# Architecture Overview

## System Architecture

### High-Level Architecture

```mermaid
graph TB
    subgraph "User Interface Layer"
        U[Terminal Interface]
        I[Input Handler]
        R[Terminal Renderer]
    end
    
    subgraph "Core System"
        E[Event Bus]
        P[Plugin Registry]
        C[Config Manager]
        S[State Manager]
    end
    
    subgraph "Plugin Layer"
        L[LLM Plugin]
        EI[Enhanced Input Plugin]
        Q[Query Enhancer Plugin]
        FS[Fullscreen Plugins]
        T[Test Plugin]
    end

    subgraph "Fullscreen Framework"
        FCI[FullScreen Command Integrator]
        FSM[FullScreen Manager]
        FSR[FullScreen Renderer]
        MP[Matrix Plugin]
        EP[Example Plugin]
    end
    
    subgraph "External Services"
        A[AI APIs]
        G[GitHub API]
        D[Databases]
    end
    
    U --> I
    I --> E
    E --> P
    P --> L
    P --> EI
    P --> Q
    P --> FS
    P --> T
    FCI --> FSM
    FSM --> FSR
    FSM --> MP
    FSM --> EP
    FCI --> E
    R --> U
    E --> R
    L --> A
    P --> G
    S --> D
    C --> S
```

### Core Components

#### Event Bus
**Purpose**: Central communication hub for all system components
**Key Features**:
- Asynchronous event processing
- Hook-based plugin integration
- Event cancellation support
- Priority-based hook execution

```python
class EventBus:
    async def publish_event(self, event_type: str, data: dict) -> EventResult
    async def register_hook(self, event_type: str, hook_func: callable, priority: int)
    async def unregister_hook(self, hook_id: str)
```

#### Plugin Registry
**Purpose**: Dynamic plugin discovery and lifecycle management
**Key Features**:
- Auto-discovery of plugins from directory
- Plugin dependency resolution
- Configuration merging
- Status monitoring

```python
class PluginRegistry:
    def discover_plugins(self, directory: str) -> List[Plugin]
    def register_plugin(self, plugin_class: type) -> Plugin
    def get_plugin_status(self, plugin_name: str) -> PluginStatus
```

#### Fullscreen Framework
**Purpose**: Complete terminal takeover for immersive experiences
**Key Features**:
- Dynamic plugin discovery and command registration
- Alternate buffer management with proper restoration
- Real-time animation and input handling
- Clean separation from core CLI functionality

```python
class FullScreenCommandIntegrator:
    def discover_and_register_plugins(self, plugins_dir: Path) -> int
    def _register_plugin_commands(self, plugin_class: Type) -> bool
    def unregister_plugin(self, plugin_name: str) -> bool

class FullScreenManager:
    async def launch_plugin(self, plugin_name: str) -> bool
    def register_plugin(self, plugin: FullScreenPlugin) -> bool
    def get_plugin(self, name: str) -> Optional[FullScreenPlugin]

class FullScreenRenderer:
    def setup_terminal(self) -> bool
    def restore_terminal(self) -> bool
    def write_at(self, x: int, y: int, text: str, color: str = None)
```

**Plugin Structure**:
- Located in `plugins/fullscreen/`
- Auto-discovered and registered as slash commands
- Inherit from `FullScreenPlugin` base class
- Metadata-driven command registration

## Component Architecture

### I/O System Architecture

```mermaid
graph TD
    subgraph "I/O System Components"
        TR[Terminal Renderer] --> SM[Status Renderer]
        TR --> MR[Message Renderer]
        TR --> LM[Layout Manager]
        
        IH[Input Handler] --> KP[Key Parser]
        IH --> BM[Buffer Manager]
        IH --> EH[Error Handler]
        
        VE[Visual Effects] --> TR
        TS[Terminal State] --> TR
        TA[Thinking Animation] --> LM
    end
    
    subgraph "External Interface"
        T[Terminal]
        U[User]
    end
    
    TR --> T
    T --> IH
    U --> T
```

#### Terminal Renderer
**Purpose**: Main rendering coordinator
**Responsibilities**:
- Coordinate all visual updates
- Manage render loop timing (20 FPS)
- Handle dirty region tracking
- Integrate visual effects

#### Input Handler
**Purpose**: Advanced keyboard input processing
**Responsibilities**:
- Raw terminal input capture
- Key sequence parsing
- Input validation and sanitization
- Error recovery

#### Visual Effects
**Purpose**: Centralized visual styling and effects
**Capabilities**:
- Gradient generation
- Shimmer animations
- Color management
- Theme support

