vizia_core 0.4.0

use std::any::Any;

use skia_safe::Surface;
use vizia_storage::LayoutTreeIterator;
use vizia_window::WindowDescription;

use super::EventProxy;
use crate::{cache::CachedData, prelude::*, systems::*};

#[cfg(feature = "clipboard")]
use copypasta::ClipboardProvider;

/// Context used to integrate vizia with windowing backends such as winit and baseview.
pub struct BackendContext(pub Context);

impl BackendContext {
    /// Creates a new instance of a backend context.
    pub fn new(cx: Context) -> Self {
        Self(cx)
    }

    pub fn init_accessibility_tree(&mut self) -> accesskit::TreeUpdate {
        initial_accessibility_system(&mut self.0)
    }

    /// Helper function for mutating the state of a window.
    pub fn mutate_window<W: Any, F: Fn(&mut BackendContext, &mut W)>(
        &mut self,
        window_entity: Entity,
        f: F,
    ) {
        if let Some(mut window_event_handler) = self.0.views.remove(&window_entity) {
            if let Some(window) = window_event_handler.downcast_mut::<W>() {
                f(self, window);
            }

            self.0.views.insert(window_entity, window_event_handler);
        }
    }

    /// Adds a root window view to the context.
    pub fn add_window<W: View>(&mut self, window: W) {
        self.0.views.insert(Entity::root(), Box::new(window));
    }

    /// Returns a mutable reference to the style data.
    pub fn style(&mut self) -> &mut Style {
        &mut self.0.style
    }

    /// Returns a mutable reference to the cache of computed properties data.
    pub fn cache(&mut self) -> &mut CachedData {
        &mut self.0.cache
    }

    /// Returns a reference to the keyboard modifiers state.
    pub fn modifiers(&mut self) -> &mut Modifiers {
        &mut self.0.modifiers
    }

    /// Returns the entity id of the currently focused view.
    pub fn focused(&self) -> Entity {
        self.0.focused
    }

    /// Returns the element name (e.g. `"textbox"`) of the currently focused
    /// view, or `None` if the focused entity has no view or the view doesn't
    /// declare an element name.
    ///
    /// Windowing backends can use this to decide whether a keyboard event
    /// should be reported as captured so the platform does not forward the
    /// event further — preventing the host from also processing keys
    /// intended for a focused text input.
    pub fn focused_element(&self) -> Option<&'static str> {
        self.0.views.get(&self.0.focused).and_then(|view| view.element())
    }

    pub fn add_main_window(
        &mut self,
        window_entity: Entity,
        window_description: &WindowDescription,
        dpi_factor: f32,
    ) {
        let physical_width = window_description.inner_size.width as f32 * dpi_factor;
        let physical_height = window_description.inner_size.height as f32 * dpi_factor;

        self.0.style.dpi_factor = dpi_factor as f64;

        self.0.cache.set_width(window_entity, physical_width);
        self.0.cache.set_height(window_entity, physical_height);

        self.0
            .style
            .width
            .insert(window_entity, Units::Pixels(window_description.inner_size.width as f32));
        self.0
            .style
            .height
            .insert(window_entity, Units::Pixels(window_description.inner_size.height as f32));

        self.0.style.disabled.insert(window_entity, false);

        self.0.style.pseudo_classes.insert(window_entity, PseudoClassFlags::OVER);
        self.0.style.restyle.insert(window_entity);
        self.0.style.reaccess.insert(window_entity).unwrap();

        self.0.style.position_type.insert(window_entity, PositionType::Absolute);

        self.0.tree.set_window(window_entity, true);

        // let physical_x = window_description.position.unwrap_or_default().x as f32 * dpi_factor;
        // let physical_y = window_description.position.unwrap_or_default().y as f32 * dpi_factor;

        // self.set_window_position(window_entity, physical_x, physical_y);
    }

    /// Returns a reference to the [`Environment`] model.
    pub fn environment(&self) -> &Environment {
        self.0.data::<Environment>()
    }

    /// Returns a mutable reference to the inner context.
    pub fn context(&mut self) -> &mut Context {
        &mut self.0
    }

    /// Calls the draw system.
    pub fn draw(
        &mut self,
        window_entity: Entity,
        surface: &mut Surface,
        dirty_surface: &mut Surface,
    ) -> bool {
        draw_system(&mut self.0, window_entity, surface, dirty_surface)
    }

    /// Set the current entity. This is useful in user code when you're performing black magic and
    /// want to trick other parts of the code into thinking you're processing some other part of the
    /// tree.
    pub fn set_current(&mut self, e: Entity) {
        self.0.current = e;
    }

    /// Sets the scale factor used by the application.
    pub fn set_scale_factor(&mut self, scale: f64) {
        self.0.style.dpi_factor = scale;
    }

