"""
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)})