[FE] Manage & Apply Competencies: delete a Competency Criteria Group

[thelmick-unicon]

Frontend implementation in frontend-app-authoring. Parent design: #648. Foundation this builds on: #670 (page shell), #671 (creates and renders the groups this ticket deletes). Siblings on the same page: #672 (creates associations), 5.10d (deletes a single association — reuses this ticket's group-removal logic when the last association in a group is removed; no GitHub issue yet).

Blocked by: #675 (backend delete-group endpoint, cascades associations); #672 (the activeGroupId scheme this ticket recomputes after a deletion); #681 (GET groups + criteria endpoint, needed to render the groups this ticket deletes).

Use Case

As a course author who created a Competency Criteria Group in error, or whose rule structure has changed, I want to delete a Competency Criteria Group, whether it is an unbacked placeholder box or a real, persisted group with associations, so that the competency's rule structure reflects only the groups I actually intend to keep, without leaving stray boxes or reloading the page.

Description

This ticket adds a delete action to a Competency Criteria Group box, covering both an unbacked placeholder box (a client-side-only removal) and a real, persisted group (which also removes whatever associations it contains).

Current behavior

#671 renders a competency's Competency Criteria Group box(es), with no way to delete one yet.

Requested change

This ticket builds and renders the delete/trash affordance on each group box, following the design, and wires it to the following behavior. Clicking it:

• If the box is the not-yet-backed placeholder (no group_id yet), it is removed from local render state only. No backend call is made, since nothing has been persisted.
• If the box is a real, persisted group, it is deleted via [Placeholder for BE] Build Update/Delete endpoint to handle a user removing a Competency Criteria Group. #675, which cascades its associations away in the same call.
• If the deleted group was the active group ([FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672's activeGroupId), the active target automatically becomes one of the remaining real groups (the first remaining in the list) if any remain, or the placeholder box if none do.
• If the deleted group is the only remaining group for the competency, the page falls back to a placeholder box, exactly as [Placeholder for FE] Build the create / remove Competency Criteria Group interactions #671/[FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672 already render for "no real groups yet." This ticket does not build new placeholder-rendering logic; it only triggers the existing conditional by shrinking the group list to zero.

Explicitly out of scope

• Removal-confirmation dialogs and in-use/learner-status warnings: Use Case 10. This ticket performs a direct delete on click, per the same precedent the pre-split design used for this action.
• Creating a group, nesting, and the AND/OR operator control: [Placeholder for FE] Build the create / remove Competency Criteria Group interactions #671.
• Deleting a single association without deleting its group: 5.10d.
• The exact backend request/response contract: [Placeholder for BE] Build Update/Delete endpoint to handle a user removing a Competency Criteria Group. #675's own ticket.

Acceptance Criteria

Frontend ticket. Testable once #671's groups render, #672's active-group scheme exists, and #675 exists.

Scenario: Delete an unbacked placeholder box
  Given a Competency Criteria Group box exists but no subsection has been selected into it yet
  When I click that box's delete affordance
  Then the box is removed from the page immediately
  And no backend request is made

Scenario: Delete a persisted group
  Given a Competency Criteria Group has been persisted to the backend, with or without associated subsections
  When I click that group's delete affordance
  Then the group and any associations it contains are deleted
  And the group no longer appears on the page

Scenario: Deleting the active group when other groups remain
  Given the active group has one or more other real, persisted sibling groups
  When I delete the active group
  Then one of the remaining sibling groups becomes the new active group automatically
  And subsequent subsection selections target that remaining group

Scenario: Deleting the last remaining group falls back to the placeholder
  Given the group I delete is the only remaining group for the competency
  When I delete it
  Then no real groups remain for the competency
  And a placeholder box is shown as the new implicit active target

Scenario: Backend rejects the delete request
  Given a delete request to the backend fails
  When I click delete on a persisted group
  Then the group remains visible on the page
  And an error is shown, following this feature's existing generic-error-handling pattern (#672's Technical Details → Logic)

Scenario: A course author without write access cannot delete a group
  Given I lack studio write access to the course the competency's groups belong to
  Then the delete affordance is not rendered

Technical Details

Data Structures

• deleteCompetencyCriteriaGroup(groupId) (data/api.ts): DELETE call to [Placeholder for BE] Build Update/Delete endpoint to handle a user removing a Competency Criteria Group. #675's endpoint. Contract assumed to mirror [BE] Build endpoint for creating Competency Criteria when a gradeable-subsection association is selected #665's URL shape (e.g. DELETE .../competencies/<tag_id>/groups/<group_id>/); the exact shape is [Placeholder for BE] Build Update/Delete endpoint to handle a user removing a Competency Criteria Group. #675's own ticket to define, not this one's.
• useDeleteCompetencyCriteriaGroup (data/apiHooks.ts): a React Query mutation hook mirroring [FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672's useCreateCompetencyCriterion conventions (matching useCreateTag's pattern); invalidates the GET ([Placeholder for BE] Build GET endpoint to fetch Competency Criteria Groups and Criteria for a competency #681) query on success so the group list refetches without the deleted group.

