re_viewer_context 0.32.1

use std::collections::BTreeMap;

use itertools::Itertools as _;
use nohash_hasher::IntSet;
use re_chunk_store::MissingChunkReporter;
use re_log_types::EntityPath;
use re_sdk_types::ViewClassIdentifier;
use vec1::Vec1;

use super::ViewContext;
use crate::{
    IndicatedEntities, PerVisualizerType, QueryRange, RecommendedMappings, SystemExecutionOutput,
    ViewClassRegistryError, ViewId, ViewQuery, ViewSpawnHeuristics, ViewSystemExecutionError,
    ViewSystemIdentifier, ViewSystemRegistrator, ViewerContext, VisualizableReason,
};

#[derive(Clone, Copy, Debug, Default, PartialEq, PartialOrd, Ord, Eq)]
pub enum ViewClassLayoutPriority {
    /// This view can share space with others
    ///
    /// Used for boring things like text and plots.
    Low,

    #[default]
    Medium,

    /// Give this view lots of space.
    /// Used for spatial views (2D/3D).
    High,
}

/// Recommended visualizers for an entity, split into all recommendations and the subset to auto-spawn.
///
/// `auto_spawned` is always a subset of `all_recommendations`.
/// By default, all recommendations are also auto-spawned.
pub struct RecommendedVisualizers {
    /// All recommended visualizers (used for UI purposes like "add visualizer" menus).
    all_recommendations: BTreeMap<ViewSystemIdentifier, Vec1<RecommendedMappings>>,

    /// The subset of [`Self::all_recommendations`] that should be automatically spawned.
    auto_spawned: BTreeMap<ViewSystemIdentifier, Vec1<RecommendedMappings>>,
}

impl RecommendedVisualizers {
    /// Creates a new [`RecommendedVisualizers`] where all recommendations are auto-spawned.
    pub fn new(
        recommended_and_auto_spawned: BTreeMap<ViewSystemIdentifier, Vec1<RecommendedMappings>>,
    ) -> Self {
        Self {
            auto_spawned: recommended_and_auto_spawned.clone(),
            all_recommendations: recommended_and_auto_spawned,
        }
    }

    pub fn empty() -> Self {
        Self::new(Default::default())
    }

    pub fn default(visualizer: ViewSystemIdentifier) -> Self {
        Self::new(std::iter::once((visualizer, Default::default())).collect())
    }

    pub fn default_many(visualizers: impl IntoIterator<Item = ViewSystemIdentifier>) -> Self {
        let recommended = visualizers
            .into_iter()
            .map(|v| (v, Default::default()))
            .collect();
        Self::new(recommended)
    }

    /// Inserts visualizer recommendations, merging with any existing mappings for the same visualizer.
    ///
    /// Duplicate mappings are removed.
    /// If `auto_spawn` is true, this recommendation will also spawn a view.
    pub fn insert(
        &mut self,
        visualizer: ViewSystemIdentifier,
        mappings: Vec1<RecommendedMappings>,
        auto_spawn: bool,
    ) {
        if auto_spawn {
            Self::extend_mappings_unique(&mut self.auto_spawned, visualizer, mappings.clone());
        }
        Self::extend_mappings_unique(&mut self.all_recommendations, visualizer, mappings);
    }

    /// All recommended visualizers, including those not auto-spawned.
    pub fn all_recommendations(
        &self,
    ) -> &BTreeMap<ViewSystemIdentifier, Vec1<RecommendedMappings>> {
        &self.all_recommendations
    }

    /// Consumes self and returns the auto-spawned recommendations.
    ///
    /// Auto-spanned recommendations are always a subset of all recommendations.
    pub fn into_auto_spawned(self) -> BTreeMap<ViewSystemIdentifier, Vec1<RecommendedMappings>> {
        self.auto_spawned
    }

    fn extend_mappings_unique(
        map: &mut BTreeMap<ViewSystemIdentifier, Vec1<RecommendedMappings>>,
        visualizer: ViewSystemIdentifier,
        mappings: Vec1<RecommendedMappings>,
    ) {
        match map.entry(visualizer) {
            std::collections::btree_map::Entry::Occupied(mut entry) => {
                let existing = entry.get_mut();
                existing.extend(mappings);
                *existing = Vec1::try_from_vec(existing.iter().cloned().unique().collect())
                    .expect("There was already at least one mapping.");
            }
            std::collections::btree_map::Entry::Vacant(entry) => {
                entry.insert(mappings);
            }
        }
    }
}

/// Callback that renders the active visualizers in the selection panel.
pub type VisualizersSectionUi<'a> = Box<dyn Fn(&mut egui::Ui, &ViewContext<'_>) + 'a>;

/// Output of [`ViewClass::visualizers_section`].
pub struct VisualizersSectionOutput<'a> {
    /// Renders the active visualizers in the selection panel.
    pub ui: VisualizersSectionUi<'a>,

    /// Per-entity options for the "add visualizer" menu.
    /// Recommended visualizers for an entity may or may not be identical to [`ViewClass::recommended_visualizers_for_entity`].
    pub add_options: Vec<(EntityPath, RecommendedVisualizers)>,
}

