# Gallery System Implementation

## Overview
Comprehensive album-based gallery system with Zonerama integration, displaying albums with photo previews, detailed album pages, and interactive photo modals.

## Features Implemented

### 1. Homepage Gallery Section
**File**: `frontend/src/components/home/PhotosSection.tsx`

- Displays 5 most recent albums from Zonerama
- Each album shows:
  - Cover image (first photo from album)
  - Album title
  - Date
  - Photo count
- Links to individual album detail pages
- "Zobrazit vše" button linking to full gallery page
- Zonerama copyright attribution notice

### 2. Gallery Page (Album Grid)
**File**: `frontend/src/pages/GalleryPage.tsx`

- Shows all available albums in a responsive grid (1/2/3 columns)
- Albums sorted by most recent first (based on API response order)
- Each album card displays:
  - Cover image or placeholder
  - Album title
  - Date and photo count
  - View count badge (if available)
- Click on album navigates to album detail page
- Zonerama attribution banner at top
- Loading, error, and empty states

### 3. Album Detail Page
**File**: `frontend/src/pages/AlbumDetailPage.tsx`

- Displays all photos from a specific album
- Breadcrumb navigation (Home → Galerie → Album)
- Album header with:
  - Album title
  - Date, photo count, view count
  - "Zobrazit na Zonerama" button (external link)
- Responsive photo grid (2/3/4/5 columns based on screen size)
- Zonerama attribution notice
- Click on any photo opens modal preview

### 4. Photo Modal
**File**: `frontend/src/components/gallery/PhotoModal.tsx`

Interactive modal for photo viewing with:
- **Full-size photo display** - Shows image at max 80vh height
- **Copy button** - Copies image to clipboard (with fallback to URL copy)
- **Download button** - Downloads image to user's device
- **View Original button** - Opens photo on Zonerama website
- **Album title display**
- **Zonerama copyright notice**
- Dark backdrop with blur effect
- Responsive design

### 5. Backend Updates
**File**: `internal/controllers/gallery_controller.go`

**Fixed**: Album fetching to properly parse Zonerama API response structure:
- Zonerama API returns `{"input_link": "...", "albums": [...]}`
- Updated `FetchAlbum` to handle wrapped response correctly
- Extracts first album from albums array

### 6. Routing
**File**: `frontend/src/App.tsx`

Added route for album detail pages:
```
/galerie/album/:id
```

## API Endpoints Used

### Public Endpoints
- `GET /api/v1/gallery/albums` - Get all albums
- `GET /api/v1/gallery/albums/:id` - Get single album with photos

### Admin Endpoints (existing)
- `GET /api/v1/admin/gallery/profile` - Get Zonerama profile metadata
- `POST /api/v1/admin/gallery/albums/fetch` - Fetch single album from Zonerama
- `DELETE /api/v1/admin/gallery/albums/:id` - Delete album

## Data Flow

1. **Prefetch Service** (`internal/services/prefetch_service.go`)
   - Periodically fetches albums from Zonerama API
   - Stores in `cache/prefetch/zonerama_albums.json`
   - Also maintains `cache/prefetch/zonerama_profile.json` for metadata

2. **Gallery Controller** serves cached albums to frontend
   - Albums ordered by most recent first (based on fetch order)
   - Includes full photo data for each album

3. **Frontend Components** 
   - HomePage shows 5 most recent albums
   - GalleryPage shows all albums
   - AlbumDetailPage displays individual album photos
   - PhotoModal provides interactive photo viewing

## Zonerama Attribution

Copyright notices added to:
- **PhotoModal**: Footer with Zonerama link
- **AlbumDetailPage**: Info banner above photo grid
- **GalleryPage**: Info banner in header
- **PhotosSection (Homepage)**: Small banner above album grid

Format: "📸 Všechny fotografie jsou z platformy [Zonerama](https://zonerama.com)"

## User Experience Flow

1. User visits homepage → sees 5 recent albums
2. Clicks "Zobrazit vše" → navigates to full gallery
3. Clicks on album → views all photos in album
4. Clicks on photo → opens modal with copy/download/view original options
5. Can navigate back via breadcrumbs or browser back button

## Responsive Design

- **Mobile** (base): 1 column albums, 2 column photos
- **Tablet** (md): 2 column albums, 3 column photos
- **Desktop** (lg): 3 column albums, 4 column photos
- **Large Desktop** (xl): 5 column photos in album detail

## Future Enhancements (Optional)

- Pagination for large album collections
- Image lazy loading optimization
- Lightbox navigation (prev/next photo in modal)
- Album search/filter functionality
- Share functionality for photos/albums
- Photo metadata display (if available from Zonerama)

## Testing Checklist

- [ ] Homepage displays 5 most recent albums
- [ ] Gallery page shows all albums
- [ ] Album detail page loads correctly with photos
- [ ] Photo modal opens on photo click
- [ ] Copy button works (image or URL fallback)
- [ ] Download button downloads photo
- [ ] View original link opens Zonerama page
- [ ] All Zonerama attributions visible
- [ ] Responsive layout works on mobile/tablet/desktop
- [ ] Loading and error states display correctly
- [ ] Empty states show appropriate messages
- [ ] Navigation and breadcrumbs work correctly

## Files Modified/Created

### Created:
- `frontend/src/components/gallery/PhotoModal.tsx`
- `frontend/src/pages/AlbumDetailPage.tsx`
- `GALLERY_SYSTEM_IMPLEMENTATION.md`

### Modified:
- `frontend/src/pages/GalleryPage.tsx`
- `frontend/src/components/home/PhotosSection.tsx`
- `frontend/src/App.tsx`
- `internal/controllers/gallery_controller.go`
