BREP_render 0.1.0

//! Per-entity + group visibility for a solid's faces / edges / vertices.
//!
//! The whole-solid + whole-scene toggles already live on
//! [`SolidDisplay::visible`](crate::scene::SolidDisplay) /
//! [`RenderScene::set_visible`]. THIS module adds the finer grain the Scene tree
//! needs: an INDIVIDUAL face, edge or vertex can be hidden, and a WHOLE GROUP
//! (all faces / all edges / all vertices of a solid) toggled — with a tristate
//! ([`GroupState`]) group readout for the UI checkbox.
//!
//! # Where the state lives
//!
//! Each [`SolidDisplay`] carries an [`EntityVisibility`] — a set of HIDDEN
//! indices per kind (default-visible: an empty set = everything shown). The key
//! is the entity's INDEX in the solid's `faces` / `edges` / `vertices` list, the
//! exact index the render pass and the Scene tree already enumerate by (so a
//! hidden face maps straight onto a mesh triangle-range skip — see
//! [`crate::render`]). Reused solids keep their sets across history reruns (the
//! pipeline clones the `SolidDisplay`); a freshly re-tessellated solid resets to
//! all-visible, mirroring how the per-solid `visible` flag behaves.
//!
//! # How faces actually hide (the render mechanism)
//!
//! A solid's mesh emits each face's triangles as one contiguous run (the kernel
//! groups by `face_ids`), and the renderer already keeps a per-face
//! `first_index/index_count` range. The face pass, instead of one whole-mesh
//! draw, walks the faces and coalesces CONTIGUOUS VISIBLE ranges into draw
//! calls, breaking (flushing) the run at every hidden face — so a hidden face's
//! triangles are simply never submitted. Edges/vertices skip their line
//! segments / point sprites the same way. No mesh is rebuilt; visibility is
//! purely a draw-time mask, so toggling is free of any re-tessellation.

use crate::engine_state::EngineState;
use crate::scene::{RenderScene, SolidDisplay};
use std::collections::HashSet;

/// Which sub-entity list of a solid a visibility toggle addresses.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum EntityKind {
    Face,
    Edge,
    Vertex,
}

impl EntityKind {
    /// Parse the Scene-tree / verifier kind token (`"face"` / `"edge"` /
    /// `"vertex"`, case-insensitive). `None` for anything else.
    pub fn parse(kind: &str) -> Option<Self> {
        match kind.to_ascii_lowercase().as_str() {
            "face" => Some(Self::Face),
            "edge" => Some(Self::Edge),
            "vertex" => Some(Self::Vertex),
            _ => None,
        }
    }

    /// The lowercase token (round-trips with [`parse`](Self::parse)).
    pub fn as_str(self) -> &'static str {
        match self {
            Self::Face => "face",
            Self::Edge => "edge",
            Self::Vertex => "vertex",
        }
    }
}

/// A group checkbox's tristate: every entity of the kind shown, none shown, or a
/// mix. An empty group reads [`All`](GroupState::All) — nothing to hide.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum GroupState {
    All,
    Partial,
    None,
}

impl GroupState {
    /// The lowercase token the verifier asserts against (`"all"` / `"partial"` /
    /// `"none"`).
    pub fn as_str(self) -> &'static str {
        match self {
            Self::All => "all",
            Self::Partial => "partial",
            Self::None => "none",
        }
    }
}

/// The hidden-entity sets of ONE solid (empty = all visible). Indices are into
/// the owning [`SolidDisplay`]'s `faces` / `edges` / `vertices`.
#[derive(Debug, Clone, Default, serde::Serialize, serde::Deserialize)]
pub struct EntityVisibility {
    hidden_faces: HashSet<usize>,
    hidden_edges: HashSet<usize>,
    hidden_vertices: HashSet<usize>,
}

impl EntityVisibility {
    fn set_of(&self, kind: EntityKind) -> &HashSet<usize> {
        match kind {
            EntityKind::Face => &self.hidden_faces,
            EntityKind::Edge => &self.hidden_edges,
            EntityKind::Vertex => &self.hidden_vertices,
        }
    }

    fn set_mut(&mut self, kind: EntityKind) -> &mut HashSet<usize> {
        match kind {
            EntityKind::Face => &mut self.hidden_faces,
            EntityKind::Edge => &mut self.hidden_edges,
            EntityKind::Vertex => &mut self.hidden_vertices,
        }
    }

