/*

Copyright (C) 2011-2013 Jacob Dawid

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave 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 GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_QSCINTILLA

#if defined (HAVE_QSCI_QSCILEXEROCTAVE_H)
#define HAVE_LEXER_OCTAVE
#include <Qsci/qscilexeroctave.h>
#elif defined (HAVE_QSCI_QSCILEXERMATLAB_H)
#define HAVE_LEXER_MATLAB
#include <Qsci/qscilexermatlab.h>
#endif
#include <Qsci/qscilexercpp.h>
#include <Qsci/qscilexerbash.h>
#include <Qsci/qscilexerperl.h>
#include <Qsci/qscilexerbatch.h>
#include <Qsci/qscilexerdiff.h>
#include <Qsci/qsciprinter.h>
#include "resource-manager.h"
#include <QApplication>
#include <QFileDialog>
#include <QMessageBox>
#include <QTextStream>
#include <QVBoxLayout>
#include <QInputDialog>
#include <QPrintDialog>
#include <QDateTime>

#include "file-editor-tab.h"
#include "file-editor.h"

#include "file-ops.h"

#include "debug.h"
#include "octave-qt-link.h"
#include "version.h"
#include "utils.h"
#include "defaults.h"

// Make parent null for the file editor tab so that warning
// WindowModal messages don't affect grandparents.
file_editor_tab::file_editor_tab (const QString& directory_arg)
{
  QString directory = directory_arg;
  _lexer_apis = 0;
  _app_closing = false;
  _is_octave_file = true;

  // Make sure there is a slash at the end of the directory name
  // for identification when saved later.
  if (directory.count () && directory.at (directory.count () - 1) != '/')
    directory.append ("/");

  _file_name = directory;
  _file_system_watcher.setObjectName ("_qt_autotest_force_engine_poller");

  _edit_area = new octave_qscintilla (this);
  // Connect signal for command execution to a slot of this tab which in turn
  // emits a signal connected to the main window.
  // Direct connection is not possible because tab's parent is null.
  connect (_edit_area,
           SIGNAL (execute_command_in_terminal_signal (const QString&)),
           this,
           SLOT (execute_command_in_terminal (const QString&)));

  connect (_edit_area,
           SIGNAL (cursorPositionChanged (int, int)),
           this,
           SLOT (handle_cursor_moved (int,int)));

  connect (_edit_area, SIGNAL (create_context_menu_signal (QMenu*)),
           this, SLOT (create_context_menu (QMenu*)));

  // create statusbar for row/col indicator
  _status_bar = new QStatusBar (this);

  _row_indicator = new QLabel ("", this);
  _row_indicator->setMinimumSize (30,0);
  QLabel *row_label = new QLabel (tr ("Line:"), this);
  _col_indicator = new QLabel ("", this);
  _col_indicator->setMinimumSize (25,0);
  QLabel *col_label = new QLabel (tr ("Col:"), this);
  _status_bar->addPermanentWidget (row_label, 0);
  _status_bar->addPermanentWidget (_row_indicator, 0);
  _status_bar->addPermanentWidget (col_label, 0);
  _status_bar->addPermanentWidget (_col_indicator, 0);

  // Leave the find dialog box out of memory until requested.
  _find_dialog = 0;
  _find_dialog_is_visible = false;

  // symbols
  _edit_area->setMarginType (1, QsciScintilla::SymbolMargin);
  _edit_area->setMarginSensitivity (1, true);
  _edit_area->markerDefine (QsciScintilla::RightTriangle, bookmark);
  _edit_area->markerDefine (QPixmap (":/actions/icons/redled.png"),
                            breakpoint);
  _edit_area->markerDefine (QPixmap (":/actions/icons/bookmark.png"),
                            debugger_position);

  connect (_edit_area, SIGNAL (marginClicked (int, int,
                                              Qt::KeyboardModifiers)),
           this, SLOT (handle_margin_clicked (int, int,
                                              Qt::KeyboardModifiers)));

  // line numbers
  _edit_area->setMarginsForegroundColor (QColor (96, 96, 96));
  _edit_area->setMarginsBackgroundColor (QColor (232, 232, 220));
  _edit_area->setMarginType (2, QsciScintilla::TextMargin);

  // other features
  _edit_area->setBraceMatching (QsciScintilla::StrictBraceMatch);
  _edit_area->setAutoIndent (true);
  _edit_area->setIndentationWidth (2);
  _edit_area->setIndentationsUseTabs (false);

  _edit_area->setUtf8 (true);

  // auto completion
  _edit_area->SendScintilla (QsciScintillaBase::SCI_AUTOCSETCANCELATSTART, false);

  QVBoxLayout *edit_area_layout = new QVBoxLayout ();
  edit_area_layout->addWidget (_edit_area);
  edit_area_layout->addWidget (_status_bar);
  edit_area_layout->setMargin (0);
  setLayout (edit_area_layout);

  // connect modified signal
  connect (_edit_area, SIGNAL (modificationChanged (bool)),
           this, SLOT (update_window_title (bool)));

  connect (_edit_area, SIGNAL (copyAvailable (bool)),
           this, SLOT (handle_copy_available (bool)));

  connect (_edit_area, SIGNAL (qsci_has_focus_signal (bool)),
           this, SLOT (edit_area_has_focus (bool)));

  connect (&_file_system_watcher, SIGNAL (fileChanged (const QString&)),
           this, SLOT (file_has_changed (const QString&)));

  QSettings *settings = resource_manager::get_settings ();
  if (settings)
    notice_settings (settings);
}

file_editor_tab::~file_editor_tab (void)
{
  // Destroy items attached to _edit_area.
  QsciLexer *lexer = _edit_area->lexer ();
  if (lexer)
    {
      delete lexer;
      _edit_area->setLexer (0);
    }
  if (_find_dialog)
    {
      delete _find_dialog;
      _find_dialog = 0;
    }

