LibGUI: Indent selected text on tab press

If selected text is less than a whole line, usual delete/replace takes
place. Otherwise, if the selected text is a whole line or spans
multiple lines, the selection will be indented.

1 files changed, 27 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGUI/TextDocument.cpp b/Userland/Libraries/LibGUI/TextDocument.cpp
index 10a8f76cb3..cc0f60d1ad 100644
--- a/Userland/Libraries/LibGUI/TextDocument.cpp
+++ b/Userland/Libraries/LibGUI/TextDocument.cpp
@@ -932,6 +932,33 @@ String ReplaceAllTextCommand::action_text() const
     return m_action_text;
 }
 
+IndentSelection::IndentSelection(TextDocument& document, size_t tab_width, TextRange const& range)
+    : TextDocumentUndoCommand(document)
+    , m_tab_width(tab_width)
+    , m_range(range)
+{
+}
+
+void IndentSelection::redo()
+{
+    auto const tab = String::repeated(' ', m_tab_width);
+
+    for (size_t i = m_range.start().line(); i <= m_range.end().line(); i++) {
+        m_document.insert_at({ i, 0 }, tab, m_client);
+    }
+
+    m_document.set_all_cursors(m_range.start());
+}
+
+void IndentSelection::undo()
+{
+    for (size_t i = m_range.start().line(); i <= m_range.end().line(); i++) {
+        m_document.remove({ { i, 0 }, { i, m_tab_width } });
+    }
+
+    m_document.set_all_cursors(m_range.start());
+}
+
 TextPosition TextDocument::insert_at(TextPosition const& position, StringView text, Client const* client)
 {
     TextPosition cursor = position;