brep_render/engine_state/

scene_query.rs

use super::*;

impl EngineState {
    /// Ranked candidate list under CSS-pixel `(x, y)`, kernel names, priority
    /// VERTEX > EDGE > FACE > … > SOLID.
    ///
    /// SCENE ONLY, deliberately: this R3-boundary accessor (and its
    /// [`hover_json`](Self::hover_json) sibling) reports kernel-named GEOMETRY, and
    /// its in-tree consumer is the sketch's external-edge picker, which wants
    /// edges. The construction PLANE cards join the pick list one level up, in
    /// [`pick_candidates_at`](Self::pick_candidates_at) — that is what the
    /// selection paths and the app's pick-list popup consume.
    pub fn pick_json(&self, x: f64, y: f64) -> String {
        let candidates = pick::pick(&self.scene, &self.camera, x, y, &self.pick_options());
        pick::candidates_to_json(&candidates)
    }

    /// The single best candidate under `(x, y)` (hover), or `null`.
    pub fn hover_json(&self, x: f64, y: f64) -> String {
        let candidates = pick::pick(&self.scene, &self.camera, x, y, &self.pick_options());
        match candidates.first() {
            Some(best) => pick::candidates_to_json(std::slice::from_ref(best))
                .strip_prefix('[')
                .and_then(|s| s.strip_suffix(']'))
                .map(str::to_string)
                .unwrap_or_else(|| "null".to_string()),
            None => "null".to_string(),
        }
    }

    // --- Settings / emphasis / visibility (R11/R14/R17) -------------------

    pub fn apply_settings_json(&mut self, json: &str) -> Result<(), String> {
        let prev_lod = self.settings.lod_factor;
        self.settings.apply_json(json)?;
        self.settings_generation = self.settings_generation.wrapping_add(1);
        self.dirty = true;
        // Push the (possibly changed) ViewCube size into the widget so the rendered
        // cube AND its hit-test rect track the setting. Always re-pushed (idempotent
        // for an unchanged value) so this ONE choke point covers panel edits, boot
        // restore, and Reset-to-defaults alike.
        self.widgets.set_viewcube_size(self.settings.viewcube_size_px);
        // Projection rides in the settings JSON as `orthographic` (see `settings_json`)
        // so the toolbar toggle AND a reload both go through this ONE apply path — the
        // same way wireframe does. It is NOT a `RenderSettings` field: read it straight
        // off the JSON and drive the camera. A PARTIAL apply (the wireframe toggle's
        // `{"wireframe":true}`) omits the key and leaves the projection untouched, and
        // the panel's full-buffer apply carries the live value (so it's a no-op).
        if let Some(want_ortho) = serde_json::from_str::<serde_json::Value>(json)
            .ok()
            .and_then(|v| v.get("orthographic").and_then(|o| o.as_bool()))
        {
            let is_ortho = matches!(
                self.camera.projection,
                crate::view::Projection::Orthographic { .. }
            );
            if want_ortho != is_ortho {
                self.set_projection(if want_ortho { "orthographic" } else { "perspective" });
            }
        }
        // The LOD factor scales DISPLAY tessellation, so a change must re-run so the
        // resident meshes re-tessellate at the new chord tolerance (the runner drops
        // its reuse baseline when the lod differs). Every OTHER setting is pure
        // render state and needs no re-run. Skip the re-run when there are no
        // features (e.g. boot restores a saved `lodFactor` before any document is
        // loaded): the run would be empty, and the real doc load re-runs with the
        // lod already injected.
        if self.settings.lod_factor != prev_lod && !self.history.is_empty() {
            self.rerun_history();
        }
        // Sketch colors live in the settings too: when a sketch is being edited, push
        // the (possibly) new palette into the live session and re-push the overlay so
        // an edited color takes effect immediately (mirrors how a wireframe/lod change
        // refreshes the view). Compute the palette first to avoid a split borrow.
        if self.sketch_edit.is_some() {
            let colors = self.settings.sketch_colors();
            if let Some(edit) = self.sketch_edit.as_mut() {
                edit.session.colors = colors;
            }
            self.refresh_sketch_overlay();
        }
        Ok(())
    }

