#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.Diagnostics;
using System.Text;

using Microsoft.Win32;

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

namespace Nuclex.NAnt.Tasks {

  /// <summary>Invokes the 7-Zip file compression utility</summary>
  public static class SevenZip {

    #region class ErrorCapturer

    /// <summary>Captures the error message reported by 7-Zip, if any</summary>
    private class ErrorCapturer {

      /// <summary>Called when 7-Zip outputs data to the stderr stream</summary>
      /// <param name="sender">Process that is outputting data</param>
      /// <param name="arguments">Contains the data that was sent to stderr</param>
      public void SevenZipErrorDataReceived(
        object sender, DataReceivedEventArgs arguments
      ) {
        processLine(arguments.Data);
        Debug.WriteLine("stderr: " + arguments.Data);
      }

      /// <summary>Called when 7-Zip outputs data to the stdout stream</summary>
      /// <param name="sender">Process that is outputting data</param>
      /// <param name="arguments">Contains the data that was sent to stdout</param>
      public void SevenZipOutputDataReceived(
        object sender, DataReceivedEventArgs arguments
      ) {
        processLine(arguments.Data);
        Debug.WriteLine("stdout: " + arguments.Data);
      }

      /// <summary>The error message if an error has occured</summary>
      public string ErrorMessage {
        get { return this.errorMessage.ToString(); }
      }

      /// <summary>Whether an error has occured at all</summary>
      public bool ErrorOccured {
        get { return this.gotError; }
      }

      /// <summary>Processes a single line from 7-Zip's output</summary>
      /// <param name="line">Line the 7-Zip executable has printed</param>
      private void processLine(string line) {
        if(string.IsNullOrEmpty(line)) {
          if(this.gotError) {
            this.errorComplete = true;
          }
        } else if(this.gotError) {
          if(!this.errorComplete) {
            if(this.errorMessage == null) {
              this.errorMessage = new StringBuilder();
              this.errorMessage.AppendLine();
            }
            this.errorMessage.AppendLine(line);
          }
        } else {
          int errorIndex = line.IndexOf(
            "error", StringComparison.InvariantCultureIgnoreCase
          );

          if(errorIndex != -1) {
            this.gotError = true;
          }
        }
      }

      /// <summary>True if an error has occured</summary>
      private bool gotError;
      /// <summary>Whether the error message is complete</summary>
      private bool errorComplete;
      /// <summary>The suspected error message from 7-Zip</summary>
      private StringBuilder errorMessage;

    }

    #endregion // class ErrorCapturer

    /// <summary>Runs the 7-Zip executable</summary>
    /// <param name="workingDirectory">Working directory in which to start 7-Zip</param>
    /// <param name="commandLine">Command line arguments to pass to 7-Zip</param>
    public static void Run(string workingDirectory, string commandLine) {

      ErrorCapturer errorCapturer = new ErrorCapturer();

      // Configure the startup options for the 7-Zip process
      Process sevenZip = new Process();
      sevenZip.StartInfo.Arguments = commandLine;
      sevenZip.StartInfo.CreateNoWindow = true;
      sevenZip.StartInfo.FileName = Helpers.SevenZipLocator.Location;
      sevenZip.StartInfo.WorkingDirectory = workingDirectory;
      sevenZip.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
      sevenZip.StartInfo.RedirectStandardOutput = true;
      sevenZip.StartInfo.RedirectStandardError = true;
      sevenZip.StartInfo.UseShellExecute = false;
      sevenZip.OutputDataReceived += new DataReceivedEventHandler(
        errorCapturer.SevenZipOutputDataReceived
      );
      sevenZip.ErrorDataReceived += new DataReceivedEventHandler(
        errorCapturer.SevenZipErrorDataReceived
      );
      
      // Start the 7-Zip process and wait for it to end
      sevenZip.Start();
      sevenZip.BeginOutputReadLine();
      sevenZip.BeginErrorReadLine();
      sevenZip.WaitForExit();

      // Check if 7-Zip failed and throw an exception if it did
      int exitCode = sevenZip.ExitCode;
      if(exitCode != 0) {
        throw new InvalidOperationException(errorCapturer.ErrorMessage ?? "unknown error");
      }

    }
   
  }

} // namespace Nuclex.NAnt.Tasks