refactor: Spaltenaufteilung ueberlappender Termine aus WeeklyView herausloesen

Erster kleiner Schnitt aus Phase A des CodeScene-Auftrags: die Ueberlappungs-
Berechnung war ein rein funktionaler, aber verschachtelter Block mitten in der
Komponente. Sie liegt jetzt als layoutDaySegments/computeEventOverlapLayout in
src/lib/weekly/event-layout.ts und ist mit node:test abgedeckt (einzelner
Termin, Ueberschneidung, direkte Abfolge, drei gleichzeitige Termine,
Reihenfolgeunabhaengigkeit).

Kein sichtbares Verhalten geaendert; der Algorithmus ist unveraendert
uebernommen. WeeklyView.tsx: 9683 -> 9642 Zeilen.

v1.121.2

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "my-weekly-todo-list",
-  "version": "1.121.1",
+  "version": "1.121.2",
   "description": "A web-based weekly task management application that organizes to-dos and calendar events in a single, intuitive weekly view",
   "main": "index.js",
   "scripts": {

src/components/WeeklyView.tsx

@@ -108,6 +108,7 @@ import {
     stripHtml, DEFAULT_SOMEDAY_SLOT_COUNT, getSomedaySlotCount, invertColor,
 } from "@/lib/weekly/format";
 import { isAllDayEvent } from "@/lib/weekly/date-utils";
+import { computeEventOverlapLayout } from "@/lib/weekly/event-layout";
 
 // Types
 import UserMenu from "./UserMenu";
@@ -2655,53 +2656,11 @@ export default function WeeklyView() {
         [getEventsForDate, effectiveCellDuration],
     );
 
-    // Precompute overlap layout per day: { [segmentKey]: { column, totalColumns } }
-    const eventOverlapLayout = useMemo(() => {
-        const layout: Record<string, { column: number; totalColumns: number }> = {};
-        for (const daySegments of eventSegmentsByDay.values()) {
-            // Sort by start time, then by duration (longer first)
-            const segments = [...daySegments].sort((a, b) => {
-                const diff = new Date(a.startTime).getTime() - new Date(b.startTime).getTime();
-                if (diff !== 0) return diff;
-                return (new Date(b.endTime).getTime() - new Date(b.startTime).getTime()) -
-                       (new Date(a.endTime).getTime() - new Date(a.startTime).getTime());
-            });
-            // Greedy column assignment: first column whose last entry ended before this start
-            const columns: CalendarEventSegment[][] = [];
-            for (const segment of segments) {
-                const start = new Date(segment.startTime).getTime();
-                const free = columns.find(
-                    (col) => new Date(col[col.length - 1].endTime).getTime() <= start,
+    // Spaltenaufteilung ueberlappender Termine je Tag (siehe lib/weekly/event-layout).
+    const eventOverlapLayout = useMemo(
+        () => computeEventOverlapLayout(eventSegmentsByDay),
+        [eventSegmentsByDay],
     );
-                if (free) {
-                    free.push(segment);
-                } else {
-                    columns.push([segment]);
-                }
-            }
-            // Group width = number of columns that actually overlap this segment
-            for (const segment of segments) {
-                const start = new Date(segment.startTime).getTime();
-                const end = new Date(segment.endTime).getTime();
-                let overlappingCols = 0;
-                let segmentCol = 0;
-                columns.forEach((col, index) => {
-                    const overlaps = col.some(
-                        (other) =>
-                            new Date(other.startTime).getTime() < end &&
-                            new Date(other.endTime).getTime() > start,
-                    );
-                    if (overlaps) overlappingCols++;
-                    if (col.includes(segment)) segmentCol = index;
-                });
-                layout[segment.segmentKey] = {
-                    column: segmentCol,
-                    totalColumns: Math.max(overlappingCols, 1),
-                };
-            }
-        }
-        return layout;
-    }, [eventSegmentsByDay]);
 
     // Calculate event duration in pixels for proper height display
     const getEventDuration = (event: CalendarEvent): number => {