    /// The FULL current settings as JSON (the round-trip counterpart of
    /// [`apply_settings_json`]): the schema-driven form seeds its widgets from
    /// this and the storage seam persists it.
    pub fn settings_json(&self) -> String {
        // Projection is live CAMERA state surfaced to the settings layer as a boolean
        // (`orthographic`) so the toolbar toggle persists and the settings panel can
        // round-trip it without clobbering. DERIVE it from the camera here — it is
        // never a stored `RenderSettings` field — so it can NEVER drift from the
        // actual projection no matter which code path last changed it.
        let mut value: serde_json::Value =
            serde_json::from_str(&self.settings.to_json()).unwrap_or(serde_json::Value::Null);
        if let Some(obj) = value.as_object_mut() {
            obj.insert(
                "orthographic".into(),
                serde_json::Value::Bool(matches!(
                    self.camera.projection,
                    crate::view::Projection::Orthographic { .. }
                )),
            );
        }
        value.to_string()
    }

    /// The current per-solid metadata color overrides as JSON —
    /// `[{"name": "...", "override": "#rrggbb" | null}, …]`. Lets a UI list the
    /// scene's solids with their current override so the picker reflects state.
    pub fn solid_color_overrides_json(&self) -> String {
        let solids: Vec<serde_json::Value> = self
            .scene
            .solids()
            .iter()
            .map(|solid| {
                let over = solid.color_override.map(|rgb| {
                    let q = |c: f32| (c.clamp(0.0, 1.0) * 255.0).round() as u32;
                    format!("#{:02x}{:02x}{:02x}", q(rgb[0]), q(rgb[1]), q(rgb[2]))
                });
                serde_json::json!({ "name": solid.name, "override": over })
            })
            .collect();
        serde_json::Value::Array(solids).to_string()
    }

    pub fn apply_emphasis_json(&mut self, json: &str) -> Result<(), String> {
        self.emphasis.apply_json(json)?;
        self.dirty = true;
        Ok(())
    }

    pub fn set_visible(&mut self, name: &str, visible: bool) -> bool {
        let ok = self.scene.set_visible(name, visible);
        if ok {
            self.dirty = true;
        }
        ok
    }

    /// Set (or clear) a solid's LIVE per-solid color override (R14) without a
    /// history rerun — the app assigning a metadata color updates the view
    /// immediately. `color_hex` is a CSS hex string (`#rrggbb`); `None` or an
    /// empty/unparseable string clears back to the hashed/uniform base color.
    /// Marks dirty; returns false if the solid name is unknown.
    pub fn set_color_override(&mut self, name: &str, color_hex: Option<&str>) -> bool {
        let color = match color_hex {
            Some(hex) if !hex.trim().is_empty() => crate::style::parse_css_hex(hex),
            _ => None,
        };
        let ok = self.scene.set_color_override(name, color);
        if ok {
            self.dirty = true;
        }
        ok
    }

    pub fn scene_listing_json(&self) -> String {
        self.scene.listing_json()
    }

    // --- Overlay widgets --------------------------------------------------

    /// The BASE bbox the camera depth-range fit starts from: the visible SOLIDS
    /// unioned with the pushed OVERLAY groups (sketch curves/points, dimension
    /// leaders, constraint glyphs — the `set_overlay` channel). Folding in the
    /// groups stops orbiting an editing sketch from clipping it against the
    /// solids-only bounds (the reported clipping when "Lock to sketch" is off).
    /// The render path ([`Self::fit_camera_and_overlay`]) unions the FULL widget
    /// overlay's world bounds (datum planes, world axes, frames, transform
    /// gizmo — NOT in this bbox's channels) and the world origin on top of this
    /// before fitting, so construction geometry never clips. Callers must bind
    /// this to a local before `camera.fit_depth_range` (which needs
    /// `&mut self.camera`).
    pub fn depth_range_bbox(&self) -> crate::camera::Aabb {
        let mut bbox = self.scene.bbox();
        bbox.union(&self.widgets.overlay_groups_bbox());
        bbox
    }

