From 5674786acd9574a52b9149966043c246baddc7c0 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Mon, 30 Oct 2023 15:25:06 -0400
Subject: [PATCH] add feature to comment out and uncomment lines and selections
 from context menu

---
 tools/lammps-gui/CMakeLists.txt |  2 +-
 tools/lammps-gui/codeeditor.cpp | 96 +++++++++++++++++++++++++++++++--
 tools/lammps-gui/codeeditor.h   |  4 ++
 3 files changed, 98 insertions(+), 4 deletions(-)

diff --git a/tools/lammps-gui/CMakeLists.txt b/tools/lammps-gui/CMakeLists.txt
index e83db05fdd..caae722865 100644
--- a/tools/lammps-gui/CMakeLists.txt
+++ b/tools/lammps-gui/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.16)
 
-project(lammps-gui VERSION 1.5.9 LANGUAGES CXX)
+project(lammps-gui VERSION 1.5.10 LANGUAGES CXX)
 
 set(CMAKE_AUTOUIC ON)
 set(CMAKE_AUTOMOC ON)
diff --git a/tools/lammps-gui/codeeditor.cpp b/tools/lammps-gui/codeeditor.cpp
index 672c009c35..ab8007805a 100644
--- a/tools/lammps-gui/codeeditor.cpp
+++ b/tools/lammps-gui/codeeditor.cpp
@@ -34,6 +34,7 @@
 #include <QShortcut>
 #include <QStringListModel>
 #include <QTextBlock>
+#include <QTextDocumentFragment>
 #include <QUrl>
 
 #include <string>
@@ -424,7 +425,7 @@ void CodeEditor::setVarNameList()
 
     LammpsWrapper *lammps = &qobject_cast<LammpsGui *>(parent())->lammps;
     int nvar              = lammps->id_count("variable");
-    constexpr int BUFLEN = 256;
+    constexpr int BUFLEN  = 256;
     char buffer[BUFLEN];
     for (int i = 0; i < nvar; ++i) {
         memset(buffer, 0, BUFLEN);
@@ -683,17 +684,34 @@ void CodeEditor::contextMenuEvent(QContextMenuEvent *event)
     QString page, help;
     find_help(page, help);
 
-    // print augmented context menu if an entry was found
     auto *menu = createStandardContextMenu();
     menu->addSeparator();
+    if (textCursor().hasSelection()) {
+        auto action1 = menu->addAction("Comment out selection");
+        action1->setIcon(QIcon(":/icons/expand-text.png"));
+        connect(action1, &QAction::triggered, this, &CodeEditor::comment_selection);
+        auto action2 = menu->addAction("Uncomment selection");
+        action2->setIcon(QIcon(":/icons/expand-text.png"));
+        connect(action2, &QAction::triggered, this, &CodeEditor::uncomment_selection);
+    } else {
+        auto action1 = menu->addAction("Comment out line");
+        action1->setIcon(QIcon(":/icons/expand-text.png"));
+        connect(action1, &QAction::triggered, this, &CodeEditor::comment_line);
+        auto action2 = menu->addAction("Uncomment line");
+        action2->setIcon(QIcon(":/icons/expand-text.png"));
+        connect(action2, &QAction::triggered, this, &CodeEditor::uncomment_line);
+    }
+    menu->addSeparator();
+
+    // print augmented context menu if an entry was found
     if (!help.isEmpty()) {
         auto action = menu->addAction(QString("Display available completions for '%1'").arg(help));
         action->setIcon(QIcon(":/icons/expand-text.png"));
         connect(action, &QAction::triggered, this, &CodeEditor::runCompletion);
+        menu->addSeparator();
     }
 
     if (!page.isEmpty()) {
-        menu->addSeparator();
         auto action = menu->addAction(QString("Reformat '%1' command").arg(help));
         action->setIcon(QIcon(":/icons/format-indent-less-3.png"));
         connect(action, &QAction::triggered, this, &CodeEditor::reformatCurrentLine);
@@ -741,6 +759,78 @@ void CodeEditor::reformatCurrentLine()
     }
 }
 
+void CodeEditor::comment_line()
+{
+    auto cursor = textCursor();
+    cursor.movePosition(QTextCursor::StartOfLine);
+    cursor.insertText("#");
+}
+
+void CodeEditor::comment_selection()
+{
+    auto cursor = textCursor();
+    auto text   = cursor.selection().toPlainText();
+    auto lines  = text.split('\n');
+    QString newtext;
+    for (auto line : lines) {
+        newtext.append('#');
+        newtext.append(line);
+        newtext.append('\n');
+    }
+    if (newtext.isEmpty()) newtext = "#\n";
+    cursor.insertText(newtext);
+    setTextCursor(cursor);
+}
+
+void CodeEditor::uncomment_selection()
+{
+    auto cursor = textCursor();
+    auto text   = cursor.selection().toPlainText();
+    auto lines  = text.split('\n');
+    QString newtext;
+    for (auto line : lines) {
+        QString newline;
+        bool start = true;
+        for (auto letter : line) {
+            if (start && (letter == '#')) {
+                start = false;
+                continue;
+            }
+            if (start && !letter.isSpace()) start = false;
+            newline.append(letter);
+        }
+        newtext.append(newline);
+        newtext.append('\n');
+    }
+    cursor.insertText(newtext);
+    setTextCursor(cursor);
+}
+
+void CodeEditor::uncomment_line()
+{
+    auto cursor = textCursor();
+    auto text   = cursor.block().text();
+    QString newtext;
+    bool start = true;
+    for (auto letter : text) {
+        if (start && (letter == '#')) {
+            start = false;
+            continue;
+        }
+        if (start && !letter.isSpace()) start = false;
+        newtext.append(letter);
+    }
+
+    // perform edit but only if text has changed
+    if (QString::compare(text, newtext)) {
+        cursor.beginEditBlock();
+        cursor.movePosition(QTextCursor::StartOfLine);
+        cursor.movePosition(QTextCursor::EndOfLine, QTextCursor::KeepAnchor, 1);
+        cursor.insertText(newtext);
+        cursor.endEditBlock();
+    }
+}
+
 void CodeEditor::runCompletion()
 {
     QAbstractItemView *popup = nullptr;
diff --git a/tools/lammps-gui/codeeditor.h b/tools/lammps-gui/codeeditor.h
index 703b2ffd3c..744953af06 100644
--- a/tools/lammps-gui/codeeditor.h
+++ b/tools/lammps-gui/codeeditor.h
@@ -81,6 +81,10 @@ private slots:
     void reformatCurrentLine();
     void runCompletion();
     void insertCompletedCommand(const QString &completion);
+    void comment_selection();
+    void uncomment_selection();
+    void comment_line();
+    void uncomment_line();
 
 private:
     QWidget *lineNumberArea;