  // Destroy _edit_area.
  delete _edit_area;
}

void
file_editor_tab::closeEvent (QCloseEvent *e)
{
  // ignore close event if file is not saved and user cancels
  // closing this window
  if (check_file_modified () == QMessageBox::Cancel)
    e->ignore ();
  else
    e->accept ();
}

void
file_editor_tab::execute_command_in_terminal (const QString& command)
{
  emit execute_command_in_terminal_signal (command); // connected to main window
}

void
file_editor_tab::set_file_name (const QString& fileName)
{
  // update tracked file if we really have a file on disk
  QStringList trackedFiles = _file_system_watcher.files ();
  if (!trackedFiles.isEmpty ())
    _file_system_watcher.removePath (_file_name);
  if (!fileName.isEmpty ())
    _file_system_watcher.addPath (fileName);
  _file_name = fileName;

  // update lexer after _file_name change
  update_lexer ();

  // update the file editor with current editing directory
  emit editor_state_changed (_copy_available, _file_name, _is_octave_file);

  // add the new file to the mru list
  emit mru_add_file (_file_name);
}

// valid_file_name (file): checks whether "file" names a file
// by default, "file" is empty, then _file_name is checked
bool
file_editor_tab::valid_file_name (const QString& file)
{
  QString file_name;
  if (file.isEmpty ())
    file_name = _file_name;
  else
    file_name = file;
  return (! file_name.isEmpty ()
          && file_name.at (file_name.count () - 1) != '/');
}

void
file_editor_tab::handle_margin_clicked (int margin, int line,
                                        Qt::KeyboardModifiers state)
{
  if (margin == 1)
    {
      unsigned int markers_mask = _edit_area->markersAtLine (line);

      if (state & Qt::ControlModifier)
        {
          if (markers_mask && (1 << bookmark))
            _edit_area->markerDelete (line, bookmark);
          else
            _edit_area->markerAdd (line, bookmark);
        }
      else
        {
          if (markers_mask && (1 << breakpoint))
            request_remove_breakpoint (line);
          else
            request_add_breakpoint (line);
        }
    }
}

void
file_editor_tab::update_lexer ()
{
  if (_lexer_apis)
    _lexer_apis->cancelPreparation ();  // stop preparing if apis exists

  QsciLexer *lexer = _edit_area->lexer ();
  delete lexer;
  lexer = 0;

  _is_octave_file = false;

  if (_file_name.endsWith (".m")
      || _file_name.endsWith ("octaverc"))
    {
#if defined (HAVE_LEXER_OCTAVE)
      lexer = new QsciLexerOctave ();
#elif defined (HAVE_LEXER_MATLAB)
      lexer = new QsciLexerMatlab ();
#endif
      _is_octave_file = true;
    }

  if (! lexer)
    {
      if (_file_name.endsWith (".c")
          || _file_name.endsWith (".cc")
          || _file_name.endsWith (".cpp")
          || _file_name.endsWith (".cxx")
          || _file_name.endsWith (".c++")
          || _file_name.endsWith (".h")
          || _file_name.endsWith (".hh")
          || _file_name.endsWith (".hpp")
          || _file_name.endsWith (".h++"))
        {
          lexer = new QsciLexerCPP ();
        }
      else if (_file_name.endsWith (".pl"))
        {
          lexer = new QsciLexerPerl ();
        }
      else if (_file_name.endsWith (".bat"))
        {
          lexer = new QsciLexerBatch ();
        }
      else if (_file_name.endsWith (".diff"))
        {
          lexer = new QsciLexerDiff ();
        }
      else if (! valid_file_name ())
        {
          // new, no yet named file: let us assume it is octave
#if defined (HAVE_LEXER_OCTAVE)
          lexer = new QsciLexerOctave ();
          _is_octave_file = true;
#elif defined (HAVE_LEXER_MATLAB)
          lexer = new QsciLexerMatlab ();
          _is_octave_file = true;
#else
          lexer = new QsciLexerBash ();
#endif
        }
      else
        {
          // other or no extension
          lexer = new QsciLexerBash ();
        }
    }

  QSettings *settings = resource_manager::get_settings ();

  // build information for auto completion (APIs)
  _lexer_apis = new QsciAPIs(lexer);

  if (_lexer_apis)
    {
      bool update_apis_file = false;  // flag, whether update of apis files

      // get path to prepared api info
      QDesktopServices desktopServices;
      QString prep_apis_path
        = desktopServices.storageLocation (QDesktopServices::HomeLocation)
          + "/.config/octave/"  + QString(OCTAVE_VERSION) + "/qsci/";

      // get settings which infos are used for octave
      bool octave_builtins = settings->value (
                  "editor/codeCompletion_octave_builtins", true).toBool ();
      bool octave_functions = settings->value (
                  "editor/codeCompletion_octave_functions", true).toBool ();

      if (_is_octave_file)
        {
          // octave file: keywords are always used
          _prep_apis_file = prep_apis_path + lexer->lexer () + "_k";

          if (octave_builtins)
            _prep_apis_file = _prep_apis_file + "b";  // use builtins, too

          if (octave_functions)
            _prep_apis_file = _prep_apis_file + "f";  // use keywords, too

          _prep_apis_file = _prep_apis_file + ".pap"; // final name of apis file

          // check whether the APIs info needs to be prepared and saved
          QFileInfo apis_file = QFileInfo (_prep_apis_file);
          update_apis_file = ! apis_file.exists ();  // flag whether apis file needs update

          // function list depends on installed packages: check mod. date
          if (! update_apis_file & octave_functions)
            {
              // check whether package file is newer than apis_file
              QDateTime apis_date = apis_file.lastModified ();

              // compare to local package list
              // FIXME: How to get user chosen location?
              QFileInfo local_pkg_list = QFileInfo (
                desktopServices.storageLocation (QDesktopServices::HomeLocation)
                + "/.octave_packages");
              if (local_pkg_list.exists ()
                  & (apis_date < local_pkg_list.lastModified ()) )
                update_apis_file = true;

