# Customization for Developers

## 🎯 Overview

This guide helps developers customize ALwrity for specific needs. You'll learn how to extend functionality, create custom components, integrate with external systems, and tailor the platform to your requirements.

## 🚀 What You'll Achieve

### Custom Development
- **Feature Extensions**: Extend existing features and functionality
- **Custom Components**: Create custom UI components and interfaces
- **API Extensions**: Extend API endpoints and functionality
- **Integration Development**: Develop custom integrations

### Platform Tailoring
- **Brand Customization**: Customize branding and user interface
- **Workflow Customization**: Customize workflows and processes
- **Business Logic**: Implement custom business logic
- **Data Models**: Extend data models and schemas

## 📋 Customization Framework

### Extension Points
**Backend Extensions**:
1. **API Endpoints**: Add custom API endpoints
2. **Services**: Extend or create new services
3. **Models**: Add custom data models
4. **Middleware**: Create custom middleware

**Frontend Extensions**:
- **Components**: Create custom React components
- **Hooks**: Develop custom React hooks
- **Pages**: Add new pages and routes
- **Themes**: Create custom themes and styling

### Customization Levels
**Configuration Customization**:
- **Environment Variables**: Customize via environment settings
- **Feature Flags**: Enable/disable features via configuration
- **UI Themes**: Customize appearance and branding
- **Workflow Settings**: Adjust workflow parameters

**Code Customization**:
- **Plugin Architecture**: Develop plugins for extensibility
- **API Extensions**: Extend API functionality
- **Custom Services**: Implement custom business logic
- **Database Extensions**: Add custom database schemas

## 🛠️ Backend Customization

### API Extensions
**Custom Endpoints**:
```python
# backend/api/custom_endpoints.py
from fastapi import APIRouter

router = APIRouter(prefix="/api/custom", tags=["custom"])

@router.get("/my-feature")
async def my_custom_feature():
    """Custom feature endpoint."""
    return {"message": "Custom feature response"}
```

**Service Extensions**:
```python
# backend/services/custom_service.py
class CustomService:
    async def process_custom_data(self, data: dict) -> dict:
        """Process custom data."""
        # Custom business logic here
        return processed_data
```

### Model Extensions
**Custom Models**:
```python
# backend/models/custom_models.py
from sqlalchemy import Column, Integer, String, DateTime
from backend.models.base import Base

class CustomData(Base):
    __tablename__ = "custom_data"
    
    id = Column(Integer, primary_key=True)
    name = Column(String(255), nullable=False)
    created_at = Column(DateTime, default=datetime.utcnow)
```

**Pydantic Models**:
```python
# backend/models/custom_requests.py
from pydantic import BaseModel

class CustomRequest(BaseModel):
    field1: str
    field2: int
    field3: Optional[str] = None

class CustomResponse(BaseModel):
    result: str
    data: dict
```

### Middleware Customization
**Custom Middleware**:
```python
# backend/middleware/custom_middleware.py
from fastapi import Request
from starlette.middleware.base import BaseHTTPMiddleware

class CustomMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request: Request, call_next):
        # Custom middleware logic
        response = await call_next(request)
        return response
```

## 🎯 Frontend Customization

### Component Development
**Custom Components**:
```typescript
// frontend/src/components/Custom/CustomComponent.tsx
import React from 'react';

interface CustomComponentProps {
  title: string;
  data: any[];
  onAction: (item: any) => void;
}

export const CustomComponent: React.FC<CustomComponentProps> = ({
  title,
  data,
  onAction
}) => {
  return (
    <div className="custom-component">
      <h2>{title}</h2>
      {data.map((item, index) => (
        <div key={index} onClick={() => onAction(item)}>
          {item.name}
        </div>
      ))}
    </div>
  );
};
```

**Custom Hooks**:
```typescript
// frontend/src/hooks/useCustomData.ts
import { useState, useEffect } from 'react';

export const useCustomData = (endpoint: string) => {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await fetch(`/api/custom/${endpoint}`);
        const result = await response.json();
        setData(result);
      } catch (err) {
        setError(err);
      } finally {
        setLoading(false);
      }
    };

    fetchData();
  }, [endpoint]);

  return { data, loading, error };
};
```

### Theme Customization
**Custom Themes**:
```css
/* frontend/src/themes/custom-theme.css */
:root {
  --primary-color: #your-brand-color;
  --secondary-color: #your-secondary-color;
  --accent-color: #your-accent-color;
  --background-color: #your-background-color;
  --text-color: #your-text-color;
}

.custom-theme {
  --primary-color: var(--primary-color);
  --secondary-color: var(--secondary-color);
  /* Additional custom variables */
}
```