}

// ============================================================================
// Scene-tree accessors (appended — see the engine-native Scene panel slice).
// Kept as a SEPARATE `impl` block so concurrent panel work does not conflict
// with the primary surface above; purely additive over the existing
// scene / emphasis API (`scene_listing_json`, `set_visible`, `selection_json`,
// `clear_selection`, `apply_emphasis_json`).
// ============================================================================
impl EngineState {
    /// A RICHER scene listing than [`scene_listing_json`](Self::scene_listing_json)
    /// (which is counts only): per solid the individual face + edge kernel NAMES
    /// and vertex refs (topo id + world position), plus visibility — the shape the
    /// engine-native Scene tree lists entities from and the headed verifier asserts
    /// against. Vertices carry no kernel name, so they are keyed by topo id + world
    /// position (the same shape the emphasis vertex-ref selection uses).
    pub fn scene_entities_json(&self) -> String {
        let solids: Vec<serde_json::Value> = self
            .scene
            .solids()
            .iter()
            // Committed-sketch SHEETS are scene solids (pickable/measurable) but list
            // under "Sketches" (`committed_sketches`), not among the real solids.
            .filter(|solid| !solid.is_sketch)
            .map(|solid| {
                let faces: Vec<&str> = solid.faces.iter().map(|f| f.name.as_str()).collect();
                let edges: Vec<&str> = solid.edges.iter().map(|e| e.name.as_str()).collect();
                let vertices: Vec<serde_json::Value> = solid
                    .vertices
                    .iter()
                    .map(|v| serde_json::json!({ "topoId": v.topo_id, "position": v.position }))
                    .collect();
                serde_json::json!({
                    "name": solid.name,
                    "visible": solid.visible,
                    "faces": faces,
                    "edges": edges,
                    "vertices": vertices,
                })
            })
            .collect();
        serde_json::Value::Array(solids).to_string()
    }

    /// Drive the engine SELECTION by kernel NAME from a UI tree (the name-based
    /// analogue of [`select_top_at`](Self::select_top_at), which picks under the
    /// cursor). Replaces the current selection with the single named `solid` /
    /// `face` / `edge` so clicking a Scene-tree row highlights that entity in the
    /// viewport (the render pass reads `emphasis`). Vertices have no kernel name —
    /// use [`select_vertex_by_position`](Self::select_vertex_by_position). Returns
    /// false for an unknown `kind` or an empty `name`.
    pub fn select_by_name(&mut self, kind: &str, name: &str) -> bool {
        // A construction datum/plane routes to its own name-keyed selection.
        if kind == "datum" {
            return self.select_datum(name);
        }
        if name.is_empty() || !matches!(kind, "solid" | "face" | "edge") {
            return false;
        }
        let had_datum = !self.emphasis.selected_datums.is_empty();
        self.emphasis.selected_solids.clear();
        self.emphasis.selected_faces.clear();
        self.emphasis.selected_edges.clear();
        self.emphasis.selected_vertices.clear();
        self.emphasis.selected_datums.clear();
        match kind {
            "solid" => {
                self.emphasis.selected_solids.insert(name.to_string());
            }
            "face" => {
                self.emphasis.selected_faces.insert(name.to_string());
            }
            "edge" => {
                self.emphasis.selected_edges.insert(name.to_string());
            }
            _ => unreachable!(),
        }
        self.emphasis.generation = self.emphasis.generation.wrapping_add(1);
        self.dirty = true;
        if had_datum {
            self.refresh_construction_datums();
        }
        true
    }