              // compare to global package list
              // FIXME: How to get user chosen location?
              QFileInfo global_pkg_list = QFileInfo (
                                        QString::fromStdString (Voctave_home)
                                        + "/share/octave/octave_packages");
               if (global_pkg_list.exists ()
                   & (apis_date < global_pkg_list.lastModified ()) )
                update_apis_file = true;
            }
          }
        else  // no octave file, just add extension
          {
            _prep_apis_file = prep_apis_path + lexer->lexer () + ".pap";
          }

      if (update_apis_file | !_lexer_apis->loadPrepared (_prep_apis_file))
        {
          // no prepared info loaded, prepare and save if possible

          // create raw apis info
          QString keyword;
          QStringList keyword_list;
          int i,j;

          if (_is_octave_file)
            {
              // octave: get keywords from internal informations depending on
              //         user preferences

              // keywords are always used
              add_octave_apis (F__keywords__ ());       // add new entries

              if (octave_builtins)
                add_octave_apis (F__builtins__ ());       // add new entries

              if (octave_functions)
                add_octave_apis (F__list_functions__ ()); // add new entries

            }
          else
            {

              _prep_apis_file = prep_apis_path + lexer->lexer () + ".pap";

              for (i=1; i<=3; i++) // test the first 5 keyword sets
                {
                  keyword = QString(lexer->keywords (i));           // get list
                  keyword_list = keyword.split (QRegExp ("\\s+"));  // split
                  for (j = 0; j < keyword_list.size (); j++)        // add to API
                    _lexer_apis->add (keyword_list.at (j));
                }
            }

          // dsiconnect slot for saving prepared info if already connected
          disconnect (_lexer_apis, SIGNAL (apiPreparationFinished ()), 0, 0);
          // check whether path for prepared info exists or can be created
          if (QDir("/").mkpath (prep_apis_path))
            {
              // path exists, apis info can be saved there
              connect (_lexer_apis, SIGNAL (apiPreparationFinished ()),
                       this, SLOT (save_apis_info ()));
            }
          _lexer_apis->prepare ();  // prepare apis info
        }
    }

  lexer->readSettings (*settings);

  _edit_area->setLexer (lexer);

  // fix line number width with respect to the font size of the lexer
  if (settings->value ("editor/showLineNumbers", true).toBool ())
    auto_margin_width ();
  else
    _edit_area->setMarginWidth (2,0);

}

// function for adding entries to the octave lexer's APIs
void
file_editor_tab::add_octave_apis (octave_value_list key_ovl)
{
  octave_value keys = key_ovl(0);
  Cell key_list = keys.cell_value ();

  for (int idx = 0; idx < key_list.numel (); idx++)
    _lexer_apis->add (QString (key_list.elem (idx).string_value ().data ()));
}

void
file_editor_tab::save_apis_info ()
{
  _lexer_apis->savePrepared (_prep_apis_file);
}

QString
file_editor_tab::comment_string (const QString& lexer)
{
  if (lexer == "octave" || lexer == "matlab")
    return QString("%");
  else if (lexer == "perl" || lexer == "bash" || lexer == "diff")
    return QString("#");
  else if (lexer == "cpp")
    return ("//");
  else if (lexer == "batch")
    return ("REM ");
  else
    return ("%");  // should never happen
}

// slot for fetab_set_focus: sets the focus to the current edit area
void
file_editor_tab::set_focus (const QWidget *ID)
{
  if (ID != this)
    return;
  _edit_area->setFocus ();
}

void
file_editor_tab::context_help (const QWidget *ID, bool doc)
{
  if (ID != this)
    return;

  _edit_area->context_help_doc (doc);
}

void
file_editor_tab::context_edit (const QWidget *ID)
{
  if (ID != this)
    return;

  _edit_area->context_edit ();
}

void
file_editor_tab::save_file (const QWidget *ID)
{
  if (ID != this)
    return;

  save_file (_file_name);
}
void

file_editor_tab::save_file (const QWidget *ID, const QString& fileName,
                            bool remove_on_success)
{
  if (ID != this)
    return;

  save_file (fileName, remove_on_success);
}

void
file_editor_tab::save_file_as (const QWidget *ID)
{
  if (ID != this)
    return;

  save_file_as ();
}

void
file_editor_tab::print_file (const QWidget *ID)
{
  if (ID != this)
    return;

  QsciPrinter *printer = new QsciPrinter (QPrinter::HighResolution);

  QPrintDialog printDlg (printer, this);

  if (printDlg.exec () == QDialog::Accepted)
    printer->printRange (_edit_area);

  delete printer;
}

void
file_editor_tab::run_file (const QWidget *ID)
{
  if (ID != this)
    return;

  if (_edit_area->isModified ())
    save_file (_file_name);

  QFileInfo info (_file_name);
  emit run_file_signal (info);
}

void
file_editor_tab::context_run (const QWidget *ID)
{
  if (ID != this)
    return;

  _edit_area->context_run ();
}

void
file_editor_tab::toggle_bookmark (const QWidget *ID)
{
  if (ID != this)
    return;

  int line, cur;
  _edit_area->getCursorPosition (&line, &cur);

  if (_edit_area->markersAtLine (line) && (1 << bookmark))
    _edit_area->markerDelete (line, bookmark);
  else
    _edit_area->markerAdd (line, bookmark);
}

void
file_editor_tab::next_bookmark (const QWidget *ID)
{
  if (ID != this)
    return;

  int line, cur;
  _edit_area->getCursorPosition (&line, &cur);

  if (_edit_area->markersAtLine (line) && (1 << bookmark))
    line++; // we have a breakpoint here, so start search from next line

  int nextline = _edit_area->markerFindNext (line, (1 << bookmark));

  _edit_area->setCursorPosition (nextline, 0);
}

void
file_editor_tab::previous_bookmark (const QWidget *ID)
{
  if (ID != this)
    return;

  int line, cur;
  _edit_area->getCursorPosition (&line, &cur);

  if (_edit_area->markersAtLine (line) && (1 << bookmark))
    line--; // we have a breakpoint here, so start search from prev line

  int prevline = _edit_area->markerFindPrevious (line, (1 << bookmark));

  _edit_area->setCursorPosition (prevline, 0);
}

void
file_editor_tab::remove_bookmark (const QWidget *ID)
{
  if (ID != this)
    return;

