From f0698acd596f7725fc3cff9d51be81c047a01bbb Mon Sep 17 00:00:00 2001
From: Edward Betts <edward@4angle.com>
Date: Thu, 26 Feb 2026 15:31:13 +0000
Subject: [PATCH] Base trip timezone differences on trip dates and remove live
 local-time column

---
 templates/trip_page.html | 19 ----------------
 web_view.py              | 48 +++++++++++++++++++++++++++++++---------
 2 files changed, 38 insertions(+), 29 deletions(-)

diff --git a/templates/trip_page.html b/templates/trip_page.html
index 86f4064..b32346d 100644
--- a/templates/trip_page.html
+++ b/templates/trip_page.html
@@ -108,7 +108,6 @@
               <th>Destination</th>
               <th>Timezone</th>
               <th>Difference from UK</th>
-              <th>Current local time</th>
             </tr>
           </thead>
           <tbody>
@@ -117,7 +116,6 @@
               <td>{{ item.destination_label }}</td>
               <td>{{ item.timezone or "Unknown" }}</td>
               <td class="destination-offset">{{ item.offset_display }}</td>
-              <td class="destination-time" {% if item.timezone %}data-timezone="{{ item.timezone }}"{% endif %}>{{ item.current_time or "Unknown" }}</td>
             </tr>
           {% endfor %}
           </tbody>
@@ -490,22 +488,5 @@ var routes = {{ routes | tojson }};
 
 build_map("map", coordinates, routes);
 
-function updateDestinationTimes() {
-  for (const el of document.querySelectorAll(".destination-time[data-timezone]")) {
-    const tz = el.dataset.timezone;
-    el.textContent = new Intl.DateTimeFormat("en-GB", {
-      timeZone: tz,
-      weekday: "short",
-      hour: "2-digit",
-      minute: "2-digit",
-      second: "2-digit",
-      hour12: false
-    }).format(new Date());
-  }
-}
-
-updateDestinationTimes();
-setInterval(updateDestinationTimes, 1000);
-
 </script>
 {% endblock %}
diff --git a/web_view.py b/web_view.py
index b6afc9a..ea2d5c8 100755
--- a/web_view.py
+++ b/web_view.py
@@ -790,6 +790,40 @@ def _format_offset_from_uk(offset_minutes: int) -> str:
     return f"{sign}{hours:02d}:{mins:02d} vs UK"
 
 
+def _trip_offset_minutes(
+    trip_start: date, trip_end: date, destination_timezone: str
+) -> list[int]:
+    """Unique UTC offset differences vs UK across the trip date range."""
+    destination_tz = ZoneInfo(destination_timezone)
+    uk_timezone = ZoneInfo("Europe/London")
+    current = trip_start
+    offsets: set[int] = set()
+
+    while current <= trip_end:
+        instant = datetime(
+            current.year, current.month, current.day, 12, tzinfo=timezone.utc
+        )
+        destination_offset = instant.astimezone(destination_tz).utcoffset()
+        uk_offset = instant.astimezone(uk_timezone).utcoffset()
+        if destination_offset is not None and uk_offset is not None:
+            offsets.add(int((destination_offset - uk_offset).total_seconds() // 60))
+        current += timedelta(days=1)
+
+    return sorted(offsets)
+
+
+def _format_trip_offset_display(offsets: list[int]) -> str:
+    """Format trip-range offsets; include variation if DST changes during trip."""
+    if not offsets:
+        return "Timezone unknown"
+    if len(offsets) == 1:
+        return _format_offset_from_uk(offsets[0])
+    return (
+        "Varies during trip: "
+        f"{_format_offset_from_uk(offsets[0])} to {_format_offset_from_uk(offsets[-1])}"
+    )
+
+
 def _timezone_from_coordinates(latitude: float, longitude: float) -> str | None:
     """Resolve IANA timezone name from coordinates."""
     timezone_finder = _get_timezone_finder()
@@ -853,8 +887,8 @@ def get_destination_timezones(trip: Trip) -> list[StrDict]:
             if candidate:
                 per_location[key].append(candidate)
 
-    home_now = datetime.now(ZoneInfo("Europe/London"))
     destination_times: list[StrDict] = []
+    trip_end = trip.end or trip.start
 
     for location, country in trip.locations():
         country_code = country.alpha_2.lower()
@@ -881,15 +915,10 @@ def get_destination_timezones(trip: Trip) -> list[StrDict]:
                 timezone_name = country_timezones[0]
 
         offset_display = "Timezone unknown"
-        current_time = None
         if timezone_name:
-            dest_now = datetime.now(ZoneInfo(timezone_name))
-            dest_offset = dest_now.utcoffset()
-            home_offset = home_now.utcoffset()
-            if dest_offset is not None and home_offset is not None:
-                offset_minutes = int((dest_offset - home_offset).total_seconds() // 60)
-                offset_display = _format_offset_from_uk(offset_minutes)
-            current_time = dest_now.strftime("%a %H:%M:%S")
+            offset_display = _format_trip_offset_display(
+                _trip_offset_minutes(trip.start, trip_end, timezone_name)
+            )
 
         destination_times.append(
             {
@@ -898,7 +927,6 @@ def get_destination_timezones(trip: Trip) -> list[StrDict]:
                 "country_flag": country.flag,
                 "timezone": timezone_name,
                 "offset_display": offset_display,
-                "current_time": current_time,
             }
         )