feat: add GroupSelection subtree select/deselect logic

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01WYqycDFsynHH9VnnK7LNSf
2026-09-19 16:57:49 +02:00
parent 5ca42a4e2a
commit 62835dcd38
2 changed files with 80 additions and 0 deletions
@@ -0,0 +1,38 @@
+import Foundation
+
+public enum GroupSelection {
+    /// `groupId` and all of its descendant subgroup IDs, found by searching `root`'s tree.
+    /// Returns an empty set if `groupId` isn't found anywhere in `root`.
+    public static func subtreeIds(of groupId: UUID, in root: Group) -> Set<UUID> {
+        guard let found = findGroup(groupId, in: root) else { return [] }
+        return allIds(in: found)
+    }
+
+    /// Toggles `groupId` and its full subtree in `current`: if the group is already selected,
+    /// it and its subtree are removed; otherwise they're added.
+    public static func toggling(_ groupId: UUID, in root: Group, current: Set<UUID>) -> Set<UUID> {
+        let subtree = subtreeIds(of: groupId, in: root)
+        guard !subtree.isEmpty else { return current }
+        if current.contains(groupId) {
+            return current.subtracting(subtree)
+        } else {
+            return current.union(subtree)
+        }
+    }
+
+    private static func findGroup(_ id: UUID, in group: Group) -> Group? {
+        if group.id == id { return group }
+        for sub in group.subgroups {
+            if let found = findGroup(id, in: sub) { return found }
+        }
+        return nil
+    }
+
+    private static func allIds(in group: Group) -> Set<UUID> {
+        var ids: Set<UUID> = [group.id]
+        for sub in group.subgroups {
+            ids.formUnion(allIds(in: sub))
+        }
+        return ids
+    }
+}