  _edit_area->markerDeleteAll (bookmark);
}

void
file_editor_tab::add_breakpoint_callback (const bp_info& info)
{
  bp_table::intmap line_info;
  line_info[0] = info.line;

  if (octave_qt_link::file_in_path (info.file, info.dir))
    bp_table::add_breakpoint (info.function_name, line_info);
}

void
file_editor_tab::remove_breakpoint_callback (const bp_info& info)
{
  bp_table::intmap line_info;
  line_info[0] = info.line;

  if (octave_qt_link::file_in_path (info.file, info.dir))
    bp_table::remove_breakpoint (info.function_name, line_info);
}

void
file_editor_tab::remove_all_breakpoints_callback (const bp_info& info)
{
  if (octave_qt_link::file_in_path (info.file, info.dir))
    bp_table::remove_all_breakpoints_in_file (info.function_name, true);
}

file_editor_tab::bp_info::bp_info (const QString& fname, int l)
  : line (l), file (fname.toStdString ())
{
  QFileInfo file_info (fname);

  QString q_dir = file_info.absolutePath ();
  QString q_function_name = file_info.fileName ();

  // We have to cut off the suffix, because octave appends it.
  q_function_name.chop (file_info.suffix ().length () + 1);

  dir = q_dir.toStdString ();
  function_name = q_function_name.toStdString ();

  // Is the last component of DIR @foo?  If so, strip it and prepend it
  // to the name of the function.

  size_t pos = dir.rfind (file_ops::dir_sep_chars ());

  if (pos != std::string::npos && pos < dir.length () - 1)
    {
      if (dir[pos+1] == '@')
        {
          function_name = file_ops::concat (dir.substr (pos+1), function_name);

          dir = dir.substr (0, pos);
        }
    }
}

void
file_editor_tab::request_add_breakpoint (int line)
{
  bp_info info (_file_name, line+1);

  octave_link::post_event
    (this, &file_editor_tab::add_breakpoint_callback, info);
}

void
file_editor_tab::request_remove_breakpoint (int line)
{
  bp_info info (_file_name, line+1);

  octave_link::post_event
    (this, &file_editor_tab::remove_breakpoint_callback, info);
}

void
file_editor_tab::toggle_breakpoint (const QWidget *ID)
{
  if (ID != this)
    return;

  int line, cur;
  _edit_area->getCursorPosition (&line, &cur);

  if (_edit_area->markersAtLine (line) && (1 << breakpoint))
    request_remove_breakpoint (line);
  else
    request_add_breakpoint (line);
}

void
file_editor_tab::next_breakpoint (const QWidget *ID)
{
  if (ID != this)
    return;

  int line, cur;
  _edit_area->getCursorPosition (&line, &cur);

  if (_edit_area->markersAtLine (line) && (1 << breakpoint))
    line++; // we have a breakpoint here, so start search from next line

  int nextline = _edit_area->markerFindNext (line, (1 << breakpoint));

  _edit_area->setCursorPosition (nextline, 0);
}

void
file_editor_tab::previous_breakpoint (const QWidget *ID)
{
  if (ID != this)
    return;

  int line, cur, prevline;
  _edit_area->getCursorPosition (&line, &cur);

  if (_edit_area->markersAtLine (line) && (1 << breakpoint))
    line--; // we have a breakpoint here, so start search from prev line

  prevline = _edit_area->markerFindPrevious (line, (1 << breakpoint));

  _edit_area->setCursorPosition (prevline, 0);
}

void
file_editor_tab::remove_all_breakpoints (const QWidget *ID)
{
  if (ID != this)
    return;

  bp_info info (_file_name);

  octave_link::post_event
    (this, &file_editor_tab::remove_all_breakpoints_callback, info);
}

void
file_editor_tab::scintilla_command (const QWidget *ID, unsigned int sci_msg)
{
  if (ID != this)
    return;

  _edit_area->SendScintilla (sci_msg);
}

void
file_editor_tab::comment_selected_text (const QWidget *ID)
{
  if (ID != this)
    return;

  do_comment_selected_text (true);
}

void
file_editor_tab::uncomment_selected_text (const QWidget *ID)
{
  if (ID != this)
    return;

  do_comment_selected_text (false);
}

void
file_editor_tab::indent_selected_text (const QWidget *ID)
{
  if (ID != this)
    return;

  do_indent_selected_text (true);
}

void
file_editor_tab::unindent_selected_text (const QWidget *ID)
{
  if (ID != this)
    return;

  do_indent_selected_text (false);
}


void
file_editor_tab::zoom_in (const QWidget *ID)
{
  if (ID != this)
    return;

  _edit_area->zoomIn (1);
  auto_margin_width ();
}

void
file_editor_tab::zoom_out (const QWidget *ID)
{
  if (ID != this)
    return;

  _edit_area->zoomOut (1);
  auto_margin_width ();
}

void
file_editor_tab::zoom_normal (const QWidget *ID)
{
  if (ID != this)
    return;

  _edit_area->zoomTo (0);
  auto_margin_width ();
}


void
file_editor_tab::handle_find_dialog_finished (int)
{
  // Find dialog is going to hide.  Save location of window for
  // when it is reshown.
  _find_dialog_geometry = _find_dialog->geometry ();
  _find_dialog_is_visible = false;
}

void
file_editor_tab::find (const QWidget *ID)
{
  if (ID != this)
    return;

  // The find_dialog feature doesn't need a slot for return info.
  // Rather than Qt::DeleteOnClose, let the find feature hang about
  // in case it contains useful information like previous searches
  // and so on.  Perhaps one find dialog for the whole editor is
  // better, but individual find dialogs has the nice feature of
  // retaining position per file editor tabs, which can be undocked.

  if (!_find_dialog)
    {
      _find_dialog = new find_dialog (_edit_area,
                                      qobject_cast<QWidget *> (sender ()));
      connect (_find_dialog, SIGNAL (finished (int)),
               this, SLOT (handle_find_dialog_finished (int)));
      _find_dialog->setWindowModality (Qt::NonModal);
      _find_dialog_geometry = _find_dialog->geometry ();
    }

  if (!_find_dialog->isVisible ())
    {
      _find_dialog->setGeometry (_find_dialog_geometry);
      _find_dialog->show ();
      _find_dialog_is_visible = true;
    }