    /// Select a single vertex by its owning solid + world position — vertices have
    /// no kernel name, so emphasis keys them by solid + position (matched with a
    /// tolerance in the render pass). Replaces the current selection. Returns false
    /// for an empty solid name.
    pub fn select_vertex_by_position(&mut self, solid: &str, position: [f64; 3]) -> bool {
        if solid.is_empty() {
            return false;
        }
        let had_datum = !self.emphasis.selected_datums.is_empty();
        self.emphasis.selected_solids.clear();
        self.emphasis.selected_faces.clear();
        self.emphasis.selected_edges.clear();
        self.emphasis.selected_vertices.clear();
        self.emphasis.selected_datums.clear();
        self.emphasis.selected_vertices.push(crate::style::VertexRef {
            solid: solid.to_string(),
            position,
        });
        self.emphasis.generation = self.emphasis.generation.wrapping_add(1);
        self.dirty = true;
        if had_datum {
            self.refresh_construction_datums();
        }
        true
    }
}

// Scene-tree accessor tests — kept in their OWN module (appended) so they do not
// conflict with the primary `mod tests` above.
#[cfg(test)]
mod scene_tree_tests {
    use super::*;

    fn cube_history(name: &str) -> String {
        serde_json::json!({
            "expressions": "",
            "configurator": {},
            "features": [{
                "type": "P.CU",
                "inputParams": {
                    "id": name,
                    "sizeX": 10.0, "sizeY": 10.0, "sizeZ": 10.0,
                    "transform": {
                        "position": [0.0, 0.0, 0.0],
                        "rotationEuler": [0.0, 0.0, 0.0],
                        "scale": [1.0, 1.0, 1.0]
                    },
                    "boolean": { "targets": [], "operation": "NONE" }
                },
                "persistentData": {}
            }]
        })
        .to_string()
    }

    #[test]
    fn scene_entities_json_lists_solid_faces_edges_vertices() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();
        let listing: serde_json::Value =
            serde_json::from_str(&engine.scene_entities_json()).unwrap();
        let arr = listing.as_array().unwrap();
        assert_eq!(arr.len(), 1);
        let solid = &arr[0];
        assert_eq!(solid["name"], "Box");
        assert_eq!(solid["visible"], true);
        // A cube has 6 faces, 12 edges, 8 vertices.
        assert_eq!(solid["faces"].as_array().unwrap().len(), 6);
        assert_eq!(solid["edges"].as_array().unwrap().len(), 12);
        assert_eq!(solid["vertices"].as_array().unwrap().len(), 8);
        // Each vertex ref carries a position triple.
        assert_eq!(solid["vertices"][0]["position"].as_array().unwrap().len(), 3);
    }

    #[test]
    fn select_by_name_solid_sets_emphasis_and_replaces() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();
        assert!(engine.select_by_name("solid", "Box"));
        assert!(engine.emphasis.selected_solids.contains("Box"));
        // A second solid selection REPLACES the first (single-select).
        engine.emphasis.selected_faces.insert("stale".into());
        assert!(engine.select_by_name("solid", "Box"));
        assert!(engine.emphasis.selected_faces.is_empty());
    }

    #[test]
    fn select_by_name_rejects_unknown_kind_or_empty_without_clearing() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();
        engine.select_by_name("solid", "Box");
        // An unknown kind / empty name is a no-op that keeps the current selection.
        assert!(!engine.select_by_name("blob", "Box"));
        assert!(!engine.select_by_name("solid", ""));
        assert!(engine.emphasis.selected_solids.contains("Box"));
    }

    #[test]
    fn select_vertex_by_position_records_vertex_ref() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();
        assert!(engine.select_vertex_by_position("Box", [1.0, 2.0, 3.0]));
        assert_eq!(engine.emphasis.selected_vertices.len(), 1);
        let vr = &engine.emphasis.selected_vertices[0];
        assert_eq!(vr.solid, "Box");
        assert_eq!(vr.position, [1.0, 2.0, 3.0]);
        // Empty solid name is rejected.
        assert!(!engine.select_vertex_by_position("", [0.0, 0.0, 0.0]));
    }

