Add event preview with two-step download flow

web/app.py

@@ -11,7 +11,7 @@ import os
 import secrets
 
 from fastapi import Depends, FastAPI, File, Form, HTTPException, Request, UploadFile, status
-from fastapi.responses import FileResponse, HTMLResponse
+from fastapi.responses import FileResponse, HTMLResponse, JSONResponse
 from fastapi.security import HTTPBasic, HTTPBasicCredentials
 from fastapi.templating import Jinja2Templates
 from starlette.background import BackgroundTask
@@ -55,6 +55,58 @@ def index(request: Request, _: None = Depends(require_auth)):
     )
 
 
+@app.post("/preview")
+async def preview_pdf(
+    file: UploadFile = File(...),
+    _: None = Depends(require_auth),
+):
+    filename = file.filename or "dienstplan.pdf"
+    if not filename.lower().endswith(".pdf"):
+        return JSONResponse(
+            {"error": "Bitte eine PDF-Datei hochladen."},
+            status_code=400,
+        )
+
+    data = await file.read()
+    if not data:
+        return JSONResponse(
+            {"error": "Die Datei ist leer."},
+            status_code=400,
+        )
+
+    with tempfile.TemporaryDirectory(prefix="pdf_to_ics_web_preview_") as temp_dir:
+        temp_dir_path = Path(temp_dir)
+        pdf_path = temp_dir_path / "upload.pdf"
+        pdf_path.write_bytes(data)
+
+        dienstplan = extract_dienstplan_data(str(pdf_path))
+        if not dienstplan.get("events"):
+            return JSONResponse(
+                {"error": "Keine Dienstplan-Events in der PDF gefunden."},
+                status_code=422,
+            )
+
+        events_preview = []
+        for event in dienstplan["events"]:
+            events_preview.append({
+                "date": event["date"].strftime("%d.%m.%Y") if event["date"] else "",
+                "service": event["service"] or "—",
+                "time": f"{event['start_time']}-{event['end_time']}" if event["start_time"] and event["end_time"] else "—",
+            })
+
+        return JSONResponse({
+            "success": True,
+            "filename": filename,
+            "metadata": {
+                "name": f"{dienstplan.get('vorname', '')} {dienstplan.get('name', '')}".strip(),
+                "personalnummer": dienstplan.get("personalnummer", "—"),
+                "betriebshof": dienstplan.get("betriebshof", "—"),
+                "count": len(dienstplan["events"]),
+            },
+            "events": events_preview,
+        })
+
+
 @app.post("/convert")
 async def convert_pdf(
     request: Request,