src/lib/weekly/event-layout.ts

@@ -0,0 +1,79 @@
+import type { CalendarEventSegment } from "@/lib/weekly/types";
+
+/**
+ * Spaltenaufteilung sich ueberlappender Termine im Tagesraster.
+ *
+ * Reine Funktionen ohne Komponenten-State und ohne Laufzeit-Importe, damit die
+ * Regeln mit node:test pruefbar bleiben — lagen bis v1.121.2 in WeeklyView.tsx.
+ */
+
+export interface EventColumnPlacement {
+    /** 0-basierte Spalte innerhalb der Ueberlappungsgruppe. */
+    column: number;
+    /** Breite der Gruppe in Spalten; mindestens 1. */
+    totalColumns: number;
+}
+
+const startMs = (segment: CalendarEventSegment): number =>
+    new Date(segment.startTime).getTime();
+const endMs = (segment: CalendarEventSegment): number =>
+    new Date(segment.endTime).getTime();
+
+/**
+ * Ordnet die Abschnitte eines Tages in Spalten an.
+ *
+ * Frueher Start zuerst, bei gleichem Start der laengere Termin. Jeder Abschnitt
+ * kommt in die erste Spalte, deren letzter Eintrag bereits beendet ist. Die
+ * Gruppenbreite ist die Anzahl der Spalten, die den Abschnitt zeitlich schneiden.
+ */
+export function layoutDaySegments(
+    daySegments: CalendarEventSegment[],
+): Record<string, EventColumnPlacement> {
+    const layout: Record<string, EventColumnPlacement> = {};
+
+    const segments = [...daySegments].sort((a, b) => {
+        const byStart = startMs(a) - startMs(b);
+        if (byStart !== 0) return byStart;
+        return endMs(b) - startMs(b) - (endMs(a) - startMs(a));
+    });
+
+    const columns: CalendarEventSegment[][] = [];
+    for (const segment of segments) {
+        const free = columns.find((col) => endMs(col[col.length - 1]) <= startMs(segment));
+        if (free) {
+            free.push(segment);
+        } else {
+            columns.push([segment]);
+        }
+    }
+
+    for (const segment of segments) {
+        const start = startMs(segment);
+        const end = endMs(segment);
+        let overlappingCols = 0;
+        let segmentCol = 0;
+        columns.forEach((col, index) => {
+            if (col.some((other) => startMs(other) < end && endMs(other) > start)) {
+                overlappingCols++;
+            }
+            if (col.includes(segment)) segmentCol = index;
+        });
+        layout[segment.segmentKey] = {
+            column: segmentCol,
+            totalColumns: Math.max(overlappingCols, 1),
+        };
+    }
+
+    return layout;
+}
+
+/** Spaltenaufteilung fuer alle Tage, gebuendelt nach segmentKey. */
+export function computeEventOverlapLayout(
+    segmentsByDay: Map<string, CalendarEventSegment[]>,
+): Record<string, EventColumnPlacement> {
+    const layout: Record<string, EventColumnPlacement> = {};
+    for (const daySegments of segmentsByDay.values()) {
+        Object.assign(layout, layoutDaySegments(daySegments));
+    }
+    return layout;
+}

tests/unit/event-layout.test.ts

@@ -0,0 +1,74 @@
+import { test, describe } from "node:test";
+import assert from "node:assert/strict";
+import { layoutDaySegments, computeEventOverlapLayout } from "../../src/lib/weekly/event-layout.ts";
+import type { CalendarEventSegment } from "../../src/lib/weekly/types.ts";
+
+/**
+ * Charakterisierungstests der Spaltenaufteilung im Tagesraster.
+ *
+ * Beobachtbares Verhalten: Termine, die sich zeitlich überschneiden, stehen
+ * nebeneinander statt übereinander; Termine, die sich nicht berühren, bekommen
+ * die volle Breite.
+ */
+
+const at = (h: number, min = 0) => new Date(2026, 8, 10, h, min, 0, 0).toISOString();
+
+const segment = (key: string, startHour: number, endHour: number): CalendarEventSegment => ({
+    id: key,
+    title: key,
+    startTime: at(startHour),
+    endTime: at(endHour),
+    source: "google",
+    segmentKey: key,
+    segmentIndex: 0,
+    segmentCount: 1,
+    continuesFromPreviousDay: false,
+    continuesOnNextDay: false,
+    sourceEvent: { id: key, title: key, startTime: at(startHour), endTime: at(endHour), source: "google" },
+});
+
+describe("layoutDaySegments", () => {
+    test("ein einzelner Termin nimmt die volle Breite ein", () => {
+        const layout = layoutDaySegments([segment("a", 9, 10)]);
+        assert.deepEqual(layout.a, { column: 0, totalColumns: 1 });
+    });
+
+    test("zwei überschneidende Termine teilen sich zwei Spalten", () => {
+        const layout = layoutDaySegments([segment("a", 9, 11), segment("b", 10, 12)]);
+        assert.equal(layout.a.totalColumns, 2);
+        assert.equal(layout.b.totalColumns, 2);
+        assert.notEqual(layout.a.column, layout.b.column);
+    });
+
+    test("aufeinanderfolgende Termine bekommen dieselbe Spalte und volle Breite", () => {
+        const layout = layoutDaySegments([segment("a", 9, 10), segment("b", 10, 11)]);
+        assert.deepEqual(layout.a, { column: 0, totalColumns: 1 });
+        assert.deepEqual(layout.b, { column: 0, totalColumns: 1 });
+    });
+
+    test("drei gleichzeitige Termine ergeben drei Spalten", () => {
+        const layout = layoutDaySegments([segment("a", 9, 12), segment("b", 9, 12), segment("c", 9, 12)]);
+        const columns = ["a", "b", "c"].map((k) => layout[k].column).sort();
+        assert.deepEqual(columns, [0, 1, 2]);
+        assert.equal(layout.a.totalColumns, 3);
+    });
+
+    test("die Reihenfolge der Eingabe ändert das Ergebnis nicht", () => {
+        const forward = layoutDaySegments([segment("a", 9, 11), segment("b", 10, 12)]);
+        const backward = layoutDaySegments([segment("b", 10, 12), segment("a", 9, 11)]);
+        assert.deepEqual(forward, backward);
+    });
+});
+
+describe("computeEventOverlapLayout", () => {
+    test("fasst mehrere Tage in einer Zuordnung zusammen", () => {
+        const layout = computeEventOverlapLayout(
+            new Map([
+                ["2026-09-10", [segment("a", 9, 11), segment("b", 10, 12)]],
+                ["2026-09-11", [segment("c", 9, 10)]],
+            ]),
+        );
+        assert.equal(layout.a.totalColumns, 2);
+        assert.equal(layout.c.totalColumns, 1);
+    });
+});