nicegui/nicegui/element.py

from __future__ import annotations

import inspect
import re
from copy import copy
from pathlib import Path
from typing import TYPE_CHECKING, Any, ClassVar, Dict, Iterator, List, Optional, Sequence, Union, cast, overload

from typing_extensions import Self

from . import core, events, helpers, json, storage
from .awaitable_response import AwaitableResponse, NullResponse
from .classes import Classes
from .context import context
from .dependencies import Component, Library, register_library, register_resource, register_vue_component
from .elements.mixins.visibility import Visibility
from .event_listener import EventListener
from .props import Props
from .slot import Slot
from .style import Style
from .tailwind import Tailwind
from .version import __version__

if TYPE_CHECKING:
    from .client import Client

# https://www.w3.org/TR/xml/#sec-common-syn
TAG_START_CHAR = r':|[A-Z]|_|[a-z]|[\u00C0-\u00D6]|[\u00D8-\u00F6]|[\u00F8-\u02FF]|[\u0370-\u037D]|[\u037F-\u1FFF]|[\u200C-\u200D]|[\u2070-\u218F]|[\u2C00-\u2FEF]|[\u3001-\uD7FF]|[\uF900-\uFDCF]|[\uFDF0-\uFFFD]|[\U00010000-\U000EFFFF]'
TAG_CHAR = TAG_START_CHAR + r'|-|\.|[0-9]|\u00B7|[\u0300-\u036F]|[\u203F-\u2040]'
TAG_PATTERN = re.compile(fr'^({TAG_START_CHAR})({TAG_CHAR})*$')


class Element(Visibility):
    component: Optional[Component] = None
    libraries: ClassVar[List[Library]] = []
    extra_libraries: ClassVar[List[Library]] = []
    exposed_libraries: ClassVar[List[Library]] = []
    _default_props: ClassVar[Dict[str, Any]] = {}
    _default_classes: ClassVar[List[str]] = []
    _default_style: ClassVar[Dict[str, str]] = {}

    def __init__(self, tag: Optional[str] = None, *, _client: Optional[Client] = None) -> None:
        """Generic Element

        This class is the base class for all other UI elements.
        But you can use it to create elements with arbitrary HTML tags.

        :param tag: HTML tag of the element
        :param _client: client for this element (for internal use only)
        """
        super().__init__()
        self.client = _client or context.client
        self.id = self.client.next_element_id
        self.client.next_element_id += 1
        self.tag = tag if tag else self.component.tag if self.component else 'div'
        if not TAG_PATTERN.match(self.tag):
            raise ValueError(f'Invalid HTML tag: {self.tag}')
        self._classes: Classes[Self] = Classes(self._default_classes, element=cast(Self, self))
        self._style: Style[Self] = Style(self._default_style, element=cast(Self, self))
        self._props: Props[Self] = Props(self._default_props, element=cast(Self, self))
        self._markers: List[str] = []
        self._event_listeners: Dict[str, EventListener] = {}
        self._text: Optional[str] = None
        self.slots: Dict[str, Slot] = {}
        self.default_slot = self.add_slot('default')
        self._deleted: bool = False

        self.client.elements[self.id] = self
        self.parent_slot: Optional[Slot] = None
        slot_stack = context.slot_stack
        if slot_stack:
            self.parent_slot = slot_stack[-1]
            self.parent_slot.children.append(self)

        self.tailwind = Tailwind(self)

        self.client.outbox.enqueue_update(self)
        if self.parent_slot:
            self.client.outbox.enqueue_update(self.parent_slot.parent)

    def __init_subclass__(cls, *,
                          component: Union[str, Path, None] = None,
                          dependencies: List[Union[str, Path]] = [],  # noqa: B006
                          libraries: List[Union[str, Path]] = [],  # noqa: B006  # DEPRECATED
                          exposed_libraries: List[Union[str, Path]] = [],  # noqa: B006  # DEPRECATED
                          extra_libraries: List[Union[str, Path]] = [],  # noqa: B006  # DEPRECATED
                          default_classes: Optional[str] = None,
                          default_style: Optional[str] = None,
                          default_props: Optional[str] = None,
                          ) -> None:
        super().__init_subclass__()
        base = Path(inspect.getfile(cls)).parent

