feat(inserts): compare track effect configurations with A and B (phase 93)

docs/CREATIVE_WORKFLOWS.md

@@ -26,3 +26,12 @@ including output gain. Copying neither loads modules nor changes undo history;
 pasting prepares the candidate and is undoable. The clipboard is internal to
 this session and clears on successful New/Open. Preparation errors keep both
 the destination and clipboard intact.
+
+## Compare effect configurations
+
+**Rack actions → Compare** captures or recalls A and B. Each slot is bound to the
+track where it was captured; Recall is available only on that track. Capturing
+copies metadata without affecting undo or loading modules. Recall prepares a
+fresh chain and is undoable; histories and opaque plugin states are excluded.
+The two comparison slots clear on successful New/Open. Comparisons stop
+transport when recalled, following the existing safe insert-edit workflow.

docs/ROADMAP.md

@@ -2103,12 +2103,12 @@ Implemented: session-local independent chain copy/paste with explicit destinatio
 Capture and recall two track-bound effect configurations, with clear readiness indicators, safe preparation, undo and cleanup on document replacement.
 
 ### Tasks and acceptance criteria
-- [ ] Implement the workflow with bounded validation, safe preparation and documented limits.
-- [ ] Pass meaningful core and/or GUI checks, including error and undo behavior.
-- [ ] Document results and commit this phase separately.
+- [x] Implement the workflow with bounded validation, safe preparation and documented limits.
+- [x] Pass meaningful core and/or GUI checks, including error and undo behavior.
+- [x] Document results and commit this phase separately.
 
 ### Implementation status
-Planned.
+Implemented: two independent track-bound chain comparison slots, with disabled Recall until captured on the current track. Capture is metadata-only; recall prepares fresh instances and records one undo edit. GUI capture/recall, A/B values, undo, cross-track rejection and New cleanup checks passed with a warning-enabled build.
 
 ---
 

src/gui/track_inserts.hpp

@@ -28,6 +28,7 @@ class TrackInsertsPanel : public Fl_Group {
     xtc_track_chain cached_{};
     xtc_track_chain clipboard_{};
     bool clipboard_ready_=false;
+    struct Comparison {xtc_track_chain chain{};uint64_t track=UINT64_MAX;bool ready=false;} comparisons_[2];
     std::vector<uint64_t> ids_;
     std::vector<std::string> names_;
     void result(xtc_result r) { if(r!=XTC_OK)owner_->report_error("Track inserts",r);refresh(true); }
@@ -53,6 +54,10 @@ class TrackInsertsPanel : public Fl_Group {
         gain_=new Fl_Value_Input(x+360,y+52,100,26,"Chain gain");gain_->bounds(0,4);gain_->step(.01);gain_->when(FL_WHEN_RELEASE);
         for(auto *input:{wet_,gain_})input->callback([](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->set_mix(p->wet_->value(),p->gain_->value()));},this);
         actions_=new Fl_Menu_Button(x+486,y+52,150,26,"Rack actions");
+        actions_->add("Compare/Capture A",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->comparison(0,true));},this);
+        actions_->add("Compare/Recall A",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->comparison(0,false));},this,FL_MENU_INACTIVE);
+        actions_->add("Compare/Capture B",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->comparison(1,true));},this);
+        actions_->add("Compare/Recall B",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->comparison(1,false));},this,FL_MENU_INACTIVE);
         actions_->add("Copy chain",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->copy_chain());},this);
         actions_->add("Paste chain (replace)",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->paste_chain());},this,FL_MENU_INACTIVE);
         actions_->add("Duplicate effect",0,[](Fl_Widget *,void *c){auto *p=static_cast<TrackInsertsPanel *>(c);p->result(p->duplicate_slot());},this);
@@ -68,9 +73,21 @@ class TrackInsertsPanel : public Fl_Group {
     void select_track(uint64_t id) {track_=id;refresh(true);}
     const xtc_graph *graph() const {return model_;}
     void add(const char *file,unsigned int index) { result(owner_->add_track_effect(track_,file,index)); }
-    void clear_session() {clipboard_={};clipboard_ready_=false;update_actions();}
+    void clear_session() {clipboard_={};clipboard_ready_=false;for(auto &slot:comparisons_)slot=Comparison{};update_actions();}
     bool clipboard_ready() const {return clipboard_ready_;}
+    bool comparison_ready(unsigned int slot) const {return slot<2 && comparisons_[slot].ready && comparisons_[slot].track==track_;}
+    xtc_result comparison(unsigned int slot,bool capture) {
+        if(slot>=2)return XTC_ERR_INVALID_ARGUMENT;
+        if(capture) {
+            xtc_track_chain chain{};auto r=xtc_project_get_chain(owner_->project_.get(),track_,&chain);
+            if(r==XTC_OK){comparisons_[slot].chain=chain;comparisons_[slot].track=track_;comparisons_[slot].ready=true;update_actions();}
+            return r;
+        }
+        if(!comparison_ready(slot))return XTC_ERR_NOT_FOUND;
+        return owner_->set_track_chain(track_,comparisons_[slot].chain);
+    }
     void update_actions() {
+        for(unsigned int slot=0;slot<2;++slot){int item=actions_->find_index(slot ? "Compare/Recall B" : "Compare/Recall A");if(item>=0)actions_->mode(item,comparison_ready(slot) ? 0 : FL_MENU_INACTIVE);}
         int index=actions_->find_index("Paste chain (replace)");
         if(index>=0)actions_->mode(index,clipboard_ready_ ? 0 : FL_MENU_INACTIVE);
     }
@@ -148,6 +165,7 @@ class TrackInsertsPanel : public Fl_Group {
         if(rebuild){ids_=ids;names_=names;tracks_->clear();for(const auto &name:names) {tracks_->add("track");tracks_->replace(tracks_->size()-2,name.c_str());}}
         if(std::find(ids_.begin(),ids_.end(),track_)==ids_.end())track_=ids_.empty() ? UINT64_MAX : ids_[0];
         for(size_t i=0;i<ids_.size();++i)if(ids_[i]==track_)tracks_->value(static_cast<int>(i));
+        update_actions();
         xtc_track_chain chain{};chain.output_gain=1;
         if(track_!=UINT64_MAX)xtc_project_get_chain(project,track_,&chain);
         if(!rebuild && !std::memcmp(&cached_,&chain,sizeof(chain)))return;

