using HtmlAgilityPack;
using System;
using System.ComponentModel;
using System.Drawing;
using System.IO;
using System.Net;
using System.Windows.Forms;
using HtmlDocument = HtmlAgilityPack.HtmlDocument;

namespace bzit.bomg
{
    public class BookmarkItem
    {
        public delegate void RetrieveCompleted(BookmarkItem sender, bool hasError, string message);

		public RetrieveCompleted OnRetrieveCompleted { get; set; } = null;

		public TreeNode TreeViewNode { get; protected set; }

		public byte[] IconData { get; set; } = null;

		public string SiteName { get; set; } = null;
		public string SiteAddress { get; set; }		
		public string Description { get; set; }
		public string IconAddress { get; protected set; }
		public string Fullpath { get; set; }
		public string Created { get; set; }	

		protected const char pathSeparator = '|';

        //protected TreeNode treeNode = null;
        protected BackgroundWorker mainThread = null;
        
        protected bool hasRetrieveError = false;
        protected string retrieveErrorMessage = null;

        public BookmarkItem()
        {
            this.Clear();
        }

        public new string ToString()
        {
            string rv = "";
            rv += "Name=" + this.Fullpath + Environment.NewLine;
            rv += "Address=" + this.SiteAddress + Environment.NewLine;
            rv += "Description=" + this.Description + Environment.NewLine;
            rv += "Created=" + this.Created?.Trim();
            
            return rv;
        }

        #region public properties

        
        //{
        //    get
        //    {
        //        return this.treeNode;
        //    }

        //    set
        //    {
        //        this.treeNode = value;
        //    }
        //}
                
        public Bitmap Icon
        {
            get
            {
                if (this.IconData == null)
                {
                    return null;
                }

                try
                {
                    Image img = Image.FromStream(new MemoryStream(this.IconData));
                    return new Bitmap(img, 16, 16);
                }
                catch
                {
                    return null;
                }
            }
        }


        
        #endregion

        #region public methods

        public void Clear()
        {
            this.Fullpath = string.Empty;
            this.SiteAddress = string.Empty;
            this.Description = string.Empty;
            this.Created = string.Empty;

            if (this.mainThread == null)
            {
                this.mainThread = new BackgroundWorker();
                this.mainThread.WorkerReportsProgress = this.mainThread.WorkerSupportsCancellation = true;
                this.mainThread.DoWork += retrieveWorker_DoWork;
                this.mainThread.RunWorkerCompleted += retrieveWorker_RunWorkerCompleted;
            }
        }
        
        public string GetName()
        {
            if (this.Fullpath.Contains(pathSeparator.ToString()))
            {
                return decodePath(this.Fullpath.Substring(this.Fullpath.LastIndexOf(pathSeparator) + 1)).Trim();
            }

            return decodePath(this.Fullpath).Trim();
        }

        public void ChangeName(string newName)
        {
            string prefix = (this.Fullpath.Contains(pathSeparator.ToString()) ? this.Fullpath.Substring(0, this.Fullpath.IndexOf(pathSeparator)).Trim() : string.Empty);

            this.Fullpath = string.Concat(prefix, pathSeparator, encodePath(newName.Trim()));
        }

        public void GetFaviconAddress()
        {
            hasRetrieveError = false;
            retrieveErrorMessage = string.Empty;

            this.IconData = null;

            WebClient webClient = new WebClient();
            webClient.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.NoCacheNoStore);

            string sourceCode = string.Empty;

            try
            {
                sourceCode = webClient.DownloadString(this.SiteAddress);
            }
            catch (Exception exc)
            {
                hasRetrieveError = true;
                retrieveErrorMessage = exc.Message;
                return;
            }

            HtmlAgilityPack.HtmlDocument document = new HtmlAgilityPack.HtmlDocument();
            document.LoadHtml(sourceCode);

			// favicon
			this.IconAddress = parseSiteIcon(document);
			if (!string.IsNullOrWhiteSpace(this.IconAddress))
			{
				Uri iconAddressURI;
				bool rv = Uri.TryCreate(new Uri(this.SiteAddress), this.IconAddress, out iconAddressURI);
				if (rv)
				{
					this.IconAddress = iconAddressURI.ToString();
				}
			}

			// load favicon image
			if (!string.IsNullOrEmpty(this.IconAddress))
			{
				try
				{
					this.IconData = webClient.DownloadData(this.IconAddress);

					if (!RyzStudio.IO.FileType.IsImage(this.IconData))
					{
						this.IconData = null;
					}
				}
				catch
				{
					this.IconData = null;
					this.IconAddress = null;
				}
			}

			//// parse icon
			//HtmlAgilityPack.HtmlNodeCollection hnc = document.DocumentNode.SelectNodes("//link");
   //         if (hnc != null)
   //         {
   //             foreach (HtmlAgilityPack.HtmlNode node in hnc)
   //             {
   //                 if (node.Attributes["rel"] == null)
   //                 {
   //                     continue;
   //                 }

   //                 string nodeAttr = node.Attributes["rel"].Value.Trim();
   //                 if (nodeAttr.ToLower().Contains("icon"))
   //                 {
   //                     if (!string.IsNullOrEmpty(this.IconAddress))
   //                     {
   //                         continue;
   //                     }

   //                     if (node.Attributes["href"] != null)
   //                     {
   //                         Uri iconPath;
   //                         bool rv = Uri.TryCreate(new Uri(this.SiteAddress), WebUtility.HtmlDecode(node.Attributes["href"].Value).Trim(), out iconPath);
   //                         if (rv)
   //                         {
   //                             this.IconAddress = iconPath.ToString();
   //                         }

   //                         break;
   //                     }
   //                 }
   //             }
   //         }

