# LifeRPG Plugin System

This document outlines the design and implementation of the LifeRPG plugin system using WebAssembly (WASM) for secure sandboxing.

## Overview

The LifeRPG plugin system enables users and developers to extend the functionality of the application without modifying the core codebase. Plugins run in a secure sandbox environment with controlled access to application resources.

## Design Goals

1. **Security**: Plugins must run in a secure sandbox with explicit permissions
2. **Performance**: Minimal overhead for plugin execution
3. **Simplicity**: Easy to develop and deploy plugins
4. **Portability**: Plugins should work across all platforms (web, mobile, desktop)
5. **Versioning**: Support for plugin versioning and compatibility checking

## Architecture

### High-Level Architecture

```
┌───────────────────────────────────────────────────────────────┐
│                       LifeRPG Core                            │
│                                                               │
│  ┌─────────────────┐   ┌─────────────────┐   ┌─────────────┐  │
│  │  Plugin Manager │   │ Plugin Registry │   │ Core API    │  │
│  └────────┬────────┘   └───────┬─────────┘   └──────┬──────┘  │
│           │                    │                    │         │
└───────────┼────────────────────┼────────────────────┼─────────┘
            │                    │                    │
            ▼                    ▼                    ▼
┌───────────────────────────────────────────────────────────────┐
│                       Plugin Interface                         │
│                                                               │
│  ┌─────────────────┐   ┌─────────────────┐   ┌─────────────┐  │
│  │  Host Functions │   │ Extension Points│   │ Plugin API  │  │
│  └─────────────────┘   └─────────────────┘   └─────────────┘  │
│                                                               │
└───────────────────────────────────────────────────────────────┘
            │                    │                    │
            ▼                    ▼                    ▼
┌───────────────────────────────────────────────────────────────┐
│                       Plugin Sandbox                           │
│                                                               │
│  ┌─────────────────┐   ┌─────────────────┐   ┌─────────────┐  │
│  │  WASM Runtime   │   │ Resource Limits │   │ Plugin Code │  │
│  └─────────────────┘   └─────────────────┘   └─────────────┘  │
│                                                               │
└───────────────────────────────────────────────────────────────┘
```

### Key Components

#### 1. Plugin Manager

The Plugin Manager is responsible for:
- Loading and unloading plugins
- Managing plugin lifecycle
- Enforcing permissions and resource limits
- Handling plugin errors and crashes

```typescript
class PluginManager {
  // Load a plugin from a WASM binary
  async loadPlugin(pluginId: string, wasmBinary: ArrayBuffer): Promise<Plugin>;
  
  // Unload a plugin
  async unloadPlugin(pluginId: string): Promise<void>;
  
  // Get a list of loaded plugins
  getLoadedPlugins(): Plugin[];
  
  // Enable/disable a plugin
  setPluginEnabled(pluginId: string, enabled: boolean): void;
}
```

#### 2. Plugin Registry

The Plugin Registry manages:
- Plugin metadata storage
- Version compatibility checking
- Plugin discovery and marketplace
- User plugin preferences

```typescript
class PluginRegistry {
  // Register a new plugin
  async registerPlugin(metadata: PluginMetadata, wasmBinary: ArrayBuffer): Promise<string>;
  
  // Update an existing plugin
  async updatePlugin(pluginId: string, metadata: PluginMetadata, wasmBinary: ArrayBuffer): Promise<void>;
  
  // Get plugin metadata
  getPluginMetadata(pluginId: string): PluginMetadata;
  
  // List available plugins
  listAvailablePlugins(filters?: PluginFilters): PluginMetadata[];
  
  // Check if a plugin is compatible with the current app version
  isPluginCompatible(pluginId: string): boolean;
}
```

#### 3. Plugin Interface

The Plugin Interface defines:
- Host functions available to plugins
- Extension points where plugins can integrate
- Standard plugin API

```typescript
interface PluginInterface {
  // Core APIs available to plugins
  core: {
    // Data access APIs
    data: {
      getHabits(): Promise<Habit[]>;
      getProjects(): Promise<Project[]>;
      // ...etc
    };
    
    // UI integration
    ui: {
      registerView(viewId: string, component: PluginView): void;
      registerMenuItem(menuId: string, item: MenuItem): void;
      // ...etc
    };
    
    // Events
    events: {
      on(event: string, callback: Function): void;
      emit(event: string, data: any): void;
      // ...etc
    };
  };
  
  // Host environment information
  environment: {
    appVersion: string;
    platform: 'web' | 'mobile' | 'desktop';
    capabilities: string[];
  };
  
  // Utilities
  utils: {
    logger: Logger;
    storage: PluginStorage;
    http: HttpClient;
  };
}
```

