenge";
var PAGE_CACHE = "challenge.html";

try
{
    string html;

    if (File.Exists(PAGE_CACHE))
    {
        Console.WriteLine("Loading HTML from cache...");
        html = await File.ReadAllTextAsync(PAGE_CACHE);
    }
    else
    {
        Console.WriteLine("Downloading HTML...");
        try
        {
            using HttpClient client = new HttpClient();
            html = await client.GetStringAsync(CHALLENGE_URL);

            // Write to cache
            await File.WriteAllTextAsync(PAGE_CACHE, html);
            Console.WriteLine("HTML cached to file.");
        }
        catch (HttpRequestException e)
        {
            Console.WriteLine($"HTTP error: {e.Message}");
            return;
        }
    }

    var doc = new HtmlDocument();
    doc.LoadHtml(html);

    // Find all <section> with data-id starting with "92"
    var sections = doc.DocumentNode.SelectNodes("//section[starts-with(@data-id, '92')]");
    if (sections == null) return;

    foreach (var section in sections)
    {
        // Find <article> children with data-class ending in "45"
        var articles = section.SelectNodes(".//article[substring(@data-class, string-length(@data-class) - 1) = '45']");
        if (articles == null) continue;

        foreach (var article in articles)
        {
            // Find <div> children with data-tag containing "78"
            var divs = article.SelectNodes(".//div[contains(@data-tag, '78')]");
            if (divs == null) continue;

            foreach (var div in divs)
            {
                // Find all <b> tags nested inside this div
                var bTags = div.SelectNodes(".//b[contains(concat(' ', normalize-space(@class), ' '), ' ref ')]");
                if (bTags == null) continue;

                foreach (var b in bTags)
                {
                    Console.Write(b.GetAttributeValue("value", null));
                }
            }
        }
    }
    // end with newline
    Console.WriteLine();
}
catch
{
    Console.WriteLine("Unable to get HTML from page!");
}