    #[test]
    fn set_visible_toggles_solid_and_shows_in_listing() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();
        assert!(engine.set_visible("Box", false));
        let listing: serde_json::Value =
            serde_json::from_str(&engine.scene_entities_json()).unwrap();
        assert_eq!(listing[0]["visible"], false);
        assert!(!engine.set_visible("Nope", false));
    }
}

// ============================================================================
// Inspector mass properties (appended — see the Inspector-panel slice).
// SEPARATE `impl` block so concurrent panel work appending to the primary block
// does not conflict; purely additive over the existing history/scene API.
// ============================================================================
impl EngineState {
    /// The resident kernel handle of every solid currently displayed, keyed by
    /// name. Obtained by replaying the CURRENT rolled-to history prefix through
    /// [`brep_kernel::execute_history`]: after a build the incremental cache
    /// holds exactly this prefix, so the replay is a clean cache hit — it
    /// re-tessellates nothing and hands back the SAME handles the scene was built
    /// from (mirrors the pipeline's `fold_history`: removals then additions).
    /// `pub(super)`: the interference check (`engine_state::interference`) reads
    /// the same warm main-side handle map for its non-destructive booleans.
    pub(super) fn resident_solid_handles(&self) -> HashMap<String, u32> {
        let request: HistoryRequest = match serde_json::from_value(self.history.prefix_request()) {
            Ok(request) => request,
            Err(_) => return HashMap::new(),
        };
        let result = brep_kernel::execute_history(&request);
        let mut handles: HashMap<String, u32> = HashMap::new();
        for feature in &result.results {
            for removed in &feature.removed {
                handles.remove(removed);
            }
            for added in &feature.added {
                handles.insert(added.name.clone(), added.handle);
            }
        }
        handles
    }

    /// Mass properties for the Inspector panel, from the kernel's exact
    /// (divergence-theorem) integrator. `name = Some(solid)` reports that resident
    /// solid; `None` reports the whole model. `density` (mass units per mm³; the
    /// kernel length convention is millimetres) scales `mass` and the inertia
    /// tensor — the centroid and principal axes are density-independent.
    ///
    /// Returns JSON:
    /// ```json
    /// { "ok": true, "target": "Box", "solidCount": 1, "density": 1.0,
    ///   "volume": 5738.05, "surfaceArea": 2927.79, "mass": 5738.05,
    ///   "centroid": [10.0, 10.0, 10.0],
    ///   "inertia": [[..],[..],[..]] | null,
    ///   "principalMoments": [a,b,c] | null,
    ///   "principalAxes": [[..],[..],[..]] | null }
    /// ```
    /// A single resolved solid carries the full centroidal inertia tensor +
    /// principal axes/moments; a multi-solid aggregate reports summed volume /
    /// area / mass and the volume-weighted centroid, with the tensor fields
    /// `null` (select one solid for its inertia). `ok:false` with a `message` on
    /// no solids / an unknown name / an integrator failure.
    pub fn mass_properties_json(&self, name: Option<&str>, density: f64) -> String {
        let handles = self.resident_solid_handles();

        // Resolve the target solids: a named solid (must be resident) or, for the
        // whole model, every scene solid that has resident geometry (draw order).
        let targets: Vec<String> = match name {
            Some(name) if handles.contains_key(name) => vec![name.to_string()],
            Some(name) => {
                return serde_json::json!({
                    "ok": false,
                    "message": format!("solid '{name}' has no resident geometry"),
                })
                .to_string();
            }
            None => self
                .scene
                .solids()
                .iter()
                .map(|solid| solid.name.clone())
                .filter(|name| handles.contains_key(name))
                .collect(),
        };
        if targets.is_empty() {
            return serde_json::json!({ "ok": false, "message": "no solids" }).to_string();
        }

