Soon fixing timeone in wakeup plot

plan.md

@@ -1,17 +1,13 @@
-# Plan: Fix Timezone issues in WakeupPlot
+# Plan: Fix Wakeup Plot Timezone Display
+
+## Status: COMPLETED
 
 ## Problem
-`WakeupPlot.tsx` uses an incorrect manual calculation for timezone offsets and a dubious `isLikelyOffset` heuristic. This causes incorrect time displays (e.g., subtracting the offset instead of adding it).
+`WakeupPlot.tsx` shows incorrect wakeup times (e.g., showing 01:00 instead of 05:00 when input is 03:00 UTC in Stockholm). This was caused by sending a local reference time to the backend, which then calculated a delta relative to that time being treated as UTC.
 
-## Goal
-Align `WakeupPlot.tsx` with `BedtimePlot.tsx` by using the existing `getLocalOffsetFromReference` utility to correctly apply client-side timezone adjustments.
+## Solution
+1. **Frontend API Fix**: Modified `fetchWakeSleepTimes` in `frontend/src/api/client.ts` to convert the local `wakeup_ref` and `bedtime_ref` HH:MM strings into UTC HH:MM strings before sending them to the backend.
+2. **Frontend Component Fix**: Updated `WakeupPlot.tsx` and `BedtimePlot.tsx` to use the returned `wakeup_minutes`/`bedtime_minutes` (which is now a correctly calculated timezone-invariant delta) directly as the offset from reference, instead of attempting to re-adjust it using local timezone offsets.
 
-## Steps
-1. **Modify `frontend/src/components/stats/WakeupPlot.tsx`**:
-   - Remove the `isLikelyOffset` logic and manual offset calculations.
-   - Use `getLocalOffsetFromReference(day.wakeup_minutes, wakeup_ref)` to calculate the correct local offset.
-2. **Verify**:
-   - Ensure the component renders correctly with the new logic.
-
-## Files to change
-- `frontend/src/components/stats/WakeupPlot.tsx`
+## Verification
+Verified with Playwright test in `Europe/Stockholm` timezone: 03:00 UTC input correctly displays as 05:00.