/// Defines a class of view without any concrete types making it suitable for storage and interfacing.
///
/// Each View in the viewer's viewport has a single class assigned immutable at its creation time.
/// The class defines all aspects of its behavior.
/// It determines which entities are queried, how they are rendered, and how the user can interact with them.
//
// TODO(andreas): Consider formulating a view instance context object that is passed to all
// methods that operate on concrete views as opposed to be about general information on the class.
pub trait ViewClass: Send + Sync {
    /// Identifier string of this view class.
    ///
    /// By convention we use `PascalCase`.
    fn identifier() -> ViewClassIdentifier
    where
        Self: Sized;

    /// Ordering hint for view class recommendations. Lower values are recommended *more*.
    ///
    /// If tied, the display name is used as a tiebreaker in lexicographical order.
    fn recommendation_order(&self) -> i32 {
        0
    }

    /// User-facing name of this view class.
    ///
    /// Used for UI display.
    fn display_name(&self) -> &'static str;

    // TODO(RR-4506): Remove this flag (and all sites that branch on it) once the Status view
    // graduates from experimental.
    /// Whether this view class is still experimental.
    ///
    /// Experimental views are shown in a separate "Experimental" section at the bottom of the
    /// "add view" picker (with a warning icon), and surface an inline warning banner in the
    /// selection panel when a view of this kind is selected. They are otherwise fully functional.
    fn is_experimental(&self) -> bool {
        false
    }

    /// Icon used to identify this view class.
    fn icon(&self) -> &'static re_ui::Icon {
        &re_ui::icons::VIEW_GENERIC
    }

    fn help(&self, os: egui::os::OperatingSystem) -> re_ui::Help;

    /// Called once upon registration of the class
    ///
    /// This can be used to register all built-in [`crate::ViewContextSystem`] and [`crate::VisualizerSystem`].
    fn on_register(
        &self,
        system_registry: &mut ViewSystemRegistrator<'_>,
    ) -> Result<(), ViewClassRegistryError>;

    /// Called once for every new view instance of this class.
    ///
    /// The state is *not* persisted across viewer sessions, only shared frame-to-frame.
    fn new_state(&self) -> Box<dyn ViewState>;

    /// Preferred aspect ratio for the ui tiles of this view.
    fn preferred_tile_aspect_ratio(&self, _state: &dyn ViewState) -> Option<f32> {
        None
    }

    /// Controls how likely this view will get a large tile in the ui.
    fn layout_priority(&self) -> ViewClassLayoutPriority;

    /// Controls whether the visible time range UI should be displayed for this view.
    fn supports_visible_time_range(&self) -> bool {
        false
    }

    /// Default query range for this view.
    //TODO(#6918): also provide ViewerContext and ViewId, to enable reading view properties.
    fn default_query_range(&self, _state: &dyn ViewState) -> QueryRange {
        QueryRange::LatestAt
    }

    /// Determines a suitable origin given the provided set of entities.
    ///
    /// This function only considers the transform topology, disregarding the actual visualizability
    /// of the entities.
    fn recommended_origin_for_entities(
        &self,
        entities: &IntSet<EntityPath>,
        _entity_db: &re_entity_db::EntityDb,
    ) -> Option<EntityPath> {
        // For example: when creating a view from a single entity, we want that
        // entity to be the origin of the view.
        // If we select two sibling entities, we want their parent to be the origin.
        Some(EntityPath::common_ancestor_of(entities.iter()))
    }

    /// Auto picked visualizers for an entity if there was not explicit selection.
    ///
    /// Helpful for customizing fallback behavior for types that are insufficient
    /// to determine indicated on their own.
    ///
    /// Will only be called for entities where the selected visualizers have not
    /// been overridden by the blueprint.
    ///
    /// `visualizers_with_reason` contains the visualizers that are visualizable for this entity,
    /// along with the reason why they are visualizable.
    ///
    /// This interface provides a default implementation which will return all visualizers
    /// which are both visualizable and indicated for the given entity.
    fn recommended_visualizers_for_entity(
        &self,
        entity_path: &EntityPath,
        visualizers_with_reason: &[(ViewSystemIdentifier, &VisualizableReason)],
        indicated_entities_per_visualizer: &PerVisualizerType<&IndicatedEntities>,
    ) -> RecommendedVisualizers {
        let recommended = visualizers_with_reason
            .iter()
            .filter_map(|(visualizer, _reason)| {
                if indicated_entities_per_visualizer
                    .get(visualizer)
                    .is_some_and(|matching_list| matching_list.contains(entity_path))
                {
                    Some((*visualizer, Default::default()))
                } else {
                    None
                }
            })
            .collect();

        RecommendedVisualizers::new(recommended)
    }

    /// Custom UI and add-visualizer options for the "Visualizers" section in the selection panel.
    ///
    /// Returns `None` if the view doesn't provide a custom visualizers section (the default).
    fn visualizers_section<'a>(
        &'a self,
        _ctx: &'a ViewContext<'a>,
    ) -> Option<VisualizersSectionOutput<'a>> {
        None
    }

