From ba175168140417a0220df1e7426b24448c048327 Mon Sep 17 00:00:00 2001
From: Lars <Lars@stommer.de>
Date: Tue, 7 Oct 2025 11:31:47 +0200
Subject: [PATCH] =?UTF-8?q?app/routers/graph.py=20hinzugef=C3=BCgt?=
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---
 app/routers/graph.py | 54 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 app/routers/graph.py

diff --git a/app/routers/graph.py b/app/routers/graph.py
new file mode 100644
index 0000000..8ef613a
--- /dev/null
+++ b/app/routers/graph.py
@@ -0,0 +1,54 @@
+"""
+app/routers/graph.py — Graph-Endpunkte (WP-04)
+
+Zweck:
+    Liefert die Nachbarschaft einer Note/ID als JSON-Graph (Nodes/Edges/Stats).
+Kompatibilität:
+    Python 3.12+, FastAPI 0.110+, qdrant-client 1.x
+Version:
+    0.1.0  (Erstanlage)
+Stand:
+    2025-10-07
+Bezug:
+    - app/core/graph_adapter.py
+    - app/models/dto.py
+Nutzung:
+    app.include_router(graph.router, prefix="/graph", tags=["graph"])
+Änderungsverlauf:
+    0.1.0 (2025-10-07) – Erstanlage.
+"""
+
+from __future__ import annotations
+from typing import List, Optional
+from fastapi import APIRouter, Query
+from qdrant_client import QdrantClient
+from app.models.dto import GraphResponse, NodeDTO, EdgeDTO
+from app.core.graph_adapter import expand
+from app.config import get_settings
+
+router = APIRouter()
+
+@router.get("/{note_id}", response_model=GraphResponse)
+def get_graph(note_id: str, depth: int = 1, edge_types: Optional[List[str]] = Query(None)) -> GraphResponse:
+    s = get_settings()
+    client = QdrantClient(url=s.QDRANT_URL, api_key=s.QDRANT_API_KEY)
+
+    sg = expand(client, s.COLLECTION_PREFIX, [note_id], depth=depth, edge_types=edge_types)
+
+    # Seed-Node (Payload optional später ergänzen über get_note_payload)
+    nodes = [NodeDTO(id=note_id, type="note",
+                     title=None, tags=[],
+                     in_degree=sg.in_degree.get(note_id, 0),
+                     out_degree=sg.out_degree.get(note_id, 0))]
+
+    # direkte Out-Kanten des Seeds
+    edges = []
+    for e in sg.adj.get(note_id, []):
+        edges.append(EdgeDTO(
+            id=f"{note_id}->{e['target']}:{e['kind']}",
+            kind=e["kind"], source=note_id, target=e["target"],
+            weight=float(e["weight"]), direction="out"
+        ))
+
+    return GraphResponse(center_note_id=note_id, nodes=nodes, edges=edges,
+                         stats={"node_count": len(nodes), "edge_count": len(edges)})