using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Xml;

using NAnt.Core;
using NAnt.Core.Attributes;
using NAnt.Core.Types;

namespace ASPCommenter
{
	/// <summary>
	/// NAnt task to extract XML comments from ASP files
	/// </summary>
	[TaskName("getcomment")]
	public class ExtractCommentTask : Task
	{
		private FileSet m_fileset = new FileSet();
		private FileInfo m_output;
		private string m_basedir = @"\";
		private Encoding m_enc = Encoding.GetEncoding(1252);
		
		/// <summary>
		/// Get or set the file to extract comment from
		/// </summary>
		[BuildElement("fileset", Required=true)]
		public FileSet Fileset
		{
			get
			{
				return m_fileset;
			}
		}

		/// <summary>
		/// Get or set the output XML file to write comments to
		/// </summary>
		[TaskAttribute("output", Required=true)]
		public FileInfo Output
		{
			get
			{
				return m_output;
			}
			set
			{
				m_output = value;
			}
		}

		/// <summary>
		/// The base directory where the code is localted. Relative to the project base
		/// directory.
		/// </summary>
		[TaskAttribute("basedir")]
		public FileInfo BaseDirectory
		{
			get
			{
				return m_output;
			}
			set
			{
				m_output = value;
			}
		}

		protected override void ExecuteTask()
		{
			ExtractComment();
		}

		public void ExtractComment()
		{
			XmlTextWriter writer = new XmlTextWriter(m_output.FullName, m_enc);
			
			Log(Level.Info, "Extracting comments");

			writer.WriteStartDocument();
			writer.WriteStartElement("doc");

			foreach(string file in m_fileset.FileNames)
			{
				ExtractComment(file, ref writer);
			}

			writer.WriteEndDocument();

			writer.Close();
		}

		public void ExtractComment(string file, ref XmlTextWriter writer)
		{
			Regex rxComment = new Regex("(''').*\n");
			Regex rxLine = new Regex(".*\n");
			Regex rxDeclaration = new Regex("(sub|function).*[a-z].*\n");
			MatchCollection matches;
			StreamReader reader = new StreamReader(file, m_enc);
			
			string content;
			string comment = "";
			string declaration;
			string nextLine;
			string relativeFile = file.Replace(Project.BaseDirectory + m_basedir, "");

			
			Log(Level.Info, "\tFrom {0}", relativeFile, m_output.FullName);
			
			content = reader.ReadToEnd();
			reader.Close();
			matches = rxComment.Matches(content);

			writer.WriteStartElement("file");
			writer.WriteAttributeString("path", relativeFile);
			foreach(Match m in matches)
			{
				comment += m.Value.Substring(4, m.Length - 4);
				nextLine = rxLine.Match(content, m.Index + m.Length).Value;

				if (rxDeclaration.IsMatch(nextLine)) 
				{
					declaration = rxDeclaration.Match(nextLine).Value;
					declaration = declaration.Remove(declaration.Length - 2, 2);

					try
					{
						CheckXml(comment);
						writer.WriteStartElement("member");
						writer.WriteAttributeString("signature", declaration);
						writer.WriteRaw(comment);
						writer.WriteEndElement();
					}
					catch (XmlException ex)
					{
						Log(Level.Error, "\t\tInvalid XML in {0} comments : {1}", declaration, ex.Message);
					}

					comment = "";
					declaration = "";
				}
			}
			writer.WriteEndElement();
		}

		private void CheckXml(string xml)
		{
			XmlValidatingReader vr = new XmlValidatingReader(xml, XmlNodeType.Element, null);
			while(vr.Read()) {}
			vr.Close();
		}

	}

}