from collections.abc import Generator, Iterable from copy import deepcopy from typing import Any, Callable, Dict, Iterator, List, Literal, Optional, Union from ..events import GenericEventArguments, Handler, ValueChangeEventArguments from .choice_element import ChoiceElement from .mixins.disableable_element import DisableableElement from .mixins.label_element import LabelElement from .mixins.validation_element import ValidationDict, ValidationElement, ValidationFunction class Select(LabelElement, ValidationElement, ChoiceElement, DisableableElement, component='select.js'): def __init__(self, options: Union[List, Dict], *, label: Optional[str] = None, value: Any = None, on_change: Optional[Handler[ValueChangeEventArguments]] = None, with_input: bool = False, new_value_mode: Optional[Literal['add', 'add-unique', 'toggle']] = None, multiple: bool = False, clearable: bool = False, validation: Optional[Union[ValidationFunction, ValidationDict]] = None, key_generator: Optional[Union[Callable[[Any], Any], Iterator[Any]]] = None, ) -> None: """Dropdown Selection This element is based on Quasar's `QSelect `_ component. The options can be specified as a list of values, or as a dictionary mapping values to labels. After manipulating the options, call `update()` to update the options in the UI. If `with_input` is True, an input field is shown to filter the options. If `new_value_mode` is not None, it implies `with_input=True` and the user can enter new values in the input field. See `Quasar's documentation `_ for details. Note that this mode is ineffective when setting the `value` property programmatically. You can use the `validation` parameter to define a dictionary of validation rules, e.g. ``{'Too long!': lambda value: len(value) < 3}``. The key of the first rule that fails will be displayed as an error message. Alternatively, you can pass a callable that returns an optional error message. To disable the automatic validation on every value change, you can use the `without_auto_validation` method. :param options: a list ['value1', ...] or dictionary `{'value1':'label1', ...}` specifying the options :param label: the label to display above the selection :param value: the initial value :param on_change: callback to execute when selection changes :param with_input: whether to show an input field to filter the options :param new_value_mode: handle new values from user input (default: None, i.e. no new values) :param multiple: whether to allow multiple selections :param clearable: whether to add a button to clear the selection :param validation: dictionary of validation rules or a callable that returns an optional error message (default: None for no validation) :param key_generator: a callback or iterator to generate a dictionary key for new values """ self.multiple = multiple if multiple: if value is None: value = [] elif not isinstance(value, list): value = [value] else: value = value[:] # NOTE: avoid modifying the original list which could be the list of options (#3014) super().__init__(label=label, options=options, value=value, on_change=on_change, validation=validation) if isinstance(key_generator, Generator): next(key_generator) # prime the key generator, prepare it to receive the first value self.key_generator = key_generator if new_value_mode is not None: if isinstance(options, dict) and new_value_mode == 'add' and key_generator is None: raise ValueError('new_value_mode "add" is not supported for dict options without key_generator') self._props['new-value-mode'] = new_value_mode with_input = True if with_input: self.original_options = deepcopy(options) self._props['use-input'] = True self._props['hide-selected'] = not multiple self._props['fill-input'] = True self._props['input-debounce'] = 0 self._props['multiple'] = multiple self._props['clearable'] = clearable self._is_showing_popup = False self.on('popup-show', lambda e: setattr(e.sender, '_is_showing_popup', True)) self.on('popup-hide', lambda e: setattr(e.sender, '_is_showing_popup', False)) @property def is_showing_popup(self) -> bool: """Whether the options popup is currently shown.""" return self._is_showing_popup def _event_args_to_value(self, e: GenericEventArguments) -> Any: # pylint: disable=too-many-nested-blocks if self.multiple: if e.args is None: return [] else: if self._props.get('new-value-mode') == 'add-unique': # handle issue #4896: eliminate duplicate arguments for arg1 in [a for a in e.args if isinstance(a, str)]: for arg2 in [a for a in e.args if isinstance(a, dict)]: if arg1 == arg2['label']: e.args.remove(arg1) break args = [self._values[arg['value']] if isinstance(arg, dict) else arg for arg in e.args] for arg in e.args: if isinstance(arg, str): self._handle_new_value(arg) return [arg for arg in args if arg in self._values] else: # noqa: PLR5501 if e.args is None: return None else: # noqa: PLR5501 if isinstance(e.args, str): new_value = self._handle_new_value(e.args) return new_value if new_value in self._values else None else: return self._values[e.args['value']] def _value_to_model_value(self, value: Any) -> Any: # pylint: disable=no-else-return if self.multiple: result = [] for item in value or []: try: index = self._values.index(item) result.append({'value': index, 'label': self._labels[index]}) except ValueError: pass return result else: try: index = self._values.index(value) return {'value': index, 'label': self._labels[index]} except ValueError: return None def _generate_key(self, value: str) -> Any: if isinstance(self.key_generator, Generator): return self.key_generator.send(value) if isinstance(self.key_generator, Iterable): return next(self.key_generator) if callable(self.key_generator): return self.key_generator(value) return value def _handle_new_value(self, value: str) -> Any: mode = self._props['new-value-mode'] if isinstance(self.options, list): if mode == 'add': self.options.append(value) elif mode == 'add-unique': if value not in self.options: self.options.append(value) elif mode == 'toggle': if value in self.options: self.options.remove(value) else: self.options.append(value) # NOTE: self._labels and self._values are updated via self.options since they share the same references return value else: key = value if mode == 'add': key = self._generate_key(value) self.options[key] = value elif mode == 'add-unique': if value not in self.options.values(): key = self._generate_key(value) self.options[key] = value elif mode == 'toggle': if value in self.options: self.options.pop(value) else: key = self._generate_key(value) self.options.update({key: value}) self._update_values_and_labels() return key