# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

Calendar Plantempus is a professional TypeScript calendar component with offline-first architecture, drag-and-drop functionality, and real-time synchronization capabilities.

## Build & Development Commands

```bash
# Build the project (bundles to wwwroot/js/calendar.js)
npm run build

# Watch mode for development
npm run watch

# Clean build output
npm run clean

# Type check only
npx tsc --noEmit

# Run all tests
npm test

# Run tests in watch mode
npm run test

# Run tests once and exit
npm run test:run

# Run tests with UI
npm run test:ui

# CSS Development
npm run css:build          # Build CSS
npm run css:watch          # Watch and rebuild CSS
npm run css:build:prod     # Build minified production CSS
npm run css:analyze        # Analyze CSS metrics
```

## Architecture

### Core Design Pattern: Dependency Injection with NovaDI

The application uses **NovaDI** (@novadi/core) for dependency injection. All managers, services, and repositories are registered in `src/index.ts` and resolved through the DI container.

**Key principle**: Never instantiate managers or services directly with `new`. Always use constructor injection and register types in the container.

### Event-Driven Architecture

The application uses a **centralized EventBus** (`src/core/EventBus.ts`) built on DOM CustomEvents for all inter-component communication. This is the ONLY way components should communicate.

- All event types are defined in `src/constants/CoreEvents.ts` (reduced from 102+ to ~20 core events)
- Components emit events via `eventBus.emit(CoreEvents.EVENT_NAME, payload)`
- Components subscribe via `eventBus.on(CoreEvents.EVENT_NAME, handler)`
- Never call methods directly between managers - always use events

### Manager Hierarchy

**CalendarManager** (`src/managers/CalendarManager.ts`) - Top-level coordinator
- Manages calendar state (current view, current date)
- Orchestrates initialization sequence
- Coordinates other managers via EventBus

**Key Managers**:
- **EventManager** - Event CRUD operations, data loading from repository
- **GridManager** - Renders time grid structure
- **ViewManager** - Handles view switching (day/week/month)
- **NavigationManager** - Date navigation and period calculations
- **DragDropManager** - Advanced drag-and-drop with smooth animations, type conversion (timed ↔ all-day), scroll compensation
- **ResizeHandleManager** - Event resizing with visual feedback
- **AllDayManager** - All-day event layout and rendering
- **HeaderManager** - Date headers and all-day event container
- **ScrollManager** - Scroll behavior and position management
- **EdgeScrollManager** - Automatic scrolling at viewport edges during drag

### Repository Pattern

Event data access is abstracted through the **IEventRepository** interface (`src/repositories/IEventRepository.ts`):
- **IndexedDBEventRepository** - Primary: Local storage with offline support
- **ApiEventRepository** - Sends changes to backend API
- **MockEventRepository** - Legacy: Loads from JSON file

All repository methods accept an `UpdateSource` parameter ('local' | 'remote') to distinguish user actions from remote updates.

### Offline-First Sync Architecture

**SyncManager** (`src/workers/SyncManager.ts`) provides background synchronization:
1. Local changes are written to **IndexedDB** immediately
2. Operations are queued in **OperationQueue**
3. SyncManager processes queue when online (5-second polling)
4. Failed operations retry with exponential backoff (max 5 retries)
5. Events have `syncStatus`: 'synced' | 'pending' | 'error'

### Rendering Strategy Pattern

**EventRenderingService** (`src/renderers/EventRendererManager.ts`) uses strategy pattern:
- **IEventRenderer** interface defines rendering contract
- **DateEventRenderer** - Renders timed events in day columns
- **AllDayEventRenderer** - Renders all-day events in header
- Strategies can be swapped without changing core logic

### Layout Engines

**EventStackManager** (`src/managers/EventStackManager.ts`) - Uses CSS flexbox for overlapping events:
- Groups overlapping events into stacks
- Calculates flex positioning (basis, grow, shrink)
- Handles multi-column spanning events

**AllDayLayoutEngine** (`src/utils/AllDayLayoutEngine.ts`) - Row-based layout for all-day events:
- Detects overlaps and assigns row positions
- Supports collapsed view (max 4 rows) with "+N more" indicator
- Calculates container height dynamically

### Configuration System

Configuration is loaded from `wwwroot/data/calendar-config.json` via **ConfigManager**:
- **GridSettings** - Hour height, work hours, snap interval
- **DateViewSettings** - Period type, first day of week
- **TimeFormatConfig** - Timezone, locale, 12/24-hour format
- **WorkWeekSettings** - Configurable work week presets
- **Interaction** - Enable/disable drag, resize, create

Access via injected `Configuration` instance, never load config directly.