**Styled Components**:
```typescript
// frontend/src/components/Custom/StyledComponents.tsx
import styled from 'styled-components';

export const CustomContainer = styled.div`
  background-color: var(--primary-color);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
`;

export const CustomButton = styled.button`
  background-color: var(--accent-color);
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  cursor: pointer;
  
  &:hover {
    opacity: 0.8;
  }
`;
```

## 📊 Integration Development

### External API Integration
**API Client**:
```python
# backend/services/external_api_client.py
import httpx
from typing import Dict, Any

class ExternalAPIClient:
    def __init__(self, api_key: str, base_url: str):
        self.api_key = api_key
        self.base_url = base_url
        self.client = httpx.AsyncClient()

    async def get_data(self, endpoint: str) -> Dict[str, Any]:
        """Get data from external API."""
        headers = {"Authorization": f"Bearer {self.api_key}"}
        response = await self.client.get(
            f"{self.base_url}/{endpoint}",
            headers=headers
        )
        return response.json()
```

**Integration Service**:
```python
# backend/services/integration_service.py
class IntegrationService:
    def __init__(self):
        self.external_client = ExternalAPIClient(
            api_key=settings.EXTERNAL_API_KEY,
            base_url=settings.EXTERNAL_API_URL
        )

    async def sync_data(self) -> Dict[str, Any]:
        """Sync data with external service."""
        external_data = await self.external_client.get_data("sync")
        # Process and store data
        return {"status": "synced", "data": external_data}
```

### Database Integration
**Custom Database Operations**:
```python
# backend/services/custom_db_service.py
from sqlalchemy.orm import Session
from backend.models.custom_models import CustomData

class CustomDBService:
    def __init__(self, db: Session):
        self.db = db

    async def create_custom_data(self, data: dict) -> CustomData:
        """Create custom data record."""
        custom_data = CustomData(**data)
        self.db.add(custom_data)
        self.db.commit()
        return custom_data

    async def get_custom_data(self, data_id: int) -> CustomData:
        """Get custom data by ID."""
        return self.db.query(CustomData).filter(
            CustomData.id == data_id
        ).first()
```

## 🎯 Advanced Customization

### Plugin Architecture
**Plugin Interface**:
```python
# backend/plugins/base_plugin.py
from abc import ABC, abstractmethod
from typing import Dict, Any

class BasePlugin(ABC):
    @abstractmethod
    def initialize(self, config: Dict[str, Any]) -> None:
        """Initialize plugin with configuration."""
        pass

    @abstractmethod
    def execute(self, data: Dict[str, Any]) -> Dict[str, Any]:
        """Execute plugin logic."""
        pass

    @abstractmethod
    def cleanup(self) -> None:
        """Cleanup plugin resources."""
        pass
```

**Plugin Implementation**:
```python
# backend/plugins/custom_plugin.py
from backend.plugins.base_plugin import BasePlugin

class CustomPlugin(BasePlugin):
    def initialize(self, config: Dict[str, Any]) -> None:
        """Initialize custom plugin."""
        self.config = config
        # Initialize plugin resources

    def execute(self, data: Dict[str, Any]) -> Dict[str, Any]:
        """Execute custom plugin logic."""
        # Process data according to plugin logic
        return {"processed": data, "plugin": "custom"}

    def cleanup(self) -> None:
        """Cleanup plugin resources."""
        # Clean up resources
```

### Custom Workflows
**Workflow Engine**:
```python
# backend/services/workflow_engine.py
from typing import List, Dict, Any

class WorkflowStep:
    def __init__(self, name: str, function: callable):
        self.name = name
        self.function = function

class WorkflowEngine:
    def __init__(self):
        self.steps: List[WorkflowStep] = []

    def add_step(self, step: WorkflowStep):
        """Add workflow step."""
        self.steps.append(step)

    async def execute_workflow(self, data: Dict[str, Any]) -> Dict[str, Any]:
        """Execute workflow with data."""
        result = data
        for step in self.steps:
            result = await step.function(result)
        return result
```

## 🛠️ Configuration Management

### Environment Configuration
**Custom Environment Variables**:
```python
# backend/config/custom_config.py
from pydantic import BaseSettings

class CustomSettings(BaseSettings):
    custom_api_key: str
    custom_api_url: str
    custom_feature_enabled: bool = False
    custom_timeout: int = 30

    class Config:
        env_file = ".env"
```