        def glob_absolute_paths(file: Union[str, Path]) -> List[Path]:
            path = Path(file)
            if not path.is_absolute():
                path = base / path
            return sorted(path.parent.glob(path.name), key=lambda p: p.stem)

        if libraries:
            helpers.warn_once(f'The `libraries` parameter for subclassing "{cls.__name__}" is deprecated. '
                              'It will be removed in NiceGUI 3.0. '
                              'Use `dependencies` instead.')
        if exposed_libraries:
            helpers.warn_once(f'The `exposed_libraries` parameter for subclassing "{cls.__name__}" is deprecated. '
                              'It will be removed in NiceGUI 3.0. '
                              'Use `dependencies` instead.')
        if extra_libraries:
            helpers.warn_once(f'The `extra_libraries` parameter for subclassing "{cls.__name__}" is deprecated. '
                              'It will be removed in NiceGUI 3.0. '
                              'Use `dependencies` instead.')

        cls.component = copy(cls.component)
        cls.libraries = copy(cls.libraries)
        cls.extra_libraries = copy(cls.extra_libraries)
        cls.exposed_libraries = copy(cls.exposed_libraries)
        if component:
            for path in glob_absolute_paths(component):
                cls.component = register_vue_component(path)
        for library in libraries:
            for path in glob_absolute_paths(library):
                cls.libraries.append(register_library(path))
        for library in extra_libraries:
            for path in glob_absolute_paths(library):
                cls.extra_libraries.append(register_library(path))
        for library in exposed_libraries + dependencies:
            for path in glob_absolute_paths(library):
                cls.exposed_libraries.append(register_library(path, expose=True))

        cls._default_props = copy(cls._default_props)
        cls._default_classes = copy(cls._default_classes)
        cls._default_style = copy(cls._default_style)
        cls.default_classes(default_classes)
        cls.default_style(default_style)
        cls.default_props(default_props)

    def add_resource(self, path: Union[str, Path]) -> None:
        """Add a resource to the element.

        :param path: path to the resource (e.g. folder with CSS and JavaScript files)
        """
        resource = register_resource(Path(path))
        self._props['resource_path'] = f'/_nicegui/{__version__}/resources/{resource.key}'

    def add_slot(self, name: str, template: Optional[str] = None) -> Slot:
        """Add a slot to the element.

        NiceGUI is using the slot concept from Vue:
        Elements can have multiple slots, each possibly with a number of children.
        Most elements only have one slot, e.g. a `ui.card` (QCard) only has a default slot.
        But more complex elements like `ui.table` (QTable) can have more slots like "header", "body" and so on.
        If you nest NiceGUI elements via with `ui.row(): ...` you place new elements inside of the row's default slot.
        But if you use with `table.add_slot(...): ...`, you enter a different slot.

        The slot stack helps NiceGUI to keep track of which slot is currently used for new elements.
        The `parent` field holds a reference to its element.
        Whenever an element is entered via a `with` expression, its default slot is automatically entered as well.

        :param name: name of the slot
        :param template: Vue template of the slot
        :return: the slot
        """
        self.slots[name] = Slot(self, name, template)
        return self.slots[name]

    def __enter__(self) -> Self:
        self.default_slot.__enter__()
        return self

    def __exit__(self, *_) -> None:
        self.default_slot.__exit__(*_)

    def __iter__(self) -> Iterator[Element]:
        for slot in self.slots.values():
            yield from slot

    def _collect_slot_dict(self) -> Dict[str, Any]:
        return {
            name: {
                'ids': [child.id for child in slot],
                **({'template': slot.template} if slot.template is not None else {}),
            }
            for name, slot in self.slots.items()
            if slot != self.default_slot
        }

