Amazon Business API integration replacing browser automation

- Add amazon_api.py with Reconciliation + Document API client
- OAuth flow with manual code exchange for local installations
- Dual mode: API (recommended) or Browser automation (fallback)
- New settings: amazon_app_id, amazon_client_id, amazon_client_secret, amazon_refresh_token
- Platform UI with mode switcher, API credential fields, OAuth button
- Scheduler supports both API and browser modes
- README with full Amazon API setup guide
- httpx added for async HTTP requests

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/main.py

@@ -31,6 +31,12 @@ from app.amazon_processor import (
     close_interactive_login as amazon_close_interactive,
     is_interactive_login_active as amazon_login_active,
 )
+from app.amazon_api import (
+    get_oauth_authorize_url,
+    exchange_auth_code,
+    check_api_configured,
+    process_amazon_api,
+)
 
 logging.basicConfig(
     level=getattr(logging, os.environ.get("LOG_LEVEL", "INFO").upper(), logging.INFO),
@@ -388,6 +394,10 @@ async def api_amazon_settings(request: Request):
         "amazon_email": body.get("amazon_email", ""),
         "amazon_password": body.get("amazon_password") or current.get("amazon_password", ""),
         "amazon_since_date": body.get("amazon_since_date", ""),
+        "amazon_mode": body.get("amazon_mode", "browser"),
+        "amazon_app_id": body.get("amazon_app_id", ""),
+        "amazon_client_id": body.get("amazon_client_id", ""),
+        "amazon_client_secret": body.get("amazon_client_secret") or current.get("amazon_client_secret", ""),
     }
     await save_settings(data)
     return JSONResponse({"success": True})
@@ -395,9 +405,110 @@ async def api_amazon_settings(request: Request):
 
 @app.get("/api/amazon-status")
 async def api_amazon_status():
-    valid = await amazon_check_session()
-    login_active = amazon_login_active()
-    return JSONResponse({"session_valid": valid, "login_active": login_active})
+    settings = await get_settings()
+    mode = settings.get("amazon_mode", "browser")
+
+    if mode == "api":
+        api_status = await check_api_configured()
+        return JSONResponse({
+            "mode": "api",
+            "session_valid": api_status.get("authorized", False),
+            "login_active": False,
+            "api_configured": api_status.get("configured", False),
+            "api_authorized": api_status.get("authorized", False),
+        })
+    else:
+        valid = await amazon_check_session()
+        login_active = amazon_login_active()
+        return JSONResponse({
+            "mode": "browser",
+            "session_valid": valid,
+            "login_active": login_active,
+        })
+
+
+def _get_oauth_redirect_uri(request: Request) -> str:
+    """Get OAuth redirect URI from env var or request."""
+    base = os.environ.get("OAUTH_REDIRECT_BASE", "").rstrip("/")
+    if not base:
+        base = str(request.base_url).rstrip("/")
+    return f"{base}/api/amazon-oauth-callback"
+
+
+@app.get("/api/amazon-oauth-url")
+async def api_amazon_oauth_url(request: Request):
+    """Generate OAuth authorization URL for Amazon Business API."""
+    settings = await get_settings()
+    app_id = settings.get("amazon_app_id", "")
+    if not app_id:
+        return JSONResponse({"error": "App-ID nicht konfiguriert"}, status_code=400)
+
+    redirect_uri = _get_oauth_redirect_uri(request)
+    domain = settings.get("amazon_domain", "amazon.de")
+    state = str(uuid.uuid4())
+
+    url = get_oauth_authorize_url(app_id, redirect_uri, domain, state)
+    return JSONResponse({"url": url, "state": state})
+
+
+@app.get("/api/amazon-oauth-callback")
+async def api_amazon_oauth_callback(request: Request):
+    """Handle OAuth callback from Amazon."""
+    code = request.query_params.get("spapi_oauth_code") or request.query_params.get("code", "")
+    error = request.query_params.get("error", "")
+
+    if error:
+        return HTMLResponse(f"<h2>Autorisierung fehlgeschlagen</h2><p>{error}</p><p>Fenster kann geschlossen werden.</p>")
+
+    if not code:
+        return HTMLResponse("<h2>Fehler: Kein Autorisierungscode erhalten</h2><p>Fenster kann geschlossen werden.</p>")
+
+    settings = await get_settings()
+    client_id = settings.get("amazon_client_id", "")
+    client_secret = settings.get("amazon_client_secret", "")
+    redirect_uri = _get_oauth_redirect_uri(request)
+
+    result = await exchange_auth_code(code, client_id, client_secret, redirect_uri)
+
+    if "error" in result:
+        return HTMLResponse(f"<h2>Token-Exchange fehlgeschlagen</h2><p>{result['error']}</p>")
+
+    refresh_token = result.get("refresh_token", "")
+    if refresh_token:
+        await save_settings({"amazon_refresh_token": refresh_token})
+        return HTMLResponse(
+            "<h2>Autorisierung erfolgreich!</h2>"
+            "<p>Refresh-Token wurde gespeichert. Dieses Fenster kann geschlossen werden.</p>"
+            "<script>window.close();</script>"
+        )
+
+    return HTMLResponse("<h2>Fehler: Kein Refresh-Token erhalten</h2>")
+
+
+@app.post("/api/amazon-oauth-exchange")
+async def api_amazon_oauth_exchange(request: Request):
+    """Manual OAuth code exchange - user pastes the code from the redirect URL."""
+    body = await request.json()
+    code = body.get("code", "").strip()
+    if not code:
+        return JSONResponse({"error": "Kein Code angegeben"}, status_code=400)
+
+    settings = await get_settings()
+    client_id = settings.get("amazon_client_id", "")
+    client_secret = settings.get("amazon_client_secret", "")
+    redirect_uri = _get_oauth_redirect_uri(request)
+
+    result = await exchange_auth_code(code, client_id, client_secret, redirect_uri)
+
+    if "error" in result:
+        return JSONResponse({"error": result["error"]}, status_code=400)
+
+    refresh_token = result.get("refresh_token", "")
+    if refresh_token:
+        await save_settings({"amazon_refresh_token": refresh_token})
+        return JSONResponse({"success": True})
+
+    return JSONResponse({"error": "Kein Refresh-Token erhalten"}, status_code=400)
 
 
 @app.post("/api/amazon-login")
@@ -462,7 +573,12 @@ async def api_amazon_logout():
 
 @app.post("/api/amazon-process")
 async def api_amazon_process():
-    result = await process_amazon()
+    settings = await get_settings()
+    mode = settings.get("amazon_mode", "browser")
+    if mode == "api":
+        result = await process_amazon_api()
+    else:
+        result = await process_amazon()
     return JSONResponse(result)