Extract duplicate into core; support it in the script engine + wx GUI

A script using `duplicate` failed with "unsupported command 'duplicate'"
because the clone logic was still inline in the tui command. Extract it to
core/app/edit.hpp::duplicate_module(System*, src, dst) -> {ok, error, parts,
signals}: a deep clone of a module (parts, pins with spec + nc_origin, signals
with type overrides, pin→signal wiring; no connections), refusing on an unknown
source or an already-taken destination name.

  - the tui `duplicate` command renders the result (output unchanged);
  - the script engine dispatches `duplicate` to it — the failing script now runs;
  - the wx GUI gains Edit ▸ Duplicate module… (PickModule + a name prompt).

tests/test_edit.cpp: deep clone wires to the clone's own signal (not the
source's) and preserves the type; unknown source / existing destination
refused. 412 core assertions green; tui + wx build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/core/app/edit.cpp

@@ -1,11 +1,16 @@
 #include "core/app/edit.hpp"
 
 #include "core/domain/bsdl_model.hpp"
+#include "core/domain/modules.hpp"
 #include "core/domain/parts.hpp"
 #include "core/domain/pin_model.hpp"
+#include "core/domain/pins.hpp"
 #include "core/domain/signals.hpp"
+#include "core/domain/system.hpp"
 #include "core/domain/transform_vpx.hpp"  // ValidatePartForKind
 
+#include <exception>
+
 namespace app {
 
 SetConnectorTypeResult set_connector_type(Part *part, const std::string &kind)
@@ -75,4 +80,58 @@ SetSignalTypeResult set_signal_type(Signal *sig, const std::string &type_name)
     return r;
 }
 
+DuplicateResult duplicate_module(System *sys, const std::string &src_name,
+                                 const std::string &dst_name)
+{
+    DuplicateResult r;
+    if (!sys) { r.error = "no system"; return r; }
+
+    Module *src;
+    try { src = sys->modules()->get(src_name); }
+    catch (const std::exception &) {
+        r.error = "unknown module: " + src_name;
+        return r;
+    }
+    if (sys->modules()->exists(dst_name)) {
+        r.error = "duplicate refused: module '" + dst_name + "' already exists.";
+        return r;
+    }
+
+    Module *dst = new Module(dst_name);
+
+    // Signals first (preserve type overrides), so pins can re-wire to them.
+    for (auto &skv : *src->signals) {
+        Signal *ss = skv.second;
+        Signal *ds = new Signal(ss->name);
+        ds->type = ss->type;
+        dst->signals->add(ds);
+    }
+
+    // Parts, pins (spec + nc_origin), and the pin→signal wiring.
+    for (auto &pkv : *src) {
+        Part *sp = pkv.second;
+        Part *dp = new Part(sp->name);
+        dp->connector_type = sp->connector_type;
+        for (auto &nkv : *sp) {
+            Pin *sn = nkv.second;
+            Pin *dn = new Pin(sn->name);
+            dn->spec = sn->spec;
+            dn->nc_origin = sn->nc_origin;
+            dp->add(dn);
+            if (sn->signal()) {
+                Signal *ds = dst->signals->get(sn->signal()->name);
+                ds->add(dn);
+                dn->connect(ds);
+            }
+        }
+        dst->add(dp);
+    }
+
+    sys->modules()->add(dst);
+    r.parts   = (int)dst->size();
+    r.signals = (int)dst->signals->size();
+    r.ok = true;
+    return r;
+}
+
 }  // namespace app

src/core/app/edit.hpp

@@ -7,6 +7,7 @@
 
 class Part;
 class Signal;
+class System;
 
 // Application layer: UI-independent part-editing operations any frontend can
 // call. No console, no dialogs, no FTXUI — Part in, result struct out.
@@ -52,6 +53,21 @@ struct SetSignalTypeResult {
 // Fails (ok=false, error set, no mutation) on an unrecognised name.
 SetSignalTypeResult set_signal_type(Signal *sig, const std::string &type_name);
 
+// Outcome of cloning a module under a new name.
+struct DuplicateResult {
+    bool ok = false;
+    std::string error;  ///< unknown source, or destination name already taken
+    int parts = 0;
+    int signals = 0;
+};
+
+// Deep-clone module `src_name` as `dst_name`: parts, pins (spec + nc_origin),
+// signals (with type overrides) and the pin→signal wiring — but not the
+// system's connections. Fails (ok=false, error set, no change) when the source
+// is unknown or the destination name already exists.
+DuplicateResult duplicate_module(System *sys, const std::string &src_name,
+                                 const std::string &dst_name);
+
 }  // namespace app
 
