The final Composer slice per design doc §12. Lawyer gains full
control over section composition: drag-and-drop reorder, per-section
delete, "+ Add section" picker for custom slugs that don't appear in
the base's default spec. Combined with Slice B's hide toggle, this
closes out the A→F sequence — Composer A→F is complete.
Backend (internal/services/submission_section_service.go, +120 LoC):
- SectionService.Create — adds a new section row to a draft. Validates
section_key + labels + kind (must be prose/requests/evidence).
Auto-assigns next order_index when OrderIndex=0; collisions on
(draft_id, section_key) surface as ErrInvalidInput.
- SectionService.Delete — removes one section by id. Returns
ErrSubmissionSectionNotFound when nothing was deleted.
- SectionService.Reorder — accepts a sequence of section_ids, rewrites
every row's order_index to (1..N)×10 transactionally. Returns the
refreshed list. Sections not present in the sequence are silently
ignored (defensive — partial reorder doesn't lose rows).
Handlers (internal/handlers/submission_sections.go, +180 LoC):
- POST /api/submission-drafts/{draft_id}/sections — owner-scoped via
SubmissionDraftService.Get. 400 on slug collision / invalid kind.
- DELETE /api/submission-drafts/{draft_id}/sections/{section_id} —
owner + section-belongs-to-draft cross-check. 204 on success.
- POST /api/submission-drafts/{draft_id}/sections/reorder — accepts
{"section_order": [uuid, uuid, ...]}; returns refreshed sections list.
Frontend (frontend/src/client/submission-draft.ts, +260 LoC):
- Each section row gains a drag handle (⋮⋮) on the left of the head.
Drag handle is the only draggable element; contentEditable
selections inside the editor body keep working. HTML5 native DnD,
no library.
- Drop-target highlighting via .submission-draft-section--drop-target
(border-top accent). Cleanup on dragend / drop / cancel.
- Per-section "Delete" button next to the existing Hide/Include
toggle. Confirm prompt prevents accidental loss of typed prose.
- "+ Add section" trailing affordance below the section list opens an
inline form (slug + DE label + EN label + kind dropdown). Submit
POSTs to the new endpoint; on success splices the row into
state.view.sections and re-paints.
CSS (frontend/src/styles/global.css, +65 LoC):
- .submission-draft-section-handle (grab cursor + hover background +
active=grabbing).
- .submission-draft-section--dragging / --drop-target visual states.
- .submission-draft-add-section form layout (dashed border + lime
primary submit).
Tests (internal/services/submission_section_slice_f_test.go, NEW,
TEST_DATABASE_URL-gated):
- Create custom section + slug-collision surface as ErrInvalidInput.
- Delete + repeat-delete returns ErrSubmissionSectionNotFound.
- Reorder reverses 10 seeded sections + verifies the resulting
order_index sequence is ascending and matches the input order.
Build hygiene: go build/vet/test -short clean (all packages);
bun run build clean (2906 i18n keys, data-i18n scan clean).
Hard rules honoured:
- NO new migrations (Slice F is pure code on Slice A's schema).
- NO behavior change for pre-Composer drafts (no section rows → no
drag handles to drag).
- {{rule.X}} aliases preserved (custom sections render through the
same composer pipeline as default sections).
- Q2/Q9/Q10 ratifications preserved.
This closes the Composer slice sequence A → F. The full feature set
ratified by m on 2026-05-26 is now in place:
A — base picker + read-only section list (mig 146/147/148)
B — editable prose + anchor-spliced render + MD→OOXML walker
C — building-blocks library + section picker (mig 149)
D — rich prose (headings, lists, blockquote, hyperlinks)
E — specialist bases lg-duesseldorf + upc-formal (mig 150)
F — section reorder / delete / add custom
t-paliad-318 Slice F