#### 4. WASM Sandbox

The WASM Sandbox provides:
- Secure execution environment
- Memory and CPU limits
- Network access controls
- Storage quotas

```typescript
class WasmSandbox {
  // Create a new sandbox with specified limits
  constructor(options: SandboxOptions);
  
  // Load WASM binary into the sandbox
  async loadWasmModule(binary: ArrayBuffer): Promise<WasmModule>;
  
  // Execute a function in the sandbox
  async callFunction(functionName: string, ...args: any[]): Promise<any>;
  
  // Set resource limits
  setResourceLimits(limits: ResourceLimits): void;
  
  // Check resource usage
  getResourceUsage(): ResourceUsage;
  
  // Terminate sandbox (for runaway plugins)
  terminate(): void;
}
```

## Plugin Development

### Plugin Structure

A plugin consists of:
1. WASM binary (compiled from various languages)
2. Manifest file (metadata, permissions, extension points)
3. Optional assets (images, styles, etc.)

```json
// plugin.json manifest example
{
  "id": "com.example.myplugin",
  "name": "My Custom Plugin",
  "version": "1.0.0",
  "author": "Example Developer",
  "description": "A custom plugin for LifeRPG",
  "homepage": "https://example.com/myplugin",
  "targetApiVersion": "1.0",
  "minAppVersion": "2.0.0",
  "permissions": [
    "habits:read",
    "projects:read",
    "ui:dashboard",
    "storage:plugin"
  ],
  "extensionPoints": [
    "dashboard.widget",
    "habit.actions",
    "reports.custom"
  ],
  "entryPoint": "initialize",
  "resourceLimits": {
    "memory": "16MB",
    "storage": "5MB",
    "cpu": "moderate"
  }
}
```

### Supported Languages

Plugins can be developed in any language that compiles to WebAssembly:

1. **TypeScript/JavaScript** (via AssemblyScript)
2. **Rust** (native WASM support)
3. **C/C++** (via Emscripten)
4. **Go** (with WASM target)

The recommended language is TypeScript with AssemblyScript for ease of development and type safety.

### Development Workflow

1. **Setup**: Use the LifeRPG Plugin SDK
   ```bash
   npm install @liferpg/plugin-sdk
   ```

2. **Develop**: Create your plugin using the plugin template
   ```typescript
   // plugin.ts
   import { LifeRPG, PluginContext } from '@liferpg/plugin-sdk';
   
   export function initialize(context: PluginContext): void {
     // Register a dashboard widget
     context.ui.registerDashboardWidget({
       id: 'my-custom-widget',
       title: 'My Widget',
       size: 'medium',
       render: () => {
         // Return widget HTML/components
         return `<div>My Custom Widget</div>`;
       }
     });
     
     // Listen for events
     context.events.on('habit.completed', (habit) => {
       context.logger.info(`Habit completed: ${habit.title}`);
     });
   }
   ```

3. **Build**: Compile to WASM
   ```bash
   npm run build
   ```

4. **Test**: Use the plugin development server
   ```bash
   npm run dev
   ```

5. **Package**: Create a plugin package
   ```bash
   npm run package
   ```

6. **Publish**: Submit to the LifeRPG plugin marketplace or distribute directly

## Extension Points

The plugin system offers various extension points where plugins can integrate with the application:

### UI Extension Points

1. **Dashboard Widgets**: Add custom widgets to the dashboard
2. **Habit Views**: Custom views for habits
3. **Project Views**: Custom views for projects
4. **Reports**: Custom reporting and analytics
5. **Settings Pages**: Add custom settings pages
6. **Navigation Items**: Add items to navigation menus

### Data Extension Points

1. **Custom Fields**: Add custom fields to habits, projects, etc.
2. **Data Validators**: Add custom validation rules
3. **Data Processors**: Process data before/after CRUD operations
4. **Exporters/Importers**: Custom data export/import formats

### Logic Extension Points

1. **Achievement Rules**: Define custom achievement conditions
2. **Habit Completion Rules**: Custom rules for habit completion
3. **Scoring Algorithms**: Custom XP calculation
4. **Notification Triggers**: Custom notification conditions

## Security Model

### Permission System

Plugins must request permissions for the resources they need to access:

```
habits:read      - Read habit data
habits:write     - Create/update habits
projects:read    - Read project data
projects:write   - Create/update projects
ui:dashboard     - Add dashboard widgets
ui:settings      - Add settings pages
storage:plugin   - Use plugin storage
network:same-origin - Make network requests to same origin
network:external - Make network requests to external domains
```

Permissions are shown to users during plugin installation and updates.