    def _to_dict(self) -> Dict[str, Any]:
        return {
            'tag': self.tag,
            **({'text': self._text} if self._text is not None else {}),
            **{
                key: value
                for key, value in {
                    'class': self._classes,
                    'style': self._style,
                    'props': self._props,
                    'slots': self._collect_slot_dict(),
                    'children': [child.id for child in self.default_slot.children],
                    'events': [listener.to_dict() for listener in self._event_listeners.values()],
                    'component': {
                        'key': self.component.key,
                        'name': self.component.name,
                        'tag': self.component.tag
                    } if self.component else None,
                    'libraries': [
                        {
                            'key': library.key,
                            'name': library.name,
                        } for library in self.libraries
                    ],
                }.items()
                if value
            },
        }

    @property
    def classes(self) -> Classes[Self]:
        """The classes of the element."""
        return self._classes

    @classmethod
    def default_classes(cls,
                        add: Optional[str] = None, *,
                        remove: Optional[str] = None,
                        toggle: Optional[str] = None,
                        replace: Optional[str] = None) -> type[Self]:
        """Apply, remove, toggle, or replace default HTML classes.

        This allows modifying the look of the element or its layout using `Tailwind <https://v3.tailwindcss.com/>`_ or `Quasar <https://quasar.dev/>`_ classes.

        Removing or replacing classes can be helpful if predefined classes are not desired.
        All elements of this class will share these HTML classes.
        These must be defined before element instantiation.

        :param add: whitespace-delimited string of classes
        :param remove: whitespace-delimited string of classes to remove from the element
        :param toggle: whitespace-delimited string of classes to toggle (*added in version 2.7.0*)
        :param replace: whitespace-delimited string of classes to use instead of existing ones
        """
        cls._default_classes = Classes.update_list(cls._default_classes, add, remove, toggle, replace)
        return cls

    @property
    def style(self) -> Style[Self]:
        """The style of the element."""
        return self._style

    @classmethod
    def default_style(cls,
                      add: Optional[str] = None, *,
                      remove: Optional[str] = None,
                      replace: Optional[str] = None) -> type[Self]:
        """Apply, remove, or replace default CSS definitions.

        Removing or replacing styles can be helpful if the predefined style is not desired.
        All elements of this class will share these CSS definitions.
        These must be defined before element instantiation.

        :param add: semicolon-separated list of styles to add to the element
        :param remove: semicolon-separated list of styles to remove from the element
        :param replace: semicolon-separated list of styles to use instead of existing ones
        """
        if replace is not None:
            cls._default_style.clear()
        for key in Style.parse(remove):
            cls._default_style.pop(key, None)
        cls._default_style.update(Style.parse(add))
        cls._default_style.update(Style.parse(replace))
        return cls

    @property
    def props(self) -> Props[Self]:
        """The props of the element."""
        return self._props

    @classmethod
    def default_props(cls,
                      add: Optional[str] = None, *,
                      remove: Optional[str] = None) -> type[Self]:
        """Add or remove default props.

        This allows modifying the look of the element or its layout using `Quasar <https://quasar.dev/>`_ props.
        Since props are simply applied as HTML attributes, they can be used with any HTML element.
        All elements of this class will share these props.
        These must be defined before element instantiation.

        Boolean properties are assumed ``True`` if no value is specified.

        :param add: whitespace-delimited list of either boolean values or key=value pair to add
        :param remove: whitespace-delimited list of property keys to remove
        """
        for key in Props.parse(remove):
            if key in cls._default_props:
                del cls._default_props[key]
        for key, value in Props.parse(add).items():
            cls._default_props[key] = value
        return cls

    def mark(self, *markers: str) -> Self:
        """Replace markers of the element.

        Markers are used to identify elements for querying with `ElementFilter </documentation/element_filter>`_
        which is heavily used in testing
        but can also be used to reduce the number of global variables or passing around dependencies.

