app/core/graph_adapter.py hinzugefügt

app/core/graph_adapter.py

@@ -0,0 +1,92 @@
+"""
+app/core/graph_adapter.py — Adjazenzaufbau & Subgraph-Expansion (WP-04)
+
+Zweck:
+    Baut aus Qdrant-Edges (Collection: *_edges) einen leichten In-Memory-Graph
+    und liefert Edge-basierte Kennzahlen (In-Degree, Out-Degree, edge_bonus).
+Kompatibilität:
+    Python 3.12+, qdrant-client 1.x
+Version:
+    0.1.0  (Erstanlage)
+Stand:
+    2025-10-07
+Bezug:
+    - WP-04 Edge-Gewichtungen und Heuristiken
+    - app/core/qdrant_points.py (get_edges_for_sources)
+Nutzung:
+    from app.core.graph_adapter import expand
+Änderungsverlauf:
+    0.1.0 (2025-10-07) – Erstanlage.
+"""
+
+from __future__ import annotations
+from typing import Dict, List, Optional, DefaultDict
+from collections import defaultdict
+from qdrant_client import QdrantClient
+from app.core.qdrant_points import get_edges_for_sources
+
+EDGE_BASE_WEIGHTS = {
+    "references": 0.20,
+    "belongs_to": 0.10,
+    "next": 0.06,
+    "prev": 0.06,
+    "backlink": 0.04,
+    "references_at": 0.08,
+}
+
+
+class Subgraph:
+    """Leichtgewichtiger Subgraph mit Adjazenzlisten & einfachen Kennzahlen."""
+
+    def __init__(self):
+        self.adj: DefaultDict[str, List[Dict]] = defaultdict(list)
+        self.in_degree: DefaultDict[str, int] = defaultdict(int)
+        self.out_degree: DefaultDict[str, int] = defaultdict(int)
+
+    def add_edge(self, e: Dict):
+        src = e["source"]; tgt = e["target"]; kind = e["kind"]
+        weight = e.get("weight", EDGE_BASE_WEIGHTS.get(kind, 0.0))
+        self.adj[src].append({"target": tgt, "kind": kind, "weight": weight})
+        self.out_degree[src] += 1
+        self.in_degree[tgt] += 1
+
+    def aggregate_edge_bonus(self, node_id: str) -> float:
+        return sum(edge["weight"] for edge in self.adj.get(node_id, []))
+
+    def centrality_bonus(self, node_id: str) -> float:
+        import math
+        # Log-gedämpfter Bonus, hart begrenzt
+        return min(math.log1p(self.in_degree.get(node_id, 0)) / 10.0, 0.15)
+
+
+def expand(client: QdrantClient, prefix: str, seeds: List[str],
+           depth: int = 1, edge_types: Optional[List[str]] = None) -> Subgraph:
+    """
+    Expandiert ab Seeds entlang von Edges (bis depth), optional gefiltert nach Typen.
+    Seeds sind stabile payload-IDs (z. B. note_id, chunk_id).
+    """
+    sg = Subgraph()
+    frontier = set(seeds)
+    visited = set()
+
+    for _ in range(max(depth, 0)):
+        if not frontier:
+            break
+
+        edges = get_edges_for_sources(client, prefix, list(frontier), edge_types=edge_types, limit=2048)
+        next_frontier = set()
+        for pl in edges:
+            e = {
+                "source": pl.get("source_id"),
+                "target": pl.get("target_id"),
+                "kind": pl.get("kind", "edge"),
+                "weight": pl.get("weight", EDGE_BASE_WEIGHTS.get(pl.get("kind", "edge"), 0.0)),
+            }
+            sg.add_edge(e)
+            if e["target"]:
+                next_frontier.add(e["target"])
+
+        visited |= frontier
+        frontier = next_frontier - visited
+
+    return sg