7.7 KiB
Feature Specification: Fitbit-Garmin Local Sync
Feature Branch: 001-fitbit-garmin-sync
Created: December 22, 2025
Status: Implemented
Input: User description: "Fitbit-Garmin Local Sync application to synchronize health and fitness data between Fitbit and Garmin Connect platforms"
User Scenarios & Testing (mandatory)
User Story 1 - Sync Weight Data from Fitbit to Garmin (Priority: P1)
A user with both Fitbit and Garmin devices wants to transfer their weight data from Fitbit to Garmin in a secure, automated way. The user accesses the web interface, triggers the sync process, and the system safely transfers their weight history from Fitbit to Garmin without duplicating entries.
Why this priority: This is the foundational functionality that provides immediate value to users with both platforms, solving a common data silo problem.
Independent Test: Can be fully tested by configuring Fitbit and Garmin credentials, triggering a weight sync, and verifying weight entries appear in Garmin without duplication. Delivers core value of unified health data.
Acceptance Scenarios:
- Given user has configured Fitbit and Garmin credentials, When user clicks "Sync Weight" button, Then system fetches weight history from Fitbit and uploads to Garmin, tracking synced entries to prevent duplicates
- Given user has previously synced weight data, When user runs sync again, Then system only uploads new weight entries that haven't been synced before
User Story 2 - Archive Activity Files from Garmin (Priority: P2)
A user wants to preserve their historical activity data from Garmin by downloading original files (.fit, .gpx, .tcx) and storing them in the database. The user accesses the web interface, triggers the activity archiving process, and the system downloads activity files and stores them in the PostgreSQL database with proper organization. The system handles multi-factor authentication flows required by Garmin.
Why this priority: Provides backup and archival capabilities that users value for data preservation and analysis, building on the core sync functionality.
Independent Test: Can be tested by triggering the activity archiving process and verifying original activity files are downloaded and stored in the database with proper organization.
Acceptance Scenarios:
- Given user has configured Garmin credentials, When user clicks "Archive Activities" button, Then system fetches activity list and downloads original files stored in database
- Given user has previously downloaded activity files, When user runs archiving again, Then system only downloads activities that haven't been downloaded before
User Story 3 - Download Comprehensive Health Metrics from Garmin (Priority: P3)
A user wants to store all available health metrics from Garmin for local analysis and backup. The user accesses the web interface, triggers the metrics download process, and the system retrieves a comprehensive range of health metrics (steps, calories, heart rate, sleep, etc.) and stores them in a local database.
Why this priority: Provides complete health data backup and analysis capabilities, extending beyond basic sync to comprehensive data management.
Independent Test: Can be tested by triggering the metrics download and verifying that various types of health metrics are stored in the database with proper timestamps and types.
Acceptance Scenarios:
- Given user has configured Garmin credentials, When user triggers health metrics download, Then system retrieves and stores comprehensive health metrics in local database
- Given user wants to query health metrics, When user makes API call to metrics endpoint, Then system returns requested metrics filtered by date range and type
Edge Cases
- What happens when API rate limits are exceeded during sync operations?
- How does system handle authentication token expiration during long-running sync processes?
- What occurs when local storage is insufficient for activity file downloads?
- How does system handle duplicate data detection when timestamps are slightly different?
Requirements (mandatory)
Functional Requirements
- FR-001: System MUST authenticate with both Fitbit (OAuth 2.0) and Garmin Connect (username/password with garth library) APIs
- FR-002: System MUST securely store API credentials, tokens, and configuration in a PostgreSQL database
- FR-003: System MUST synchronize weight data from Fitbit to Garmin, including historical records
- FR-004: System MUST track synced entries to prevent duplicate uploads
- FR-005: System MUST download original activity files (.fit, .gpx, .tcx) from Garmin and store them in the PostgreSQL database
- FR-006: System MUST download comprehensive health metrics from Garmin including daily summaries, heart rate, sleep data, stress levels, and body composition
- FR-007: System MUST provide a web-based user interface with status dashboard and sync controls
- FR-008: System MUST provide API endpoints for triggering sync operations and querying data
- FR-009: System MUST implement robust error handling and retry mechanisms for API failures
- FR-010: System MUST support both global (garmin.com) and China (garmin.cn) Garmin domains
- FR-011: System MUST automatically refresh OAuth tokens when they expire
- FR-012: System MUST log all sync operations with timestamps, status, and results
- FR-013: System MUST allow users to trigger sync operations through UI buttons
- FR-014: System MUST support querying health metrics by date range, type, and other criteria
- FR-015: System MUST implement ACID-compliant data storage for consistency and integrity
- FR-016: System MUST handle multi-factor authentication flows for Garmin Connect when required by user's account settings
- FR-017: System MUST provide current authentication status and token expiration information in the web UI
- FR-018: System MUST securely store and manage Garmin OAuth tokens and session information
Key Entities
- Configuration: Application settings including API credentials, sync settings, and database connection parameters
- Weight Record: Individual weight entries with timestamps, values, and sync status with unique identifiers to prevent duplicate processing
- Activity Metadata: Information about Garmin activities including download status, file content stored in database, and activity details
- Health Metric: Comprehensive health data including type, timestamp, values across categories (steps, calories, heart rate, sleep, etc.)
- Sync Log: Operation logs with timestamps, status, and results for monitoring and troubleshooting
- API Token: OAuth tokens for Fitbit and Garmin with expiration tracking and refresh mechanisms
- Authentication Status: Current authentication state for both Fitbit and Garmin, including token expiration times and last login information
Success Criteria (mandatory)
Measurable Outcomes
- SC-001: Users can successfully sync weight data from Fitbit to Garmin with 95% success rate for valid entries
- SC-002: System can download and archive 1000 activity files without errors within 2 hours
- SC-003: System can retrieve and store comprehensive health metrics for a full year of data within 4 hours
- SC-004: All sensitive data (credentials, tokens, health stats) remains stored locally without external cloud services
- SC-005: User can complete setup and authentication for both Fitbit and Garmin within 10 minutes
- SC-006: System prevents duplicate data uploads/downloads with 99.9% accuracy
- SC-007: Web interface loads and responds to user actions within 3 seconds under normal conditions