        :param markers: list of strings or single string with whitespace-delimited markers; replaces existing markers
        """
        self._markers = [word for marker in markers for word in marker.split()]
        return self

    def tooltip(self, text: str) -> Self:
        """Add a tooltip to the element.

        :param text: text of the tooltip
        """
        from .elements.tooltip import Tooltip  # pylint: disable=import-outside-toplevel, cyclic-import
        with self:
            Tooltip(text)
        return self

    @overload
    def on(self,
           type: str,  # pylint: disable=redefined-builtin
           *,
           js_handler: Optional[str] = None,
           ) -> Self:
        ...

    @overload
    def on(self,
           type: str,  # pylint: disable=redefined-builtin
           handler: Optional[events.Handler[events.GenericEventArguments]] = None,
           args: Union[None, Sequence[str], Sequence[Optional[Sequence[str]]]] = None,
           *,
           throttle: float = 0.0,
           leading_events: bool = True,
           trailing_events: bool = True,
           ) -> Self:
        ...

    def on(self,
           type: str,  # pylint: disable=redefined-builtin
           handler: Optional[events.Handler[events.GenericEventArguments]] = None,
           args: Union[None, Sequence[str], Sequence[Optional[Sequence[str]]]] = None,
           *,
           throttle: float = 0.0,
           leading_events: bool = True,
           trailing_events: bool = True,
           js_handler: Optional[str] = None,
           ) -> Self:
        """Subscribe to an event.

        :param type: name of the event (e.g. "click", "mousedown", or "update:model-value")
        :param handler: callback that is called upon occurrence of the event
        :param args: arguments included in the event message sent to the event handler (default: `None` meaning all)
        :param throttle: minimum time (in seconds) between event occurrences (default: 0.0)
        :param leading_events: whether to trigger the event handler immediately upon the first event occurrence (default: `True`)
        :param trailing_events: whether to trigger the event handler after the last event occurrence (default: `True`)
        :param js_handler: JavaScript code that is executed upon occurrence of the event, e.g. `(evt) => alert(evt)` (default: `None`)
        """
        if handler and js_handler:
            raise ValueError('Either handler or js_handler can be specified, but not both')

        if handler or js_handler:
            listener = EventListener(
                element_id=self.id,
                type=helpers.event_type_to_camel_case(type),
                args=[args] if args and isinstance(args[0], str) else args,  # type: ignore
                handler=handler,
                js_handler=js_handler,
                throttle=throttle,
                leading_events=leading_events,
                trailing_events=trailing_events,
                request=storage.request_contextvar.get(),
            )
            self._event_listeners[listener.id] = listener
            self.update()
        return self

    def _handle_event(self, msg: Dict) -> None:
        listener = self._event_listeners[msg['listener_id']]
        storage.request_contextvar.set(listener.request)
        args = events.GenericEventArguments(sender=self, client=self.client, args=msg['args'])
        events.handle_event(listener.handler, args)

    def update(self) -> None:
        """Update the element on the client side."""
        if self.is_deleted:
            return
        self.client.outbox.enqueue_update(self)

    def run_method(self, name: str, *args: Any, timeout: float = 1) -> AwaitableResponse:
        """Run a method on the client side.

        If the function is awaited, the result of the method call is returned.
        Otherwise, the method is executed without waiting for a response.

        :param name: name of the method
        :param args: arguments to pass to the method
        :param timeout: maximum time to wait for a response (default: 1 second)
        """
        if not core.loop:
            return NullResponse()
        return self.client.run_javascript(f'return runMethod({self.id}, "{name}", {json.dumps(args)})', timeout=timeout)

    def get_computed_prop(self, prop_name: str, *, timeout: float = 1) -> AwaitableResponse:
        """Return a computed property.

        This function should be awaited so that the computed property is properly returned.