   //         // default favicon
   //         if (string.IsNullOrEmpty(this.IconAddress))
   //         {
   //             Uri iconPath;
   //             if (Uri.TryCreate(new Uri(this.SiteAddress), "/favicon.ico", out iconPath))
   //             {
   //                 this.IconAddress = iconPath.ToString();
   //             }
   //         }

   //         // load icon image            
   //         if (!string.IsNullOrEmpty(this.IconAddress))
   //         {
   //             try
   //             {
   //                 this.IconData = webClient.DownloadData(this.IconAddress);

   //                 if (!RyzStudio.IO.FileType.IsImage(this.IconData))
   //                 {
   //                     this.IconData = null;
   //                 }
   //             }
   //             catch
   //             {
   //                 // do nothing
   //             }
   //         }
        }

        public void RetrieveAsync()
        {            
            if (this.mainThread.IsBusy)
            {
                return;
            }

            this.mainThread.RunWorkerAsync();
        }

        public void RetrieveAsync(string address)
        {
            if (this.mainThread.IsBusy)
            {
                return;
            }

            this.SiteAddress = address;
            this.mainThread.RunWorkerAsync();
        }

        #endregion


        protected void retrieveWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            hasRetrieveError = false;
            retrieveErrorMessage = string.Empty;

            this.IconData = null;
            this.Fullpath = string.Empty;
            this.Description = string.Empty;
            this.IconAddress = string.Empty;

            WebClient webClient = new WebClient();            
            webClient.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.NoCacheNoStore);

			string sourceCode = string.Empty;

            try
            {
                sourceCode = webClient.DownloadString(this.SiteAddress);
            }
            catch (Exception exc)
            {
                hasRetrieveError = true;
                retrieveErrorMessage = exc.Message;
                return;
            }

            HtmlDocument document = new HtmlDocument();
            document.LoadHtml(sourceCode);

			// title
			this.SiteName = parseSiteTitle(document);

			// description
			this.Description = parseSiteDescription(document);

			// favicon
			this.IconAddress = parseSiteIcon(document);
			if (!string.IsNullOrWhiteSpace(this.IconAddress))
			{
				Uri iconAddressURI;
				bool rv = Uri.TryCreate(new Uri(this.SiteAddress), this.IconAddress, out iconAddressURI);
				if (rv)
				{
					this.IconAddress = iconAddressURI.ToString();
				}
			}

            // load favicon image
            if (!string.IsNullOrWhiteSpace(this.IconAddress))
            {
                try
                {
                    this.IconData = webClient.DownloadData(this.IconAddress);

                    if (!RyzStudio.IO.FileType.IsImage(this.IconData))
                    {
                        this.IconData = null;
                    }
                }
                catch
                {
					this.IconData = null;
					this.IconAddress = null;
				}
            }
        }

        protected void retrieveWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            this.OnRetrieveCompleted?.Invoke(this, hasRetrieveError, retrieveErrorMessage);
        }

        protected string encodePath(string text) => System.Web.HttpUtility.UrlEncode(text);

        protected string decodePath(string text) => System.Web.HttpUtility.UrlDecode(text);

		protected string parseTagValue(HtmlDocument doc, string xpath, string defaultValue = "")
		{
			HtmlNodeCollection hnc = doc.DocumentNode.SelectNodes(xpath);
			if (hnc == null)
			{
				return defaultValue;
			}

			if (hnc.Count <= 0)
			{
				return defaultValue;
			}

			foreach (HtmlNode hn in hnc)
			{
				if (string.IsNullOrWhiteSpace(hn.InnerHtml))
				{
					continue;
				}

				string rs = WebUtility.HtmlDecode(hn.InnerHtml)?.Replace("\r", "")?.Replace("\n", " ")?.Trim();
				if (string.IsNullOrWhiteSpace(rs))
				{
					continue;
				}

				return rs;
			}

			return defaultValue;
		}

		protected string parseTagValue_Attr(HtmlDocument doc, string xpath, string attr, string defaultValue = "")
		{
			HtmlNodeCollection hnc = doc.DocumentNode.SelectNodes(xpath);
			if (hnc == null)
			{
				return defaultValue;
			}

			if (hnc.Count <= 0)
			{
				return defaultValue;
			}

			foreach (HtmlNode hn in hnc)
			{
				if (hn.Attributes[attr] == null)
				{
					continue;
				}

				if (string.IsNullOrWhiteSpace(hn.Attributes[attr].Value))
				{
					continue;
				}

				return System.Web.HttpUtility.HtmlDecode(hn.Attributes[attr].Value?.Trim());
			}
			
			return defaultValue;
		}

		protected string parseSiteTitle(HtmlDocument doc)
		{
			string rs = null;

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue(doc, "//title", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@property='og:title']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@name='twitter:title']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@property='og:site_name']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@itemprop='name']", "content", string.Empty);
			}

			return rs;
		}

		protected string parseSiteDescription(HtmlDocument doc)
		{
			string rs = null;

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@name='description']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@property='og:description']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@name='twitter:description']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@property='og:description']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@itemprop='description']", "content", string.Empty);
			}

			return rs;
		}

		protected string parseSiteIcon(HtmlDocument doc)
		{
			string rs = null;

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//link[@rel='shortcut icon']", "href", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//link[@rel='icon']", "href", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//link[@rel='apple-touch-icon']", "href", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//link[@rel='apple-touch-icon-precomposed']", "href", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@property='og:image']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@name='twitter:image']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@property='og:image']", "content", string.Empty);
			}

			if (string.IsNullOrWhiteSpace(rs))
			{
				rs = parseTagValue_Attr(doc, "//meta[@itemprop='image']", "content", string.Empty);
			}

			return rs;
		}


	}
}