 #endif  // _APP_EDIT_HPP_

src/core/app/script.cpp

@@ -248,6 +248,15 @@ private:
                  + " ports bound" + (r.unbound ? (", " + std::to_string(r.unbound) + " unbound") : ""));
             return true;
         }
+        if (cmd == "duplicate") {
+            if (!need(2)) return false;
+            DuplicateResult r = duplicate_module(sys_.get(), a[0], a[1]);
+            if (!r.ok) { emit(r.error); return false; }
+            emit("duplicate: '" + a[0] + "' → '" + a[1] + "'  ("
+                 + std::to_string(r.parts) + " part(s), "
+                 + std::to_string(r.signals) + " signal(s))");
+            return true;
+        }
         if (cmd == "verify") {
             render_verify();
             return true;

src/frontends/tui/commands.cpp

@@ -595,51 +595,12 @@ void Tui::RegisterCommands() {
          {"new module name", Completion::None}},
         [this](const std::vector<std::string> &args) {
             if (!sys) { Print("no system: run 'new' first."); return; }
-
-            Module *src;
-            try { src = sys->modules()->get(args[0]); }
-            catch (const std::exception &) {
-                Print("unknown module: " + args[0]); return;
-            }
-            if (sys->modules()->exists(args[1])) {
-                Print("duplicate refused: module '" + args[1] + "' already exists.");
-                return;
-            }
-
-            Module *dst = new Module(args[1]);
-
-            // 1. Copy signals (preserve type overrides).
-            for (auto &skv : *src->signals) {
-                Signal *ss = skv.second;
-                Signal *ds = new Signal(ss->name);
-                ds->type = ss->type;
-                dst->signals->add(ds);
-            }
-
-            // 2. Copy parts, pins, and re-wire pin→signal.
-            for (auto &pkv : *src) {
-                Part *sp = pkv.second;
-                Part *dp = new Part(sp->name);
-                dp->connector_type = sp->connector_type;
-                for (auto &nkv : *sp) {
-                    Pin *sn = nkv.second;
-                    Pin *dn = new Pin(sn->name);
-                    dn->spec = sn->spec;
-                    dn->nc_origin = sn->nc_origin;
-                    dp->add(dn);
-                    if (sn->signal()) {
-                        Signal *ds = dst->signals->get(sn->signal()->name);
-                        ds->add(dn);
-                        dn->connect(ds);
-                    }
-                }
-                dst->add(dp);
-            }
-
-            sys->modules()->add(dst);
+            app::DuplicateResult r =
+                app::duplicate_module(sys.get(), args[0], args[1]);
+            if (!r.ok) { Print(r.error); return; }
             Print("duplicate: '" + args[0] + "' → '" + args[1] + "'"
-                  + "  (" + std::to_string(dst->size()) + " part(s), "
-                  + std::to_string(dst->signals->size()) + " signal(s))");
+                  + "  (" + std::to_string(r.parts) + " part(s), "
+                  + std::to_string(r.signals) + " signal(s))");
         },
         /*prompt_for_missing=*/ true,
         "clone a module under a new name (parts, pins, signals; no connections)",

src/frontends/wx/wx_frame.cpp

@@ -42,6 +42,7 @@ enum {
     ID_ATTACH_BSDL,
     ID_SET_SIGNAL_TYPE,
     ID_CONNECT,
+    ID_DUPLICATE,
     ID_VERIFY,
     ID_QUIT,
     ID_ABOUT,
@@ -132,6 +133,8 @@ EssimFrame::EssimFrame(WxFrontend &fe)
     edit->Append(ID_SET_SIGNAL_TYPE, "Set &signal type…\tCtrl-G");
     edit->AppendSeparator();
     edit->Append(ID_CONNECT, "C&onnect parts…\tCtrl-O");
+    edit->AppendSeparator();
+    edit->Append(ID_DUPLICATE, "&Duplicate module…\tCtrl-D");
 
     auto *sysm = new wxMenu;
     sysm->Append(ID_VERIFY, "&Verify\tCtrl-K");
@@ -195,6 +198,7 @@ EssimFrame::EssimFrame(WxFrontend &fe)
     Bind(wxEVT_MENU, &EssimFrame::OnAttachBsdl, this, ID_ATTACH_BSDL);
     Bind(wxEVT_MENU, &EssimFrame::OnSetSignalType, this, ID_SET_SIGNAL_TYPE);
     Bind(wxEVT_MENU, &EssimFrame::OnConnect, this, ID_CONNECT);
+    Bind(wxEVT_MENU, &EssimFrame::OnDuplicateModule, this, ID_DUPLICATE);
     Bind(wxEVT_MENU, &EssimFrame::OnVerify,  this, ID_VERIFY);
     Bind(wxEVT_MENU, &EssimFrame::OnQuit,    this, ID_QUIT);
     Bind(wxEVT_MENU, &EssimFrame::OnAbout,   this, ID_ABOUT);
@@ -594,6 +598,29 @@ void EssimFrame::OnSetSignalType(wxCommandEvent &) {
     RebuildModelView();
 }
 
