feat(scan control): add support for literals

bec_widgets/widgets/control/scan_control/scan_group_box.py

@@ -1,4 +1,4 @@
-from typing import Literal
+from typing import Literal, Sequence
 
 from bec_lib.logger import bec_logger
 from bec_qthemes import material_icon
@@ -36,7 +36,7 @@ class ScanArgType:
     BOOL = "bool"
     STR = "str"
     DEVICEBASE = "DeviceBase"
-    LITERALS = "dict"
+    LITERALS_DICT = "dict"  # Used when the type is provided as a dict with Literal key
 
 
 class SettingsDialog(QDialog):
@@ -83,6 +83,39 @@ class ScanSpinBox(QSpinBox):
             self.setValue(default)
 
 
+class ScanLiteralsComboBox(QComboBox):
+    def __init__(
+        self, parent=None, arg_name: str | None = None, default: str | None = None, *args, **kwargs
+    ):
+        super().__init__(parent=parent, *args, **kwargs)
+        self.arg_name = arg_name
+        self.default = default
+        if default is not None:
+            self.setCurrentText(default)
+
+    def set_literals(self, literals: Sequence[str | int | float | None]) -> None:
+        """
+        Set the list of literals for the combo box.
+
+        Args:
+            literals: List of literal values (can be strings, integers, floats or None)
+        """
+        self.clear()
+        literals = set(literals)  # Remove duplicates
+        if None in literals:
+            literals.remove(None)
+            self.addItem("")
+
+        self.addItems([str(value) for value in literals])
+
+        # find index of the default value
+        index = max(self.findText(str(self.default)), 0)
+        self.setCurrentIndex(index)
+
+    def get_value(self) -> str | None:
+        return self.currentText() if self.currentText() else None
+
+
 class ScanDoubleSpinBox(QDoubleSpinBox):
     def __init__(
         self, parent=None, arg_name: str = None, default: float | None = None, *args, **kwargs
@@ -137,7 +170,7 @@ class ScanGroupBox(QGroupBox):
         ScanArgType.INT: ScanSpinBox,
         ScanArgType.BOOL: ScanCheckBox,
         ScanArgType.STR: ScanLineEdit,
-        ScanArgType.LITERALS: QComboBox,  # TODO figure out combobox logic
+        ScanArgType.LITERALS_DICT: ScanLiteralsComboBox,
     }
 
     device_selected = Signal(str)
@@ -226,7 +259,11 @@ class ScanGroupBox(QGroupBox):
         for column_index, item in enumerate(group_inputs):
             arg_name = item.get("name", None)
             default = item.get("default", None)
-            widget_class = self.WIDGET_HANDLER.get(item["type"], None)
+            item_type = item.get("type", None)
+            if isinstance(item_type, dict) and "Literal" in item_type:
+                widget_class = self.WIDGET_HANDLER.get(ScanArgType.LITERALS_DICT, None)
+            else:
+                widget_class = self.WIDGET_HANDLER.get(item["type"], None)
             if widget_class is None:
                 logger.error(
                     f"Unsupported annotation '{item['type']}' for parameter '{item['name']}'"
@@ -239,6 +276,8 @@ class ScanGroupBox(QGroupBox):
                 widget.set_device_filter(BECDeviceFilter.DEVICE)
                 self.selected_devices[widget] = ""
                 widget.device_selected.connect(self.emit_device_selected)
+            if isinstance(widget, ScanLiteralsComboBox):
+                widget.set_literals(item["type"].get("Literal", []))
             tooltip = item.get("tooltip", None)
             if tooltip is not None:
                 widget.setToolTip(item["tooltip"])
@@ -336,6 +375,8 @@ class ScanGroupBox(QGroupBox):
             widget = self.layout.itemAtPosition(1, i).widget()
             if isinstance(widget, DeviceLineEdit) and device_object:
                 value = widget.get_current_device().name
+            elif isinstance(widget, ScanLiteralsComboBox):
+                value = widget.get_value()
             else:
                 value = WidgetIO.get_value(widget)
             kwargs[widget.arg_name] = value

tests/unit_tests/test_scan_control.py

@@ -210,6 +210,15 @@ available_scans_message = AvailableResourceMessage(
                                 "default": False,
                                 "expert": False,
                             },
+                            {
+                                "arg": False,
+                                "name": "optim_trajectory",
+                                "type": {"Literal": ("option1", "option2", "option3", None)},
+                                "display_name": "Optim Trajectory",
+                                "tooltip": None,
+                                "default": None,
+                                "expert": False,
+                            },
                         ],
                     }
                 ],
@@ -304,7 +313,10 @@ def test_on_scan_selected(scan_control, scan_name):
             label = kwarg_box.layout.itemAtPosition(0, index).widget()
             assert label.text() == kwarg_info["display_name"]
             widget = kwarg_box.layout.itemAtPosition(1, index).widget()
-            expected_widget_type = kwarg_box.WIDGET_HANDLER.get(kwarg_info["type"], None)
+            if isinstance(kwarg_info["type"], dict) and "Literal" in kwarg_info["type"]:
+                expected_widget_type = kwarg_box.WIDGET_HANDLER.get("dict", None)
+            else:
+                expected_widget_type = kwarg_box.WIDGET_HANDLER.get(kwarg_info["type"], None)
             assert isinstance(widget, expected_widget_type)
 
 
@@ -441,7 +453,7 @@ def test_run_grid_scan_with_parameters(scan_control, mocked_client):
         args_row2["steps"],
     ]
     assert called_args == tuple(expected_args_list)
-    assert called_kwargs == kwargs | {"metadata": {"sample_name": ""}}
+    assert called_kwargs == kwargs | {"metadata": {"sample_name": ""}, "optim_trajectory": None}
 
     # Check the emitted signal
     mock_slot.assert_called_once()