From 01ad572499aa39f52e8cd6e5afe706b22f773d3e Mon Sep 17 00:00:00 2001
From: Gary Talent <gtalent2@gmail.com>
Date: Tue, 3 Dec 2019 18:01:00 -0600
Subject: [PATCH] [nostalgia/core/studio] Make Pixel updates in TileSheetEditor
 use undo stack

---
 src/nostalgia/core/studio/consts.hpp          |  5 ++
 src/nostalgia/core/studio/tilesheeteditor.cpp | 81 +++++++++++++++++--
 src/nostalgia/core/studio/tilesheeteditor.hpp |  3 +
 3 files changed, 83 insertions(+), 6 deletions(-)

diff --git a/src/nostalgia/core/studio/consts.hpp b/src/nostalgia/core/studio/consts.hpp
index e6b22e50..1aa1b904 100644
--- a/src/nostalgia/core/studio/consts.hpp
+++ b/src/nostalgia/core/studio/consts.hpp
@@ -12,4 +12,9 @@ namespace nostalgia::core {
 
 constexpr auto PluginName = "NostalgiaCore";
 
+// Command IDs to use with QUndoCommand::id()
+enum class CommandId {
+	UpdatePixel = 1,
+};
+
 }
diff --git a/src/nostalgia/core/studio/tilesheeteditor.cpp b/src/nostalgia/core/studio/tilesheeteditor.cpp
index 8b2ed192..f07d7350 100644
--- a/src/nostalgia/core/studio/tilesheeteditor.cpp
+++ b/src/nostalgia/core/studio/tilesheeteditor.cpp
@@ -7,11 +7,13 @@
  */
 
 #include <QHeaderView>
+#include <QPointer>
 #include <QQmlContext>
 #include <QQuickItem>
 #include <QQuickWidget>
 #include <QSettings>
 #include <QSplitter>
+#include <QUndoCommand>
 #include <QVBoxLayout>
 
 #include "consts.hpp"
@@ -28,16 +30,83 @@ QColor toQColor(Color16 nc) {
 }
 
 
+class UpdatePixelsCommand: public QUndoCommand {
+	private:
+		struct PixelUpdate {
+			QPointer<QQuickItem> item;
+			int oldColorId = 0;
+
+			bool operator==(const PixelUpdate &o) const {
+				return item == o.item;
+			}
+
+			bool operator<(const PixelUpdate &o) const {
+				return item < o.item;
+			}
+		};
+
+		uint64_t cmdIdx = 0;
+		int m_newColorId = 0;
+		const QStringList &m_palette;
+		QVector<uint8_t> &m_pixels;
+		QVector<PixelUpdate> m_pixelUpdates;
+
+	public:
+		UpdatePixelsCommand(QVector<uint8_t> &pixels, const QStringList &palette, const QVariantList &pixelItems, int newColorId, uint64_t cmdIdx): m_palette(palette), m_pixels(pixels) {
+			m_newColorId = newColorId;
+			cmdIdx = cmdIdx;
+			for (auto &pi : pixelItems) {
+				PixelUpdate pu;
+				auto p = qobject_cast<QQuickItem*>(pi.value<QObject*>());
+				pu.item = p;
+				pu.oldColorId = m_palette.indexOf(p->property("color").toString());
+				m_pixelUpdates.push_back(std::move(pu));
+			}
+		}
+
+		virtual ~UpdatePixelsCommand() = default;
+
+		int id() const override {
+			return static_cast<int>(CommandId::UpdatePixel);
+		}
+
+		bool mergeWith(const QUndoCommand *cmd) override {
+			auto other = static_cast<const UpdatePixelsCommand*>(cmd);
+			if (cmdIdx == other->cmdIdx) {
+				m_pixelUpdates.append(other->m_pixelUpdates);
+				// inefficient, but probably not worth optimizing, but something to
+				// look at if this operation becomes a performace problem
+				std::sort(m_pixelUpdates.begin(), m_pixelUpdates.end());
+				m_pixelUpdates.erase(std::unique(m_pixelUpdates.begin(), m_pixelUpdates.end()), m_pixelUpdates.end());
+				return true;
+			}
+			return false;
+		}
+
+		void redo() override {
+			for (int i = 0; i < m_pixelUpdates.size(); i++) {
+				const auto &pu = m_pixelUpdates[i];
+				pu.item->setProperty("color", m_palette[m_newColorId]);
+				m_pixels[i] = m_newColorId;
+			}
+		}
+
+		void undo() override {
+			for (int i = 0; i < m_pixelUpdates.size(); i++) {
+				const auto &pu = m_pixelUpdates[i];
+				pu.item->setProperty("color", pu.oldColorId);
+				m_pixels[i] = pu.oldColorId;
+			}
+		}
+};
+
+
 QString SheetData::pixel(int index) {
 	return m_palette[m_pixels[index]];
 }
 
-void SheetData::updatePixels(QVariantList pixels) {
-	for (auto pi : pixels) {
-		// TODO: replace with push to QUndoStack
-		auto p = qobject_cast<QQuickItem*>(pi.value<QObject*>());
-		p->setProperty("color", m_palette[m_selectedColor]);
-	}
+void SheetData::updatePixels(QVariantList pixelItems) {
+	m_cmdStack.push(new UpdatePixelsCommand(m_pixels, m_palette, pixelItems, m_selectedColor, m_cmdIdx++));
 }
 
 int SheetData::columns() {
diff --git a/src/nostalgia/core/studio/tilesheeteditor.hpp b/src/nostalgia/core/studio/tilesheeteditor.hpp
index 1c8aa560..043c72d8 100644
--- a/src/nostalgia/core/studio/tilesheeteditor.hpp
+++ b/src/nostalgia/core/studio/tilesheeteditor.hpp
@@ -12,6 +12,7 @@
 #include <QStringList>
 #include <QStringView>
 #include <QTableWidget>
+#include <QUndoStack>
 #include <QVariant>
 #include <QWidget>
 
@@ -26,6 +27,8 @@ class SheetData: public QObject {
 	Q_PROPERTY(int rows READ rows WRITE setRows NOTIFY rowsChanged)
 
 	private:
+		uint64_t m_cmdIdx = 0;
+		QUndoStack m_cmdStack;
 		QStringList m_palette;
 		QVector<uint8_t> m_pixels;
 		int m_columns = 2;