        // Per-solid density mass properties straight from the kernel.
        let mut props = Vec::with_capacity(targets.len());
        for target in &targets {
            match brep_kernel::mass_properties_handle_native(handles[target], density) {
                Ok(properties) => props.push(properties),
                Err(error) => {
                    return serde_json::json!({
                        "ok": false,
                        "message": format!("{target}: {error}"),
                    })
                    .to_string();
                }
            }
        }

        let target_label = if targets.len() == 1 {
            targets[0].clone()
        } else {
            "(whole model)".to_string()
        };

        if props.len() == 1 {
            // Single solid: the full tensor + principal frame are meaningful.
            let p = &props[0];
            serde_json::json!({
                "ok": true,
                "target": target_label,
                "solidCount": 1,
                "density": p.density,
                "volume": p.volume,
                "surfaceArea": p.surface_area,
                "mass": p.mass,
                "centroid": [p.centroid.x, p.centroid.y, p.centroid.z],
                "inertia": p.inertia,
                "principalMoments": p.principal_moments,
                "principalAxes": p.principal_axes,
            })
            .to_string()
        } else {
            // Aggregate: additive scalars + volume-weighted centroid. Combining
            // the tensors needs a parallel-axis shift per solid; left to the
            // single-solid view rather than approximated here.
            let volume: f64 = props.iter().map(|p| p.volume).sum();
            let surface_area: f64 = props.iter().map(|p| p.surface_area).sum();
            let mass: f64 = props.iter().map(|p| p.mass).sum();
            let centroid = if volume.abs() > f64::EPSILON {
                let mut acc = [0.0f64; 3];
                for p in &props {
                    acc[0] += p.volume * p.centroid.x;
                    acc[1] += p.volume * p.centroid.y;
                    acc[2] += p.volume * p.centroid.z;
                }
                [acc[0] / volume, acc[1] / volume, acc[2] / volume]
            } else {
                [0.0, 0.0, 0.0]
            };
            serde_json::json!({
                "ok": true,
                "target": target_label,
                "solidCount": props.len(),
                "density": density,
                "volume": volume,
                "surfaceArea": surface_area,
                "mass": mass,
                "centroid": centroid,
                "inertia": serde_json::Value::Null,
                "principalMoments": serde_json::Value::Null,
                "principalAxes": serde_json::Value::Null,
            })
            .to_string()
        }
    }
}

#[cfg(test)]
mod inspector_tests {
    use super::*;

    /// The same 3-feature seed the app boots with: a 20 mm cube `Box`, a r=6
    /// h=30 cylinder `Pin` through its centre, and `Cut` = SUBTRACT(Box, [Pin]).
    /// The SUBTRACT result reuses the target's name, so the final solid is `Box`.
    fn seed_history() -> String {
        serde_json::json!({
            "expressions": "",
            "configurator": {},
            "features": [
                {
                    "type": "P.CU",
                    "inputParams": {
                        "id": "Box",
                        "sizeX": 20.0, "sizeY": 20.0, "sizeZ": 20.0,
                        "transform": {
                            "position": [0.0, 0.0, 0.0],
                            "rotationEuler": [0.0, 0.0, 0.0],
                            "scale": [1.0, 1.0, 1.0]
                        },
                        "boolean": { "targets": [], "operation": "NONE" }
                    },
                    "persistentData": {}
                },
                {
                    "type": "P.CY",
                    "inputParams": {
                        "id": "Pin",
                        "radius": 6.0, "height": 30.0,
                        "transform": {
                            "position": [10.0, -5.0, 10.0],
                            "rotationEuler": [0.0, 0.0, 0.0],
                            "scale": [1.0, 1.0, 1.0]
                        },
                        "boolean": { "targets": [], "operation": "NONE" }
                    },
                    "persistentData": {}
                },
                {
                    "type": "B",
                    "inputParams": {
                        "id": "Cut",
                        "targetSolid": "Box",
                        "boolean": { "operation": "SUBTRACT", "targets": ["Pin"] }
                    },
                    "persistentData": {}
                }
            ]
        })
        .to_string()
    }

