feat: Add multi-provider support for OpenRouter, Gemini, and enhanced provider management

[somdipto]

Multi-Provider Support for ByteBot

Fixes #144

🎯 Overview

This PR implements comprehensive multi-provider support for ByteBot, allowing users to seamlessly switch between different AI providers (OpenRouter, Gemini, Anthropic, OpenAI) based on their needs, costs, and preferences.

✨ Features Added

🏗️ Core Architecture

• BaseProvider Interface: Unified contract for all AI providers with methods for send(), stream(), healthCheck(), and getAvailableModels()
• Provider Manager Service: Central service for managing provider discovery, status, and switching
• Dynamic Provider Detection: Automatic enable/disable based on API key configuration

🤖 New Provider Implementation

• OpenRouter Service: Complete implementation supporting multiple models through unified API
• OpenAI-Compatible Integration: Seamless integration with OpenRouter's API
• Model Enumeration: Support for various models (Claude, GPT, Llama, Mistral, etc.)

🔧 Enhanced Existing Providers

• Anthropic Service: Added BaseProvider interface implementation
• OpenAI Service: Enhanced with health checks and model listing
• Google Gemini Service: Improved with BaseProvider compliance

🌐 API Endpoints

New REST endpoints for provider management:

• GET /providers - List all providers with status
• GET /providers/enabled - Get only enabled providers
• GET /providers/models - Get all available models
• GET /providers/:id/models - Get provider-specific models
• POST /providers/:id/test - Test provider connectivity
• POST /providers/refresh - Refresh provider status

🔑 Enhanced API Key Management

• Support for multiple provider API keys
• Secure key storage and validation
• Provider-specific key testing
• Environment variable configuration

🧪 Testing

• Unit Tests: Comprehensive test coverage for all services
• Integration Tests: End-to-end API endpoint testing
• Provider-Specific Tests: OpenRouter service validation
• Mock Testing: Proper mocking of external API calls

📁 Files Added/Modified

New Files:

packages/bytebot-agent/src/
├── providers/
│   ├── base-provider.interface.ts
│   ├── provider-manager.service.ts
│   ├── providers.controller.ts
│   ├── providers.module.ts
│   └── tests/
├── openrouter/
│   ├── openrouter.service.ts
│   ├── openrouter.constants.ts
│   ├── openrouter.tools.ts
│   ├── openrouter.module.ts
│   └── tests/
├── api-keys/
│   ├── api-keys.service.ts
│   ├── api-keys.controller.ts
│   └── dto/
└── docs/multi-provider-support.md

Modified Files:

• Enhanced existing provider services (Anthropic, OpenAI, Google)
• Updated agent processor and modules
• Extended type definitions

🚀 Usage

Environment Configuration

ANTHROPIC_API_KEY=your_anthropic_key
OPENAI_API_KEY=your_openai_key
GEMINI_API_KEY=your_gemini_key
OPENROUTER_API_KEY=your_openrouter_key

API Usage Examples

# Get available providers
curl http://localhost:3000/providers

# Get all models
curl http://localhost:3000/providers/models

# Test provider connectivity
curl -X POST http://localhost:3000/providers/openrouter/test

🎯 Benefits

• Cost Optimization: Switch providers based on pricing
• Reliability: Graceful fallback when providers are unavailable
• Future-Proof: Easy addition of new providers
• Unified Interface: Consistent API across all providers
• Health Monitoring: Built-in provider status monitoring

🔄 Backward Compatibility

• ✅ Fully backward compatible with existing installations
• ✅ No breaking changes to existing APIs
• ✅ Existing provider configurations continue to work
• ✅ Optional feature - providers work independently

📋 Testing Instructions

1. Install dependencies: npm install
2. Build project: npm run build
3. Run tests: npm test
4. Test specific providers: npm test -- --testPathPattern="providers"

📚 Documentation

Complete documentation added in docs/multi-provider-support.md including:

• Architecture overview
• Implementation guide
• Usage examples
• Provider addition instructions

✅ Issue Requirements Fulfilled

• Define a base provider interface ✅
• Build adapters for OpenRouter and Gemini ✅
• Make config/UI switch to select provider ✅
• Add tests (unit & integration) ✅
• Update documentation and usage examples ✅

🔍 Review Notes

• All changes follow existing code patterns and conventions
• Comprehensive error handling and logging
• Production-ready with proper TypeScript types
• Follows NestJS best practices
• Maintains security standards for API key handling

Ready for review and testing! 🚀