# Upstream Bose Service Simulation - Concept Overview

## Executive Summary

This document serves as the entry point for understanding the comprehensive plan to enhance the SoundTouch service with advanced state management capabilities, preparing for the eventual shutdown of Bose's upstream services while providing a superior local management experience.

## Project Objectives

### Primary Goal
Create a robust replacement for Bose's upstream services that can seamlessly handle the transition from cloud-dependent to fully autonomous operation while maintaining and improving upon the existing functionality.

### Key Outcomes
- **Zero-downtime transition** from Bose services to local management
- **Enhanced visibility** into device states, health, and system operations
- **Data preservation** during migrations with full rollback capabilities
- **Improved reliability** through local control and reduced external dependencies
- **Future-proof architecture** that can evolve beyond Bose's original design

## Architecture Vision

### Current State
The existing SoundTouch service provides:
- BMX service for TuneIn integration
- Marge service for account and device management
- Basic mirroring of upstream Bose endpoints
- File-based persistence for device data
- Migration support for device directory structures

### Enhanced State (This Project)
The enhanced system will add:
- **Comprehensive Account Management** with explicit creation and migration tracking
- **Device Lifecycle Management** with full state machine and event processing
- **Advanced Mirroring** with disparity detection and analysis
- **Dual-Source Data Management** supporting gradual migration strategies
- **Real-time Monitoring** with health checks and performance metrics
- **Text-based Storage** optimized for debugging and small hardware deployments

## Use Case Coverage

### Case 0: Account Management
- **Explicit Account Creation**: Accounts created through deliberate user action
- **Mirror-Enhanced Setup**: Use upstream data to enrich account creation
- **Passive Data Collection**: Record account information during normal operations

### Case 1a: Fresh Device Registration
- **Factory Reset Support**: Handle devices with no prior Bose association
- **Default Configuration**: Initialize devices with sensible presets and sources
- **Local-First Setup**: Complete registration without upstream dependencies

### Case 1b: Bose Account Migration
- **Data Preservation**: Maintain existing presets, recents, and sources
- **Gradual Migration**: Support partial migration while maintaining upstream compatibility
- **Rollback Capability**: Revert to Bose services if needed

### Case 2: Lifecycle and State Management
- **Real-time State Tracking**: Monitor device states and health continuously
- **Event-Driven Updates**: Process device events asynchronously
- **Disparity Detection**: Identify differences between local and upstream behavior
- **Comprehensive Logging**: Maintain detailed audit trails for troubleshooting

## Technical Approach

### Design Principles
1. **Text-First Storage**: Human-readable formats (JSON, XML, logs) for easy debugging
2. **Small Hardware Optimization**: Designed for Raspberry Pi Zero 2W deployments
3. **Mirror-First Strategy**: Keep upstream mirroring active until migration complete
4. **Event-Driven Architecture**: Asynchronous processing with comprehensive event tracking
5. **Backward Compatibility**: Seamless integration with existing installations

### Data Structure
```
data/
├── accounts/{account-id}/
│   ├── account.json              # Account metadata and settings
│   ├── account-events.log        # High-level account behavior tracking
│   ├── devices/{device-id}/
│   │   ├── lifecycle.json        # Device state and history
│   │   ├── info.xml             # Device information (existing)
│   │   ├── presets.xml          # Device presets (existing)
│   │   ├── recents.xml          # Recent plays (existing)
│   │   ├── sources.xml          # Configured sources (existing)
│   │   └── events.log           # Device event history
│   └── sessions/                # Recorded interaction sessions (existing)
└── system/
    ├── discovery.log            # Device discovery events
    └── migration.log           # Migration activities
```

### Development Targets
- **Simplicity**: Keep It Simple, Stupid (KISS) principle over optimization
- **Quality**: 100% test pass rate and lint-clean code for every change
- **Compatibility**: Zero breaking changes to existing functionality
- **Leveraging**: Reuse existing systems (interaction recording, parity detection)

## Implementation Strategy

### Phase 1: Foundation (2-3 weeks) - Small, Testable Steps
- Account management foundation with basic create/read operations
- Device lifecycle data models and simple state tracking
- Basic API endpoints with comprehensive testing
- Integration with existing datastore patterns

### Phase 2: Device Lifecycle (2-3 weeks) - Build on Existing Systems
- Event processing using existing WebSocket system
- Lifecycle integration with current discovery and migration
- Enhanced logging building on existing parity detection
- Simple state machine with thorough testing

### Phase 3: Enhanced Features (2-3 weeks) - Leverage Current Systems
- Improve existing parity mismatch detection with better categorization
- Smart data source routing with fallback mechanisms
- Basic monitoring using existing health check patterns
- Reuse interaction recording for request/response tracking

## Key Benefits

### For Users
- **Continuity**: Seamless operation when Bose services shut down
- **Reliability**: Local control reduces dependency on external services
- **Visibility**: Clear insight into device states and system health
- **Control**: Full management of device data and configurations

### For Developers
- **Simplicity**: KISS principle makes code easy to understand and maintain
- **Quality**: Comprehensive testing and linting ensures reliable code
- **Debugging**: Text-based storage enables easy troubleshooting
- **Testing**: Every change requires full test suite pass and lint compliance

### For Community
- **Open Source**: Transparent implementation available for community contributions
- **Standards**: Well-documented APIs and data formats
- **Collaboration**: Disparity detection helps improve implementation accuracy
- **Future-Proof**: Architecture designed to outlast original Bose services

### Technical Risks
- **Data Loss Prevention**: Atomic file operations and comprehensive testing
- **Complexity Creep**: KISS principle and simple-first approach
- **Compatibility Issues**: Extensive regression testing and existing system reuse
- **Code Quality**: Mandatory linting and test coverage for every change

### Operational Risks
- **Service Disruption**: Small, incremental changes with rollback capability
- **Testing Overhead**: Automated quality gates (`golangci-lint run --fix` + `go test ./...`)
- **Migration Challenges**: Leverage existing migration system and patterns
- **Maintenance Burden**: Simple, well-tested code is easier to maintain

### Technical
- All tests pass consistently (100%)
- Zero linting issues in codebase
- No breaking changes to existing functionality
- Code coverage maintained or improved

### Quality Assurance
- Every commit passes `golangci-lint run --fix`
- Every milestone passes `go test ./...`
- Integration tests verify existing functionality
- Simple, maintainable code that follows Go idioms

## Documentation Structure

This concept is detailed across several documents:

- **[upstream-service-simulation.md](./upstream-service-simulation.md)**: Complete architectural concept with detailed use cases and implementation guidelines
- **[implementation-roadmap.md](./implementation-roadmap.md)**: Detailed project phases, milestones, and delivery timeline
- **[technical-specification.md](./technical-specification.md)**: Comprehensive technical details including APIs, data models, and performance requirements

## Getting Started

1. **Review the Concept**: Read through the main concept document to understand the full scope
2. **Examine Technical Details**: Review the technical specification for implementation details
3. **Follow the Roadmap**: Use the implementation roadmap for project planning and execution
4. **Integration Planning**: Consider how the enhanced features will integrate with existing deployments

## Next Steps

1. **Stakeholder Review**: Gather feedback on the concept and approach
2. **Technical Validation**: Prototype key components to validate technical assumptions
3. **Resource Planning**: Allocate development resources for the three-phase implementation
4. **Community Engagement**: Share plans with the community for feedback and contributions

This enhanced state management system represents a significant evolution of the SoundTouch service, transforming it from a basic replacement into a comprehensive, future-proof device management platform that can serve users well beyond the Bose service shutdown timeline.