    #[test]
    fn seed_box_mass_properties_match_analytic_cube() {
        let mut engine = EngineState::new();
        engine.set_history_json(&seed_history()).unwrap();
        // Roll back to just the plain 20 mm cube (before the hole).
        engine.roll_to(0);
        assert_eq!(engine.scene.solids().len(), 1);

        let value: serde_json::Value =
            serde_json::from_str(&engine.mass_properties_json(Some("Box"), 1.0)).unwrap();
        assert_eq!(value["ok"], true);
        assert_eq!(value["solidCount"], 1);
        // 20 mm cube: V = 8000, A = 6·400 = 2400, centroid at the centre (10,10,10).
        assert!((value["volume"].as_f64().unwrap() - 8000.0).abs() < 1e-6);
        assert!((value["surfaceArea"].as_f64().unwrap() - 2400.0).abs() < 1e-6);
        for component in value["centroid"].as_array().unwrap() {
            assert!((component.as_f64().unwrap() - 10.0).abs() < 1e-6);
        }
        // A single solid carries the inertia tensor + principal frame.
        assert!(value["inertia"].is_array());
        assert!(value["principalAxes"].is_array());

        // Density scales mass linearly (mass = density · volume).
        let scaled: serde_json::Value =
            serde_json::from_str(&engine.mass_properties_json(Some("Box"), 2.5)).unwrap();
        assert!((scaled["mass"].as_f64().unwrap() - 2.5 * 8000.0).abs() < 1e-6);
    }

    #[test]
    fn seed_boolean_result_is_cube_with_through_hole() {
        let mut engine = EngineState::new();
        engine.set_history_json(&seed_history()).unwrap();
        // The full seed leaves one solid: the cube minus the pin.
        assert_eq!(engine.scene.solids().len(), 1);

        // No selection → whole model; with one solid that resolves to the single
        // solid's full properties.
        let value: serde_json::Value =
            serde_json::from_str(&engine.mass_properties_json(None, 1.0)).unwrap();
        assert_eq!(value["ok"], true);
        assert_eq!(value["solidCount"], 1);
        // V = cube − cylinder-through-hole = 8000 − π·6²·20.
        let expected = 8000.0 - std::f64::consts::PI * 36.0 * 20.0;
        assert!(
            (value["volume"].as_f64().unwrap() - expected).abs() < 1e-2,
            "hole volume {} vs {expected}",
            value["volume"]
        );
        // Symmetric about the cube centre in X and Z.
        let centroid = value["centroid"].as_array().unwrap();
        assert!((centroid[0].as_f64().unwrap() - 10.0).abs() < 1e-6);
        assert!((centroid[2].as_f64().unwrap() - 10.0).abs() < 1e-6);
    }

    #[test]
    fn unknown_solid_reports_not_ok() {
        let mut engine = EngineState::new();
        engine.set_history_json(&seed_history()).unwrap();
        let value: serde_json::Value =
            serde_json::from_str(&engine.mass_properties_json(Some("Nope"), 1.0)).unwrap();
        assert_eq!(value["ok"], false);
    }
}

// ============================================================================
// Selection filter (which entity KINDS a plain viewport click may select) +
// the quick selection actions (clear / hide). Appended as its OWN type + a
// SEPARATE `impl` block so concurrent edits to the primary block don't conflict;
// purely additive over the existing selection/pick API.
//
// Mirrors the earlier `SelectionFilter.allowedSelectionTypes`: the picker reports
// EVERYTHING under the cursor (priority VERTEX > EDGE > FACE > SOLID), and the
// filter narrows what a click actually grabs. `select_top_at` reuses the
// existing `pick::pick_filtered` with the enabled kinds — the SAME type-
// constrained pick the reference-selection widget uses — so a click resolves the
// top-priority candidate whose kind is enabled and selects THAT kind (a FACE-only
// filter selects a face, a SOLID-only filter the owning solid).
// ============================================================================