Move towards editor undo (surge-synthesizer#6004)

This is a basic infrastucture which moves us towards undo
in an editor. Lots missing here all detailed in a checklist
in surge-synthesizer#694 but with this commit parameter changes, modulation changes,
osc and fx changes all push into the undo stack. Use a simple limit
of 250 gestures per instance captured.

src/surge-xt/CMakeLists.txt

@@ -95,6 +95,7 @@ target_sources(${PROJECT_NAME} PRIVATE
   gui/SurgeJUCEHelpers.h
   gui/SurgeJUCELookAndFeel.cpp
   gui/SurgeJUCELookAndFeel.h
+  gui/UndoManager.cpp
   gui/overlays/AboutScreen.cpp
   gui/overlays/AboutScreen.h
   gui/overlays/CoveringMessageOverlay.cpp

src/surge-xt/SurgeSynthProcessor.cpp

@@ -15,6 +15,11 @@
 #include "version.h"
 #include "sst/plugininfra/cpufeatures.h"
 
+/*
+ * This is a bit odd but - this is an editor concept with the lifetime of the processor
+ */
+#include "gui/UndoManager.h"
+
 //==============================================================================
 SurgeSynthProcessor::SurgeSynthProcessor()
     : juce::AudioProcessor(BusesProperties()
@@ -429,7 +434,9 @@ void SurgeSynthProcessor::surgeParameterUpdated(const SurgeSynthesizer::ID &id,
 {
     auto spar = paramsByID[id];
     if (spar)
+    {
         spar->setValueNotifyingHost(f);
+    }
 }
 
 void SurgeSynthProcessor::surgeMacroUpdated(const long id, float f)

src/surge-xt/SurgeSynthProcessor.h

@@ -26,6 +26,14 @@
 #include <execinfo.h>
 #endif
 
+namespace Surge
+{
+namespace GUI
+{
+struct UndoManager;
+}
+} // namespace Surge
+
 //==============================================================================
 /**
  */
@@ -247,5 +255,9 @@ class SurgeSynthProcessor : public juce::AudioProcessor,
 
     int checkNamesEvery = 0;
 
+  public:
+    std::unique_ptr<Surge::GUI::UndoManager> undoManager;
+
+  private:
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(SurgeSynthProcessor)
 };

src/surge-xt/gui/SurgeGUIEditor.cpp

@@ -418,6 +418,11 @@ SurgeGUIEditor::SurgeGUIEditor(SurgeSynthEditor *jEd, SurgeSynthesizer *synth)
     juce::Desktop::getInstance().addFocusChangeListener(this);
 
     setupKeymapManager();
+
+    if (!juceEditor->processor.undoManager)
+        juceEditor->processor.undoManager =
+            std::make_unique<Surge::GUI::UndoManager>(this, this->synth);
+    juceEditor->processor.undoManager->resetEditor(this);
 }
 
 SurgeGUIEditor::~SurgeGUIEditor()
@@ -2143,6 +2148,20 @@ void SurgeGUIEditor::controlBeginEdit(Surge::GUI::IComponentTagValue *control)
     int ptag = tag - start_paramtags;
     if (ptag >= 0 && ptag < synth->storage.getPatch().param_ptr.size())
     {
+        if (mod_editor)
+        {
+            auto mci = dynamic_cast<Surge::Widgets::ModulatableControlInterface *>(control);
+            if (mci)
+            {
+                undoManager()->pushModulationChange(ptag, modsource, current_scene, modsource_index,
+                                                    mci->modValue);
+            }
+        }
+        else
+        {
+            undoManager()->pushParameterChange(ptag,
+                                               synth->storage.getPatch().param_ptr[ptag]->val);
+        }
         juceEditor->beginParameterEdit(synth->storage.getPatch().param_ptr[ptag]);
     }
     else if (tag_mod_source0 + ms_ctrl1 <= tag &&
@@ -2177,6 +2196,30 @@ void SurgeGUIEditor::controlEndEdit(Surge::GUI::IComponentTagValue *control)
     }
 }
 
+const std::unique_ptr<Surge::GUI::UndoManager> &SurgeGUIEditor::undoManager()
+{
+    return juceEditor->processor.undoManager;
+}
+
+void SurgeGUIEditor::setParamFromUndo(int paramId, pdata val)
+{
+    auto p = synth->storage.getPatch().param_ptr[paramId];
+    auto id = synth->idForParameter(p);
+    juceEditor->beginParameterEdit(p);
+    p->val = val;
+    synth->sendParameterAutomation(id, synth->getParameter01(id));
+    juceEditor->endParameterEdit(p);
+    synth->refresh_editor = true;
+}
+
+void SurgeGUIEditor::setModulationFromUndo(int paramId, modsources ms, int scene, int idx,
+                                           float val)
+{
+    auto p = synth->storage.getPatch().param_ptr[paramId];
+    // FIXME scene and index
+    synth->setModulation(p->id, ms, scene, idx, val);
+    synth->refresh_editor = true;
+}
 //------------------------------------------------------------------------------------------------
 
 long SurgeGUIEditor::applyParameterOffset(long id) { return id - start_paramtags; }
@@ -2422,6 +2465,8 @@ void SurgeGUIEditor::showSettingsMenu(const juce::Point<int> &where,
 {
     auto settingsMenu = juce::PopupMenu();
 
