# Spec: 04 · Fruit Publications

**Taiga Story:** #4 · `04-fruit-publications`
**Status:** Ready
**Branch:** `feature/04-fruit-publications`
**Depends on:** `02-manage-fruits` (fruits table)

---

## 1. Goal

Maintainers can manage publications (books, catalogues) that document fruits. Each publication has a cover image, linked fruits, linked PDFs per fruit, and linked fruit images from the publication. Fruit detail page shows descriptions and publication images.

---

## 2. Background / Scope / Context / Constraints

- `osdb_pub_id` is the unique external identifier (label: "OSDB Kürzel").
- Cover image stored as BYTEA in `publications.image_data`.
- PDF stored as BYTEA in `publication_descriptions.pdf_data` (one PDF per fruit per publication).
- Fruit images from publications stored in `publication_fruit_images` (BYTEA); `image_type` hardcoded to `'fruit'`, cannot be changed.
- On fruit detail page: show description list only if at least one description exists; link text = publication title; link opens PDF.
- On fruit detail page: show publication fruit images labeled "Publication title · Author".
- Mouseclick on cover image → overlay/drawer with full-size image.

---

## 3. Necessary Refactorings

- `fruit_images.image_type` already defined in story #2 — no changes.
- `thumbnail_data` column on `publication_fruit_images` deferred to story #7 migration.

---

## 4. Related Data Model

```sql
-- Migration: 000003_create_publications.up.sql

CREATE TABLE publications (
  id           SERIAL PRIMARY KEY,
  title        VARCHAR(255) NOT NULL,
  author       VARCHAR(255),
  osdb_pub_id  VARCHAR(50)  NOT NULL UNIQUE,
  image_data   BYTEA,
  created_at   TIMESTAMPTZ  NOT NULL DEFAULT NOW(),
  updated_at   TIMESTAMPTZ  NOT NULL DEFAULT NOW()
);

CREATE TABLE publication_fruits (
  publication_id INTEGER NOT NULL REFERENCES publications(id) ON DELETE CASCADE,
  fruit_id       INTEGER NOT NULL REFERENCES fruits(id) ON DELETE CASCADE,
  PRIMARY KEY (publication_id, fruit_id)
);

CREATE TABLE publication_descriptions (
  id             SERIAL PRIMARY KEY,
  publication_id INTEGER NOT NULL REFERENCES publications(id) ON DELETE CASCADE,
  fruit_id       INTEGER NOT NULL REFERENCES fruits(id) ON DELETE CASCADE,
  pdf_data       BYTEA   NOT NULL,
  created_at     TIMESTAMPTZ NOT NULL DEFAULT NOW(),
  UNIQUE (publication_id, fruit_id)
);

CREATE TABLE publication_fruit_images (
  id             SERIAL PRIMARY KEY,
  publication_id INTEGER      NOT NULL REFERENCES publications(id) ON DELETE CASCADE,
  fruit_id       INTEGER      NOT NULL REFERENCES fruits(id) ON DELETE CASCADE,
  filename       VARCHAR(255),
  data           BYTEA        NOT NULL,
  image_type     VARCHAR(20)  NOT NULL DEFAULT 'fruit',  -- hardcoded
  created_at     TIMESTAMPTZ  NOT NULL DEFAULT NOW()
);
-- Note: thumbnail_data column added in story #07 migration
```

---

## 5. Affected Places / Related Components

### Backend

| File | Purpose |
|------|---------|
| `backend/internal/domain/publication.go` | `Publication`, `PublicationDescription`, `PublicationFruitImage` structs |
| `backend/internal/repository/publication_repo.go` | DB queries |
| `backend/internal/handler/publication_handler.go` | Echo handlers |
| `backend/cmd/server/router.go` | Register `/api/v1/publications` routes |
| `migrations/000003_create_publications.up.sql` | Schema above |
| `migrations/000003_create_publications.down.sql` | DROP TABLEs |

### API Endpoints

| Method | Path | Description |
|--------|------|-------------|
| GET | `/api/v1/publications` | List |
| POST | `/api/v1/publications` | Create |
| GET | `/api/v1/publications/:id` | Get (with linked fruits list) |
| PUT | `/api/v1/publications/:id` | Update |
| DELETE | `/api/v1/publications/:id` | Delete |
| POST | `/api/v1/publications/:id/image` | Upload cover image |
| GET | `/api/v1/publications/:id/image` | Serve cover image |
| DELETE | `/api/v1/publications/:id/image` | Delete cover image |
| GET | `/api/v1/publications/:id/fruits` | List linked fruits |
| POST | `/api/v1/publications/:id/fruits` | Link a fruit |
| DELETE | `/api/v1/publications/:id/fruits/:fruitId` | Unlink a fruit |
| GET | `/api/v1/publications/:id/descriptions` | List descriptions (fruit + link metadata) |
| POST | `/api/v1/publications/:id/descriptions` | Upload PDF description (body: fruitId + PDF) |
| GET | `/api/v1/publications/:id/descriptions/:descId` | Serve PDF |
| DELETE | `/api/v1/publications/:id/descriptions/:descId` | Delete |
| GET | `/api/v1/publications/:id/fruit-images` | List pub fruit images |
| POST | `/api/v1/publications/:id/fruit-images` | Upload fruit image (fruitId + image) |
| GET | `/api/v1/publications/:id/fruit-images/:imgId` | Serve image |
| DELETE | `/api/v1/publications/:id/fruit-images/:imgId` | Delete |
| GET | `/api/v1/fruits/:id/descriptions` | All descriptions for a fruit (across publications) |
| GET | `/api/v1/fruits/:id/publication-images` | All pub images for a fruit |

### Frontend

| File | Purpose |
|------|---------|
| `frontend/src/api/publications.ts` | API wrapper |
| `frontend/src/stores/publicationStore.ts` | Pinia store |
| `frontend/src/views/PublicationList.vue` | List + link to detail |
| `frontend/src/views/PublicationDetail.vue` | Full management UI |
| `frontend/src/components/ImageOverlayDrawer.vue` | Full-size image overlay on click |
| `frontend/src/views/FruitDetail.vue` | Extended: descriptions section + pub images section |
| `frontend/src/router/index.ts` | Add `/publications`, `/publications/:id` |

---

## 6. Out of Scope

- Bulk import from XML (story #5)
- Thumbnail generation (story #7)
- Authentication guards (story #8)

---

## 7. Verification

| Check | Expected |
|-------|---------|
| Create publication with duplicate osdb_pub_id | 409 Conflict |
| Upload cover image → serve back → correct bytes | Pass |
| Link fruit to publication → appears in GET /publications/:id/fruits | Pass |
| Upload PDF description → GET description → Content-Type: application/pdf | Pass |
| Fruit detail page: no descriptions → section hidden | Pass |
| Fruit detail page: 1+ description → links visible | Pass |
| Click cover image thumbnail → overlay opens full-size | Pass |
| Pub fruit images on fruit detail labeled correctly | Publication title · Author shown |
| `go test ./...` | Green |
| `npm run test` | Green |

---

## 8. Open Questions

| # | Question | Impact |
|---|----------|--------|
| 1 | Is one PDF per (publication, fruit) pair enforced (UNIQUE) or allow multiples? | Schema + UI |
| 2 | Can a fruit image exist in a publication without the fruit being linked via publication_fruits? | Data integrity |
| 3 | Listing publications: include fruit count or just metadata? | API response shape |
| 4 | PDF viewer: open in new tab or inline browser PDF viewer? | UX |