ui: allow external ui to draw wildmenu

Co-authored-by: Björn Linse <bjorn.linse@gmail.com>
Updated docs and tests.

4 files changed, 147 insertions, 5 deletions

diff --git a/runtime/doc/ui.txt b/runtime/doc/ui.txt
index deac1609c0..5306126e7f 100644
--- a/runtime/doc/ui.txt
+++ b/runtime/doc/ui.txt
@@ -28,6 +28,7 @@ a dictionary with these (optional) keys:
 	`ext_popupmenu`		Externalize the popupmenu. |ui-popupmenu|
 	`ext_tabline`		Externalize the tabline. |ui-tabline|
 	`ext_cmdline`		Externalize the cmdline. |ui-cmdline|
+	`ext_wildmenu`		Externalize the tabline. |ui-ext-wildmenu|
 
 Nvim will then send msgpack-rpc notifications, with the method name "redraw"
 and a single argument, an array of screen update events.
@@ -287,4 +288,22 @@ Only sent if `ext_cmdline` option is set in |ui-options|
 	Hide the block.
 
 ==============================================================================
+Wildmenu Events							   *ui-wildmenu*
+
+Only sent if `ext_wildmenu` option is set in |ui-options|
+
+["wildmenu_show", items]
+	When `ext_wildmenu` is set to true, nvim will not draw the
+	wildmenu on the grid, instead when the wildmenu is to be displayed
+	this update is sent. `items` is an array of the completion items.
+
+["wildmenu_select", selected]
+	An item in the currently displayed wildmenu is selected. `selected`
+	is either a zero-based index into the array of items from the last
+	wildmenu event, or -1 if no item is selected.
+
+["wildmenu_hide"]
+	The wildmenu is hidden.
+
+==============================================================================
  vim:tw=78:ts=8:noet:ft=help:norl:
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
index 65357d008a..579ba1441a 100644
--- a/src/nvim/api/ui_events.in.h
+++ b/src/nvim/api/ui_events.in.h
@@ -65,6 +65,7 @@ void popupmenu_hide(void)
   FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
 void popupmenu_select(Integer selected)
   FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+
 void tabline_update(Tabpage current, Array tabs)
   FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
 
@@ -84,4 +85,10 @@ void cmdline_block_append(Array lines)
 void cmdline_block_hide(void)
   FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
 
+void wildmenu_show(Array content)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void wildmenu_select(Integer selected)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
+void wildmenu_hide(void)
+  FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY;
 #endif  // NVIM_API_UI_EVENTS_IN_H
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index e79476ab53..3d5e1a5476 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -534,6 +534,9 @@ static int command_line_execute(VimState *state, int key)
   if (!(s->c == p_wc && KeyTyped) && s->c != p_wcm
       && s->c != Ctrl_N && s->c != Ctrl_P && s->c != Ctrl_A
       && s->c != Ctrl_L) {
+    if (ui_is_external(kUIWildmenu)) {
+      ui_call_wildmenu_hide();
+    }
     if (s->xpc.xp_numfiles != -1) {
       (void)ExpandOne(&s->xpc, NULL, NULL, 0, WILD_FREE);
     }
@@ -3515,11 +3518,17 @@ ExpandOne (
         else
           findex = -1;
       }
-      if (p_wmnu)
-        win_redr_status_matches(xp, xp->xp_numfiles, xp->xp_files,
-            findex, cmd_showtail);
-      if (findex == -1)
+      if (p_wmnu) {
+        if (ui_is_external(kUIWildmenu)) {
+          ui_call_wildmenu_select(findex);
+        } else {
+          win_redr_status_matches(xp, xp->xp_numfiles, xp->xp_files,
+                                  findex, cmd_showtail);
+        }
+      }
+      if (findex == -1) {
         return vim_strsave(orig_save);
+      }
       return vim_strsave(xp->xp_files[findex]);
     } else
       return NULL;
@@ -3876,6 +3885,15 @@ static int showmatches(expand_T *xp, int wildmenu)
     showtail = cmd_showtail;
   }
 
+  if (ui_is_external(kUIWildmenu)) {
+    Array args = ARRAY_DICT_INIT;
+    for (i = 0; i < num_files; i++) {
+      ADD(args, STRING_OBJ(cstr_to_string((char *)files_found[i])));
+    }
+    ui_call_wildmenu_show(args);
+    return EXPAND_OK;
+  }
+
   if (!wildmenu) {
     msg_didany = FALSE;                 /* lines_left will be set */
     msg_start();                        /* prepare for paging */
@@ -6128,4 +6146,3 @@ static void set_search_match(pos_T *t)
     coladvance((colnr_T)MAXCOL);
   }
 }
-
diff --git a/test/functional/ui/wildmode_spec.lua b/test/functional/ui/wildmode_spec.lua
index 41a751c284..6ce76568db 100644
--- a/test/functional/ui/wildmode_spec.lua
+++ b/test/functional/ui/wildmode_spec.lua
@@ -179,3 +179,102 @@ describe('command line completion', function()
     ]])
   end)
 end)
+
+describe('External wildmenu', function()
+  local screen
+  local items, selected = nil, nil
+
+  before_each(function()
+    clear()
+    screen = Screen.new(25, 5)
+    screen:attach({rgb=true, ext_wildmenu=true})
+    screen:set_on_event_handler(function(name, data)
+      if name == "wildmenu_show" then
+        items = data[1]
+      elseif name == "wildmenu_select" then
+        selected = data[1]
+      elseif name == "wildmenu_hide" then
+        items, selected = nil, nil
+      end
+    end)
+  end)
+
+  after_each(function()
+    screen:detach()
+  end)
+
+  it('works with :sign <tab>', function()
+    local expected = {
+        'define',
+        'jump',
+        'list',
+        'place',
+        'undefine',
+        'unplace',
+    }
+
+    command('set wildmode=full')
+    command('set wildmenu')
+    feed(':sign <tab>')
+    screen:expect([[
+                               |
+      ~                        |
+      ~                        |
+      ~                        |
+      :sign define^             |
+    ]], nil, nil, function()
+      eq(expected, items)
+      eq(0, selected)
+    end)
+
+    feed('<tab>')
+    screen:expect([[
+                               |
+      ~                        |
+      ~                        |
+      ~                        |
+      :sign jump^               |
+    ]], nil, nil, function()
+      eq(expected, items)
+      eq(1, selected)
+    end)
+
+    feed('<left><left>')
+    screen:expect([[
+                               |
+      ~                        |
+      ~                        |
+      ~                        |
+      :sign ^                   |
+    ]], nil, nil, function()
+      eq(expected, items)
+      eq(-1, selected)
+    end)
+
+    feed('<right>')
+    screen:expect([[
+                               |
+      ~                        |
+      ~                        |
+      ~                        |
+      :sign define^             |
+    ]], nil, nil, function()
+      eq(expected, items)
+      eq(0, selected)
+    end)
+
+
+
+    feed('a')
+    screen:expect([[
+                               |
+      ~                        |
+      ~                        |
+      ~                        |
+      :sign definea^            |
+    ]], nil, nil, function()
+      eq(nil, items)
+      eq(nil, selected)
+    end)
+  end)
+end)