sokoban/docs/codebase-summary.md

Codebase Summary

Layout

src/
├── main.js                         # Mounts App.svelte into #app
├── App.svelte                      # Root router: menu / levels / game
├── app.css                         # Nord palette (CSS variables) + resets
├── lib/
│   ├── core/
│   │   ├── level-parser.js         # XSB text → {walls, targets, boxes, player, floors}
│   │   ├── board-model.js          # Pure game state + move/undo/win logic
│   │   ├── progress-store.js       # localStorage persistence (completed + best moves)
│   │   └── haptics.js              # navigator.vibrate wrapper (10ms on box push, 60ms on win)
│   └── data/
│       └── microban-levels.js      # 155 XSB level strings (Microban, D. W. Skinner)
└── views/
    ├── MenuView.svelte             # Title, play, progress, hints
    ├── LevelSelectView.svelte      # Paginated 5×4 grid (20/page × 8 pages)
    ├── GameView.svelte              # Board + HUD + win overlay + input + haptics
    ├── Board.svelte                # Presentational DOM board (div-per-tile, touch-action: none)
    ├── MobileControls.svelte       # On-screen D-pad + action stack (hidden on desktop)
    └── AppButton.svelte             # Shared themed button (wraps native <button>)

public/
├── style.css                       # Legacy file — theme now lives in src/app.css
├── favicon.png
└── assets/                         # bg.png, logo.png (unused, reserved)

Data flow

1. src/main.js mounts App.svelte.
2. App.svelte holds view and levelIndex state and renders one of three view components.
3. MenuView → calls onPlay() → App switches to LevelSelectView.
4. LevelSelectView reads completion + best-move data from progressStore, renders a paginated grid, calls onSelect(i) on click.
5. GameView is keyed on levelIndex ({#key levelIndex} in App) so every level change remounts it with fresh state.
6. Inside GameView: parseLevel(xsb) → new BoardModel(level), keyboard input calls model.tryMove() / model.undo(), after each mutation syncFromModel() reassigns the $state snapshots that Board reads as props.
7. On win: progressStore.recordCompletion() + overlay with NEXT / LEVELS actions.

Key design choices

• Framework-agnostic core. level-parser.js, board-model.js, progress-store.js, haptics.js, and microban-levels.js contain zero Svelte — they could be lifted into any other stack.
• BoardModel as a non-reactive ref. Svelte reactivity is driven by plain $state snapshot fields (player, boxes, moves, won) that syncFromModel() reassigns after every mutation. Cleaner than making the class instance itself reactive.
• Board is purely presentational. Takes plain props (walls, targets, floors, player, boxes, tileSize) so Svelte reactivity is predictable. Desktop & mobile share the same component; touch-action: none blocks browser gestures on all devices.
• Mobile controls opt-in. MobileControls.svelte is hidden on desktop via @media (pointer: coarse), so no UA sniffing or JS feature detection — CSS media queries handle the split.
• Haptics are graceful. haptics.js wraps navigator.vibrate with try/catch and no-op fallback. Callers can vibrate without checking support; unsupported devices silently ignore the call.
• Animations via CSS. Box and player use transform: translate() with transition: transform 110ms ease. No JS animation loop.
• Responsive tile sizing. GameView.computeTileSize() picks a tile size that fits the level inside the viewport, capped at 56 px.
• Safe-area insets. Bottom controls use env(safe-area-inset-*) for notch/Home-indicator safety on iPhones and Android phones with nav bars.
• Scoped CSS per component. Svelte SFCs keep markup, style, and logic co-located and isolate styles to the component that owns them.

File size

Every .js / .svelte file is under the 200-LOC budget, except microban-levels.js which is pure data (155 XSB strings) and exempt.