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Build Log — January 21, 2026

Build Log — January 21, 2026

Context / Focus for Today

Major focus on Garmin integration stability - fixing OAuth state handling, authentication issues, and adding a date range picker for activity imports. Also improved AI chat, training plan persistence, and various UX refinements.

Things I Got Done Today

Garmin Date Range Import Modal

New Feature: Custom Date Range Picker

  • Added date range picker modal for Garmin activity import (136 lines):
    • Modal dialog matching Strava sync modal design
    • Custom start/end date selection instead of hardcoded 90-day default
    • "Replace existing workouts" checkbox option
    • Integrated with existing sync stream API
  • Updated Header and TrainingCalendarApp to support renamed prop
  • Retry button now opens the import modal for better UX
  • Removed duplicate sync spinner (toast already provides feedback)

Garmin OAuth Fixes

State Parameter Handling

  • Fixed OAuth state corruption by Garmin (59 lines):
    • Switched from base64url encoding to simpler dot-separated format
    • Format: userId.timestamp.nonce using only URL-safe characters
    • Maintains CSRF protection via nonce and expiry validation
    • Backward compatible with legacy formats
  • Added debug logging for state decode failures:
    • Logs raw state preview and URL encoding indicators
    • Handles double-URL-encoded state from OAuth providers
    • Handles space-to-plus conversion

Authentication Fixes

  • Fixed Bearer token auth in SyncMenu Garmin disconnect:
    • Was incorrectly passing userId as query param
    • Now properly uses Bearer token authentication
  • Fixed supabase.auth.getUser() token handling:
    • Global headers don't work server-side
    • Must pass token directly as parameter
  • Use shared Supabase client in GarminDisconnectButton:
    • Singleton client has access to existing auth session

Environment Variable Fixes

  • Read Supabase env vars at request time in APIs:
    • Fixes "supabaseKey is required" in serverless environments
    • Module caching can occur before env vars are available
  • Support both SUPABASE_SECRET_KEY and SERVICE_ROLE_KEY:
    • Fallback pattern for backwards compatibility

Other Garmin Improvements

  • Handle non-array response from Garmin permissions API:
    • API may return permissions as array or object
    • Prevents "expected JSON array" errors during OAuth
  • Diagnostic logging for activity import:
    • Increased webhook query limit from 2000 to 5000
    • Log webhook fetch results (total vs fetched)
    • Log date ranges and Pull API token status
  • Increased OAuth timeout from 10 to 30 minutes for slow connections

Training Plans

Database Persistence Fix

  • Save training plans to database when loading from catalog:
    • PlanLoadWizard now calls /api/plans/generate to persist
    • Previously plans were generated client-side but never saved
    • Added auth token handling and error display
  • Correct GeneratedPlan type in PlanLoadWizard fallback

AI Coach Improvements

Duplicate Context Fix

  • Prevent duplicate context footer in AI chat responses:
    • Strip context footer from messages before sending to AI
    • Prevents footer from being in chat history
    • Server adds fresh footer to each response

UX Improvements

Sync Menu Refinements

  • Standardize Garmin icons in Sync menu:
    • Use garmin-connect-icon.png consistently
    • Removed unused Power icon import
  • Rename menu items for clarity:
    • "Sync" → "Import Activities from Garmin"
    • "Bulk Delete from Garmin" → "Bulk Delete FS workouts from Garmin"

Activity Stats Modal

  • Show activity stats modal for any external source:
    • Previously only for Garmin/Strava specifically
    • Now shows for any external_source except "ai"
    • Supports future integrations

Settings

  • Renamed "Pace Zones" to "Training Zones" in settings dropdown

In Progress

  • Garmin OAuth stability (major fixes complete, monitoring)
  • Activity import improvements (date picker complete)
  • Sync menu UX refinements (icons and naming complete)

Targets for Tomorrow

  1. Monitor Garmin OAuth — verify state format fix resolves callback issues
  2. Test date range import — ensure custom ranges work correctly
  3. Training plan persistence — verify plans save reliably from catalog
  4. Error handling — continue improving diagnostic logging

Notes / Observations

  • Garmin OAuth state corruption was the root cause of callback failures
  • Simpler dot-separated format avoids base64url issues with Garmin
  • Serverless env var timing is tricky - must read at request time
  • Date range picker gives users control over activity imports
  • Training plans weren't persisting - significant bug fix
  • AI chat context footer was duplicating on each message
  • Consistent icon usage improves visual coherence in menus
  • External source handling now future-proofed for new integrations

Momentum Score: 9 / 10

Highly productive day focused on Garmin integration stability. Fixed critical OAuth state corruption issue by switching to dot-separated format. Resolved multiple authentication bugs (Bearer tokens, Supabase client, env vars). Added user-requested date range picker for activity imports. Fixed training plan persistence bug - plans now save to database. Improved AI chat by preventing duplicate context footers. Many UX refinements to Sync menu icons and labels. Strong progress on reliability and user experience.