## Important Patterns & Conventions

### Event Type Conversion (Drag & Drop)

When dragging events between timed grid and all-day area:
- **Timed → All-day**: `DragDropManager` emits `drag:mouseenter-header`, `AllDayManager` creates all-day clone
- **All-day → Timed**: `DragDropManager` emits `drag:mouseenter-column`, `EventRenderingService` creates timed clone
- Original element is marked with `data-conversion-source="true"`
- Clone is marked with `data-converted-clone="true"`

### Scroll Compensation During Drag

`DragDropManager` tracks scroll delta during edge-scrolling:
1. Listens to `edge-scroll:scrolling` events
2. Accumulates `scrollDeltaY` from scroll events
3. Compensates dragged element position: `targetY = mouseY - scrollDeltaY - mouseOffset.y`
4. Prevents visual "jumping" during scroll

### Grid Snapping

When dropping events, snap to time grid:
1. Get mouse Y position relative to column
2. Convert to time using `PositionUtils.getTimeAtPosition()`
3. Account for `mouseOffset.y` (click position within event)
4. Snap to nearest `snapInterval` (default 15 minutes)

### Testing with Vitest

Tests use **Vitest** with **jsdom** environment:
- Setup file: `test/setup.ts`
- Test helpers: `test/helpers/dom-helpers.ts`
- Run single test: `npm test -- <test-file-name>`

## Key Files to Know

- `src/index.ts` - DI container setup and initialization
- `src/core/EventBus.ts` - Central event dispatcher
- `src/constants/CoreEvents.ts` - All event type constants
- `src/types/CalendarTypes.ts` - Core type definitions
- `src/managers/CalendarManager.ts` - Main coordinator
- `src/managers/DragDropManager.ts` - Detailed drag-drop architecture docs
- `src/configurations/CalendarConfig.ts` - Configuration schema
- `wwwroot/data/calendar-config.json` - Runtime configuration

## Common Tasks

### Adding a New Event Type to CoreEvents

1. Add constant to `src/constants/CoreEvents.ts`
2. Define payload type in `src/types/EventTypes.ts`
3. Emit with `eventBus.emit(CoreEvents.NEW_EVENT, payload)`
4. Subscribe with `eventBus.on(CoreEvents.NEW_EVENT, handler)`

### Adding a New Manager

1. Create in `src/managers/`
2. Inject dependencies via constructor (EventBus, Configuration, other managers)
3. Register in DI container in `src/index.ts`: `builder.registerType(NewManager).as<NewManager>()`
4. Communicate via EventBus only, never direct method calls
5. Initialize in CalendarManager if needed

### Modifying Event Data

Always go through EventManager:
- Create: `eventManager.createEvent(eventData)`
- Update: `eventManager.updateEvent(id, updates)`
- Delete: `eventManager.deleteEvent(id)`

EventManager handles repository calls, event emission, and UI updates.

### Debugging

Debug mode is enabled in development:
```javascript
eventBus.setDebug(true); // In src/index.ts
```

Access debug interface in browser console:
```javascript
window.calendarDebug.eventBus.getEventLog()
window.calendarDebug.calendarManager
window.calendarDebug.eventManager
```

## Dependencies

- **@novadi/core** - Dependency injection framework
- **date-fns** / **date-fns-tz** - Date manipulation and timezone support
- **fuse.js** - Fuzzy search for event filtering
- **esbuild** - Fast bundler for development
- **vitest** - Testing framework
- **postcss** - CSS processing and optimization