textual/src/textual/view.py

from __future__ import annotations

from abc import ABC, abstractmethod
from itertools import chain
import logging
from typing import Iterable, TYPE_CHECKING

from rich.console import Console, ConsoleOptions, RenderResult, RenderableType
import rich.repr
from rich.style import Style

from . import events
from .layout import Layout, NoWidget
from .layouts.dock import DockLayout
from .geometry import Dimensions, Point, Region
from .messages import UpdateMessage, LayoutMessage

from .widget import Widget, Widget


if TYPE_CHECKING:
    from .app import App

log = logging.getLogger("rich")


@rich.repr.auto
class View(Widget):
    def __init__(self, layout: Layout = None, name: str | None = None) -> None:
        self.layout: Layout = layout or DockLayout()
        self.mouse_over: Widget | None = None
        self.focused: Widget | None = None
        self.size = Dimensions(0, 0)
        self.widgets: set[Widget] = set()
        self.named_widgets: dict[str, Widget] = {}
        super().__init__(name)

    def __rich_console__(
        self, console: Console, options: ConsoleOptions
    ) -> RenderResult:
        return
        yield

    def __rich_repr__(self) -> rich.repr.RichReprResult:
        yield "name", self.name

    @property
    def is_visual(self) -> bool:
        return False

    @property
    def is_root_view(self) -> bool:
        return self.parent is self.app

    def is_mounted(self, widget: Widget) -> bool:
        return widget in self.widgets

    def render(self) -> RenderableType:
        return self.layout

    def get_offset(self, widget: Widget) -> Point:
        return self.layout.get_offset(widget)

    async def message_update(self, message: UpdateMessage) -> None:
        widget = message.widget
        assert isinstance(widget, Widget)
        display_update = self.root_view.layout.update_widget(self.console, widget)
        if display_update is not None:
            self.app.display(display_update)

    async def message_layout(self, message: LayoutMessage) -> None:
        await self.root_view.refresh_layout()

    async def mount(self, *anon_widgets: Widget, **widgets: Widget) -> None:

        name_widgets: Iterable[tuple[str | None, Widget]]
        name_widgets = chain(
            ((None, widget) for widget in anon_widgets), widgets.items()
        )
        for name, widget in name_widgets:
            name = name or widget.name
            if name:
                self.named_widgets[name] = widget
            await self.app.register(widget)
            widget.set_parent(self)
            await widget.post_message(events.Mount(sender=self))
            self.widgets.add(widget)

        self.require_repaint()

    async def refresh_layout(self) -> None:

        if not self.size or not self.is_root_view:
            return

        width, height = self.console.size
        hidden, shown, resized = self.layout.reflow(width, height)
        self.app.refresh()

        for widget in self.layout.get_widgets():
            if not self.is_mounted(widget):
                await self.mount(widget)

        for widget in hidden:
            widget.post_message_no_wait(events.Hide(self))
        for widget in shown:
            widget.post_message_no_wait(events.Show(self))

        send_resize = shown
        send_resize.update(resized)

        for widget, region in self.layout:
            if widget in send_resize:
                widget.post_message_no_wait(
                    events.Resize(self, region.width, region.height)
                )

    async def on_resize(self, event: events.Resize) -> None:
        self.size = Dimensions(event.width, event.height)
        await self.refresh_layout()

    def get_widget_at(self, x: int, y: int) -> tuple[Widget, Region]:
        return self.layout.get_widget_at(x, y)

    def get_style_at(self, x: int, y: int) -> Style:
        return self.layout.get_style_at(x, y)

    def get_widget_region(self, widget: Widget) -> Region:
        return self.layout.get_widget_region(widget)

    async def _on_mouse_move(self, event: events.MouseMove) -> None:
        try:
            if self.app.mouse_captured:
                widget = self.app.mouse_captured
                region = self.get_widget_region(widget)
            else:
                widget, region = self.get_widget_at(event.x, event.y)
                log.debug("WIDGET %r", widget)
        except NoWidget:
            await self.app.set_mouse_over(None)
        else:
            await self.app.set_mouse_over(widget)

            await widget.forward_event(
                events.MouseMove(
                    self,
                    event.x - region.x,
                    event.y - region.y,
                    event.delta_x,
                    event.delta_y,
                    event.button,
                    event.shift,
                    event.meta,
                    event.ctrl,
                    screen_x=event.screen_x,
                    screen_y=event.screen_y,
                    style=event.style,
                )
            )

    async def forward_event(self, event: events.Event) -> None:

        if isinstance(event, (events.Enter, events.Leave)):
            await self.post_message(event)

        elif isinstance(event, events.MouseMove):
            event.style = self.get_style_at(event.screen_x, event.screen_y)
            await self._on_mouse_move(event)

        elif isinstance(event, events.MouseEvent):
            try:
                if self.app.mouse_captured:
                    widget = self.app.mouse_captured
                    region = self.get_widget_region(widget)
                else:
                    widget, region = self.get_widget_at(event.x, event.y)
            except NoWidget:
                pass
            else:
                if isinstance(event, events.MouseDown) and widget.can_focus:
                    await self.app.set_focus(widget)
                event.style = self.get_style_at(event.screen_x, event.screen_y)
                await widget.forward_event(event.offset(-region.x, -region.y))

        elif isinstance(event, (events.MouseScrollDown, events.MouseScrollUp)):
            try:
                widget, _region = self.get_widget_at(event.x, event.y)
            except NoWidget:
                return
            scroll_widget = widget or self.focused
            if scroll_widget is not None:
                await scroll_widget.forward_event(event)
        else:
            if self.focused is not None:
                await self.focused.forward_event(event)

    async def action_toggle(self, name: str) -> None:
        widget = self.named_widgets[name]
        widget.visible = not widget.visible
        await self.post_message(LayoutMessage(self))
        # await self.refresh_layout()