# V2 Architecture Implementation Roadmap

## 📋 Overview

This roadmap outlines the implementation plan for V2 pipeline architecture with the following key phases:

1. **V2 Basic Architecture** - Core virtual pipeline components
2. **Dynamic Connection System** - Runtime module connection
3. **V1/V2 Migration System** - Gradual switching mechanism
4. **ProviderComposite (3.5)** - Internalize compatibility into Provider with protocol guards, type-only providers
5. **Configuration & Validation** - Migration tools and validation
6. **Testing & Optimization** - Comprehensive testing and performance tuning

## 🚀 Phase 1: V2 Basic Architecture (3-4 days)

### 1.1 Core Module Registry Implementation
**Files**: `src/modules/pipeline/v2/core/module-registry.ts`

**Tasks**:
- [ ] Implement V2ModuleRegistry with factory pattern
- [ ] Add instance caching and lifecycle management
- [ ] Implement lazy loading and cleanup mechanisms
- [ ] Add module type validation and error handling

**Acceptance Criteria**:
- Module types can be registered and retrieved
- Instances are created on-demand with proper caching
- Memory management prevents leaks
- Comprehensive error handling and logging

### 1.2 Static Instance Pool Implementation
**Files**: `src/modules/pipeline/v2/core/static-instance-pool.ts`

**Tasks**:
- [ ] Implement StaticInstancePool for multi-configuration modules
- [ ] Add configuration hashing and deduplication
- [ ] Implement preload mechanism based on route analysis
- [ ] Add instance health monitoring and recycling

**Acceptance Criteria**:
- Multiple configurations per module type supported
- Same configurations share instances (deduplication)
- Preload works based on route table analysis
- Idle instances are properly cleaned up

### 1.3 Dynamic Router Implementation
**Files**: `src/modules/pipeline/v2/core/dynamic-router.ts`

**Tasks**:
- [ ] Implement DynamicRouter with request pattern matching
- [ ] Add route priority mechanisms (fail fast on unmatched routes)
- [ ] Implement module chain building logic
- [ ] Add request routing performance optimization

**Acceptance Criteria**:
- Requests are correctly routed based on patterns
- Route priorities are respected
- Fail fast on unmatched routes (no fallback)
- Performance meets benchmarks

### 1.4 Virtual Module Chain Implementation
**Files**: `src/modules/pipeline/v2/core/virtual-module-chain.ts`

**Tasks**:
- [ ] Implement VirtualModuleChain for temporary connections
- [ ] Add VirtualModuleConnection for lightweight linking
- [ ] Implement chain execution and cleanup
- [ ] Add connection state management

**Acceptance Criteria**:
- Module chains can be built and executed
- Connections are established and cleaned properly
- Chain execution follows module order
- Resources are properly released after execution

## 🔗 Phase 2: Dynamic Connection System (2-3 days)

### 2.1 Dynamic Connector Implementation
**Files**: `src/modules/pipeline/v2/core/dynamic-connector.ts`

**Tasks**:
- [ ] Implement DynamicConnector for runtime connections
- [ ] Add connection establishment and teardown
- [ ] Implement error handling and recovery
- [ ] Add connection monitoring and metrics

**Acceptance Criteria**:
- Dynamic connections are established on-demand
- Connections are properly torn down after execution
- Connection errors are handled gracefully
- Performance metrics are collected

### 2.2 Connection State Management
**Files**: `src/modules/pipeline/v2/core/module-connection.ts`

**Tasks**:
- [ ] Implement ModuleConnection and InstanceConnection
- [ ] Add connection health monitoring
- [ ] Implement connection lifecycle callbacks
- [ ] Add connection metadata and debugging support

**Acceptance Criteria**:
- Connection states are properly tracked
- Health monitoring works correctly
- Lifecycle callbacks fire appropriately
- Debugging information is available

### 2.3 Hybrid Router Implementation
**Files**: `src/modules/pipeline/v2/core/hybrid-router.ts`

**Tasks**:
- [ ] Implement HybridDynamicRouter with static instance integration
- [ ] Add configuration resolution with conditional selection (fail fast on unmatched conditions)
- [ ] Implement module chain building from static pool
- [ ] Add request processing with connection management

**Acceptance Criteria**:
- Static instances are properly utilized
- Configurations are resolved correctly
- Module chains use static instances efficiently
- Request processing maintains performance

