1 files changed, 184 insertions, 0 deletions

diff --git a/src/mevvlfs.rs b/src/mevvlfs.rs
new file mode 100644
index 0000000..370ad96
--- /dev/null
+++ b/src/mevvlfs.rs
@@ -0,0 +1,184 @@
+use crate::*;
+
+// Make Edge-Vertex-Vertex-Loop-Face-Shell
+
+pub struct Mevvlfs<'brand, 'arena, V> {
+    body: ptr!(Body),
+    data: [V; 2],
+}
+
+impl<'brand, 'arena, V> Mevvlfs<'brand, 'arena, V> {
+    pub fn new(body: ptr!(Body), data: [V; 2]) -> Self {
+        Self { body, data }
+    }
+}
+
+impl<'brand, 'arena, V> Operator<'brand, 'arena, V> for Mevvlfs<'brand, 'arena, V> {
+    type Inverse = Kevvlfs<'brand, 'arena, V>;
+    type Error = Infallible;
+    type Check = ();
+
+    fn check(&self, _dcel: &Dcel<'brand, 'arena, V>) -> Result<Self::Check, Self::Error> {
+        Ok(())
+    }
+
+    fn apply(
+        self,
+        dcel: &mut Dcel<'brand, 'arena, V>,
+    ) -> Result<Self::Inverse, OperatorErr<Self, Self::Error>> {
+        try_check!(self, dcel);
+
+        let Mevvlfs {
+            body,
+            data: [d1, d2],
+        } = self;
+
+        let shell = body.add_new_shell(dcel);
+        let face = shell.add_new_face(dcel);
+        let (edge, [a, b]) = Edge::create(*shell, dcel);
+        let loop_ = Loop::new(dcel);
+        let v1 = shell.add_new_vertex(d1, dcel);
+        let v2 = shell.add_new_vertex(d2, dcel);
+
+        loop_.set_face(*face, dcel);
+        face.set_outer_loop(*loop_, dcel);
+
+        a.update_origin(*v1, dcel);
+        b.update_origin(*v2, dcel);
+
+        loop_.add_half_edge(a, dcel);
+        loop_.add_half_edge(b, dcel);
+
+        Ok(Kevvlfs {
+            body,
+            edge,
+            vertices: [v1, v2],
+            loop_,
+            face,
+            shell,
+        })
+    }
+}
+
+pub struct Kevvlfs<'brand, 'arena, V> {
+    pub body: ptr!(Body),
+    pub edge: own!(Edge),
+    pub vertices: [own!(Vertex); 2],
+    pub loop_: own!(Loop),
+    pub face: own!(Face),
+    pub shell: own!(Shell),
+}
+
+#[derive(Debug, Error)]
+pub enum KevvlfsError {
+    #[error("edge vertices do not equal vertices")]
+    EdgeVerticesMismatch,
+    #[error("half_edge loop does not equal loop")]
+    HalfEdgeLoopMismatch,
+    #[error("loop is not cycle between half edges")]
+    InvalidLoop,
+    #[error("face outer loop does not match loop")]
+    FaceOuterLoopMismatch,
+    #[error("face has inner loops")]
+    FaceHasInnerLoops,
+    #[error("shell has more than one face")]
+    ShellHasMoreThanOneFace,
+    #[error("shell face does not match face")]
+    ShellFaceMismatch,
+    #[error("shell body does not match body")]
+    ShellBodyMismatch,
+}
+
+impl<'brand, 'arena, V> Kevvlfs<'brand, 'arena, V> {
+    pub fn new(
+        body: ptr!(Body),
+        edge: own!(Edge),
+        vertices: [own!(Vertex); 2],
+        loop_: own!(Loop),
+        face: own!(Face),
+        shell: own!(Shell),
+    ) -> Self {
+        Self {
+            body,
+            edge,
+            vertices,
+            loop_,
+            face,
+            shell,
+        }
+    }
+}
+
+impl<'brand, 'arena, V> Operator<'brand, 'arena, V> for Kevvlfs<'brand, 'arena, V> {
+    type Inverse = Mevvlfs<'brand, 'arena, V>;
+    type Error = KevvlfsError;
+    type Check = ();
+
+    fn check(&self, dcel: &Dcel<'brand, 'arena, V>) -> Result<Self::Check, Self::Error> {
+        let Kevvlfs {
+            body,
+            edge,
+            vertices: [v1, v2],
+            loop_,
+            face,
+            shell,
+        } = self;
+
+        mklens!(dcel, edge, loop_, face, shell, body, v1, v2);
+
+        let [a, b] = edge.half_edges();
+        let edge_verts = edge.vertices();
+
+        or_err(
+            edge_verts == [v1, v2] || edge_verts == [v2, v1],
+            KevvlfsError::EdgeVerticesMismatch,
+        )?;
+
+        or_err(a.loop_() == loop_, KevvlfsError::HalfEdgeLoopMismatch)?;
+        or_err(a.next() == b, KevvlfsError::InvalidLoop)?;
+        or_err(b.next() == a, KevvlfsError::InvalidLoop)?;
+
+        or_err(
+            face.outer_loop() == loop_,
+            KevvlfsError::FaceOuterLoopMismatch,
+        )?;
+        or_err(
+            face.maybe_inner_loops().is_none(),
+            KevvlfsError::FaceHasInnerLoops,
+        )?;
+
+        or_err(face.next() == face, KevvlfsError::ShellHasMoreThanOneFace)?;
+        or_err(shell.faces() == face, KevvlfsError::ShellFaceMismatch)?;
+        or_err(shell.body() == body, KevvlfsError::ShellBodyMismatch)?;
+
+        Ok(())
+    }
+
+    fn apply(
+        self,
+        dcel: &mut Dcel<'brand, 'arena, V>,
+    ) -> Result<Self::Inverse, OperatorErr<Self, Self::Error>> {
+        try_check!(self, dcel);
+
+        let Kevvlfs {
+            body,
+            edge,
+            vertices,
+            loop_,
+            face,
+            shell,
+        } = self;
+
+        body.remove_shell(*shell, dcel);
+
+        edge.destroy(dcel);
+        loop_.free(dcel);
+        face.free(dcel);
+        shell.free(dcel);
+
+        Ok(Mevvlfs {
+            body,
+            data: vertices.map(|v| v.destroy(dcel)),
+        })
+    }
+}