    /// Sets the size of the window.
    pub fn set_window_size(
        &mut self,
        window_entity: Entity,
        physical_width: f32,
        physical_height: f32,
    ) {
        self.0.cache.set_bounds(
            window_entity,
            BoundingBox::from_min_max(0.0, 0.0, physical_width, physical_height),
        );

        let logical_width = self.0.style.physical_to_logical(physical_width);
        let logical_height = self.0.style.physical_to_logical(physical_height);
        self.0.style.width.insert(window_entity, Units::Pixels(logical_width));
        self.0.style.height.insert(window_entity, Units::Pixels(logical_height));

        self.0.style.needs_relayout();
        self.0.style.needs_retransform(window_entity);
        self.0.style.needs_reclip(window_entity);
    }

    /// Temporarily sets the current entity, calls the provided closure, and then resets the current entity back to previous.
    pub fn with_current(&mut self, e: Entity, f: impl FnOnce(&mut Context)) {
        let prev = self.0.current;
        self.0.current = e;
        f(&mut self.0);
        self.0.current = prev;
    }

    /// Returns the scale factor.
    pub fn scale_factor(&self) -> f32 {
        self.0.scale_factor()
    }

    /// You should not call this method unless you are writing a windowing backend, in which case
    /// you should consult the existing windowing backends for usage information.
    pub fn set_event_proxy(&mut self, proxy: Box<dyn EventProxy>) {
        if self.0.event_proxy.is_some() {
            panic!("Set the event proxy twice. This should never happen.");
        }

        self.0.event_proxy = Some(proxy);
    }

    /// You should not call this method unless you are writing a windowing backend, in which case
    /// you should consult the existing windowing backends for usage information.
    #[cfg(feature = "clipboard")]
    pub fn set_clipboard_provider(&mut self, clipboard: Box<dyn ClipboardProvider>) {
        self.0.clipboard = clipboard;
    }

    /// Send an event with custom origin and propagation information.
    pub fn send_event(&mut self, event: Event) {
        self.0.event_queue.push_back(event);
    }

    /// Check whether there are any events in the queue waiting for the next event dispatch cycle.
    pub fn has_queued_events(&self) -> bool {
        !self.0.event_queue.is_empty()
    }

    pub fn renegotiate_language(&mut self) {
        self.0.resource_manager.renegotiate_language();
    }

    /// Calls the accessibility system and updates the accesskit node tree.
    pub fn process_tree_updates(&mut self) {
        accessibility_system(&mut self.0);
    }

    /// Calls the style system to match entities with shared styles.
    pub fn process_style_updates(&mut self) {
        style_system(&mut self.0);

        // Load any unloaded images and remove unused images.
        image_system(&mut self.0);
    }

    // Returns true if animations are playing
    pub fn process_animations(&mut self) -> bool {
        animation_system(&mut self.0)
    }

    /// Massages the style system until everything is coherent
    pub fn process_visual_updates(&mut self) {
        // Perform layout.
        layout_system(&mut self.0);
    }

    pub fn emit_origin<M: Send + Any>(&mut self, message: M) {
        self.0.event_queue.push_back(
            Event::new(message)
                .target(self.0.current)
                .origin(Entity::root())
                .propagate(Propagation::Up),
        );
    }

    pub fn emit_window_event<M: Send + Any>(&mut self, window_entity: Entity, message: M) {
        self.0.event_queue.push_back(
            Event::new(message)
                .target(window_entity)
                .origin(window_entity)
                .propagate(Propagation::Up),
        );
    }

    pub fn needs_refresh(&mut self, window_entity: Entity) {
        self.0.cache.path.remove(window_entity);
        self.0.style.system_flags = SystemFlags::all();
        self.0.needs_redraw(window_entity);
        self.0.style.needs_restyle(window_entity);
        self.0.style.needs_relayout();
        let iter = LayoutTreeIterator::full(&self.0.tree);
        for entity in iter {
            self.0.style.needs_text_layout(entity);
            self.0.style.needs_text_update(entity);
            self.0.style.needs_restyle(entity);
        }
    }

    pub fn process_timers(&mut self) {
        self.0.tick_timers();
    }

    pub fn get_next_timer_time(&self) -> Option<Instant> {
        let timer_time = self.0.running_timers.peek().map(|timer_state| timer_state.time);
        let scheduled_event_time = self.0.event_schedule.peek().map(|timed_event| timed_event.time);

        match (timer_time, scheduled_event_time) {
            (Some(t1), Some(t2)) => Some(t1.min(t2)),
            (Some(t), None) => Some(t),
            (None, Some(t)) => Some(t),
            _ => None,
        }
    }

    pub fn emit_scheduled_events(&mut self) {
        let now = Instant::now();
        while let Some(timed_event) = self.0.event_schedule.peek() {
            if timed_event.time <= now {
                self.0.event_queue.push_back(self.0.event_schedule.pop().unwrap().event);
            } else {
                break;
            }
        }
    }
}