# Clock Bug Fix, NTP Auto-Sync, and Sleep Persistence

**Date**: 2026-02-17

## Task Description

Three clock-related improvements:
1. Fix SetTimeActivity immediately dismissing when opened
2. Add automatic NTP time sync on WiFi connection
3. Verify time persistence across deep sleep modes

## Changes Made

### 1. Bug Fix: SetTimeActivity immediate dismiss (`src/activities/settings/SetTimeActivity.cpp`)
- **Root cause**: `loop()` used `wasReleased()` for Back, Confirm, Left, and Right buttons. The parent `SettingsActivity` enters this subactivity on a `wasPressed()` event, so the button release from the original press immediately triggered the exit path.
- **Fix**: Changed all four `wasReleased()` calls to `wasPressed()`, matching the pattern used by all other subactivities (e.g., `LanguageSelectActivity`).

### 2. Shared NTP Utility (`src/util/TimeSync.h`, `src/util/TimeSync.cpp`)
- Created `TimeSync` namespace with three functions:
  - `startNtpSync()` -- non-blocking: configures and starts SNTP service
  - `waitForNtpSync(int timeoutMs = 5000)` -- blocking: starts SNTP and polls until sync completes or timeout
  - `stopNtpSync()` -- stops the SNTP service

### 3. NTP on WiFi Connection (`src/activities/network/WifiSelectionActivity.cpp`)
- Added `#include "util/TimeSync.h"` and call to `TimeSync::startNtpSync()` in `checkConnectionStatus()` right after `WL_CONNECTED` is detected. This is non-blocking so it doesn't delay the UI flow.

### 4. KOReaderSync refactor (`src/activities/reader/KOReaderSyncActivity.cpp`)
- Removed the local `syncTimeWithNTP()` anonymous namespace function and `#include <esp_sntp.h>`
- Replaced both call sites with `TimeSync::waitForNtpSync()` (blocking, since KOReader needs accurate time for API requests)
- Added `#include "util/TimeSync.h"`

### 5. Boot time debug log (`src/main.cpp`)
- Added `#include <ctime>` and a debug log in `setup()` that prints the current RTC time on boot (or "not set" if epoch). This helps verify time persistence across deep sleep during testing.

## Sleep Persistence Notes

- ESP32-C3's default ESP-IDF config uses both RTC and high-resolution timers for timekeeping
- The RTC timer continues during deep sleep, so `time()` / `gettimeofday()` return correct wall-clock time after wake (with drift from the internal ~150kHz RC oscillator)
- Time does NOT survive a full power-on reset (RTC timer resets)
- NTP auto-sync on WiFi connection handles drift correction

## Build Verification

- `pio run -e mod` -- SUCCESS (RAM: 31.0%, Flash: 78.8%)

## Follow-up Items

- Test on hardware: set time manually, sleep, wake, verify time in serial log
- Test NTP: connect to WiFi from Settings, verify time updates automatically
- Consider adding `TimeSync::stopNtpSync()` call when WiFi is disconnected (currently SNTP just stops getting responses, which is harmless)