/* This ASP.NET sample demonstrates the use of the DNS control in the ASP.NET environment.
 * The text entered is checked as to whether it is a url, an email address, or a dot address
 * and resolved appropriately.
 */
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Dns
{
	/// <summary>
	/// Summary description for WebForm1.
	/// </summary>
	public class WebForm1 : System.Web.UI.Page
	{
		protected System.Web.UI.WebControls.Label lblResolve;
		protected System.Web.UI.WebControls.TextBox txtResolve;
		protected System.Web.UI.WebControls.Button cmdResolve;
		protected System.Web.UI.WebControls.Label lblDnsServers;
		protected System.Web.UI.WebControls.TextBox txtDns1;
		protected System.Web.UI.WebControls.TextBox txtDns2;
		protected System.Web.UI.WebControls.TextBox txtDns3;
		protected System.Web.UI.WebControls.Label lblResults;
		protected System.Web.UI.WebControls.TextBox txtResults;

		// dns control
		protected DartUtilDotnet.Dns Dns1 = new DartUtilDotnet.Dns();

		// array to hold list of dns servers
		protected System.Collections.ArrayList ArrListDnsServers = new System.Collections.ArrayList();

		public WebForm1()
		{
			Page.Init += new System.EventHandler(Page_Init);
		}

		private void Page_Load(object sender, System.EventArgs e)
		{
			// init dns server array
			if(txtDns1.Text != "")
				ArrListDnsServers.Add(txtDns1.Text);
			if(txtDns2.Text != "")
				ArrListDnsServers.Add(txtDns2.Text);
			if(txtDns3.Text != "")
				ArrListDnsServers.Add(txtDns3.Text);
		}

		private void Page_Init(object sender, EventArgs e)
		{
			//
			// CODEGEN: This call is required by the ASP.NET Web Form Designer.
			//
			InitializeComponent();
		}

		#region Web Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{    
			this.cmdResolve.Click += new System.EventHandler(this.cmdResolve_Click);
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion

		private void cmdResolve_Click(object sender, System.EventArgs e)
		{
			string url = "";
			url = txtResolve.Text;

			// check for null servers
			if(ArrListDnsServers.Count == 0)
				txtResults.Text = "Unable to resolve. No DNS Server specified.";
			// check for null url
			else if(url == "")
				txtResults.Text = "Unable to resolve. No address was specified.";
			else
			{
				// all fields appear to have data... let's process
				Dns1.Timeout = 5000;
				Dns1.Names.Delimiter = ", ";
				Dns1.Addresses.Delimiter = ", ";
				
				// this array is used in a clumsy attempt to determine
				// if a url is in dot notation
				char[] temp = new Char[15];

				// read url into chararray
				temp = url.ToCharArray(0, url.Length);
				
				// check to see if first and last char is numeric, if so resolve as dot notation
				if((temp[0] >= 48 && temp[0] <= 57) && (temp[temp.Length-1] >= 48 && temp[temp.Length-1] <= 57))
					ResolveDotAddress(url);
				// check to see if it contains an @ symbol, if so resolve as email
				else if(url.IndexOf("@", 0, url.Length)!= -1)
					ResolveEmailAddress(url);
				// otherwise resolve as url
				else
					ResolveNameAddress(url);

			}

		}

		private void ResolveEmailAddress(string url)
		{

			bool done = false;
			int i=0;

			// iterate through server list and attempt to resolve, if successful- quit, if not go on to next, if at end, display error
			while(!done && i < ArrListDnsServers.Count)
			{
				Dns1.ServerName = ArrListDnsServers[i].ToString();
				try
				{
					Dns1.GetMailServer(url);
					if(Dns1.Names.Count != 0 || Dns1.Addresses.Count != 0)
					{
						txtResults.Text = "Email address " + url + " resolved.\n";
						txtResults.Text = txtResults.Text + "DNS Used: " + Dns1.ServerName + "\n";
						txtResults.Text = txtResults.Text + "Mail Server: " + Dns1.Names.All + "\n";
						done = true;
					}
					else
					{
						if(i == ArrListDnsServers.Count - 1)
							txtResults.Text = "Error, cannot resolve";
					}
				}
				catch(Exception ResolveError)
				{
					if(i== ArrListDnsServers.Count - 1)
						txtResults.Text = "Error: " + ResolveError.Message;
				}
				finally
				{
					i++;
				}
			}
		}

		private void ResolveDotAddress(string url)
		{
			bool done = false;
			int i=0;
			// iterate through server list and attempt to resolve, if successful- quit, if not go on to next, if at end, display error
			while(!done && i < ArrListDnsServers.Count)
			{
				Dns1.ServerName = ArrListDnsServers[i].ToString();
				try
				{
					Dns1.GetName(url);
					if(Dns1.Names.Count != 0 || Dns1.Addresses.Count != 0)
					{
						txtResults.Text = "Dot address " + url + " resolved.\n";
						txtResults.Text = txtResults.Text + "DNS Used: " + Dns1.ServerName + "\n";
						txtResults.Text = txtResults.Text + "Name(s): " + Dns1.Names.All + "\n";
						done = true;
					}
					else
					{
						if(i == ArrListDnsServers.Count - 1)
							txtResults.Text = "Error, cannot resolve";
					}
				}
				catch(Exception ResolveError)
				{
					if(i== ArrListDnsServers.Count - 1)
						txtResults.Text = "Error: " + ResolveError.Message;
				}
				finally
				{
					i++;
				}
			}
		}

		private void ResolveNameAddress(string url)
		{
			bool done = false;
			int i=0;
			// iterate through server list and attempt to resolve, if successful- quit, if not go on to next, if at end, display error
			while(!done && i < ArrListDnsServers.Count)
			{
				Dns1.ServerName = ArrListDnsServers[i].ToString();
				try
				{
					Dns1.GetAddress(url);
					if(Dns1.Names.Count != 0 || Dns1.Addresses.Count != 0)
					{
						txtResults.Text = "Address " + url + " resolved.\n";
						txtResults.Text = txtResults.Text + "DNS Used: " + Dns1.ServerName + "\n";
						txtResults.Text = txtResults.Text + "Address(es): " + Dns1.Addresses.All + "\n";
						done = true;
					}
					else
					{
						if(i == ArrListDnsServers.Count - 1)
							txtResults.Text = "Error, cannot resolve";
					}
				}
				catch(Exception ResolveError)
				{
					if(i== ArrListDnsServers.Count - 1)
						txtResults.Text = "Error: " + ResolveError.Message;
				}
				finally
				{
					i++;
				}
			}
		}

	}
}