using System;
using System.Collections;
using System.Globalization;
using System.IO;
using System.Text.RegularExpressions;

namespace ThoughtWorks.CruiseControl.Core.Sourcecontrol
{
	public class MksHistoryParser : IHistoryParser
	{
		private static Regex SUBPROJECT_SEARCH_REGEX = new Regex(@"^\s*((Subproject\schanged|Dropped\ssubproject|Added\ssubproject):\s+(?<SubprojectName>.*?)(\s+at.*(\r\n|$)|\s+was.*(\r\n|$)|\s+now.*(\r\n|$)|\s+from.*(\r\n|$)|(\r\n|$)))",
            RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | RegexOptions.ExplicitCapture | RegexOptions.IgnoreCase | RegexOptions.Multiline);
		private static Regex MODIFICATION_SEARCH_REGEX = new Regex(@"^\s*(?<ModificationType>(Member\srevision|Revision|Added|Dropped|Deleted))\s(changed|member):\s+(?<Filename>.*?)\s+(at|was|now|from).*\s(?<NewRevision>\d+(\.\d+)*)(\r\n|$)", 
            RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | RegexOptions.ExplicitCapture | RegexOptions.IgnoreCase | RegexOptions.Multiline);
		private static Regex MEMBER_INFO_REGEX = new Regex(@".*?\s+Created\sBy:\s+.*\((?<UserName>.*)\)\son\s(?<ModifiedTime>.*)\r\n(.|\r\n)*?\s+Revision\sDescription:\r\n\s*(?<Comment>(.|\r\n)*?)\s+Labels:(.|\r\n|$)*?",
            RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | RegexOptions.ExplicitCapture | RegexOptions.IgnoreCase);

		public virtual Modification[] Parse(TextReader history, DateTime from, DateTime to)
		{
			ArrayList result = new ArrayList();
            string modifications = history.ReadToEnd();
            MatchCollection subprojectMatches = SUBPROJECT_SEARCH_REGEX.Matches(modifications);
            MatchCollection revisionMatches = MODIFICATION_SEARCH_REGEX.Matches(modifications);

			foreach (Match revisionMatch in revisionMatches)
			{
				string SubProjectPath = string.Empty;

				for (int i = subprojectMatches.Count - 1; i >= 0; i--)
				{
					if (subprojectMatches[i].Index < revisionMatch.Index)
					{
						SubProjectPath = ParseSubprojectFolder(subprojectMatches[i].Groups["SubprojectName"].Value.Trim());
						break;
					}
				}
				Modification modification = CreateModification(revisionMatch, SubProjectPath);
				result.Add(modification);
			}

			return (Modification[]) result.ToArray(typeof (Modification));
		}

		public virtual void ParseMemberInfoAndAddToModification(Modification modification, StringReader reader)
		{

			MatchCollection memberInfoMatches = MEMBER_INFO_REGEX.Matches(reader.ReadToEnd());
			foreach (Match match in memberInfoMatches)
			{
				modification.UserName = match.Groups["UserName"].Value.Trim();
				modification.ModifiedTime = ParseDate(match.Groups["ModifiedTime"].Value.Trim());
				modification.Comment = match.Groups["Comment"].Value.Trim();  
			}

		}

		// Dates returned from some versions of MKS seem to be in format Aug 26, 2005 - 5:32 AM, but I haven't been
		// able to verify this for all locales.  This format is not supported by DateTime.Parse under .NET 2.0.
		// So we TryParseExact to see if just this format can be read.
		//
		// Later versions of MKS (like 2007) return dates in format Aug 26, 2005 05:32:23 AM CST.  For this case,
		// trim off the time zone, because again, DateTime.Parse will get unhappy.
	    private static DateTime ParseDate(string dateString)
	    {
			DateTime date;

			string ParsedDateString = dateString.Remove(22).Trim();
			if (DateTime.TryParseExact(ParsedDateString, "MMM d, yyyy - h:mm tt", CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal, out date))
                return date;

			ParsedDateString = dateString.Trim().Substring(0, dateString.Trim().Length - 4); // Trim the timezone off the end of the date/time

			return Convert.ToDateTime(ParsedDateString);
	    }

		private static string ParseSubprojectFolder(string subprojectfile)
		{
			int lastIndexOfFrontSlash = subprojectfile.LastIndexOf("/");
			if (lastIndexOfFrontSlash > 0)
			{
				return subprojectfile.Substring(0, lastIndexOfFrontSlash + 1);
			}

			// If we get here, we didn't have a valid subproject filepath.
			return string.Empty;
		}

		private static Modification CreateModification(Match match, string subprojectPath)
		{
			Modification modification = new Modification();
			ParseFileAndFolderName(subprojectPath + match.Groups["Filename"].Value.Trim(), modification);
			modification.Version = match.Groups["NewRevision"].Value.Trim();
			modification.Type = ParseModificationType(match.Groups["ModificationType"].Value.Trim());
			return modification;
		}

		private static string ParseModificationType(string modificationType)
		{
			switch (modificationType)
			{
				case "Revision":
				case "Member revision":
					return "Modified";
				case "Dropped":
					return "Deleted";
				default:
					return modificationType;
			}
		}

		private static void ParseFileAndFolderName(string file, Modification modification)
		{
			int lastIndexOfFrontSlash = file.LastIndexOf("/");
			modification.FileName = file.Substring(lastIndexOfFrontSlash + 1);
			if (lastIndexOfFrontSlash > 0)
			{
				// We need to trim the leading slash and project name from the project path
				int secondIndexOfSlash = file.Substring(1).IndexOf("/");
				if (secondIndexOfSlash > 0)
				{
					modification.FolderName = file.Substring(secondIndexOfSlash + 2, lastIndexOfFrontSlash - secondIndexOfSlash - 2);
				}
			}
		}
	}
}