    /// Whether entity `index` of `kind` is currently shown.
    pub fn is_visible(&self, kind: EntityKind, index: usize) -> bool {
        !self.set_of(kind).contains(&index)
    }

    /// Whether ANY entity of `kind` is hidden — the render pass's fast-path
    /// guard (nothing hidden ⇒ keep the single whole-buffer draw).
    pub fn any_hidden(&self, kind: EntityKind) -> bool {
        !self.set_of(kind).is_empty()
    }

    /// Show/hide a single entity of `kind`.
    pub fn set_visible(&mut self, kind: EntityKind, index: usize, visible: bool) {
        if visible {
            self.set_mut(kind).remove(&index);
        } else {
            self.set_mut(kind).insert(index);
        }
    }

    /// Show/hide EVERY entity of `kind`. `count` is the number of entities of
    /// that kind, so "hide all" enumerates them (and "show all" clears).
    pub fn set_group_visible(&mut self, kind: EntityKind, count: usize, visible: bool) {
        let set = self.set_mut(kind);
        set.clear();
        if !visible {
            set.extend(0..count);
        }
    }

    /// The group tristate for `count` entities of `kind`. O(1): the hidden set
    /// satisfies `hidden ⊆ 0..count` (see [`all_hidden`](Self::all_hidden)), so its
    /// `len()` IS the hidden count — no per-entity scan. Called per solid per egui
    /// frame by the Scene panel, so the O(1) matters on point/edge-heavy models.
    pub fn group_state(&self, kind: EntityKind, count: usize) -> GroupState {
        if count == 0 {
            return GroupState::All;
        }
        let hidden = self.set_of(kind).len();
        if hidden == 0 {
            GroupState::All
        } else if hidden >= count {
            GroupState::None
        } else {
            GroupState::Partial
        }
    }

    // Render-pass conveniences (kept terse — called per solid per frame).
    pub fn is_face_visible(&self, index: usize) -> bool {
        self.is_visible(EntityKind::Face, index)
    }
    pub fn is_edge_visible(&self, index: usize) -> bool {
        self.is_visible(EntityKind::Edge, index)
    }
    pub fn is_vertex_visible(&self, index: usize) -> bool {
        self.is_visible(EntityKind::Vertex, index)
    }
    pub fn any_face_hidden(&self) -> bool {
        self.any_hidden(EntityKind::Face)
    }
    pub fn any_edge_hidden(&self) -> bool {
        self.any_hidden(EntityKind::Edge)
    }
    pub fn any_vertex_hidden(&self) -> bool {
        self.any_hidden(EntityKind::Vertex)
    }

    /// Whether EVERY entity of `kind` is hidden — O(1). A solid's hidden set is
    /// always paired with the entity counts it was built against: geometry changes
    /// replace the whole `SolidDisplay` (fresh, empty visibility), and a reused
    /// display keeps its counts AND its hidden set together — so `hidden ⊆ 0..count`
    /// holds universally and `len() == count` ⇔ the whole group is off (individual
    /// hides leave `len() < count`). `>=` rather than `==` is defensive only. The
    /// render pass uses this to skip a fully-hidden group's per-vertex draw loop.
    pub fn all_hidden(&self, kind: EntityKind, count: usize) -> bool {
        count > 0 && self.set_of(kind).len() >= count
    }
    pub fn all_vertices_hidden(&self, count: usize) -> bool {
        self.all_hidden(EntityKind::Vertex, count)
    }
}

/// The count of entities of `kind` on a solid (group toggles / tristate).
fn entity_count(solid: &SolidDisplay, kind: EntityKind) -> usize {
    match kind {
        EntityKind::Face => solid.faces.len(),
        EntityKind::Edge => solid.edges.len(),
        EntityKind::Vertex => solid.vertices.len(),
    }
}

// --- RenderScene: per-entity / group visibility (kept here, not in scene.rs, so
//     the visibility surface stays in one module) ------------------------------
impl RenderScene {
    /// Show/hide ONE face/edge/vertex of a solid. False if the solid is unknown.
    pub fn set_entity_visible(
        &mut self,
        solid: &str,
        kind: EntityKind,
        index: usize,
        visible: bool,
    ) -> bool {
        match self.solid_mut(solid) {
            Some(s) => {
                s.visibility.set_visible(kind, index, visible);
                true
            }
            None => false,
        }
    }

