Add CSS function completion provider

gaphor/ui/csscompletion.py

@@ -5,6 +5,103 @@
 from gaphor.core.styling import Style
 
 
+class CssFunctionCompletionProvider(GObject.GObject, GtkSource.CompletionProvider):
+    FUNCTIONS = [
+        "attr",
+        "calc",
+        "conic-gradient",
+        "counter",
+        "cubic-bezier",
+        "hsl",
+        "hsla",
+        "lab",
+        "lch",
+        "linear-gradient",
+        "max",
+        "min",
+        "radial-gradient",
+        "repeating-conic-gradient",
+        "repeating-linear-gradient",
+        "repeating-radial-gradient",
+        "rgb",
+        "rgba",
+        "var",
+    ]
+
+    def __init__(self):
+        super().__init__()
+        self._filter_data: FilterData = FilterData()
+
+    def do_activate(
+        self,
+        context: GtkSource.CompletionContext,
+        proposal: GtkSource.CompletionProposal,
+    ) -> None:
+        buffer = context.get_buffer()
+        buffer.begin_user_action()
+        has_selection, begin, end = context.get_bounds()
+        if has_selection:
+            buffer.delete(begin, end)
+        buffer.insert(begin, proposal.text, len(proposal.text))
+        buffer.end_user_action()
+
+    def do_display(
+        self,
+        context: GtkSource.CompletionContext,
+        proposal: GtkSource.CompletionProposal,
+        cell: GtkSource.CompletionCell,
+    ) -> None:
+        if cell.props.column == GtkSource.CompletionColumn.ICON:
+            pass
+        elif cell.props.column == GtkSource.CompletionColumn.TYPED_TEXT:
+            cell.set_text(proposal.text)
+
+    def do_get_priority(self, context: GtkSource.CompletionContext) -> int:
+        return 3
+
+    def do_get_title(self) -> str:
+        return "Functions"
+
+    def do_populate_async(self, context, cancellable, callback, user_data=None) -> None:
+        task = Gio.Task.new(self, cancellable, callback)
+        store = Gio.ListStore.new(CssFunctionProposal)
+        self._filter_data.word = context.get_word()
+
+        for function in self.FUNCTIONS:
+            proposal = CssFunctionProposal(function)
+            store.append(proposal)
+
+        def filter_fn(proposal, data):
+            return proposal.text.startswith(data.word)
+
+        store_filter = Gtk.CustomFilter.new(filter_fn, self._filter_data)
+        task.proposals = Gtk.FilterListModel.new(store, store_filter)
+        task.return_boolean(True)
+
+    def do_populate_finish(self, result: Gio.AsyncResult) -> Gio.ListModel:
+        if result.propagate_boolean():
+            return result.proposals
+
+    def do_refilter(
+        self, context: GtkSource.CompletionContext, model: Gio.ListModel
+    ) -> None:
+        word = context.get_word()
+        change = Gtk.FilterChange.DIFFERENT
+        if old_word := self._filter_data.word:
+            if word.startswith(old_word):
+                change = Gtk.FilterChange.MORE_STRICT
+            elif old_word.startswith(word):
+                change = Gtk.FilterChange.LESS_STRICT
+        self._filter_data.word = word
+        model.get_filter().changed(change)
+
+
+class CssFunctionProposal(GObject.Object, GtkSource.CompletionProposal):
+    def __init__(self, text: str):
+        super().__init__()
+        self.text: str = text
+
+
 class CssPropertyCompletionProvider(GObject.GObject, GtkSource.CompletionProvider):
     PROPERTIES = sorted(Style.__optional_keys__)
 

gaphor/ui/elementeditor.py

@@ -17,7 +17,10 @@
 )
 from gaphor.diagram.propertypages import PropertyPages, new_resource_builder
 from gaphor.ui.abc import UIComponent
-from gaphor.ui.csscompletion import CssPropertyCompletionProvider
+from gaphor.ui.csscompletion import (
+    CssFunctionCompletionProvider,
+    CssPropertyCompletionProvider,
+)
 from gaphor.ui.event import DiagramSelectionChanged
 
 log = logging.getLogger(__name__)
@@ -289,9 +292,9 @@ def open(self, builder):
         )
 
         if Gtk.get_major_version() == 4:
-            provider = CssPropertyCompletionProvider()
             view_completion = self.style_sheet_view.get_completion()
-            view_completion.add_provider(provider)
+            view_completion.add_provider(CssFunctionCompletionProvider())
+            view_completion.add_provider(CssPropertyCompletionProvider())
 
         self.event_manager.subscribe(self._model_ready)
         self.event_manager.subscribe(self._style_sheet_created)