  _find_dialog->activateWindow ();
  _find_dialog->init_search_text ();

}

void
file_editor_tab::goto_line (const QWidget *ID, int line)
{
  if (ID != this)
    return;

  if (line <= 0)  // ask for desired line
    {
      bool ok = false;
      int index;
      _edit_area->getCursorPosition (&line, &index);
      line = QInputDialog::getInt (_edit_area, tr ("Goto line"),
                                   tr ("Line number"), line+1, 1,
                                   _edit_area->lines (), 1, &ok);
      if (ok)
        {
          _edit_area->setCursorPosition (line-1, 0);
          center_current_line ();
        }
    }
  else  // go to given line without dialog
    _edit_area->setCursorPosition (line-1, 0);
}

void
file_editor_tab::show_auto_completion (const QWidget *ID)
{
  if (ID != this)
    return;

  QsciScintilla::AutoCompletionSource s = _edit_area->autoCompletionSource ();
  switch (s)
    {
      case QsciScintilla::AcsAll:
        _edit_area->autoCompleteFromAll ();
        break;

      case QsciScintilla::AcsAPIs:
        _edit_area->autoCompleteFromAPIs ();
        break;

      case QsciScintilla::AcsDocument:
        _edit_area->autoCompleteFromDocument ();
        break;

      case QsciScintilla::AcsNone:
        break;
    }
}

void
file_editor_tab::do_indent_selected_text (bool indent)
{
  // TODO
  _edit_area->beginUndoAction ();

  if (_edit_area->hasSelectedText ())
    {
      int lineFrom, lineTo, colFrom, colTo;
      _edit_area->getSelection (&lineFrom, &colFrom, &lineTo, &colTo);

      if (colTo == 0)  // the beginning of last line is not selected
        lineTo--;        // stop at line above

      for (int i = lineFrom; i <= lineTo; i++)
        {
          if (indent)
            _edit_area->indent (i);
          else
            _edit_area->unindent (i);
        }
      //set selection on (un)indented section
      _edit_area->setSelection (lineFrom, 0, lineTo,
                                _edit_area->text (lineTo).length ());
    }
  else
    {
      int cpline, col;
      _edit_area->getCursorPosition (&cpline, &col);
      if (indent)
        _edit_area->indent (cpline);
      else
        _edit_area->unindent (cpline);
    }

  _edit_area->endUndoAction ();
}

void
file_editor_tab::do_comment_selected_text (bool comment)
{
  QString comment_str = comment_string (_edit_area->lexer ()->lexer ());
  _edit_area->beginUndoAction ();

  if (_edit_area->hasSelectedText ())
    {
      int lineFrom, lineTo, colFrom, colTo;
      _edit_area->getSelection (&lineFrom, &colFrom, &lineTo, &colTo);

      if (colTo == 0)  // the beginning of last line is not selected
        lineTo--;        // stop at line above

      for (int i = lineFrom; i <= lineTo; i++)
        {
          if (comment)
            _edit_area->insertAt (comment_str, i, 0);
          else
            {
              QString line (_edit_area->text (i));
              if (line.startsWith (comment_str))
                {
                  _edit_area->setSelection (i, 0, i, comment_str.length ());
                  _edit_area->removeSelectedText ();
                }
            }
        }
      //set selection on (un)commented section
      _edit_area->setSelection (lineFrom, 0, lineTo,
                                _edit_area->text (lineTo).length ());
    }
  else
    {
      int cpline, col;
      _edit_area->getCursorPosition (&cpline, &col);
      if (comment)
        _edit_area->insertAt (comment_str, cpline, 0);
      else
        {
          QString line (_edit_area->text (cpline));
          if (line.startsWith (comment_str))
            {
              _edit_area->setSelection (cpline, 0, cpline, comment_str.length ());
              _edit_area->removeSelectedText ();
            }
        }
    }
  _edit_area->endUndoAction ();
}

void
file_editor_tab::update_window_title (bool modified)
{
  QString title ("");
  QString tooltip ("");

  if (! valid_file_name ())
    title = tr ("<unnamed>");
  else
    {
      if (_long_title)
        title = _file_name;
      else
        {
          QFileInfo file (_file_name);
          title = file.fileName ();
          tooltip = _file_name;
        }
    }

  if (modified)
    emit file_name_changed (title.prepend ("* "), tooltip);
  else
    emit file_name_changed (title, tooltip);
}

void
file_editor_tab::handle_copy_available (bool enableCopy)
{
  _copy_available = enableCopy;
  emit editor_state_changed (_copy_available, QDir::cleanPath (_file_name),
                             _is_octave_file);
}

// show_dialog: shows a modal or non modal dialog depeding on the closing
//              of the app
void
file_editor_tab::show_dialog (QDialog *dlg)
{
  dlg->setAttribute (Qt::WA_DeleteOnClose);
  if (_app_closing)
    dlg->exec ();
  else
    {
      dlg->setWindowModality (Qt::WindowModal);
      dlg->show ();
    }
}

int
file_editor_tab::check_file_modified ()
{
  int decision = QMessageBox::Yes;
  if (_edit_area->isModified ())
    {
      activateWindow ();
      raise ();
      // File is modified but not saved, ask user what to do.  The file
      // editor tab can't be made parent because it may be deleted depending
      // upon the response.  Instead, change the _edit_area to read only.
      QMessageBox::StandardButtons buttons = QMessageBox::Save |
                                             QMessageBox::Discard;
      QString available_actions;

      if (_app_closing)
        available_actions = tr ("Do you want to save or discard the changes?");
      else
        {
          buttons = buttons | QMessageBox::Cancel;  // cancel is allowed
          available_actions
            = tr ("Do you want to cancel closing, save or discard the changes?");
        }

      QString file;
      if (valid_file_name ())
          file = _file_name;
      else
          file = tr ("<unnamed>");