## 🔄 Phase 3: V1/V2 Migration System (2-3 days)

### 3.1 V2 Pipeline Assembler Implementation
**Files**: `src/modules/pipeline/v2/config/v2-pipeline-assembler.ts`

**Tasks**:
- [ ] Implement V2PipelineAssembler with simplified logic
- [ ] Add configuration validation and instance verification
- [ ] Implement prerun route validation
- [ ] Add data flow simulation and validation

**Acceptance Criteria**:
- V2 configurations are properly validated
- Static instances are verified before use
- Prerun validation catches configuration issues
- Data flow simulation works correctly

### 3.2 V1 Configuration Migration
**Files**: `src/modules/pipeline/v2/config/v1-migrator.ts`

**Tasks**:
- [ ] Implement V1ToV2Migrator for automatic conversion
- [ ] Add route table conversion from V1 format
- [ ] Implement provider and compatibility config extraction
- [ ] Add migration report generation

**Acceptance Criteria**:
- V1 configurations convert to V2 format correctly
- Route tables maintain V1 behavior in V2
- All required module types are extracted
- Migration reports are comprehensive

### 3.3 Mode Switch Implementation
**Files**: `src/core/v1-v2-switch.ts`

**Tasks**:
- [ ] Implement V1V2ModeSwitch with gradual switching
- [ ] Add compatibility validation before switch
- [ ] Implement traffic shifting mechanism
- [ ] Add manual rollback workflow and structured error logging

**Acceptance Criteria**:
- Modes can be switched without service interruption
- Compatibility validation prevents breaking changes
- Traffic can be shifted gradually
- No auto recovery; errors surface immediately with full context

## ⚙️ Phase 4: Configuration & Validation (1-2 days)

### 3.5 ProviderComposite & Type-only Providers
**Files**: `src/providers/core/composite/*`, `src/providers/core/runtime/*`, `docs/providers/*`

**Tasks**:
- [x] Internalize compatibility into Provider (ProviderComposite)
- [x] Add protocol guards and minimal shape checks (Fail Fast)
- [x] OpenAI-family aggregator (glm/lmstudio reuse; qwen safe path)
- [x] Factory protocol-first selection; normalize legacy providerType
- [x] Docs for design/testing/migration

**Acceptance Criteria**:
- Pipeline no longer needs explicit compatibility nodes
- Provider reads runtime metadata and enforces protocol guards
- SSE boundary respected (Provider→Host JSON only)
- Legacy configs run with warnings; brand handled via providerId/extensions

### 4.1 Configuration Schema Implementation
**Files**: `src/config/v2-config-schema.ts`

**Tasks**:
- [ ] Implement V2SystemConfig interface
- [ ] Add RouteDefinition and ModuleSpecification types
- [ ] Implement configuration validation rules
- [ ] Add schema documentation and examples

**Acceptance Criteria**:
- V2 configuration schema is complete
- Validation rules prevent invalid configurations
- Documentation is clear and comprehensive
- Examples cover common use cases

### 4.2 Configuration Library Implementation
**Files**: `src/config/v2-config-library.ts`

**Tasks**:
- [ ] Implement V2ConfigLibrary with predefined configurations
- [ ] Add provider, compatibility, and llmSwitch configs
- [ ] Implement configuration lookup and resolution
- [ ] Add configuration validation and defaults

**Acceptance Criteria**:
- Predefined configurations cover all providers
- Configuration lookup is efficient and reliable
- Validation catches configuration errors
- Default values are sensible

### 4.3 Prerun Validation Tools
**Files**: `src/tools/pre-run-validator.ts`

**Tasks**:
- [ ] Implement PreRunValidator for comprehensive testing
- [ ] Add route validation and data flow testing
- [ ] Implement performance validation
- [ ] Add detailed validation reporting

**Acceptance Criteria**:
- All routes can be validated before switching
- Data flow validation catches compatibility issues
- Performance validation meets requirements
- Validation reports are detailed and actionable

### 4.4 Warmup Manager Implementation
**Files**: `src/modules/pipeline/v2/core/warmup-manager.ts`

**Tasks**:
- [ ] Implement WarmupManager with intelligent preloading
- [ ] Add priority-based instance loading
- [ ] Implement instance validation and health checks
- [ ] Add warmup metrics and reporting

**Acceptance Criteria**:
- System startup is optimized with warmup
- Critical modules are loaded first
- Instance health is verified during warmup
- Warmup reports show startup status

## 🧪 Phase 5: Testing & Optimization (2-3 days)

### 5.1 Unit Testing
**Tasks**:
- [ ] Write unit tests for all V2 components
- [ ] Test configuration migration and validation
- [ ] Test dynamic connection and routing
- [ ] Test mode switching and compatibility

