From 78df5c305ee3d5824dbcd7786f6dc7df7556427f Mon Sep 17 00:00:00 2001
From: Iris Morelle <shadowm@wesnoth.org>
Date: Sat, 16 Nov 2019 05:08:14 -0300
Subject: [PATCH] gui2/edit_text: Add an option to disallow whitespace-only
 input

---
 src/gui/dialogs/edit_text.cpp | 31 +++++++++++++++++++++++++++++--
 src/gui/dialogs/edit_text.hpp | 11 ++++++++++-
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/gui/dialogs/edit_text.cpp b/src/gui/dialogs/edit_text.cpp
index 869f140be49..d3deb983cb9 100644
--- a/src/gui/dialogs/edit_text.cpp
+++ b/src/gui/dialogs/edit_text.cpp
@@ -16,7 +16,12 @@
 
 #include "gui/dialogs/edit_text.hpp"
 
+#include "gui/auxiliary/field.hpp"
+#include "gui/widgets/button.hpp"
 #include "gui/widgets/settings.hpp"
+#include "gui/widgets/text_box.hpp"
+
+#include <boost/algorithm/string/trim.hpp>
 
 namespace gui2
 {
@@ -41,14 +46,36 @@ namespace dialogs
 
 REGISTER_DIALOG(edit_text)
 
-//TODO: add  a way to disallow certain characters (like spaces or ")
 edit_text::edit_text(const std::string& title,
 					   const std::string& label,
-					   std::string& text)
+					   std::string& text,
+					   bool disallow_empty)
+	: disallow_empty_(disallow_empty)
 {
 	register_label("title", true, title, true);
 	register_label("label", true, label, true);
 	register_text("text", true, text, true);
 }
+
+void edit_text::pre_show(window& window)
+{
+	if(disallow_empty_) {
+		text_box& text = find_widget<text_box>(&window, "text", false);
+		connect_signal_notify_modified(text, std::bind(&edit_text::on_text_change, this));
+		on_text_change();
+	}
+}
+
+void edit_text::on_text_change()
+{
+	text_box& text = find_widget<text_box>(get_window(), "text", false);
+	button& ok_button = find_widget<button>(get_window(), "ok", false);
+
+	auto clean_value = text.get_value();
+	boost::trim(clean_value);
+
+	ok_button.set_active(!boost::trim_copy(text.get_value()).empty());
+}
+
 } // namespace dialogs
 } // namespace gui2
diff --git a/src/gui/dialogs/edit_text.hpp b/src/gui/dialogs/edit_text.hpp
index 29d61b5d1c4..def5b874d41 100644
--- a/src/gui/dialogs/edit_text.hpp
+++ b/src/gui/dialogs/edit_text.hpp
@@ -34,10 +34,13 @@ public:
 	 *                            - Output: The new unit name the user entered
 	 *                              if the dialog returns @ref retval::OK,
 	 *                              undefined otherwise.
+	 * @param disallow_empty      Whether to prevent the user from entering a string that is
+	 *                            empty or consists only of whitespace.
 	 */
 	edit_text(const std::string& title,
 			   const std::string& label,
-			   std::string& text);
+			   std::string& text,
+			   bool disallow_empty = false);
 
 	/**
 	 * Executes the dialog.
@@ -54,6 +57,12 @@ public:
 private:
 	/** Inherited from modal_dialog, implemented by REGISTER_DIALOG. */
 	virtual const std::string& window_id() const override;
+
+	virtual void pre_show(window& window) override;
+
+	void on_text_change();
+
+	bool disallow_empty_;
 };
 } // namespace dialogs
 } // namespace gui2