From 5995391ef9f7f3e2671df7d1666e6b70d2494353 Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Wed, 4 Aug 2021 01:55:08 -0400
Subject: [PATCH] Add basic module selection dragging.

---
 include/app/RackWidget.hpp |  1 +
 src/app/ModuleWidget.cpp   | 22 ++++++++++-----
 src/app/RackWidget.cpp     | 58 +++++++++++++++++++++++---------------
 3 files changed, 52 insertions(+), 29 deletions(-)

diff --git a/include/app/RackWidget.hpp b/include/app/RackWidget.hpp
index c2beee26..b866ff90 100644
--- a/include/app/RackWidget.hpp
+++ b/include/app/RackWidget.hpp
@@ -78,6 +78,7 @@ struct RackWidget : widget::OpaqueWidget {
 	void disconnectSelectedModulesAction();
 	void bypassSelectedModulesAction();
 	void deleteSelectedModulesAction();
+	bool requestSelectedModulePos(math::Vec delta);
 
 	// Cable methods
 
diff --git a/src/app/ModuleWidget.cpp b/src/app/ModuleWidget.cpp
index 39d8fc99..61b953b5 100644
--- a/src/app/ModuleWidget.cpp
+++ b/src/app/ModuleWidget.cpp
@@ -402,9 +402,10 @@ void ModuleWidget::onDragEnd(const DragEndEvent& e) {
 		internal->dragEnabled = true;
 
 		history::ComplexAction* h = APP->scene->rack->getModuleDragAction();
-		if (!h)
-			return;
-		APP->history->push(h);
+		if (!h->isEmpty())
+			APP->history->push(h);
+		else
+			delete h;
 	}
 }
 
@@ -429,10 +430,17 @@ void ModuleWidget::onDragMove(const DragMoveEvent& e) {
 				math::Vec pos = mousePos;
 				pos.x -= internal->dragOffset.x;
 				pos.y -= RACK_GRID_HEIGHT / 2;
-				if ((APP->window->getMods() & RACK_MOD_MASK) == RACK_MOD_CTRL)
-					APP->scene->rack->setModulePosForce(this, pos);
-				else
-					APP->scene->rack->setModulePosNearest(this, pos);
+				if (internal->selected) {
+					pos = (pos / RACK_GRID_SIZE).round() * RACK_GRID_SIZE;
+					math::Vec delta = pos.minus(box.pos);
+					APP->scene->rack->requestSelectedModulePos(delta);
+				}
+				else {
+					if ((APP->window->getMods() & RACK_MOD_MASK) == RACK_MOD_CTRL)
+						APP->scene->rack->setModulePosForce(this, pos);
+					else
+						APP->scene->rack->setModulePosNearest(this, pos);
+				}
 			}
 		}
 	}
diff --git a/src/app/RackWidget.cpp b/src/app/RackWidget.cpp
index b9fd9eef..a0f14c7b 100644
--- a/src/app/RackWidget.cpp
+++ b/src/app/RackWidget.cpp
@@ -206,12 +206,9 @@ void RackWidget::clear() {
 	// This isn't required because removing all ModuleWidgets should remove all cables, but do it just in case.
 	clearCables();
 	// Remove ModuleWidgets
-	std::list<widget::Widget*> widgets = internal->moduleContainer->children;
-	for (widget::Widget* w : widgets) {
-		ModuleWidget* moduleWidget = dynamic_cast<ModuleWidget*>(w);
-		assert(moduleWidget);
-		removeModule(moduleWidget);
-		delete moduleWidget;
+	for (ModuleWidget* mw : getModules()) {
+		removeModule(mw);
+		delete mw;
 	}
 }
 
@@ -486,9 +483,6 @@ bool RackWidget::requestModulePos(ModuleWidget* mw, math::Vec pos) {
 		// Don't intersect with self
 		if (mw == w2)
 			continue;
-		// Don't intersect with invisible modules
-		if (!w2->visible)
-			continue;
 		// Check intersection
 		math::Rect w2Box = w2->box;
 		if (mwBox.intersects(w2Box))
@@ -628,9 +622,7 @@ bool RackWidget::hasModules() {
 
 void RackWidget::updateModuleOldPositions() {
 	// Set all modules' oldPos field from their current position.
-	for (widget::Widget* w : internal->moduleContainer->children) {
-		ModuleWidget* mw = dynamic_cast<ModuleWidget*>(w);
-		assert(mw);
+	for (ModuleWidget* mw : getModules()) {
 		mw->oldPos() = mw->box.pos;
 	}
 }
@@ -638,9 +630,7 @@ void RackWidget::updateModuleOldPositions() {
 history::ComplexAction* RackWidget::getModuleDragAction() {
 	history::ComplexAction* h = new history::ComplexAction;
 
-	for (widget::Widget* w : internal->moduleContainer->children) {
-		ModuleWidget* mw = dynamic_cast<ModuleWidget*>(w);
-		assert(mw);
+	for (ModuleWidget* mw : getModules()) {
 		// Create ModuleMove action if the module was moved.
 		math::Vec oldPos = mw->oldPos();
 		if (!oldPos.equals(mw->box.pos)) {
@@ -652,18 +642,12 @@ history::ComplexAction* RackWidget::getModuleDragAction() {
 		}
 	}
 
-	if (h->isEmpty()) {
-		delete h;
-		return NULL;
-	}
 	return h;
 }
 
 void RackWidget::updateModuleSelections() {
 	math::Rect selectionBox = math::Rect::fromCorners(internal->selectionStart, internal->selectionEnd);
-	for (widget::Widget* w : internal->moduleContainer->children) {
-		ModuleWidget* mw = dynamic_cast<ModuleWidget*>(w);
-		assert(mw);
+	for (ModuleWidget* mw : getModules()) {
 		bool selected = internal->selecting && selectionBox.intersects(mw->box);
 		mw->selected() = selected;
 	}
@@ -770,6 +754,36 @@ void RackWidget::deleteSelectedModulesAction() {
 	APP->history->push(complexAction);
 }
 
+bool RackWidget::requestSelectedModulePos(math::Vec delta) {
+	// Check intersection with other modules
+	std::map<widget::Widget*, math::Rect> mwBoxes;
+	for (ModuleWidget* mw : getSelectedModules()) {
+		math::Rect mwBox = mw->box;
+		mwBox.pos += delta;
+		mwBoxes[mw] = mwBox;
+	}
+
+	for (widget::Widget* w2 : internal->moduleContainer->children) {
+		// Don't intersect with selected modules
+		auto it = mwBoxes.find(w2);
+		if (it != mwBoxes.end())
+			continue;
+		math::Rect w2Box = w2->box;
+		// Check intersection with all selected modules
+		for (const auto& pair : mwBoxes) {
+			if (pair.second.intersects(w2Box))
+				return false;
+		}
+	}
+
+	// Accept requested position
+	for (const auto& pair : mwBoxes) {
+		pair.first->setPosition(pair.second.pos);
+	}
+	RackWidget_updateExpanders(this);
+	return true;
+}
+
 void RackWidget::clearCables() {
 	incompleteCable = NULL;
 	internal->cableContainer->clearChildren();