**Acceptance Criteria**:
- Unit test coverage > 90%
- All critical paths are tested
- Edge cases are handled correctly
- Tests run reliably in CI/CD

### 5.2 Integration Testing
**Tasks**:
- [ ] Test V1/V2 mode switching end-to-end
- [ ] Test configuration migration with real configs
- [ ] Test dynamic routing with various request types
- [ ] Test performance under load

**Acceptance Criteria**:
- Mode switching works without issues
- Configuration migration preserves behavior
- Dynamic routing performs correctly
- System meets performance requirements

### 5.3 Performance Testing
**Tasks**:
- [ ] Benchmark V1 vs V2 performance
- [ ] Test connection establishment overhead
- [ ] Measure memory usage with static pools
- [ ] Optimize bottlenecks identified in testing

**Acceptance Criteria**:
- V2 performance matches or exceeds V1
- Connection overhead is minimal
- Memory usage is efficient
- No performance regressions

### 5.4 Documentation and Examples
**Tasks**:
- [ ] Write comprehensive API documentation
- [ ] Create migration guide and examples
- [ ] Document configuration options
- [ ] Create troubleshooting guide

**Acceptance Criteria**:
- Documentation is complete and accurate
- Migration guide is easy to follow
- Examples cover common scenarios
- Troubleshooting guide is helpful

## 📊 Success Metrics

### Functional Metrics
- [ ] All V1 configurations successfully migrate to V2
- [ ] V2 routing produces identical results to V1
- [ ] Mode switching completes without service interruption
- [ ] Prerun validation catches all configuration issues

### Performance Metrics
- [ ] V2 response time ≤ V1 response time + 5ms
- [ ] Connection establishment time < 1ms
- [ ] Memory usage increase < 20%
- [ ] Warmup completion time < 30 seconds

### Quality Metrics
- [ ] Unit test coverage > 90%
- [ ] Integration test success rate = 100%
- [ ] Zero critical bugs in production
- [ ] Documentation completeness score > 95%
- [ ] No fallback logic anywhere in V2 codebase (Fail Fast validation)
- [ ] All tool processing goes through llmswitch-core only
- [ ] Configuration validation passes 100% (no hardcoded values)

### "No Fallback" Validation Checklist
- [ ] RouteTable has no fallbackStrategies
- [ ] ModuleSpecification has no fallback property
- [ ] HybridRouter throws errors on condition mismatch (no fallback resolution)
- [ ] Error handling logs and metrics only (no auto recovery)
- [ ] Mode switching requires explicit operator action
- [ ] All configuration uses env vars with defaults (no hardcoded URLs/keys)
- [ ] Instance pool validation rejects invalid configs immediately

## 🚨 Risk Mitigation

### Technical Risks
| Risk | Probability | Impact | Mitigation |
|------|-------------|--------|------------|
| Performance regression | Medium | High | Comprehensive benchmarking and optimization |
| Memory leaks | Low | High | Rigorous testing and monitoring |
| Configuration migration issues | Medium | High | Extensive validation and rollback mechanism |
| Dynamic connection failures | Low | Medium | Robust error handling and retry logic |

### Operational Risks
| Risk | Probability | Impact | Mitigation |
|------|-------------|--------|------------|
| Service disruption during switch | Low | High | Gradual switching with rollback capability |
| Compatibility issues | Medium | Medium | Extensive prerun validation and testing |
| Increased complexity | High | Low | Comprehensive documentation and training |

## 📅 Timeline

| Phase | Duration | Start Date | End Date | Dependencies |
|-------|----------|-------------|-----------|--------------|
| Phase 1: V2 Basic Architecture | 3-4 days | Day 1 | Day 4 | None |
| Phase 2: Dynamic Connection System | 2-3 days | Day 5 | Day 7 | Phase 1 |
| Phase 3: V1/V2 Migration System | 2-3 days | Day 8 | Day 10 | Phase 1, 2 |
| Phase 4: Configuration & Validation | 1-2 days | Day 11 | Day 12 | Phase 3 |
| Phase 5: Testing & Optimization | 2-3 days | Day 13 | Day 15 | All previous phases |

**Total Duration**: 15 days
**Buffer Time**: 3 days (for unforeseen issues)
**Target Completion**: 18 days

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*This roadmap serves as the implementation guide for V2 architecture. All phases should be completed sequentially with proper testing and validation at each stage.*