### Plugin Architecture

```mermaid
graph TB
    subgraph "Plugin Base Class"
        BP[BasePlugin]
        BP --> I[initialize]
        BP --> RH[register_hooks]
        BP --> GSL[get_status_line]
        BP --> S[shutdown]
    end
    
    subgraph "LLM Plugin"
        LP[LLM Plugin] --> AI[AI API Client]
        LP --> TC[Tool Calling]
        LP --> TR[Thinking Rendering]
        LP --> MM[Multi-Model Support]
    end
    
    subgraph "Input Plugin"
        IP[Enhanced Input] --> PC[Pre-processing]
        IP --> V[Validation]
        IP --> H[History Management]
    end
    
    subgraph "Query Enhancer"
        QE[Query Enhancer] --> CE[Context Enrichment]
        QE --> QO[Query Optimization]
        QE --> IR[Intent Recognition]
    end
    
    BP --> LP
    BP --> IP
    BP --> QE
```

## Data Flow Architecture

### Event Processing Flow

```mermaid
sequenceDiagram
    participant U as User
    participant I as Input Handler
    participant E as Event Bus
    participant P as Plugin
    participant A as AI API
    participant R as Renderer
    
    U->>I: Key Press
    I->>E: KEY_PRESS Event
    E->>P: Pre-hook Processing
    P->>E: Enhanced Event Data
    E->>P: Main Hook Processing
    P->>A: API Request (if needed)
    A-->>P: API Response
    P->>E: Event Result
    E->>P: Post-hook Processing
    P->>R: Display Update
    R->>U: Visual Feedback
```

### Configuration Management Flow

```mermaid
graph LR
    subgraph "Configuration Sources"
        DC[Default Config]
        PC[Plugin Configs]
        EC[Environment Config]
        UC[User Config]
    end
    
    subgraph "Configuration Processing"
        CM[Config Manager]
        M[Merge Logic]
        V[Validation]
    end
    
    subgraph "Configuration Usage"
        S[System Components]
        P[Plugins]
        R[Runtime Settings]
    end
    
    DC --> CM
    PC --> CM
    EC --> CM
    UC --> CM
    CM --> M
    M --> V
    V --> S
    V --> P
    V --> R
```

## Security Architecture

### Security Layers

```mermaid
graph TB
    subgraph "Application Security"
        IS[Input Sanitization]
        AV[API Validation]
        SE[Secret Encryption]
    end
    
    subgraph "Data Security"
        DE[Data Encryption]
        AP[Access Permissions]
        AL[Audit Logging]
    end
    
    subgraph "Communication Security"
        TLS[TLS/SSL]
        AK[API Key Management]
        RT[Rate Throttling]
    end
    
    subgraph "System Security"
        PS[Process Sandboxing]
        FS[File System Permissions]
        RM[Resource Monitoring]
    end
```

### Security Controls

#### Input Security
- **Sanitization**: Remove dangerous characters and sequences
- **Validation**: Verify input format and constraints
- **Rate Limiting**: Prevent abuse through excessive requests

```python
class SecurityManager:
    def sanitize_input(self, user_input: str) -> str:
        """Remove potentially dangerous input"""
        
    def validate_api_request(self, request: dict) -> bool:
        """Validate API request structure"""
        
    def check_rate_limit(self, user_id: str) -> bool:
        """Check if user exceeds rate limits"""
```

## Performance Architecture

### Performance Optimization Strategy

```mermaid
graph TD
    subgraph "Async Architecture"
        AE[Async Event Loop]
        CP[Connection Pooling]
        NB[Non-blocking I/O]
    end
    
    subgraph "Caching Strategy"
        MC[Memory Cache]
        CC[Configuration Cache]
        RC[Response Cache]
    end
    
    subgraph "Resource Management"
        RM[Resource Monitoring]
        LC[Lifecycle Management]
        GC[Garbage Collection]
    end
    
    subgraph "Optimization Techniques"
        LP[Lazy Loading]
        BP[Batch Processing]
        PR[Priority Queuing]
    end
```

### Performance Metrics

#### System Performance
- **Render FPS**: Target 20 FPS for smooth terminal updates
- **Response Time**: < 100ms for user interactions
- **Memory Usage**: < 100MB for typical operations
- **CPU Usage**: < 5% during idle state

#### AI Performance
- **API Response Time**: Track and optimize AI API calls
- **Context Processing**: Efficient context management
- **Tool Orchestration**: Minimize overhead in multi-tool operations