    /// Show/hide a whole group (all faces / all edges / all vertices) of a solid.
    /// False if the solid is unknown.
    pub fn set_group_visible(&mut self, solid: &str, kind: EntityKind, visible: bool) -> bool {
        let Some(count) = self.solid(solid).map(|s| entity_count(s, kind)) else {
            return false;
        };
        // The solid exists (count resolved above), so `solid_mut` is Some.
        if let Some(s) = self.solid_mut(solid) {
            s.visibility.set_group_visible(kind, count, visible);
        }
        true
    }

    /// Whether entity `index` of `kind` on `solid` is shown (`None` if unknown).
    pub fn entity_visible(&self, solid: &str, kind: EntityKind, index: usize) -> Option<bool> {
        self.solid(solid).map(|s| s.visibility.is_visible(kind, index))
    }

    /// The group tristate for `solid`'s `kind` (`None` if the solid is unknown).
    pub fn group_visibility(&self, solid: &str, kind: EntityKind) -> Option<GroupState> {
        self.solid(solid)
            .map(|s| s.visibility.group_state(kind, entity_count(s, kind)))
    }
}

// --- EngineState: the UI-facing visibility API (marks dirty; the Scene panel
//     drives these and reads the queries back) ---------------------------------
impl EngineState {
    /// Show/hide ONE face/edge/vertex of a solid, by its index in the solid's
    /// face/edge/vertex list — the same index the Scene tree enumerates. Marks
    /// dirty. Returns false if the solid is unknown.
    pub fn set_entity_visible(
        &mut self,
        solid: &str,
        kind: EntityKind,
        index: usize,
        visible: bool,
    ) -> bool {
        let ok = self.scene.set_entity_visible(solid, kind, index, visible);
        if ok {
            self.dirty = true;
        }
        ok
    }

    /// Show/hide a WHOLE group (all faces / all edges / all vertices of a solid).
    /// Marks dirty. Returns false if the solid is unknown.
    pub fn set_group_visible(&mut self, solid: &str, kind: EntityKind, visible: bool) -> bool {
        let ok = self.scene.set_group_visible(solid, kind, visible);
        if ok {
            self.dirty = true;
        }
        ok
    }

    /// Whether entity `index` of `kind` on `solid` is shown (`None` if unknown).
    pub fn entity_visible(&self, solid: &str, kind: EntityKind, index: usize) -> Option<bool> {
        self.scene.entity_visible(solid, kind, index)
    }

    /// The group tristate for `solid`'s `kind` (`None` if the solid is unknown).
    pub fn group_visibility(&self, solid: &str, kind: EntityKind) -> Option<GroupState> {
        self.scene.group_visibility(solid, kind)
    }

    /// Per-entity + group visibility as JSON — the readout the headed verifier
    /// asserts against (a companion to
    /// [`scene_entities_json`](EngineState::scene_entities_json), which lists the
    /// entities but not their per-entity visibility):
    /// `[{name, visible, faces:{group, states:[bool;n]}, edges:{…}, vertices:{…}}]`
    /// where `states[i]` is entity `i`'s visibility and `group` is
    /// `"all"|"partial"|"none"`.
    pub fn scene_visibility_json(&self) -> String {
        let kinds = [
            ("faces", EntityKind::Face),
            ("edges", EntityKind::Edge),
            ("vertices", EntityKind::Vertex),
        ];
        let solids: Vec<serde_json::Value> = self
            .scene
            .solids()
            .iter()
            .map(|solid| {
                let mut obj = serde_json::Map::new();
                obj.insert("name".into(), serde_json::json!(solid.name));
                obj.insert("visible".into(), serde_json::json!(solid.visible));
                for (key, kind) in kinds {
                    let count = entity_count(solid, kind);
                    let states: Vec<bool> =
                        (0..count).map(|i| solid.visibility.is_visible(kind, i)).collect();
                    obj.insert(
                        key.into(),
                        serde_json::json!({
                            "group": solid.visibility.group_state(kind, count).as_str(),
                            "states": states,
                        }),
                    );
                }
                serde_json::Value::Object(obj)
            })
            .collect();
        serde_json::Value::Array(solids).to_string()
    }
}

