/**
 * Namespace: System.Web.UI.WebControls
 * Class:     Button
 *
 * Author:  Gaurav Vaish
 * Maintainer: gvaish@iitk.ac.in
 * Contact: <my_scripts2001@yahoo.com>, <gvaish@iitk.ac.in>
 * Implementation: yes
 * Status:  100%
 *
 * (C) Gaurav Vaish (2001)
 */

using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI;

namespace System.Web.UI.WebControls
{
	[DefaultEvent("Click")]
	[DefaultProperty("Text")]
	//TODO: [Designer("??")]
	//TODO: [DataBindingHandler("??UI.Design.TextDataBindingHandler??")]
	[ToolboxData("<{0}:Button runat=\"server\" Text=\"Button\"></{0}:Button>")]
	[PersistChildren(false)]
	[ParseChildren(true)]
	public class Button : WebControl, IPostBackEventHandler
	{
		private static readonly object ClickEvent   = new object();
		private static readonly object CommandEvent = new object();

		//private EventHandlerList ehList;

		public Button(): base (HtmlTextWriterTag.Input)
		{
		}

		public bool CausesValidation
		{
			get
			{
				Object cv = ViewState["CausesValidation"];
				if(cv!=null)
					return (Boolean)cv;
				return true;
			}
			set
			{
				ViewState["CausesValidation"] = value;
			}
		}

		public string CommandArgument
		{
			get
			{
				string ca = (string) ViewState["CommandArgument"];
				if(ca!=null)
					return ca;
				return String.Empty;
			}
			set
			{
				ViewState["CommandArgument"] = value;
			}
		}

		public string CommandName
		{
			get
			{
				string cn = (string)ViewState["CommandName"];
				if(cn!=null)
					return cn;
				return String.Empty;
			}
			set
			{
				ViewState["CommandName"] = value;
			}
		}

		public string Text
		{
			get
			{
				string text = (string)ViewState["Text"];
				if(text!=null)
					return text;
				return String.Empty;
			}
			set
			{
				ViewState["Text"] = value;
			}
		}

		public event EventHandler Click
		{
			add
			{
				Events.AddHandler(ClickEvent, value);
			}
			remove
			{
				Events.RemoveHandler(ClickEvent, value);
			}
		}

		public event CommandEventHandler Command
		{
			add
			{
				Events.AddHandler(CommandEvent, value);
			}
			remove
			{
				Events.RemoveHandler(CommandEvent, value);
			}
		}

		protected virtual void OnClick(EventArgs e)
		{
			if(Events != null)
			{
				EventHandler eh = (EventHandler)(Events[ClickEvent]);
				if(eh!= null)
					eh(this,e);
			}
		}

		protected virtual void OnCommand(CommandEventArgs e)
		{
			if(Events != null)
			{
				EventHandler eh = (EventHandler)(Events[CommandEvent]);
				if(eh!= null)
					eh(this,e);
			}
		}

		void IPostBackEventHandler.RaisePostBackEvent (string eventArgument)
		{
			if (CausesValidation)
				Page.Validate ();

			OnClick (EventArgs.Empty);
			OnCommand (new CommandEventArgs (CommandName, CommandArgument));
		}

		protected override void AddAttributesToRender (HtmlTextWriter writer)
		{
			if (Page != null)
				Page.VerifyRenderingInServerForm (this);

			writer.AddAttribute (HtmlTextWriterAttribute.Type, "submit");
			writer.AddAttribute (HtmlTextWriterAttribute.Name, base.UniqueID);
			writer.AddAttribute (HtmlTextWriterAttribute.Value, Text);
			if (Page != null && CausesValidation && Page.Validators.Count > 0) {
				writer.AddAttribute (System.Web.UI.HtmlTextWriterAttribute.Onclick,
						     Utils.GetClientValidatedEvent (Page));
				writer.AddAttribute ("language", "javascript");
			}
			base.AddAttributesToRender (writer);
		}

		protected override void RenderContents(HtmlTextWriter writer)
		{
			// Preventing base classes to do anything
		}
	}
}