using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Web.UI;

namespace ChadSoft.Web.ResponseFilters
{
    public class PluggableNavigationResponseFilter : TextProcessingResponseFilter
    {
        private readonly Control _navigationControl;

        public PluggableNavigationResponseFilter(Stream stream, Control navigationControl) : base(stream)
        {
            _navigationControl = navigationControl;
        }

        protected override string ProcessResponseText(string responseText)
        {
            /* 
             * NOTE: When using WebForms, use the line below to put the control in the server form
             *       so you can actually make use of server controls with postback, etc.
             */
            // return Regex.Replace(responseText, "<form[^>]*>", AppendControlMarkup, RegexOptions.IgnoreCase);
            
            // Append the markup of the navigation control at the beginning of the body
            return Regex.Replace(responseText, "<body[^>]*>", AppendControlMarkup, RegexOptions.IgnoreCase);
        }

        private string AppendControlMarkup(Match m)
        {
            var controlMarkup = new StringBuilder();
            var writer = new HtmlTextWriter(new StringWriter(controlMarkup));
            _navigationControl.RenderControl(writer);

            return string.Format("{0}\n{1}", m.Value, controlMarkup);
        }
    }
}