tests/integration/test_gui.cpp

@@ -239,7 +239,16 @@ int creative_workflow_tests()
     CHECK(xtc_project_get_chain(s->project(),second_track,&chain)==XTC_OK && chain.count==1 && chain.output_gain==1 && chain.slots[0].wet==1);
     CHECK(window.undo()==XTC_OK);panel->refresh(true);CHECK(xtc_project_get_chain(s->project(),second_track,&chain)==XTC_OK && chain.count==0);
     submit_result=XTC_ERR_INVALID_STATE;auto *unchanged=s->project();CHECK(panel->paste_chain()==XTC_ERR_INVALID_STATE && s->project()==unchanged);submit_result=XTC_OK;
+    panel->select_track(first_track);CHECK(panel->comparison(0,false)==XTC_ERR_NOT_FOUND);
+    CHECK(panel->comparison(0,true)==XTC_OK && panel->comparison_ready(0));
+    CHECK(panel->set_mix(.7,.9)==XTC_OK && panel->comparison(1,true)==XTC_OK);
+    CHECK(panel->comparison(0,false)==XTC_OK && xtc_project_get_chain(s->project(),first_track,&chain)==XTC_OK && chain.output_gain==.6f);
+    CHECK(panel->comparison(1,false)==XTC_OK && xtc_project_get_chain(s->project(),first_track,&chain)==XTC_OK && chain.output_gain==.9f);
+    CHECK(window.undo()==XTC_OK);panel->refresh(true);
+    CHECK(xtc_project_get_chain(s->project(),first_track,&chain)==XTC_OK && chain.output_gain==.6f);
+    panel->select_track(second_track);CHECK(!panel->comparison_ready(0) && panel->comparison(0,false)==XTC_ERR_NOT_FOUND);
     CHECK(window.new_project()==XTC_OK && !panel->clipboard_ready() && panel->paste_chain()==XTC_ERR_NOT_FOUND);
+    CHECK(!panel->comparison_ready(0) && !panel->comparison_ready(1));
     window.do_callback();puts("Creative workflow GUI checks passed.");return failures ? 1 : 0;
 }
 int track_insert_tests()