+void EssimFrame::OnDuplicateModule(wxCommandEvent &) {
+    Module *m = PickModule("Duplicate module");
+    if (!m) return;
+    const std::string src = m->name;   // m may move in the table after the add
+
+    wxTextEntryDialog dlg(this, "New module name:", "Duplicate module",
+                          wx(src) + "_copy");
+    if (dlg.ShowModal() != wxID_OK) return;
+    const std::string dst = dlg.GetValue().utf8_string();
+    if (dst.empty()) return;
+
+    app::DuplicateResult r = app::duplicate_module(fe_.system(), src, dst);
+    if (!r.ok) {
+        Log(wx(r.error));
+        wxMessageBox(wx(r.error), "Duplicate module", wxOK | wxICON_ERROR, this);
+        return;
+    }
+    Log(wx("duplicate: '" + src + "' → '" + dst + "'  ("
+           + std::to_string(r.parts) + " part(s), "
+           + std::to_string(r.signals) + " signal(s))"));
+    RebuildModelView();
+}
+
 void EssimFrame::OnVerify(wxCommandEvent &) {
     app::VerifyReport r = app::verify(fe_.system());
 

src/frontends/wx/wx_frame.hpp

@@ -28,6 +28,7 @@ private:
     void OnAttachBsdl(wxCommandEvent &);
     void OnConnect(wxCommandEvent &);
     void OnSetSignalType(wxCommandEvent &);
+    void OnDuplicateModule(wxCommandEvent &);
     void OnVerify(wxCommandEvent &);
     void OnQuit(wxCommandEvent &);
     void OnAbout(wxCommandEvent &);

tests/test_edit.cpp

@@ -1,10 +1,12 @@
 #include <doctest/doctest.h>
 
 #include "core/app/edit.hpp"
+#include "core/domain/modules.hpp"
 #include "core/domain/parts.hpp"
 #include "core/domain/pins.hpp"
 #include "core/domain/signal_type.hpp"
 #include "core/domain/signals.hpp"
+#include "core/domain/system.hpp"
 
 // app::set_connector_type is pure core: validate the kind, tag the part and
 // apply the connector model. No Print/dialog/FTXUI.
@@ -73,3 +75,39 @@ TEST_CASE("set_signal_type rejects an unknown name without mutating") {
     CHECK(r.error.find("power, gnd, other") != std::string::npos);
     CHECK(s.type == SignalType::Other);   // unchanged
 }
+
+TEST_CASE("duplicate_module deep-clones parts, pins and signals") {
+    System sys;
+    Module *a = sys.modules()->merge("A");
+    Part *p = new Part("J1"); a->add(p);
+    Pin *pin = new Pin("1"); p->add(pin);
+    Signal *s = a->signals->merge("NET");
+    s->type = SignalType::Power;
+    s->add(pin); pin->connect(s);
+
+    app::DuplicateResult r = app::duplicate_module(&sys, "A", "B");
+
+    CHECK(r.ok);
+    CHECK(r.parts == 1);
+    CHECK(r.signals == 1);
+    REQUIRE(sys.modules()->exists("B"));
+    Module *b = sys.modules()->get("B");
+    CHECK(b->signals->get("NET")->type == SignalType::Power);   // type preserved
+    Pin *bpin = b->get("J1")->get("1");
+    REQUIRE(bpin->signal() != nullptr);
+    CHECK(bpin->signal() == b->signals->get("NET"));            // wired to the clone's own signal
+    CHECK(bpin->signal() != s);                                 // not aliasing the source
+}
+
+TEST_CASE("duplicate_module refuses an unknown source or an existing destination") {
+    System sys;
+    sys.modules()->merge("A");
+
+    app::DuplicateResult dst = app::duplicate_module(&sys, "A", "A");
+    CHECK_FALSE(dst.ok);
+    CHECK(dst.error.find("already exists") != std::string::npos);
+
+    app::DuplicateResult unk = app::duplicate_module(&sys, "NOPE", "X");
+    CHECK_FALSE(unk.ok);
+    CHECK(unk.error.find("unknown module") != std::string::npos);
+}