### Sandbox Restrictions

- **Memory**: Limited heap size
- **CPU**: Execution time limits
- **Network**: Controlled via permissions
- **Storage**: Quota-based plugin storage
- **DOM**: No direct DOM access (must use provided APIs)

### Validation and Review

- **Automatic Validation**: Static analysis for security issues
- **Manual Review**: Optional review process for marketplace plugins
- **User Ratings**: Community reviews and ratings
- **Revocation**: Ability to revoke plugins with security issues

## Implementation Plan

### Phase 1: Core Infrastructure

1. Implement basic WASM sandbox
2. Create plugin manager and registry
3. Define plugin interface and host functions
4. Build plugin packaging tools

### Phase 2: Basic Extension Points

1. Implement dashboard widget extension point
2. Add settings page extension point
3. Create custom reporting extension point
4. Build plugin marketplace UI

### Phase 3: Advanced Features

1. Add more extension points
2. Implement comprehensive permission system
3. Add resource monitoring and limits
4. Create plugin developer documentation and examples

## Example Plugins

### 1. Pomodoro Timer

A plugin that adds a Pomodoro timer widget to the dashboard and integrates with habit tracking.

```typescript
// pomodoro-plugin.ts
export function initialize(context: PluginContext): void {
  // Add dashboard widget
  context.ui.registerDashboardWidget({
    id: 'pomodoro-timer',
    title: 'Pomodoro Timer',
    size: 'medium',
    render: () => {
      return renderPomodoroTimer();
    }
  });
  
  // Add settings page
  context.ui.registerSettingsPage({
    id: 'pomodoro-settings',
    title: 'Pomodoro Settings',
    render: () => {
      return renderPomodoroSettings();
    }
  });
  
  // When timer completes, offer to mark related habit as complete
  context.events.on('pomodoro.complete', async () => {
    const habits = await context.data.getHabits({ today: true });
    // Show completion dialog
  });
}
```

### 2. GitHub Integration

A plugin that connects with GitHub to track coding-related habits and progress.

```typescript
// github-plugin.ts
export function initialize(context: PluginContext): void {
  // Add GitHub connection settings
  context.ui.registerSettingsPage({
    id: 'github-settings',
    title: 'GitHub Connection',
    render: () => {
      return renderGitHubSettings();
    }
  });
  
  // Add GitHub stats widget
  context.ui.registerDashboardWidget({
    id: 'github-stats',
    title: 'GitHub Activity',
    size: 'large',
    render: async () => {
      const stats = await fetchGitHubStats();
      return renderGitHubStatsWidget(stats);
    }
  });
  
  // Sync GitHub activity daily
  context.scheduler.scheduleDaily('github-sync', async () => {
    await syncGitHubActivity();
  });
}
```

### 3. Custom Data Visualizer

A plugin that provides advanced data visualization for habit tracking.

```typescript
// data-viz-plugin.ts
export function initialize(context: PluginContext): void {
  // Register custom report
  context.ui.registerReport({
    id: 'advanced-visualization',
    title: 'Advanced Analytics',
    render: async () => {
      const habitData = await context.data.getHabitLogs({ 
        timeRange: { from: '30d' } 
      });
      return renderAdvancedVisualization(habitData);
    }
  });
  
  // Add visualization widget to dashboard
  context.ui.registerDashboardWidget({
    id: 'viz-summary',
    title: 'Progress Visualization',
    size: 'large',
    render: async () => {
      return renderVisualizationSummary();
    }
  });
}
```

## Conclusion

The LifeRPG plugin system provides a powerful yet secure way to extend the application's functionality. By using WebAssembly for sandboxing, we can offer both security and performance while supporting a wide range of programming languages for plugin development.

This design allows for a rich ecosystem of plugins that can enhance the LifeRPG experience without compromising on security or stability.

---

## Appendix: WebAssembly Resources

- [WebAssembly Official Site](https://webassembly.org/)
- [AssemblyScript](https://www.assemblyscript.org/)
- [Rust and WebAssembly](https://rustwasm.github.io/docs/book/)
- [Emscripten](https://emscripten.org/)
- [WASI: WebAssembly System Interface](https://wasi.dev/)