From 63bbe5c2ab6cedae19ffa8dc7e99d44e30147471 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Mon, 2 Nov 2026 01:21:57 +0000
Subject: [PATCH] Fix sunrise wait windows on DST change days

daily_sunrise_video.sh and sunrise-audio-capture.sh added wall-clock
seconds-since-midnight to a midnight epoch, which is 3600s off on the two
days a year the clocks change. Resolve targets with date -d "today HH:MM:SS"
instead. sunrise.py now builds local midnight with tz.localize().

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013wi3ZRpfenCe2TRwT4JFMG
---
 daily_sunrise_video.sh   | 14 ++++++++------
 sunrise-audio-capture.sh |  9 +++++----
 sunrise.py               |  4 +++-
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/daily_sunrise_video.sh b/daily_sunrise_video.sh
index eeaa7bd..d51dc18 100755
--- a/daily_sunrise_video.sh
+++ b/daily_sunrise_video.sh
@@ -65,14 +65,16 @@ if ! $TEST_MODE; then
     start_sec=$((sunrise_sec - SUNRISE_PRE_MIN * 60))
     end_sec=$((sunrise_sec + SUNRISE_POST_MIN * 60))
     echo "Window: $((start_sec/3600)):$(printf '%02d' $(((start_sec%3600)/60))) → $((end_sec/3600)):$(printf '%02d' $(((end_sec%3600)/60)))"
-    midnight=$(date -d "today 00:00:00" +%s)
-    now_day_sec=$(( $(date +%s) - midnight ))
-    if [ "$now_day_sec" -lt "$end_sec" ]; then
-        wait_sec=$(( end_sec - now_day_sec + 30 ))
-        echo "Waiting ${wait_sec}s for capture window to finish (ends $(date -d "@$(( midnight + end_sec ))" '+%H:%M:%S'))..."
+    # Resolve wall-clock targets through `date -d` instead of adding seconds-since-
+    # midnight to a midnight epoch: on a DST day (23h/25h) the two differ by 3600s.
+    end_epoch=$(date -d "today $(printf '%02d:%02d:%02d' $((end_sec/3600)) $(((end_sec%3600)/60)) $((end_sec%60)))" +%s)
+    now_epoch=$(date +%s)
+    if [ "$now_epoch" -lt "$end_epoch" ]; then
+        wait_sec=$(( end_epoch - now_epoch + 30 ))
+        echo "Waiting ${wait_sec}s for capture window to finish (ends $(date -d "@$end_epoch" '+%H:%M:%S'))..."
         sleep "$wait_sec"
     else
-        echo "Capture window already closed at $(date -d "@$(( midnight + end_sec ))" '+%H:%M:%S') — processing available images"
+        echo "Capture window already closed at $(date -d "@$end_epoch" '+%H:%M:%S') — processing available images"
     fi
 fi
 
diff --git a/sunrise-audio-capture.sh b/sunrise-audio-capture.sh
index bb539a2..aef28fe 100755
--- a/sunrise-audio-capture.sh
+++ b/sunrise-audio-capture.sh
@@ -54,12 +54,13 @@ record_dur_sec=$SUNRISE_TARGET_SECS
 
 echo "Audio window: ${half_pre}s before → ${half_post}s after sunrise (${record_dur_sec}s total)"
 
-midnight=$(date -d "today 00:00:00" +%s)
-now_day_sec=$(( $(date +%s) - midnight ))
-wait_sec=$(( record_start_sec - now_day_sec ))
+# Resolve the wall-clock start via `date -d` (not midnight epoch + seconds):
+# on a DST day (23h/25h) those differ by 3600s.
+start_epoch=$(date -d "today $(printf '%02d:%02d:%02d' $((record_start_sec/3600)) $(((record_start_sec%3600)/60)) $((record_start_sec%60)))" +%s)
+wait_sec=$(( start_epoch - $(date +%s) ))
 
 if [ "$wait_sec" -gt 0 ]; then
-    echo "Waiting ${wait_sec}s until audio window ($(date -d "@$(( midnight + record_start_sec ))" '+%H:%M:%S'))..."
+    echo "Waiting ${wait_sec}s until audio window ($(date -d "@$start_epoch" '+%H:%M:%S'))..."
     sleep "$wait_sec"
 fi
 
diff --git a/sunrise.py b/sunrise.py
index bb04a99..33898a6 100755
--- a/sunrise.py
+++ b/sunrise.py
@@ -58,7 +58,9 @@ tz        = pytz.timezone(conf['TIMEZONE'])
 # This bracket is timezone-correct and handles any UTC offset, including large
 # positive offsets (UTC+12/+14) where local midnight falls on the previous UTC day.
 now_local     = datetime.now(tz)
-midnight_local = now_local.replace(hour=0, minute=0, second=0, microsecond=0)
+# tz.localize (not .replace) so the UTC offset is re-resolved for midnight —
+# on a DST-change day now_local's offset differs from midnight's.
+midnight_local = tz.localize(datetime(now_local.year, now_local.month, now_local.day))
 t0_utc = midnight_local.astimezone(timezone.utc)
 t1_utc = t0_utc + timedelta(hours=25)   # 25 h covers any timezone's full day