# Phase 2: Drag-and-Drop Reordering

**Status:** Done
**Parent plan:** [PLAN.md](./PLAN.md)
**Domain:** frontend

## Objective

Add drag-and-drop reordering for sections within boards and widgets within/across sections using svelte-dnd-action.

## Tasks

- [x] Task 1: Install `svelte-dnd-action` package
- [x] Task 2: Create `src/lib/components/board/DraggableBoard.svelte` — board with draggable sections
- [x] Task 3: Create `src/lib/components/section/DraggableSection.svelte` — section with draggable widgets
- [x] Task 4: Create `src/lib/components/widget/DraggableWidget.svelte` — draggable widget wrapper
- [x] Task 5: Update `src/routes/boards/[boardId]/edit/+page.svelte` — replace static editor with DnD editor
- [x] Task 6: Create `src/routes/api/boards/[id]/reorder/+server.ts` — API to persist section order changes
- [x] Task 7: Create `src/routes/api/boards/[id]/sections/[sid]/reorder/+server.ts` — API to persist widget order changes
- [x] Task 8: Update `src/lib/server/services/boardService.ts` — add `reorderSections()` and `reorderWidgets()` functions
- [x] Task 9: Add visual drag handles and drop zone indicators
- [x] Task 10: Support moving widgets between sections via cross-section DnD

## Files to Modify/Create

- `package.json` — add svelte-dnd-action
- `src/lib/components/board/DraggableBoard.svelte` — NEW
- `src/lib/components/section/DraggableSection.svelte` — NEW
- `src/lib/components/widget/DraggableWidget.svelte` — NEW
- `src/routes/boards/[boardId]/edit/+page.svelte` — MODIFY
- `src/routes/api/boards/[id]/reorder/+server.ts` — NEW
- `src/routes/api/boards/[id]/sections/[sid]/reorder/+server.ts` — NEW
- `src/lib/server/services/boardService.ts` — MODIFY

## Acceptance Criteria

- Sections can be reordered via drag-and-drop in the board editor
- Widgets can be reordered within a section
- Widgets can be moved between sections
- Order changes persist via API calls
- Drag handles are visible and accessible
- Drop zones are visually indicated during drag

## Notes

- `svelte-dnd-action` works well with Svelte 5
- Use optimistic updates — reorder in UI immediately, sync to server in background
- Reorder APIs should accept an array of IDs in the new order
- Big Bang: may need integration fixes in Phase 6

## Review Checklist

- [x] All tasks completed
- [x] Code follows project conventions
- [x] No unintended side effects
- [ ] Build passes
- [ ] Tests pass (new + existing)

## Handoff to Next Phase

Phase 2 DnD is complete. Key additions:

- `svelte-dnd-action` installed and integrated with Svelte 5 (`use:dndzone`, `onconsider`/`onfinalize` event pattern)
- Board editor (`/boards/[boardId]/edit`) now uses `DraggableBoard` > `DraggableSection` > `DraggableWidget` component hierarchy
- Sections support drag-and-drop reordering with grip-dot handles; widgets support reordering within and across sections
- Two new PUT API endpoints: `/api/boards/[id]/reorder` (section order) and `/api/boards/[id]/sections/[sid]/reorder` (widget order)
- `boardService.ts` extended with `reorderSections()`, `reorderWidgets()`, and `moveWidget()` — all using `$transaction` for atomicity
- Edit page uses `invalidateAll()` for server actions (add/delete) while DnD reorder uses optimistic fetch calls
- Drop zones use dashed borders; drag handles use grip-dot SVG icons with hover opacity transitions
- No changes to auth, admin, or view-mode components