Support per-view connection boundary attachments in ordinary and state diagrams

crates/oa-desktop/src/behavior/state_edit.rs

@@ -20,6 +20,7 @@ pub enum Tool {
     Region,
     Transition,
     Reconnect { relation: Id, endpoint: Endpoint },
+    AdjustAttachment { relation: Id, end: EdgeEnd },
 }
 
 #[derive(Debug, Clone)]
@@ -66,6 +67,13 @@ pub enum Event {
         endpoint: Endpoint,
         vertex: Id,
     },
+    SetAttachment {
+        context: Context,
+        relation: Id,
+        end: EdgeEnd,
+        placement: Id,
+        attachment: Option<EdgeAttachment>,
+    },
 }
 
 impl Event {
@@ -84,7 +92,8 @@ impl Event {
             | Self::Place { context: c, .. }
             | Self::Move { context: c, .. }
             | Self::Connect { context: c, .. }
-            | Self::Reconnect { context: c, .. } => Some(*c),
+            | Self::Reconnect { context: c, .. }
+            | Self::SetAttachment { context: c, .. } => Some(*c),
         }
     }
 }
@@ -249,6 +258,36 @@ pub fn can_reconnect(
         .is_ok()
 }
 
+/// Only the actual visible transition owner can receive a visual attachment.
+/// Folded promotion, semantic ports and internal-transition rows are excluded.
+pub fn attachment_node(
+    project: &Project,
+    diagram: Id,
+    relation: Id,
+    end: EdgeEnd,
+) -> Option<projection::ProjectedNode> {
+    machine(project, diagram).ok()?;
+    let relation_record = project.relations.get(&relation)?;
+    if relation_record.kind() != RelationKind::StateTransition
+        || oa_core::routing::semantic_port_endpoint(project, relation, end).is_some()
+    {
+        return None;
+    }
+    let view = projection::project_view(project, diagram);
+    let edge = view.edges.iter().find(|edge| edge.id == relation)?;
+    let stored = project.diagrams.get(&diagram)?;
+    if projection::edge_endpoint_placements(project, stored, relation)?
+        != (edge.source, edge.target)
+    {
+        return None;
+    }
+    let owner = match end {
+        EdgeEnd::Source => edge.source,
+        EdgeEnd::Target => edge.target,
+    };
+    view.nodes.iter().find(|node| node.id == owner).cloned()
+}
+
 fn checked(project: &Project, plan: Plan) -> Result<Plan, ModelError> {
     prepare_command(project, &plan.command)?;
     Ok(plan)
@@ -492,6 +531,22 @@ pub fn plan(project: &Project, current: Context, event: &Event) -> Result<Plan,
             relation,
             None,
         ),
+        Event::SetAttachment {
+            relation,
+            end,
+            placement,
+            attachment,
+            ..
+        } => {
+            attachment_node(project, diagram, relation, end)
+                .filter(|owner| owner.id == placement)
+                .ok_or_else(|| {
+                    error("Choose the actual visible transition endpoint in this view.")
+                })?;
+            let mut route = crate::route_edit::stored_route(&project.diagrams[&diagram], relation);
+            route.set_attachment(end, attachment);
+            (Command::SetEdgeRoute { diagram, route }, relation, None)
+        }
         _ => {
             return Err(error(
                 "Handle this navigation or tool request without a model command.",
@@ -580,6 +635,85 @@ mod tests {
         plan.diagram
     }
 
+    #[test]
+    fn attachment_reset_preserves_other_end_pins_label_and_rejects_ineligible_owners() {
+        let mut f = fixture();
+        let diagram = create(&mut f);
+        let c = context(diagram);
+        let edge = f.project.relate(
+            RelationKind::StateTransition,
+            "Leave work",
+            f.leaf,
+            f.target,
+        );
+        let attachment = EdgeAttachment {
+            side: PortAnchorSide::Top,
+            offset: 0.3,
+        };
+        let mut route = crate::route_edit::stored_route(&f.project.diagrams[&diagram], edge);
+        route.source_attachment = Some(attachment);
+        route.target_attachment = Some(attachment);
+        route.waypoints.push(Position { x: 700., y: 700. });
+        // Retain the exact label value alongside the other route components.
+        route.label = Some(EdgeLabel {
+            fraction: 0.5,
+            offset: Position { x: 10., y: 20. },
+        });
+        f.project
+            .diagrams
+            .get_mut(&diagram)
+            .unwrap()
+            .routes
+            .push(route.clone());
+        let owner = attachment_node(&f.project, diagram, edge, EdgeEnd::Source).unwrap();
+        let event = Event::SetAttachment {
+            context: c,
+            relation: edge,
+            end: EdgeEnd::Source,
+            placement: owner.id,
+            attachment: None,
+        };
+        let accepted = prepare_command(&f.project, &plan(&f.project, c, &event).unwrap().command)
+            .unwrap()
+            .project;
+        route.source_attachment = None;
+        assert_eq!(accepted.diagrams[&diagram].routes, vec![route]);
+        assert_eq!(accepted.relations, f.project.relations);
+        let wrong = Event::SetAttachment {
+            context: c,
+            relation: edge,
+            end: EdgeEnd::Source,
+            placement: node(&f.project, diagram, f.target),
+            attachment: Some(attachment),
+        };
+        assert!(plan(&f.project, c, &wrong).is_err());
+        let composite = node(&f.project, diagram, f.composite);
+        f.project
+            .diagrams
+            .get_mut(&diagram)
+            .unwrap()
+            .nodes
+            .get_mut(&composite)
+            .unwrap()
+            .collapsed = true;
+        assert!(attachment_node(&f.project, diagram, edge, EdgeEnd::Source).is_none());
+        assert!(plan(&f.project, c, &event).is_err());
+        let internal = f.project.relate(
+            RelationKind::StateTransition,
+            "Internal",
+            f.target,
+            f.target,
+        );
+        if let RelationBody::StateTransition {
+            transition_kind, ..
+        } = &mut f.project.relations.get_mut(&internal).unwrap().body
+        {
+            *transition_kind = TransitionKind::Internal;
+        }
+        assert!(attachment_node(&f.project, diagram, internal, EdgeEnd::Source).is_none());
+        assert!(attachment_node(&f.project, diagram, internal, EdgeEnd::Target).is_none());
+    }
+
     #[test]
     fn view_initializes_only_its_machine_in_one_source_and_model_history_entry() {
         let f = fixture();
@@ -763,6 +897,8 @@ mod tests {
             .routes
             .push(EdgeRoute {
                 edge,
+                source_attachment: None,
+                target_attachment: None,
                 waypoints: vec![pin],
                 label: None,
             });