Logic

• This ticket renders the delete/trash affordance itself (a Paragon icon button, following the design) on each CriteriaGroupBox; [Placeholder for FE] Build the create / remove Competency Criteria Group interactions #671 does not include it. The affordance is not rendered at all — not merely disabled — for a course author without studio write access to the course.
• The delete affordance's click handler branches on whether the box is the unbacked placeholder or a real group:
  • Placeholder: remove it from local render state only.
  • Real group: call useDeleteCompetencyCriteriaGroup; on success, the invalidated GET query drops the deleted group from the rendered list.
• After a real-group deletion, if userSelectedGroupId pointed at the just-deleted group, clear it and set it to the first remaining real group's id if any remain, or leave it unset (falling through to [FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672's derived-default formula, which resolves to the placeholder) if none do.
• If deletion empties the group list entirely, the existing "zero real groups → show placeholder" conditional from [Placeholder for FE] Build the create / remove Competency Criteria Group interactions #671/[FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672 renders the placeholder automatically; this ticket adds no new placeholder-rendering logic. 5.10d's emptied-group cascade reuses this exact path rather than reimplementing it.
• On delete failure, leave the group visible and follow [FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672's generic error-handling pattern.
• No confirmation dialog: Use Case 10's job.

Example Resolution Prompt

Implement the frontend consumer of #675 in frontend-app-authoring, extending #671/#672's src/taxonomy/competency-management/criteria-groups/ directory (check whether #671/#672 already created data/api.ts/data/apiHooks.ts before adding new files). Add deleteCompetencyCriteriaGroup and useDeleteCompetencyCriteriaGroup per Technical Details → Data Structures. Build and render CriteriaGroupBox.tsx's delete/trash affordance (a Paragon icon button following the design; not rendered at all for a user without studio write access), and wire it to branch on placeholder vs. real group per Technical Details → Logic, setting userSelectedGroupId to a remaining sibling if one exists, or clearing it to fall through to the placeholder if none do. Reuse the existing "zero real groups → placeholder" conditional from #671/#672 rather than adding new placeholder-rendering logic — 5.10d depends on this same path. No confirmation dialog (Use Case 10's job). Follow #672's generic error-handling pattern on failure.

Context

• Sibling create ticket for the same entity: [Placeholder for FE] Build the create / remove Competency Criteria Group interactions #671 — renders the group boxes this ticket adds a delete affordance to.
• Companion ticket reusing this ticket's group-removal logic: 5.10d (no GitHub issue yet), which triggers this same deletion path when removing the last association in a group.
• activeGroupId scheme and derived-default formula this ticket recomputes against: [FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672 Technical Details → Data Structures.
• No genuine "last item removed → parent reverts to a placeholder" precedent exists yet in src/taxonomy/ (nothing comparable is built there today). The closest analogs in frontend-app-authoring are in src/library-authoring/: LibraryContent.tsx, LibraryCollectionComponents.tsx, and CollectionDetails.tsx each swap a list or stats view for a placeholder component once a derived count reaches zero — the same shape this ticket's "group list shrinks to zero → placeholder shows" behavior follows, via [Placeholder for FE] Build the create / remove Competency Criteria Group interactions #671/[FE] Manage & Apply Competencies: select gradeable-subsection associations and target a competency's active group #672's own existing empty-state conditional rather than a new component.

Files to create and modify

Modified files (conditional: check whether #671/#672 already created these before adding new content)

File	Nature of modification
src/taxonomy/competency-management/criteria-groups/CriteriaGroupBox.tsx (from #671)	Add and render the delete/trash affordance (Paragon icon button, per the design; hidden without studio write access), with a click handler branching on placeholder vs. real group.
src/taxonomy/competency-management/criteria-groups/CriteriaGroupTree.tsx (from #671)	Pass a delete callback down; recompute activeGroupId against the post-deletion group list.
src/taxonomy/competency-management/data/api.ts	Add deleteCompetencyCriteriaGroup.
src/taxonomy/competency-management/data/apiHooks.ts	Add useDeleteCompetencyCriteriaGroup.