+    // settingsMenu.addItem("HACK DUMP", [this]() { undoManager()->dumpStack(); });
+
     auto zoomMenu = makeZoomMenu(where, false);
     settingsMenu.addSubMenu("Zoom", zoomMenu);
 
@@ -5942,6 +5987,7 @@ void SurgeGUIEditor::broadcastMSEGState()
 void SurgeGUIEditor::repushAutomationFor(Parameter *p)
 {
     auto id = synth->idForParameter(p);
+
     synth->sendParameterAutomation(id, synth->getParameter01(id));
 }
 
@@ -6215,6 +6261,7 @@ void SurgeGUIEditor::setupKeymapManager()
                                        Surge::GUI::keyboardActionName, [](auto a, auto b) {});
 
     keyMapManager->clearBindings();
+    keyMapManager->addBinding(Surge::GUI::UNDO, {keymap_t::Modifiers::CONTROL, (int)'Z'});
     keyMapManager->addBinding(Surge::GUI::OSC_1, {keymap_t::Modifiers::ALT, (int)'1'});
     keyMapManager->addBinding(Surge::GUI::OSC_2, {keymap_t::Modifiers::ALT, (int)'2'});
     keyMapManager->addBinding(Surge::GUI::OSC_3, {keymap_t::Modifiers::ALT, (int)'3'});
@@ -6312,6 +6359,9 @@ bool SurgeGUIEditor::keyPressed(const juce::KeyPress &key, juce::Component *orig
 
             switch (action)
             {
+            case Surge::GUI::UNDO:
+                undoManager()->undo();
+                return true;
             case Surge::GUI::OSC_1:
                 changeSelectedOsc(0);
                 return true;

src/surge-xt/gui/SurgeGUIEditor.h

@@ -42,6 +42,7 @@
 #include <atomic>
 #include <cstdarg>
 #include <bitset>
+#include "UndoManager.h"
 
 class SurgeSynthEditor;
 
@@ -470,6 +471,10 @@ class SurgeGUIEditor : public Surge::GUI::IComponentTagValue::Listener,
     bool canDropTarget(const std::string &fname); // these come as const char* from vstgui
     bool onDrop(const std::string &fname);
 
+    const std::unique_ptr<Surge::GUI::UndoManager> &undoManager();
+    void setParamFromUndo(int paramId, pdata val);
+    void setModulationFromUndo(int paramId, modsources ms, int scene, int idx, float val);
+
   private:
     juce::Rectangle<int> positionForModulationGrid(modsources entry);
     juce::Rectangle<int> positionForModOverview();

src/surge-xt/gui/SurgeGUIEditorKeyboardActions.h

@@ -24,6 +24,8 @@ namespace GUI
 {
 enum KeyboardActions
 {
+    UNDO,
+
     SAVE_PATCH,
     FIND_PATCH,
     FAVORITE_PATCH,
@@ -61,6 +63,9 @@ inline std::string keyboardActionName(KeyboardActions a)
 {
     switch (a)
     {
+    case UNDO:
+        return "UNDO";
+
     case OSC_1:
         return "OSC_1";
 
@@ -127,6 +132,8 @@ inline std::string keyboardActionDescription(KeyboardActions a)
 {
     switch (a)
     {
+    case UNDO:
+        return "Undo changes";
     case SAVE_PATCH:
         return "Open Save Patch Dialog";
     case FIND_PATCH:

src/surge-xt/gui/SurgeGUIEditorValueCallbacks.cpp

@@ -1498,14 +1498,15 @@ int32_t SurgeGUIEditor::controlModifierClicked(Surge::GUI::IComponentTagValue *c
                                 addTo->addItem(displaytxt, true, isChecked, [this, p, i, tag]() {
                                     float ef =
                                         Parameter::intScaledToFloat(i, p->val_max.i, p->val_min.i);
+                                    undoManager()->pushParameterChange(p->id, p->val);
                                     synth->setParameter01(synth->idForParameter(p), ef, false,
                                                           false);
 
                                     if (p->ctrltype == ct_wstype)
                                     {
                                         updateWaveshaperOverlay();
                                     }
-                                    repushAutomationFor(p);
+                                    broadcastPluginAutomationChangeFor(p);
                                     synth->refresh_editor = true;
                                 });
                             }
@@ -1526,13 +1527,14 @@ int32_t SurgeGUIEditor::controlModifierClicked(Surge::GUI::IComponentTagValue *c
 
                             std::string displaytxt = txt;
 
-                            contextMenu.addItem(displaytxt, true, (i == p->val.i),
-                                                [this, ef, p, i]() {
-                                                    synth->setParameter01(synth->idForParameter(p),
-                                                                          ef, false, false);
-                                                    repushAutomationFor(p);
-                                                    synth->refresh_editor = true;
-                                                });
+                            contextMenu.addItem(
+                                displaytxt, true, (i == p->val.i), [this, ef, p, i]() {
+                                    undoManager()->pushParameterChange(p->id, p->val);
+                                    synth->setParameter01(synth->idForParameter(p), ef, false,
+                                                          false);
+                                    broadcastPluginAutomationChangeFor(p);
+                                    synth->refresh_editor = true;
+                                });
                         }
 
                         if (isCombOnSubtype)