#[cfg(test)]
mod 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 entity_visibility_hide_show_and_group_tristate() {
        let mut vis = EntityVisibility::default();
        // Default: all visible, group reads All.
        assert!(vis.is_visible(EntityKind::Face, 0));
        assert!(!vis.any_hidden(EntityKind::Face));
        assert_eq!(vis.group_state(EntityKind::Face, 6), GroupState::All);

        // Hide one → Partial, only that index hidden.
        vis.set_visible(EntityKind::Face, 2, false);
        assert!(!vis.is_visible(EntityKind::Face, 2));
        assert!(vis.is_visible(EntityKind::Face, 3));
        assert!(vis.any_hidden(EntityKind::Face));
        assert_eq!(vis.group_state(EntityKind::Face, 6), GroupState::Partial);

        // Re-show it → back to All.
        vis.set_visible(EntityKind::Face, 2, true);
        assert_eq!(vis.group_state(EntityKind::Face, 6), GroupState::All);

        // Hide the whole group → None, every index hidden.
        vis.set_group_visible(EntityKind::Face, 6, false);
        assert_eq!(vis.group_state(EntityKind::Face, 6), GroupState::None);
        assert!(!vis.is_visible(EntityKind::Face, 5));
        // Show one back → Partial.
        vis.set_visible(EntityKind::Face, 5, true);
        assert_eq!(vis.group_state(EntityKind::Face, 6), GroupState::Partial);
        // Kinds are independent: edges untouched.
        assert_eq!(vis.group_state(EntityKind::Edge, 12), GroupState::All);
    }

    #[test]
    fn engine_per_entity_and_group_visibility_through_scene() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();

        // Individual: hide face 0.
        assert!(engine.set_entity_visible("Box", EntityKind::Face, 0, false));
        assert_eq!(engine.entity_visible("Box", EntityKind::Face, 0), Some(false));
        assert_eq!(engine.entity_visible("Box", EntityKind::Face, 1), Some(true));
        assert_eq!(
            engine.group_visibility("Box", EntityKind::Face),
            Some(GroupState::Partial)
        );

        // Group: hide all faces → None; edges/vertices unaffected.
        assert!(engine.set_group_visible("Box", EntityKind::Face, false));
        assert_eq!(
            engine.group_visibility("Box", EntityKind::Face),
            Some(GroupState::None)
        );
        assert_eq!(
            engine.group_visibility("Box", EntityKind::Edge),
            Some(GroupState::All)
        );

        // Group: show all faces back → All.
        assert!(engine.set_group_visible("Box", EntityKind::Face, true));
        assert_eq!(
            engine.group_visibility("Box", EntityKind::Face),
            Some(GroupState::All)
        );

        // Unknown solid → false / None.
        assert!(!engine.set_entity_visible("Nope", EntityKind::Edge, 0, false));
        assert_eq!(engine.entity_visible("Nope", EntityKind::Edge, 0), None);
        assert_eq!(engine.group_visibility("Nope", EntityKind::Edge), None);
    }

    #[test]
    fn scene_visibility_json_reports_states_and_group() {
        let mut engine = EngineState::new();
        engine.set_history_json(&cube_history("Box")).unwrap();
        engine.set_entity_visible("Box", EntityKind::Edge, 3, false);

        let json: serde_json::Value =
            serde_json::from_str(&engine.scene_visibility_json()).unwrap();
        let solid = &json.as_array().unwrap()[0];
        assert_eq!(solid["name"], "Box");
        assert_eq!(solid["visible"], true);
        // A cube: 6 faces / 12 edges / 8 vertices, all faces still shown.
        assert_eq!(solid["faces"]["group"], "all");
        assert_eq!(solid["faces"]["states"].as_array().unwrap().len(), 6);
        // Edge 3 is hidden → group partial, states[3] == false.
        assert_eq!(solid["edges"]["group"], "partial");
        assert_eq!(solid["edges"]["states"][3], false);
        assert_eq!(solid["edges"]["states"][2], true);
    }

    #[test]
    fn entity_kind_token_roundtrips() {
        for k in [EntityKind::Face, EntityKind::Edge, EntityKind::Vertex] {
            assert_eq!(EntityKind::parse(k.as_str()), Some(k));
        }
        assert_eq!(EntityKind::parse("FACE"), Some(EntityKind::Face));
        assert_eq!(EntityKind::parse("solid"), None);
    }
}