From 1cbc57628619b342207819f1c98a6c64fe4fc635 Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Sun, 19 Jan 2025 11:41:08 -0600
Subject: [PATCH] [studio] Complete drag/drop support for files

---
 .../studio/applib/src/projecttreemodel.cpp    | 11 +++-------
 .../studio/applib/src/projecttreemodel.hpp    |  8 ++++++-
 .../studio/modlib/include/studio/dragdrop.hpp | 22 +++++++++++++++++++
 .../modlib/include/studio/imguiutil.hpp       |  1 +
 .../studio/modlib/include/studio/studio.hpp   |  1 +
 5 files changed, 34 insertions(+), 9 deletions(-)
 create mode 100644 src/olympic/studio/modlib/include/studio/dragdrop.hpp

diff --git a/src/olympic/studio/applib/src/projecttreemodel.cpp b/src/olympic/studio/applib/src/projecttreemodel.cpp
index 51e945ef..cc7afd1a 100644
--- a/src/olympic/studio/applib/src/projecttreemodel.cpp
+++ b/src/olympic/studio/applib/src/projecttreemodel.cpp
@@ -4,6 +4,7 @@
 
 #include <imgui.h>
 
+#include <studio/dragdrop.hpp>
 #include <studio/imguiutil.hpp>
 
 #include "projectexplorer.hpp"
@@ -54,8 +55,9 @@ void ProjectTreeModel::draw(turbine::Context &tctx) const noexcept {
 				ImGui::EndPopup();
 			}
 			ImGui::TreePop();
-			ig::dragDropSource([this] {
+			std::ignore = ig::dragDropSource([this] {
 				ImGui::Text("%s", m_name.c_str());
+				return ig::setDragDropPayload("FileRef", FileRef{fullPath<ox::String>()});
 			});
 		}
 	}
@@ -80,11 +82,4 @@ void ProjectTreeModel::drawDirContextMenu() const noexcept {
     }
 }
 
-ox::BasicString<255> ProjectTreeModel::fullPath() const noexcept {
-	if (m_parent) {
-		return m_parent->fullPath() + "/" + m_name;
-	}
-	return {};
-}
-
 }
diff --git a/src/olympic/studio/applib/src/projecttreemodel.hpp b/src/olympic/studio/applib/src/projecttreemodel.hpp
index e7060d4e..fdfc1fae 100644
--- a/src/olympic/studio/applib/src/projecttreemodel.hpp
+++ b/src/olympic/studio/applib/src/projecttreemodel.hpp
@@ -32,8 +32,14 @@ class ProjectTreeModel {
 	private:
 		void drawDirContextMenu() const noexcept;
 
+		template<typename Str = ox::BasicString<255>>
 		[[nodiscard]]
-		ox::BasicString<255> fullPath() const noexcept;
+		Str fullPath() const noexcept {
+			if (m_parent) {
+				return m_parent->fullPath<Str>() + "/" + m_name;
+			}
+			return {};
+		}
 
 };
 
diff --git a/src/olympic/studio/modlib/include/studio/dragdrop.hpp b/src/olympic/studio/modlib/include/studio/dragdrop.hpp
new file mode 100644
index 00000000..e75bb040
--- /dev/null
+++ b/src/olympic/studio/modlib/include/studio/dragdrop.hpp
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2016 - 2025 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <ox/std/string.hpp>
+#include <ox/model/def.hpp>
+
+namespace studio {
+
+struct FileRef {
+	static constexpr auto TypeName = "net.drinkingtea.studio.FileRef";
+	static constexpr auto TypeVersion = 1;
+	ox::String path;
+};
+
+OX_MODEL_BEGIN(FileRef)
+	OX_MODEL_FIELD(path)
+OX_MODEL_END()
+
+}
diff --git a/src/olympic/studio/modlib/include/studio/imguiutil.hpp b/src/olympic/studio/modlib/include/studio/imguiutil.hpp
index c82f32e8..60bff752 100644
--- a/src/olympic/studio/modlib/include/studio/imguiutil.hpp
+++ b/src/olympic/studio/modlib/include/studio/imguiutil.hpp
@@ -63,6 +63,7 @@ auto dragDropSource(auto const&cb) noexcept {
 		if (ig::DragDropSource const tgt; tgt) [[unlikely]] {
 			return cb();
 		}
+		return ox::Error{};
 	} else {
 		if (ig::DragDropSource const tgt; tgt) [[unlikely]] {
 			cb();
diff --git a/src/olympic/studio/modlib/include/studio/studio.hpp b/src/olympic/studio/modlib/include/studio/studio.hpp
index b18e8263..cd747473 100644
--- a/src/olympic/studio/modlib/include/studio/studio.hpp
+++ b/src/olympic/studio/modlib/include/studio/studio.hpp
@@ -6,6 +6,7 @@
 
 #include <studio/configio.hpp>
 #include <studio/context.hpp>
+#include <studio/dragdrop.hpp>
 #include <studio/editor.hpp>
 #include <studio/filedialog.hpp>
 #include <studio/imguiutil.hpp>