Update layout

days.js

@@ -36,9 +36,11 @@ function addDays(dateStr, n) {
 function localParts(date, tz) {
   // ponytail: no TZID means "floating" time per RFC 5545 - interpret in the
   // system's local zone (matches how node-ical encodes floating DATE values),
-  // not UTC.
+  // not UTC. A real tz (incl. "Etc/UTC" for Z-suffixed timestamps) is an
+  // absolute instant - always display it in Amsterdam, not whatever zone
+  // the source event happened to carry.
   const fmt = new Intl.DateTimeFormat('en-CA', {
-    ...(tz ? { timeZone: tz } : {}),
+    ...(tz ? { timeZone: 'Europe/Amsterdam' } : {}),
     year: 'numeric', month: '2-digit', day: '2-digit',
     hour: '2-digit', minute: '2-digit', hour12: false,
   });
@@ -58,9 +60,9 @@ function formatHour(hour) {
 }
 
 function segmentsForDay(dayStr, startLocal, lastDayStr, endLocal, isFullDay) {
-  if (isFullDay) return [0, 1, 2];
-  const dayStartHour = dayStr === startLocal.dateStr ? startLocal.hour : 0;
-  const dayEndHour = dayStr === lastDayStr ? endLocal.hour : 24;
+  const dayStartHour = isFullDay ? 0 : (dayStr === startLocal.dateStr ? startLocal.hour : 0);
+  const dayEndHour = isFullDay ? 24 : (dayStr === lastDayStr ? endLocal.hour : 24);
+  if (isFullDay) return { lit: [0, 1, 2], start: dayStartHour, end: dayEndHour };
   const lit = [];
   SEGMENT_RANGES.forEach(([segStart, segEnd], i) => {
     if (dayStartHour < segEnd && dayEndHour > segStart) lit.push(i);
@@ -69,7 +71,17 @@ function segmentsForDay(dayStr, startLocal, lastDayStr, endLocal, isFullDay) {
     const idx = SEGMENT_RANGES.findIndex(([, segEnd]) => dayStartHour < segEnd);
     lit.push(idx === -1 ? 2 : idx);
   }
-  return lit;
+  return { lit, start: dayStartHour, end: dayEndHour };
+}
+
+// two tagged events sharing a day overlap if their local-hour spans intersect
+function hasOverlap(intervals) {
+  for (let i = 0; i < intervals.length; i++) {
+    for (let j = i + 1; j < intervals.length; j++) {
+      if (intervals[i].start < intervals[j].end && intervals[j].start < intervals[i].end) return true;
+    }
+  }
+  return false;
 }
 
 function buildOverview(icsText, tagsConfig, rangeStartStr, rangeEndStr) {
@@ -79,7 +91,7 @@ function buildOverview(icsText, tagsConfig, rangeStartStr, rangeEndStr) {
   const days = {};
 
   const getDay = (dateStr) => {
-    if (!days[dateStr]) days[dateStr] = { segments: [null, null, null], events: [] };
+    if (!days[dateStr]) days[dateStr] = { segments: [null, null, null], events: [], taggedIntervals: [] };
     return days[dateStr];
   };
 
@@ -99,6 +111,8 @@ function buildOverview(icsText, tagsConfig, rangeStartStr, rangeEndStr) {
       const summary = inst.summary || '(untitled)';
       const colors = leadingEmojis(summary).map((e) => (tagsConfig[e] ? tagsConfig[e].color : UNKNOWN_EMOJI_COLOR));
       const color = colors.length === 2 ? colors : colors[0] || null;
+      // "nc" as a standalone word anywhere in the title marks a conflict as resolved
+      const noConflict = /\bnc\b/i.test(summary);
 
       const startLocal = localParts(inst.start, inst.start.tz);
       const endInstant = isFullDay
@@ -111,11 +125,12 @@ function buildOverview(icsText, tagsConfig, rangeStartStr, rangeEndStr) {
       while (true) {
         if (dayStr >= rangeStartStr && dayStr <= rangeEndStr) {
           const day = getDay(dayStr);
-          const lit = segmentsForDay(dayStr, startLocal, lastDayStr, endLocal, isFullDay);
+          const { lit, start, end } = segmentsForDay(dayStr, startLocal, lastDayStr, endLocal, isFullDay);
           for (const segIdx of lit) {
             if (color) day.segments[segIdx] = color;
             else if (!day.segments[segIdx]) day.segments[segIdx] = 'muted';
           }
+          if (color && !noConflict) day.taggedIntervals.push({ start, end });
           day.events.push({
             hour: dayStr === startLocal.dateStr ? startLocal.hour : 0,
             isFullDay,
@@ -133,7 +148,7 @@ function buildOverview(icsText, tagsConfig, rangeStartStr, rangeEndStr) {
     const lines = day.events
       .sort((a, b) => a.hour - b.hour)
       .map((e) => `${e.isFullDay ? 'All day' : formatHour(e.hour)} ${e.text}`);
-    result[dateStr] = { segments: day.segments, tooltip: lines.join('\n') };
+    result[dateStr] = { segments: day.segments, tooltip: lines.join('\n'), conflict: hasOverlap(day.taggedIntervals) };
   }
   return result;
 }