**Feature Flags**:
```python
# backend/services/feature_flags.py
class FeatureFlags:
    def __init__(self):
        self.flags = {
            "custom_feature": os.getenv("CUSTOM_FEATURE_ENABLED", "false").lower() == "true",
            "advanced_analytics": os.getenv("ADVANCED_ANALYTICS_ENABLED", "false").lower() == "true",
        }

    def is_enabled(self, feature: str) -> bool:
        """Check if feature is enabled."""
        return self.flags.get(feature, False)
```

### Frontend Configuration
**Runtime Configuration**:
```typescript
// frontend/src/config/runtime.ts
interface RuntimeConfig {
  customApiUrl: string;
  customFeatureEnabled: boolean;
  customTimeout: number;
}

export const getRuntimeConfig = (): RuntimeConfig => ({
  customApiUrl: process.env.REACT_APP_CUSTOM_API_URL || '/api/custom',
  customFeatureEnabled: process.env.REACT_APP_CUSTOM_FEATURE_ENABLED === 'true',
  customTimeout: parseInt(process.env.REACT_APP_CUSTOM_TIMEOUT || '30000'),
});
```

## 📈 Testing Customizations

### Backend Testing
**Custom Test Cases**:
```python
# tests/test_custom_features.py
import pytest
from fastapi.testclient import TestClient

def test_custom_endpoint(client: TestClient):
    """Test custom endpoint."""
    response = client.get("/api/custom/my-feature")
    assert response.status_code == 200
    assert response.json()["message"] == "Custom feature response"

def test_custom_service():
    """Test custom service."""
    service = CustomService()
    result = await service.process_custom_data({"test": "data"})
    assert result is not None
```

### Frontend Testing
**Custom Component Testing**:
```typescript
// src/components/Custom/__tests__/CustomComponent.test.tsx
import { render, screen, fireEvent } from '@testing-library/react';
import { CustomComponent } from '../CustomComponent';

test('renders custom component', () => {
  const mockData = [{ name: 'Test Item 1' }, { name: 'Test Item 2' }];
  const mockAction = jest.fn();

  render(
    <CustomComponent 
      title="Test Title" 
      data={mockData} 
      onAction={mockAction} 
    />
  );

  expect(screen.getByText('Test Title')).toBeInTheDocument();
  expect(screen.getByText('Test Item 1')).toBeInTheDocument();
});
```

## 🎯 Deployment Customizations

### Custom Docker Configuration
**Custom Dockerfile**:
```dockerfile
# Dockerfile.custom
FROM python:3.9-slim

# Install custom dependencies
RUN pip install custom-package

# Copy custom configuration
COPY custom_config.py /app/
COPY custom_plugins/ /app/plugins/

# Set custom environment
ENV CUSTOM_FEATURE_ENABLED=true
```

**Custom Docker Compose**:
```yaml
# docker-compose.custom.yml
services:
  alwrity-custom:
    build:
      context: .
      dockerfile: Dockerfile.custom
    environment:
      - CUSTOM_API_KEY=${CUSTOM_API_KEY}
      - CUSTOM_FEATURE_ENABLED=true
    volumes:
      - ./custom_plugins:/app/plugins
```

## 🎯 Best Practices

### Customization Best Practices
**Code Organization**:
1. **Separation of Concerns**: Keep custom code separate from core code
2. **Modular Design**: Design customizations as modular components
3. **Documentation**: Document all customizations thoroughly
4. **Testing**: Test all customizations thoroughly
5. **Version Control**: Use proper version control for custom code

**Performance Considerations**:
- **Optimization**: Optimize custom code for performance
- **Caching**: Implement caching for custom features
- **Resource Management**: Manage resources efficiently
- **Monitoring**: Monitor custom feature performance

## 🎯 Next Steps

### Immediate Actions (This Week)
1. **Requirements Analysis**: Define customization requirements
2. **Architecture Planning**: Plan customization architecture
3. **Development Setup**: Set up development environment for customization
4. **Proof of Concept**: Create proof of concept for key customizations

### Short-Term Planning (This Month)
1. **Core Customizations**: Implement core customization features
2. **Testing**: Develop comprehensive tests for customizations
3. **Documentation**: Document customization process and usage
4. **Integration**: Integrate customizations with existing system

### Long-Term Strategy (Next Quarter)
1. **Advanced Features**: Implement advanced customization features
2. **Plugin System**: Develop comprehensive plugin system
3. **Community**: Share customizations with community
4. **Maintenance**: Establish maintenance and update procedures

---

*Ready to customize ALwrity? Start with [Codebase Exploration](codebase-exploration.md) to understand the architecture before implementing your customizations!*
