From 5436315952eeb401f37cfac8878ece0d44ab824a Mon Sep 17 00:00:00 2001
From: Rob <rob.tranquillo@gmx.de>
Date: Tue, 21 Apr 2026 15:37:39 +0200
Subject: [PATCH] Add output filename generation and workbook save flow

---
 .github/copilot-tasks.md          | 10 +++---
 src/taetigkeitsnachweis/writer.py | 53 +++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/.github/copilot-tasks.md b/.github/copilot-tasks.md
index a43e8ed..40f5652 100644
--- a/.github/copilot-tasks.md
+++ b/.github/copilot-tasks.md
@@ -71,10 +71,10 @@ Projekt vollstaendig umsetzen: aus PS_PW.xlsx und Stellenbeschreibungen.xlsx mon
 	- [x] Template-Workbook laden
 	- [x] Sheet pro aktiver Zuordnung klonen
 	- [x] Inhalte assignment-spezifisch in Zielzellen schreiben
-- [ ] T12: Dateinamen und Speichern
-	- [ ] Muster: `Taetigkeitsnachweis_YYYY_MM_Vorname_Nachname.xlsx`
-	- [ ] Pro Mitarbeiter genau eine Datei pro Monat erzeugen
-	- [ ] Bei mehreren Zuordnungen: mehrere Sheets in derselben Datei
+- [x] T12: Dateinamen und Speichern
+	- [x] Muster: `Taetigkeitsnachweis_YYYY_MM_Vorname_Nachname.xlsx`
+	- [x] Pro Mitarbeiter genau eine Datei pro Monat erzeugen
+	- [x] Bei mehreren Zuordnungen: mehrere Sheets in derselben Datei
 
 ## Phase 7 - CLI und Benutzerfluss
 - [ ] T13: CLI in `generate.py` implementieren
@@ -111,4 +111,4 @@ Projekt vollstaendig umsetzen: aus PS_PW.xlsx und Stellenbeschreibungen.xlsx mon
 8. T15 -> T16 -> T17
 
 ## Aktueller Startpunkt
-- [ ] Naechste aktive Aufgabe: T12 (Dateinamen und Speichern)
+- [ ] Naechste aktive Aufgabe: T13 (CLI in generate.py implementieren)
diff --git a/src/taetigkeitsnachweis/writer.py b/src/taetigkeitsnachweis/writer.py
index 9a6e24b..ebcd780 100644
--- a/src/taetigkeitsnachweis/writer.py
+++ b/src/taetigkeitsnachweis/writer.py
@@ -94,3 +94,56 @@ def build_employee_workbooks(
         workbooks[employee_name] = workbook
 
     return workbooks
+
+
+def build_output_filename(
+    filename_pattern: str,
+    employee_name: str,
+    report_year: int,
+    report_month: int,
+) -> str:
+    first_name, last_name = _split_name_for_filename(employee_name)
+    safe_first = first_name.replace(" ", "_")
+    safe_last = last_name.replace(" ", "_")
+    return filename_pattern.format(
+        year=report_year,
+        month=f"{report_month:02d}",
+        first_name=safe_first,
+        last_name=safe_last,
+    )
+
+
+def save_employee_workbooks(
+    config: dict[str, Any],
+    employee_workbooks: dict[str, Workbook],
+    report_month: int,
+    report_year: int,
+    project_root: Path,
+) -> list[Path]:
+    paths_cfg = config["paths"]
+    output_cfg = config["output"]
+    filename_pattern = output_cfg["filename_pattern"]
+
+    output_dir = project_root / paths_cfg["output_dir"]
+    output_dir.mkdir(parents=True, exist_ok=True)
+
+    saved_paths: list[Path] = []
+    used_names: set[str] = set()
+
+    for employee_name, workbook in employee_workbooks.items():
+        filename = build_output_filename(
+            filename_pattern=filename_pattern,
+            employee_name=employee_name,
+            report_year=report_year,
+            report_month=report_month,
+        )
+        if filename in used_names:
+            raise ValueError(f"Output filename collision detected: {filename}")
+
+        used_names.add(filename)
+        output_path = output_dir / filename
+        workbook.save(output_path)
+        workbook.close()
+        saved_paths.append(output_path)
+
+    return saved_paths