      QMessageBox* msgBox
        = new QMessageBox (QMessageBox::Warning, tr ("Octave Editor"),
                           tr ("The file\n"
                               "%1\n"
                               "is about to be closed but has been modified.\n"
                               "%2").
                           arg (file). arg (available_actions),
                           buttons, qobject_cast<QWidget *> (parent ()));

      msgBox->setDefaultButton (QMessageBox::Save);
      _edit_area->setReadOnly (true);
      connect (msgBox, SIGNAL (finished (int)),
               this, SLOT (handle_file_modified_answer (int)));

      show_dialog (msgBox);

      return QMessageBox::Cancel;
    }
  else
    {
      // Nothing was modified, just remove from editor.
      emit tab_remove_request ();
    }

  return decision;
}

void
file_editor_tab::handle_file_modified_answer (int decision)
{
  if (decision == QMessageBox::Save)
    {
      // Save file, then remove from editor.
      save_file (_file_name, true);
    }
  else if (decision == QMessageBox::Discard)
    {
      // User doesn't want to save, just remove from editor.
      emit tab_remove_request ();
    }
  else
    {
      // User canceled, allow editing again.
      _edit_area->setReadOnly (false);
    }
}

void
file_editor_tab::set_modified (bool modified)
{
  _edit_area->setModified (modified);
}

QString
file_editor_tab::load_file (const QString& fileName)
{
  // get the absolute path
  QFileInfo file_info = QFileInfo (fileName);
  QString file_to_load;
  if (file_info.exists ())
    file_to_load = file_info.canonicalFilePath ();
  else
    file_to_load = fileName;
  QFile file (file_to_load);
  if (!file.open (QFile::ReadOnly))
    return file.errorString ();

  QTextStream in (&file);
  in.setCodec("UTF-8");
  QApplication::setOverrideCursor (Qt::WaitCursor);
  _edit_area->setText (in.readAll ());
  QApplication::restoreOverrideCursor ();

  _copy_available = false;     // no selection yet available
  set_file_name (file_to_load);
  update_window_title (false); // window title (no modification)
  _edit_area->setModified (false); // loaded file is not modified yet

  return QString ();
}

void
file_editor_tab::new_file (const QString &commands)
{
  update_window_title (false); // window title (no modification)
  _edit_area->setText (commands);
  _edit_area->setModified (false); // new file is not modified yet
}

void
file_editor_tab::save_file (const QString& saveFileName, bool remove_on_success)
{
  // If it is a new file with no name, signal that saveFileAs
  // should be performed.
  if (! valid_file_name (saveFileName))
    {
      save_file_as (remove_on_success);
      return;
    }
  // get the absolute path (if existing)
  QFileInfo file_info = QFileInfo (saveFileName);
  QString file_to_save;
  if (file_info.exists ())
    file_to_save = file_info.canonicalFilePath ();
  else
    file_to_save = saveFileName;
  QFile file (file_to_save);

  // stop watching file
  QStringList trackedFiles = _file_system_watcher.files ();
  if (trackedFiles.contains (file_to_save))
    _file_system_watcher.removePath (file_to_save);

  // open the file for writing
  if (!file.open (QIODevice::WriteOnly))
    {
      // Unsuccessful, begin watching file again if it was being
      // watched previously.
      if (trackedFiles.contains (file_to_save))
        _file_system_watcher.addPath (file_to_save);

      // Create a NonModal message about error.
      QMessageBox* msgBox
        = new QMessageBox (QMessageBox::Critical,
                           tr ("Octave Editor"),
                           tr ("Could not open file %1 for write:\n%2.").
                           arg (file_to_save).arg (file.errorString ()),
                           QMessageBox::Ok, 0);
      show_dialog (msgBox);

      return;
    }

  // save the contents into the file
  QTextStream out (&file);
  out.setCodec("UTF-8");
  QApplication::setOverrideCursor (Qt::WaitCursor);
  out << _edit_area->text ();
  out.flush ();
  QApplication::restoreOverrideCursor ();
  file.flush ();
  file.close ();

  // file exists now
  file_info = QFileInfo (file);
  file_to_save = file_info.canonicalFilePath ();

  // save file name after closing file as set_file_name starts watching again
  set_file_name (file_to_save);   // make absolute

  // set the window title to actual file name (not modified)
  update_window_title (false);

  // files is save -> not modified
  _edit_area->setModified (false);

  if (remove_on_success)
    {
      emit tab_remove_request ();
      return;  // Don't touch member variables after removal
    }
}

void
file_editor_tab::save_file_as (bool remove_on_success)
{
  // Simply put up the file chooser dialog box with a slot connection
  // then return control to the system waiting for a file selection.

  // If the tab is removed in response to a QFileDialog signal, the tab
  // can't be a parent.
  QFileDialog* fileDialog;
  if (remove_on_success)
    {
      // If tab is closed, "this" cannot be parent in which case modality
      // has no effect.  Disable editing instead.
      _edit_area->setReadOnly (true);
      fileDialog = new QFileDialog ();
    }
  else
    fileDialog = new QFileDialog (this);

  // Giving trouble under KDE (problem is related to Qt signal handling on unix,
  // see https://bugs.kde.org/show_bug.cgi?id=260719 ,
  // it had/has no effect on Windows, though)
  fileDialog->setOption(QFileDialog::DontUseNativeDialog, true);

  if (valid_file_name ())
    {
      fileDialog->selectFile (_file_name);
    }
  else
    {
      fileDialog->selectFile ("");

      if (_file_name.isEmpty ())
        fileDialog->setDirectory (QDir::currentPath ());
      else
        {
          // The file name is actually the directory name from the
          // constructor argument.
          fileDialog->setDirectory (_file_name);
        }
    }

  fileDialog->setNameFilter (tr ("Octave Files (*.m);;All Files (*)"));
  fileDialog->setDefaultSuffix ("m");
  fileDialog->setAcceptMode (QFileDialog::AcceptSave);
  fileDialog->setViewMode (QFileDialog::Detail);

  if (remove_on_success)
    {
      connect (fileDialog, SIGNAL (fileSelected (const QString&)),
               this, SLOT (handle_save_file_as_answer_close (const QString&)));

