using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace dotnet_jttt_2015_jg_wg
{
    public class Finder
    {
        private string url;

        public Finder(string adress)
        {
            url = adress;
        }

        private string GetHtml()
        {
            WebClient wc = new WebClient();
            byte[] data = wc.DownloadData(url);
            return System.Net.WebUtility.HtmlDecode(Encoding.UTF8.GetString(data));
        }

        public string findText(string textToFind)
        {
            HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
            doc.LoadHtml(GetHtml());
            var nodes = doc.DocumentNode.Descendants("img");
            string imageURL = "";
            foreach (var node in nodes)
            {
                string atribute = node.GetAttributeValue("alt", "");
                if (atribute.Contains(textToFind))
                {
                    imageURL = node.GetAttributeValue("src", "");
                }
            }
            if (!imageURL.Contains("http://"))
            {
                System.ApplicationException ex = new System.ApplicationException("Nie znaleziono obrazka zawierajacego slowo \"" + textToFind + "\"");
                throw ex;
            }
            return imageURL;
        }
    }
}