        :param prop_name: name of the computed prop
        :param timeout: maximum time to wait for a response (default: 1 second)
        """
        if not core.loop:
            return NullResponse()
        return self.client.run_javascript(f'return getComputedProp({self.id}, "{prop_name}")', timeout=timeout)

    def ancestors(self, *, include_self: bool = False) -> Iterator[Element]:
        """Iterate over the ancestors of the element.

        :param include_self: whether to include the element itself in the iteration
        """
        if include_self:
            yield self
        if self.parent_slot:
            yield from self.parent_slot.parent.ancestors(include_self=True)

    def descendants(self, *, include_self: bool = False) -> Iterator[Element]:
        """Iterate over the descendants of the element.

        :param include_self: whether to include the element itself in the iteration
        """
        if include_self:
            yield self
        for child in self:
            yield from child.descendants(include_self=True)

    def clear(self) -> None:
        """Remove all child elements."""
        self.client.remove_elements(self.descendants())
        for slot in self.slots.values():
            slot.children.clear()
        self.update()

    def move(self,
             target_container: Optional[Element] = None,
             target_index: int = -1, *,
             target_slot: Optional[str] = None) -> None:
        """Move the element to another container.

        :param target_container: container to move the element to (default: the parent container)
        :param target_index: index within the target slot (default: append to the end)
        :param target_slot: slot within the target container (default: default slot)
        """
        assert self.parent_slot is not None
        self.parent_slot.children.remove(self)
        self.parent_slot.parent.update()
        target_container = target_container or self.parent_slot.parent

        if target_slot is None:
            self.parent_slot = target_container.default_slot
        elif target_slot in target_container.slots:
            self.parent_slot = target_container.slots[target_slot]
        else:
            raise ValueError(f'Slot "{target_slot}" does not exist in the target container. '
                             f'Add it first using `add_slot("{target_slot}")`.')

        target_index = target_index if target_index >= 0 else len(self.parent_slot.children)
        self.parent_slot.children.insert(target_index, self)

        target_container.update()

    def remove(self, element: Union[Element, int]) -> None:
        """Remove a child element.

        :param element: either the element instance or its ID
        """
        if isinstance(element, int):
            children = list(self)
            element = children[element]
        self.client.remove_elements(element.descendants(include_self=True))
        assert element.parent_slot is not None
        element.parent_slot.children.remove(element)
        self.update()

    def delete(self) -> None:
        """Delete the element and all its children."""
        assert self.parent_slot is not None
        self.parent_slot.parent.remove(self)

    def _handle_delete(self) -> None:
        """Called when the element is deleted.

        This method can be overridden in subclasses to perform cleanup tasks.
        """

    @property
    def is_deleted(self) -> bool:
        """Whether the element has been deleted."""
        return self._deleted

    def __str__(self) -> str:
        result = self.tag if type(self) is Element else self.__class__.__name__  # pylint: disable=unidiomatic-typecheck

        def shorten(content: Any, length: int = 20) -> str:
            text = str(content).replace('\n', ' ').replace('\r', ' ')
            return text[:length].strip() + '...' if len(text) > length else text

        additions = []
        if self._markers:
            additions.append(f'markers={", ".join(self._markers)}')
        if self._text:
            additions.append(f'text={shorten(self._text)}')
        if hasattr(self, 'content') and self.content:  # pylint: disable=no-member
            additions.append(f'content={shorten(self.content)}')  # pylint: disable=no-member
        IGNORED_PROPS = {'loopback', 'color', 'view', 'innerHTML', 'codehilite_css_url'}
        additions += [
            f'{key}={shorten(value)}'
            for key, value in self._props.items()
            if not key.startswith('_') and key not in IGNORED_PROPS and value
        ]
        if not self.visible:
            additions.append(f'visible={self.visible}')
        if additions:
            result += f' [{", ".join(additions)}]'

        for child in self.default_slot.children:
            for line in str(child).split('\n'):
                result += f'\n {line}'

        return result