      connect (fileDialog, SIGNAL (rejected ()),
               this, SLOT (handle_save_file_as_answer_cancel ()));
    }
  else
    {
      connect (fileDialog, SIGNAL (fileSelected (const QString&)),
               this, SLOT (handle_save_file_as_answer (const QString&)));
    }

  show_dialog (fileDialog);
}

bool
file_editor_tab::check_valid_identifier (QString file_name)
{
  QFileInfo file = QFileInfo (file_name);
  QString base_name = file.baseName ();

  if ((file.suffix () == "m")
      && (! valid_identifier (base_name.toStdString ())))
    {
      int ans = QMessageBox::question (0, tr ("Octave Editor"),
         tr ("\"%1\"\n"
             "is not a valid identifier.\n\n"
             "If you keep this file name, you will not be able to\n"
             "call your script using its name as an Octave command.\n\n"
             "Do you want to choose another name?").arg (base_name),
          QMessageBox::Yes | QMessageBox::No, QMessageBox::Yes);

      if (ans == QMessageBox::Yes)
        return true;
    }

  return false;
}

void
file_editor_tab::handle_save_file_as_answer (const QString& saveFileName)
{
  if (saveFileName == _file_name)
    {
      // same name as actual file, save it as "save" would do
      save_file (saveFileName);
    }
  else
    {
      // Have editor check for conflict, do not delete tab after save.
      if (check_valid_identifier (saveFileName))
        save_file_as (false);
      else
        emit editor_check_conflict_save (saveFileName, false);
    }
}

void
file_editor_tab::handle_save_file_as_answer_close (const QString& saveFileName)
{
  // saveFileName == _file_name can not happen, because we only can get here
  // when we close a tab and _file_name is not a valid file name yet

  // Have editor check for conflict, delete tab after save.
  if (check_valid_identifier (saveFileName))
    save_file_as (true);
  else
    emit editor_check_conflict_save (saveFileName, true);
}

void
file_editor_tab::handle_save_file_as_answer_cancel ()
{
  // User canceled, allow editing again.
  _edit_area->setReadOnly (false);
}

void
file_editor_tab::file_has_changed (const QString&)
{
  // Prevent popping up multiple message boxes when the file has
  // been changed multiple times by temporarily removing from the
  // file watcher.
  QStringList trackedFiles = _file_system_watcher.files ();
  if (!trackedFiles.isEmpty ())
    _file_system_watcher.removePath (_file_name);

  if (QFile::exists (_file_name))
    {
      // Create a WindowModal message that blocks the edit area
      // by making _edit_area parent.
      QMessageBox* msgBox
        = new QMessageBox (QMessageBox::Warning,
                           tr ("Octave Editor"),
                           tr ("It seems that \'%1\' has been modified by another application. Do you want to reload it?").
                           arg (_file_name),
                           QMessageBox::Yes | QMessageBox::No, this);

      connect (msgBox, SIGNAL (finished (int)),
               this, SLOT (handle_file_reload_answer (int)));

      msgBox->setWindowModality (Qt::WindowModal);
      msgBox->setAttribute (Qt::WA_DeleteOnClose);
      msgBox->show ();
    }
  else
    {
      QString modified = "";
      if (_edit_area->isModified ())
        modified = tr ("\n\nWarning: The contents in the editor is modified!");

      // Create a WindowModal message. The file editor tab can't be made
      // parent because it may be deleted depending upon the response.
      // Instead, change the _edit_area to read only.
      QMessageBox* msgBox
        = new QMessageBox (QMessageBox::Warning, tr ("Octave Editor"),
                           tr ("It seems that the file\n"
                               "%1\n"
                               "has been deleted or renamed. Do you want to save it now?%2").
                           arg (_file_name).arg (modified),
                           QMessageBox::Save | QMessageBox::Close, 0);

      _edit_area->setReadOnly (true);

      connect (msgBox, SIGNAL (finished (int)),
               this, SLOT (handle_file_resave_answer (int)));

      msgBox->setWindowModality (Qt::WindowModal);
      msgBox->setAttribute (Qt::WA_DeleteOnClose);
      msgBox->show ();
    }
}

void
file_editor_tab::notice_settings (const QSettings *settings)
{
  // QSettings pointer is checked before emitting.

  update_lexer ();

  // code folding
  if (settings->value ("editor/code_folding",true).toBool ())
    {
      _edit_area->setMarginType (3, QsciScintilla::SymbolMargin);
      _edit_area->setFolding (QsciScintilla::BoxedTreeFoldStyle , 3);
    }
  else
    {
      _edit_area->setFolding (QsciScintilla::NoFoldStyle, 3);
    }

  // status bar
  if (settings->value ("editor/show_edit_status_bar",true).toBool ())
    _status_bar->show ();
  else
    _status_bar->hide ();

  //highlight current line color
  QVariant default_var = QColor (240, 240, 240);
  QColor setting_color = settings->value ("editor/highlight_current_line_color",
                                          default_var).value<QColor> ();
  _edit_area->setCaretLineBackgroundColor (setting_color);
  _edit_area->setCaretLineVisible
    (settings->value ("editor/highlightCurrentLine", true).toBool ());

  bool match_keywords = settings->value
                            ("editor/codeCompletion_keywords",true).toBool ();
  bool match_document = settings->value
                            ("editor/codeCompletion_document",true).toBool ();

  QsciScintilla::AutoCompletionSource source = QsciScintilla::AcsNone;
  if (match_keywords)
    if (match_document)
      source = QsciScintilla::AcsAll;
    else
      source = QsciScintilla::AcsAPIs;
  else if (match_document)
    source = QsciScintilla::AcsDocument;
  _edit_area->setAutoCompletionSource (source);

