From 69e424519d523aaae9641464c45e62cb509c4dc9 Mon Sep 17 00:00:00 2001
From: Ferdinand Urban <urban@team-tradeo.de>
Date: Tue, 28 Apr 2026 11:03:05 +0000
Subject: [PATCH] feat(excel): group entries by date, join names with ' & '

---
 js/excel.js          | 29 ++++++++++++++-----
 package.json         |  2 +-
 tests/excel.test.mjs | 67 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 8 deletions(-)
 create mode 100644 tests/excel.test.mjs

diff --git a/js/excel.js b/js/excel.js
index 36f6e78..d93c2b0 100644
--- a/js/excel.js
+++ b/js/excel.js
@@ -8,16 +8,31 @@ export function readEmployeeNames(arrayBuffer) {
     .filter(name => name.length > 0);
 }
 
+// Pure helper: returns { names: [...], dates: [...] } columns for a schedule.
+// Multiple employees per date are joined alphabetically with " & ".
+export function buildScheduleColumns(assignments, employees) {
+  const nameById = Object.fromEntries(employees.map(e => [e.id, e.name]));
+  const byDate = new Map();
+  for (const a of assignments) {
+    if (!byDate.has(a.date)) byDate.set(a.date, []);
+    byDate.get(a.date).push(nameById[a.employeeId] ?? '');
+  }
+  const sortedDates = [...byDate.keys()].sort();
+  const names = sortedDates.map(d =>
+    byDate.get(d).slice().sort((x, y) => x.localeCompare(y, 'de')).join(' & ')
+  );
+  const dates = sortedDates.map(d => {
+    const [y, m, day] = d.split('-');
+    return day + '.' + m + '.' + y;
+  });
+  return { names, dates };
+}
+
 // Exports schedule as xlsx blob
-// assignments: [{ date: "2026-04-01", employeeId }]
+// assignments: [{ date: "2026-04-01", employeeId }] — multiple entries per date allowed
 // employees: [{ id, name }]
 export function exportSchedule(assignments, employees) {
-  const nameById = Object.fromEntries(employees.map(e => [e.id, e.name]));
-  const names = assignments.map(a => nameById[a.employeeId] ?? '');
-  const dates = assignments.map(a => {
-    const [y, m, d] = a.date.split('-');
-    return d + '.' + m + '.' + y;
-  });
+  const { names, dates } = buildScheduleColumns(assignments, employees);
   const ws = XLSX.utils.aoa_to_sheet([names, dates]);
   const wb = XLSX.utils.book_new();
   XLSX.utils.book_append_sheet(wb, ws, 'Moderationsplan');
diff --git a/package.json b/package.json
index db770df..c4a0e0d 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,6 @@
   "type": "module",
   "scripts": {
     "start": "npx serve . -p 3001",
-    "test": "node tests/algorithm.test.mjs && node tests/data.test.mjs"
+    "test": "node tests/algorithm.test.mjs && node tests/data.test.mjs && node tests/excel.test.mjs"
   }
 }
diff --git a/tests/excel.test.mjs b/tests/excel.test.mjs
new file mode 100644
index 0000000..01c5806
--- /dev/null
+++ b/tests/excel.test.mjs
@@ -0,0 +1,67 @@
+import assert from 'node:assert/strict';
+import { buildScheduleColumns } from '../js/excel.js';
+
+const employees = [
+  { id: 'a1', name: 'Anna Müller' },
+  { id: 'b1', name: 'Bernd Schulz' },
+  { id: 'c1', name: 'Carla Weber' }
+];
+
+// Single employee per day
+{
+  const assignments = [
+    { date: '2026-04-01', employeeId: 'a1' },
+    { date: '2026-04-02', employeeId: 'b1' }
+  ];
+  const cols = buildScheduleColumns(assignments, employees);
+  assert.deepEqual(cols.names, ['Anna Müller', 'Bernd Schulz'], 'names per single-entry day');
+  assert.deepEqual(cols.dates, ['01.04.2026', '02.04.2026'], 'dates formatted DD.MM.YYYY');
+}
+
+// Two employees per day → joined with " & ", alphabetical
+{
+  const assignments = [
+    { date: '2026-04-01', employeeId: 'b1' },  // Bernd inserted first
+    { date: '2026-04-01', employeeId: 'a1' }   // Anna inserted second
+  ];
+  const cols = buildScheduleColumns(assignments, employees);
+  assert.equal(cols.names.length, 1, 'one column per date');
+  assert.equal(cols.names[0], 'Anna Müller & Bernd Schulz', 'names alphabetical, joined with " & "');
+  assert.equal(cols.dates[0], '01.04.2026', 'one date entry');
+}
+
+// Three employees per day
+{
+  const assignments = [
+    { date: '2026-04-01', employeeId: 'c1' },
+    { date: '2026-04-01', employeeId: 'a1' },
+    { date: '2026-04-01', employeeId: 'b1' }
+  ];
+  const cols = buildScheduleColumns(assignments, employees);
+  assert.equal(cols.names[0], 'Anna Müller & Bernd Schulz & Carla Weber', 'three names joined alphabetical');
+}
+
+// Multiple dates with multiple employees, dates ascending
+{
+  const assignments = [
+    { date: '2026-04-02', employeeId: 'a1' },
+    { date: '2026-04-01', employeeId: 'b1' },
+    { date: '2026-04-01', employeeId: 'a1' }
+  ];
+  const cols = buildScheduleColumns(assignments, employees);
+  assert.deepEqual(cols.dates, ['01.04.2026', '02.04.2026'], 'dates sorted ascending');
+  assert.deepEqual(cols.names, ['Anna Müller & Bernd Schulz', 'Anna Müller'], 'names per column in date order');
+}
+
+// Unknown employeeId: empty string slot, sorted with other names
+{
+  const assignments = [
+    { date: '2026-04-01', employeeId: 'a1' },
+    { date: '2026-04-01', employeeId: 'unknown' }
+  ];
+  const cols = buildScheduleColumns(assignments, employees);
+  // Empty-string sorts before 'Anna Müller'
+  assert.equal(cols.names[0], ' & Anna Müller', 'unknown employee → empty string in join');
+}
+
+console.log('All excel tests passed.');