feat(terminal): support theme update notifications (DEC mode 2031) (#31999)

4 files changed, 35 insertions, 0 deletions

diff --git a/src/nvim/vterm/screen.c b/src/nvim/vterm/screen.c
index c91c6fb84f..45bd5e2a27 100644
--- a/src/nvim/vterm/screen.c
+++ b/src/nvim/vterm/screen.c
@@ -784,6 +784,17 @@ static int resize(int new_rows, int new_cols, VTermStateFields *fields, void *us
   return 1;
 }
 
+static int theme(bool *dark, void *user)
+{
+  VTermScreen *screen = user;
+
+  if (screen->callbacks && screen->callbacks->theme) {
+    return (*screen->callbacks->theme)(dark, screen->cbdata);
+  }
+
+  return 1;
+}
+
 static int setlineinfo(int row, const VTermLineInfo *newinfo, const VTermLineInfo *oldinfo,
                        void *user)
 {
@@ -838,6 +849,7 @@ static VTermStateCallbacks state_cbs = {
   .settermprop = &settermprop,
   .bell = &bell,
   .resize = &resize,
+  .theme = &theme,
   .setlineinfo = &setlineinfo,
   .sb_clear = &sb_clear,
 };
diff --git a/src/nvim/vterm/state.c b/src/nvim/vterm/state.c
index 9e787acd9b..4ad07377de 100644
--- a/src/nvim/vterm/state.c
+++ b/src/nvim/vterm/state.c
@@ -819,6 +819,10 @@ static void set_dec_mode(VTermState *state, int num, int val)
     state->mode.bracketpaste = (unsigned)val;
     break;
 
+  case 2031:
+    settermprop_bool(state, VTERM_PROP_THEMEUPDATES, val);
+    break;
+
   default:
     DEBUG_LOG("libvterm: Unknown DEC mode %d\n", num);
     return;
@@ -894,6 +898,10 @@ static void request_dec_mode(VTermState *state, int num)
     reply = state->mode.bracketpaste;
     break;
 
+  case 2031:
+    reply = state->mode.theme_updates;
+    break;
+
   default:
     vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "?%d;%d$y", num, 0);
     return;
@@ -1387,6 +1395,7 @@ static int on_csi(const char *leader, const long args[], int argcount, const cha
 
     {
       char *qmark = (leader_byte == '?') ? "?" : "";
+      bool dark = false;
 
       switch (val) {
       case 0:
@@ -1403,6 +1412,13 @@ static int on_csi(const char *leader, const long args[], int argcount, const cha
         vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "%s%d;%dR", qmark, state->pos.row + 1,
                                        state->pos.col + 1);
         break;
+      case 996:
+        if (state->callbacks && state->callbacks->theme) {
+          if (state->callbacks->theme(&dark, state->cbdata)) {
+            vterm_push_output_sprintf_ctrl(state->vt, C1_CSI, "?997;%cn", dark ? '1' : '2');
+          }
+        }
+        break;
       }
     }
     break;
@@ -2268,6 +2284,9 @@ int vterm_state_set_termprop(VTermState *state, VTermProp prop, VTermValue *val)
   case VTERM_PROP_FOCUSREPORT:
     state->mode.report_focus = (unsigned)val->boolean;
     return 1;
+  case VTERM_PROP_THEMEUPDATES:
+    state->mode.theme_updates = (unsigned)val->boolean;
+    return 1;
 
   case VTERM_N_PROPS:
     return 0;
diff --git a/src/nvim/vterm/vterm_defs.h b/src/nvim/vterm/vterm_defs.h
index d0a8ba8814..9aa933bef0 100644
--- a/src/nvim/vterm/vterm_defs.h
+++ b/src/nvim/vterm/vterm_defs.h
@@ -86,6 +86,7 @@ typedef enum {
   VTERM_PROP_CURSORSHAPE,       // number
   VTERM_PROP_MOUSE,             // number
   VTERM_PROP_FOCUSREPORT,       // bool
+  VTERM_PROP_THEMEUPDATES,      // bool
 
   VTERM_N_PROPS,
 } VTermProp;
@@ -111,6 +112,7 @@ typedef struct {
   int (*settermprop)(VTermProp prop, VTermValue *val, void *user);
   int (*bell)(void *user);
   int (*resize)(int rows, int cols, void *user);
+  int (*theme)(bool *dark, void *user);
   int (*sb_pushline)(int cols, const VTermScreenCell *cells, void *user);
   int (*sb_popline)(int cols, VTermScreenCell *cells, void *user);
   int (*sb_clear)(void *user);
@@ -263,6 +265,7 @@ typedef struct {
   int (*settermprop)(VTermProp prop, VTermValue *val, void *user);
   int (*bell)(void *user);
   int (*resize)(int rows, int cols, VTermStateFields *fields, void *user);
+  int (*theme)(bool *dark, void *user);
   int (*setlineinfo)(int row, const VTermLineInfo *newinfo, const VTermLineInfo *oldinfo,
                      void *user);
   int (*sb_clear)(void *user);
diff --git a/src/nvim/vterm/vterm_internal_defs.h b/src/nvim/vterm/vterm_internal_defs.h
index 770f862ce3..d4d59867bf 100644
--- a/src/nvim/vterm/vterm_internal_defs.h
+++ b/src/nvim/vterm/vterm_internal_defs.h
@@ -119,6 +119,7 @@ struct VTermState {
     unsigned leftrightmargin:1;
     unsigned bracketpaste:1;
     unsigned report_focus:1;
+    unsigned theme_updates:1;
   } mode;
 
   VTermEncodingInstance encoding[4], encoding_utf8;