  _edit_area->setAutoCompletionReplaceWord
      (settings->value ("editor/codeCompletion_replace",false).toBool ());
  _edit_area->setAutoCompletionCaseSensitivity
      (settings->value ("editor/codeCompletion_case",true).toBool ());

  if (settings->value ("editor/codeCompletion", true).toBool ())
    _edit_area->setAutoCompletionThreshold
      (settings->value ("editor/codeCompletion_threshold",2).toInt ());
  else
    _edit_area->setAutoCompletionThreshold (-1);

  if (settings->value ("editor/show_white_space",false).toBool ())
    if (settings->value ("editor/show_white_space_indent",false).toBool ())
      _edit_area->setWhitespaceVisibility (QsciScintilla::WsVisibleAfterIndent);
    else
      _edit_area->setWhitespaceVisibility (QsciScintilla::WsVisible);
  else
    _edit_area->setWhitespaceVisibility (QsciScintilla::WsInvisible);

  if (settings->value ("editor/showLineNumbers", true).toBool ())
    {
      _edit_area->setMarginLineNumbers (2, true);
      auto_margin_width ();
      connect (_edit_area, SIGNAL (linesChanged ()),
               this, SLOT (auto_margin_width ()));
    }
  else
    {
      _edit_area->setMarginLineNumbers (2, false);
      disconnect (_edit_area, SIGNAL (linesChanged ()), 0, 0);
    }

  _edit_area->setAutoIndent
        (settings->value ("editor/auto_indent",true).toBool ());
  _edit_area->setTabIndents
        (settings->value ("editor/tab_indents_line",false).toBool ());
  _edit_area->setBackspaceUnindents
        (settings->value ("editor/backspace_unindents_line",false).toBool ());
  _edit_area->setIndentationGuides
        (settings->value ("editor/show_indent_guides",false).toBool ());

  _edit_area->setTabWidth
        (settings->value ("editor/tab_width",2).toInt ());

  _long_title = settings->value ("editor/longWindowTitle", false).toBool ();
  update_window_title (_edit_area->isModified ());

  _edit_area->setEdgeColumn (
              settings->value ("editor/long_line_column",80).toInt ());
  if (settings->value ("editor/long_line_marker",true).toBool ())
    _edit_area->setEdgeMode (QsciScintilla::EdgeLine);
  else
    _edit_area->setEdgeMode (QsciScintilla::EdgeNone);

}

void
file_editor_tab::auto_margin_width ()
{
  _edit_area->setMarginWidth (2, "1"+QString::number (_edit_area->lines ()));
}

void
file_editor_tab::conditional_close (const QWidget *ID, bool app_closing)
{
  if (ID != this)
    return;

  _app_closing = app_closing;
  close ();
}

void
file_editor_tab::change_editor_state (const QWidget *ID)
{
  if (ID != this)
    {
      // Widget may be going out of focus.  If so, record location.
      if (_find_dialog)
        {
          if (_find_dialog->isVisible ())
            {
              _find_dialog_geometry = _find_dialog->geometry ();
              _find_dialog->hide ();
            }
        }
      return;
    }

  if (_find_dialog && _find_dialog_is_visible)
    {
      _find_dialog->setGeometry (_find_dialog_geometry);
      _find_dialog->show ();
    }

  emit editor_state_changed (_copy_available, QDir::cleanPath (_file_name),
                             _is_octave_file);
}

void
file_editor_tab::file_name_query (const QWidget *ID)
{
  // A zero (null pointer) means that all file editor tabs
  // should respond, otherwise just the desired file editor tab.
  if (ID != this && ID != 0)
    return;

  // Unnamed files shouldn't be transmitted.
  if (!_file_name.isEmpty ())
    emit add_filename_to_list (_file_name, this);
}

void
file_editor_tab::handle_file_reload_answer (int decision)
{
  if (decision == QMessageBox::Yes)
    {
      // reload: file is readded to the file watcher in set_file_name ()
      load_file (_file_name);
    }
  else
    {
      // do not reload: readd to the file watche
      _file_system_watcher.addPath (_file_name);
    }
}

void
file_editor_tab::handle_file_resave_answer (int decision)
{
  // check decision of user in dialog
  if (decision == QMessageBox::Save)
    {
      save_file (_file_name);  // readds file to watcher in set_file_name ()
      _edit_area->setReadOnly (false);  // delete read only flag
    }
  else
    {
      // Definitely close the file.
      // Set modified to false to prevent the dialog box when the close event
      // is posted. If the user cancels the close in this dialog the tab is
      // left open with a non-existing file.
      _edit_area->setModified (false);
      close ();
    }
}

void
file_editor_tab::insert_debugger_pointer (const QWidget *ID, int line)
{
  if (ID != this || ID == 0)
    return;

  if (line > 0)
    {
      _edit_area->markerAdd (line-1, debugger_position);
      center_current_line ();
    }
}

void
file_editor_tab::delete_debugger_pointer (const QWidget *ID, int line)
{
  if (ID != this || ID == 0)
    return;

  if (line > 0)
    _edit_area->markerDelete (line-1, debugger_position);
}

void
file_editor_tab::do_breakpoint_marker (bool insert, const QWidget *ID, int line)
{
  if (ID != this || ID == 0)
    return;

  if (line > 0)
    {
      if (insert)
        _edit_area->markerAdd (line-1, breakpoint);
      else
        _edit_area->markerDelete (line-1, breakpoint);
    }
}


void
file_editor_tab::center_current_line ()
{
  long int visible_lines
    = _edit_area->SendScintilla (QsciScintillaBase::SCI_LINESONSCREEN);

  if (visible_lines > 2)
    {
      int line, index;
      _edit_area->getCursorPosition (&line, &index);

      int first_line = _edit_area->firstVisibleLine ();
      first_line = first_line + (line - first_line - (visible_lines-1)/2);

      _edit_area->SendScintilla (2613,first_line); // SCI_SETFIRSTVISIBLELINE
    }
}

void 
file_editor_tab::handle_cursor_moved (int line, int col)
{
  if (_edit_area->SendScintilla (QsciScintillaBase::SCI_AUTOCACTIVE))
    show_auto_completion (this);

  _row_indicator->setNum (line+1);
  _col_indicator->setNum (col+1);
}

void
file_editor_tab::create_context_menu (QMenu *menu)
{
  emit create_context_menu_tab_signal (menu);
}

void
file_editor_tab::edit_area_has_focus (bool focus)
{
  emit set_global_edit_shortcuts_signal (! focus);
}

#endif