#region CPL License
/*
Nuclex.NAnt.Tasks
Copyright (C) 2009 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;

using Microsoft.Win32;

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

namespace Nuclex.NAnt.Tasks {

  /// <summary>Deletes files from a working copy</summary>
  [TaskName("subversion-delete")]
  public class SubversionDeleteTask : Task {

    /// <summary>Initializes a new subversion add task</summary>
    public SubversionDeleteTask() {
      this.fileSets = new FileSetCollection();
    }

    /// <summary>Files that will be compressed</summary>
    [BuildElementArray("fileset")]
    public FileSetCollection FileSets {
      get { return this.fileSets; }
      set { this.fileSets = value; }
    }

    /// <summary>Executes the task</summary>
    protected override void ExecuteTask() {
      this.Log(
        Level.Info,
        "Deleting {0} files from subversion working copy.",
        this.fileSets.FileCount
      );

      for(int fileSetIndex = 0; fileSetIndex < this.fileSets.Count; ++fileSetIndex) {
        FileSet fileSet = this.fileSets[fileSetIndex];

        string fileList = createListOfFilesToDelete(fileSet);
        try {
          string commandLine = string.Format(
            "delete --targets {0} --no-auth-cache --non-interactive --force", fileList
          );

          Subversion.Run(fileSet.BaseDirectory.FullName, commandLine);
        }
        catch(InvalidOperationException exception) {
          throw new BuildException(
            "Error during Subversion delete operation: " + exception.Message,
            this.Location
          );
        }
        finally {
          File.Delete(fileList);
        }
      }
    }

    /// <summary>Creates a list of the files that need to be compressed</summary>
    /// <param name="fileSet">
    ///   File set whose file names will be written into a temporary text file
    /// </param>
    /// <returns>The path to a temporary text file containing the list of files</returns>
    /// <remarks>
    ///   The caller is responsible for deleting the returned file again when it
    ///   is no longer needed.
    /// </remarks>
    private string createListOfFilesToDelete(FileSet fileSet) {

      // This generates a temporary filename and writes an actual empty file to
      // disk which ensures that noone else can get a temp file with this name.
      string tempFile = Path.GetTempFileName();

      // Make sure the temporary file is deleted again if anything goes wrong
      try {
        using(
          FileStream tempFileStream = new FileStream(
            tempFile, FileMode.Truncate, FileAccess.Write, FileShare.None
          )
        ) {
          StreamWriter writer = new StreamWriter(tempFileStream);

          // Write the relative paths of all files in the file set into our
          // temporary text file
          for(int fileIndex = 0; fileIndex < fileSet.FileNames.Count; ++fileIndex) {
            string relativePath = PathHelper.MakeRelative(
              fileSet.BaseDirectory.FullName, fileSet.FileNames[fileIndex]
            );
            string absolutePath = Path.Combine(
              fileSet.BaseDirectory.FullName, relativePath
            );

            if(File.Exists(absolutePath)) {
              writer.WriteLine(relativePath);
            } else {
              this.Log(
                Level.Warning,
                "File '{0}' couldn't be deleted because it doesn't exist",
                absolutePath
              );
            }
          }

          writer.Flush();
        }
      }
      catch(Exception) {
        File.Delete(tempFile);
        throw;
      }

      // Nothing went wrong, leave the temporary file in place and return its path
      return tempFile;

    }

    /// <summary>Files that will be compressed</summary>
    private FileSetCollection fileSets;

  }

} // namespace Nuclex.NAnt.Tasks