## Scalability Architecture

### Horizontal Scaling Considerations

```mermaid
graph TB
    subgraph "Current Single-Process"
        CP[Core Process]
        EP[Event Processing]
        PS[Plugin System]
    end
    
    subgraph "Future Multi-Process"
        MP1[Main Process]
        WP1[Worker Process 1]
        WP2[Worker Process 2]
        WP3[Worker Process 3]
    end
    
    subgraph "Inter-Process Communication"
        MQ[Message Queue]
        SC[Shared Cache]
        EV[Event Distribution]
    end
    
    CP --> MP1
    MP1 --> WP1
    MP1 --> WP2
    MP1 --> WP3
    WP1 --> MQ
    WP2 --> MQ
    WP3 --> MQ
    MQ --> SC
    SC --> EV
```

### Plugin Scaling
- **Isolated Plugin Processes**: Run plugins in separate processes
- **Resource Limits**: Enforce memory and CPU limits per plugin
- **Health Monitoring**: Monitor plugin health and restart if needed
- **Dynamic Loading**: Load plugins on-demand to save resources

## Integration Architecture

### External System Integration

```mermaid
graph LR
    subgraph "Chat App Core"
        CA[Chat App]
        PS[Plugin System]
        EB[Event Bus]
    end
    
    subgraph "AI Services"
        CC[Claude Code]
        CAI[Claude AI]
        OAI[OpenAI]
        GC[GitHub Copilot]
    end
    
    subgraph "Development Tools"
        GH[GitHub]
        VS[VS Code]
        JB[JetBrains]
    end
    
    subgraph "Infrastructure"
        DB[(Database)]
        FS[(File System)]
        OS[Operating System]
    end
    
    CA --> PS
    PS --> EB
    EB --> CC
    EB --> CAI
    EB --> OAI
    EB --> GC
    CA --> GH
    CA --> VS
    CA --> JB
    PS --> DB
    CA --> FS
    CA --> OS
```

## Deployment Architecture

### Local Development Deployment

```mermaid
graph TB
    subgraph "Development Environment"
        DE[Developer Machine]
        PY[Python 3.11+]
        VE[Virtual Environment]
        GI[Git Repository]
    end
    
    subgraph "Runtime Components"
        CA[Chat App Process]
        DB[(SQLite Database)]
        CF[Config Files]
        LF[Log Files]
    end
    
    subgraph "External Dependencies"
        AI[AI APIs]
        GH[GitHub APIs]
        INT[Internet Connection]
    end
    
    DE --> PY
    PY --> VE
    VE --> CA
    CA --> DB
    CA --> CF
    CA --> LF
    CA --> AI
    CA --> GH
    AI --> INT
    GH --> INT
```

### Future Cloud Deployment

```mermaid
graph TB
    subgraph "Cloud Infrastructure"
        LB[Load Balancer]
        AS[App Servers]
        DB[(Managed Database)]
        FS[(File Storage)]
    end
    
    subgraph "Container Platform"
        K8[Kubernetes]
        DC[Docker Containers]
        SR[Service Registry]
    end
    
    subgraph "Monitoring & Logging"
        MO[Monitoring]
        LG[Logging]
        AL[Alerting]
    end
    
    LB --> AS
    AS --> DB
    AS --> FS
    K8 --> DC
    DC --> SR
    AS --> MO
    AS --> LG
    MO --> AL
```

## Quality Architecture

### Quality Assurance Framework

```mermaid
graph TD
    subgraph "Testing Strategy"
        UT[Unit Tests]
        IT[Integration Tests]
        E2E[End-to-End Tests]
        PT[Performance Tests]
    end
    
    subgraph "Code Quality"
        CR[Code Review]
        SCA[Static Code Analysis]
        CC[Code Coverage]
        TD[Technical Debt Tracking]
    end
    
    subgraph "Monitoring"
        APM[Application Performance Monitoring]
        EM[Error Monitoring]
        UM[Usage Monitoring]
        SM[Security Monitoring]
    end
    
    subgraph "Continuous Improvement"
        ME[Metrics Collection]
        AN[Analysis]
        IM[Improvement Planning]
        EX[Execution]
    end
    
    UT --> CR
    IT --> SCA
    E2E --> CC
    PT --> TD
    APM --> ME
    EM --> AN
    UM --> IM
    SM --> EX
```

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*This architecture overview provides a comprehensive understanding of the Chat App system design, component relationships, and architectural patterns that enable effective AI-assisted development.*