    /// Determines which views should be spawned by default for this class.
    ///
    /// Only entities matching `include_entity` should be considered,
    /// though this is only a suggestion and may be
    /// overwritten if a view decides to display more data.
    fn spawn_heuristics(
        &self,
        ctx: &ViewerContext<'_>,
        include_entity: &dyn Fn(&EntityPath) -> bool,
    ) -> ViewSpawnHeuristics;

    /// Ui shown when the user selects a view of this class.
    #[doc(alias = "settings_ui")]
    fn selection_ui(
        &self,
        _ctx: &ViewerContext<'_>,
        _ui: &mut egui::Ui,
        _state: &mut dyn ViewState,
        // TODO(RR-3076): Eventually we want to get rid of the _general_ concept of `space_origin`.
        _space_origin: &EntityPath,
        _view_id: ViewId,
    ) -> Result<(), ViewSystemExecutionError> {
        Ok(())
    }

    /// Additional UI displayed in the tab title bar, between the "maximize" and "help" buttons.
    ///
    /// Note: this is a right-to-left layout.
    fn extra_title_bar_ui(
        &self,
        _ctx: &ViewerContext<'_>,
        _ui: &mut egui::Ui,
        _state: &mut dyn ViewState,
        // TODO(RR-3076): Eventually we want to get rid of the _general_ concept of `space_origin`.
        _space_origin: &EntityPath,
        _view_id: ViewId,
    ) -> Result<(), ViewSystemExecutionError> {
        Ok(())
    }

    /// Draws the ui for this view class and handles ui events.
    ///
    /// The passed state is kept frame-to-frame.
    ///
    /// TODO(wumpf): Right now the ui methods control when and how to create [`re_renderer::ViewBuilder`]s.
    ///              In the future, we likely want to move view builder handling to `re_viewport` with
    ///              minimal configuration options exposed via [`crate::ViewClass`].
    #[doc(alias = "paint")]
    #[doc(alias = "render")]
    fn ui(
        &self,
        ctx: &ViewerContext<'_>,
        missing_chunk_reporter: &MissingChunkReporter,
        ui: &mut egui::Ui,
        state: &mut dyn ViewState,
        query: &ViewQuery<'_>,
        system_output: SystemExecutionOutput,
    ) -> Result<(), ViewSystemExecutionError>;
}

pub trait ViewClassExt<'a>: ViewClass + 'a {
    fn view_context<'b>(
        &self,
        viewer_ctx: &'b ViewerContext<'b>,
        view_id: ViewId,
        view_state: &'b dyn ViewState,
        space_origin: &'b EntityPath,
    ) -> ViewContext<'b>;
}

impl<'a, T> ViewClassExt<'a> for T
where
    T: ViewClass + 'a,
{
    fn view_context<'b>(
        &self,
        viewer_ctx: &'b ViewerContext<'b>,
        view_id: ViewId,
        view_state: &'b dyn ViewState,
        // TODO(RR-3076): Eventually we want to get rid of the _general_ concept of `space_origin`.
        space_origin: &'b EntityPath,
    ) -> ViewContext<'b> {
        ViewContext {
            viewer_ctx,
            view_id,
            view_class_identifier: T::identifier(),
            space_origin,
            view_state,
            query_result: viewer_ctx.lookup_query_result(view_id),
        }
    }
}

/// Unserialized frame to frame state of a view.
///
/// For any state that should be persisted, use the Blueprint!
/// This state is used for transient state, such as animation or uncommitted ui state like dragging a camera.
/// (on mouse release, the camera would be committed to the blueprint).
pub trait ViewState: std::any::Any + Sync + Send + re_byte_size::SizeBytes {
    /// Converts itself to a reference of [`std::any::Any`], which enables downcasting to concrete types.
    fn as_any(&self) -> &dyn std::any::Any;

    /// Converts itself to a reference of [`std::any::Any`], which enables downcasting to concrete types.
    fn as_any_mut(&mut self) -> &mut dyn std::any::Any;
}

/// Implementation of an empty view state.
impl ViewState for () {
    fn as_any(&self) -> &dyn std::any::Any {
        self
    }

    fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
        self
    }
}

pub trait ViewStateExt: ViewState {
    /// Downcasts this state to a reference of a concrete type.
    fn downcast_ref<T: ViewState>(&self) -> Result<&T, ViewSystemExecutionError> {
        self.as_any()
            .downcast_ref()
            .ok_or(ViewSystemExecutionError::StateCastError(
                std::any::type_name::<T>(),
            ))
    }

    /// Downcasts this state to a mutable reference of a concrete type.
    fn downcast_mut<T: ViewState>(&mut self) -> Result<&mut T, ViewSystemExecutionError> {
        self.as_any_mut()
            .downcast_mut()
            .ok_or(ViewSystemExecutionError::StateCastError(
                std::any::type_name::<T>(),
            ))
    }
}

impl ViewStateExt for dyn ViewState {}