from __future__ import annotations
from typing import List, Dict

def deriv_edges_for_note(note_meta: Dict, chunk_payloads: List[Dict]) -> List[Dict]:
    edges: List[Dict] = []

    # Chunk → Note (belongs_to) + prev/next
    for idx, ch in enumerate(chunk_payloads):
        edges.append({
            "src_id": ch["id"], "dst_id": note_meta["id"],
            "edge_type": "belongs_to", "scope": "chunk"
        })
        prev_id = ch.get("neighbors",{}).get("prev")
        next_id = ch.get("neighbors",{}).get("next")
        if prev_id:
            edges.append({"src_id": ch["id"], "dst_id": prev_id, "edge_type": "next", "scope": "chunk"})
            edges.append({"src_id": prev_id, "dst_id": ch["id"], "edge_type": "prev", "scope": "chunk"})
        if next_id:
            edges.append({"src_id": ch["id"], "dst_id": next_id, "edge_type": "next", "scope": "chunk"})
            edges.append({"src_id": next_id, "dst_id": ch["id"], "edge_type": "prev", "scope": "chunk"})

        # references aus wikilinks (Chunk-Scope)
        for ref in ch.get("references", []):
            tid = ref.get("target_id")
            if not tid: continue
            edges.append({"src_id": ch["id"], "dst_id": tid, "edge_type": "references", "scope": "chunk"})
            edges.append({"src_id": tid, "dst_id": ch["id"], "edge_type": "backlink", "scope": "chunk"})

    # depends_on / assigned_to (Note-Scope, aus Frontmatter)
    for dep in note_meta.get("depends_on", []) or []:
        edges.append({"src_id": note_meta["id"], "dst_id": dep, "edge_type": "depends_on", "scope": "note"})
    for ass in note_meta.get("assigned_to", []) or []:
        edges.append({"src_id": note_meta["id"], "dst_id": ass, "edge_type": "assigned_to", "scope": "note"})

    # Note-Level references (optional: falls du im Note-Payload `references` sammelst)
    for tid in note_meta.get("references", []) or []:
        edges.append({"src_id": note_meta["id"], "dst_id": tid, "edge_type": "references", "scope": "note"})
        edges.append({"src_id": tid, "dst_id": note_meta["id"], "edge_type": "backlink", "scope": "note"})

    # Dedupe
    uniq = {}
    for e in edges:
        k = (e["src_id"], e["edge_type"], e["dst_id"], e.get("scope","note"))
        uniq[k] = e
    return list(uniq.values())