#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Modul: app/core/derive_edges.py
Version: 1.5.0 (Mindnet V2)
Status: Stable

Ziele
-----
1) Beibehalten der bewährten Edge-Ableitung:
   - belongs_to (chunk -> note)
   - next / prev (Chunk-Kette)
   - references (chunk-scope) aus Chunk.window/text via `extract_wikilinks`

2) Ergänzung: typenbasierte, abgeleitete Kanten aus `config/types.yaml`:
   - Für jede gefundene Referenz werden zusätzliche Relationen aus
     `edge_defaults` des Notiztyps erzeugt (z. B. "depends_on", "related_to").
   - Optional symmetrische Relationen (z. B. "related_to", "similar_to").
   - Dedupe bleibt kompatibel (Key: kind, source_id, target_id, scope).

Hinweise
--------
- Es werden keine Markdown-Links neu geparst; wir bleiben bei der
  vorhandenen Parser-Logik (`extract_wikilinks`) zur Sicherung der Kompatibilität.
- `edge_defaults` werden sowohl für Chunk-scope-Referenzen als auch – falls
  `include_note_scope_refs=True` – für Note-scope-Referenzen angewendet.
"""

from __future__ import annotations
from typing import Dict, List, Optional, Iterable, Set

import os
import yaml

# Wikilinks-Parser beibehalten (Kompatibilität!)
from app.core.parser import extract_wikilinks


# ---------------------------- Utilities ------------------------------------

def _get(d: dict, *keys, default=None):
    for k in keys:
        if k in d and d[k] is not None:
            return d[k]
    return default

def _chunk_text_for_refs(chunk: dict) -> str:
    # bevorzugt 'window' → dann 'text' → 'content' → 'raw'
    return (
        _get(chunk, "window")
        or _get(chunk, "text")
        or _get(chunk, "content")
        or _get(chunk, "raw")
        or ""
    )

def _dedupe(seq: Iterable[str]) -> List[str]:
    seen: Set[str] = set()
    out: List[str] = []
    for s in seq:
        if s not in seen:
            seen.add(s)
            out.append(s)
    return out

def _edge(kind: str, scope: str, source_id: str, target_id: str, note_id: str, extra: Optional[dict] = None) -> dict:
    pl = {
        "kind": kind,
        "scope": scope,         # "chunk" | "note"
        "source_id": source_id,
        "target_id": target_id,
        "note_id": note_id,     # Träger/Quelle der Kante (aktuelle Note)
    }
    if extra:
        pl.update(extra)
    return pl


# ---------------------- Typen-Registry (types.yaml) ------------------------

SYM_REL = {"related_to", "similar_to"}  # symmetrische Relationstypen

def _env(n: str, default: Optional[str] = None) -> str:
    v = os.getenv(n)
    return v if v is not None else (default or "")

def _load_types_registry() -> dict:
    """Lädt die YAML-Registry aus MINDNET_TYPES_FILE oder ./config/types.yaml"""
    p = _env("MINDNET_TYPES_FILE", "./config/types.yaml")
    try:
        with open(p, "r", encoding="utf-8") as f:
            data = yaml.safe_load(f) or {}
            return data
    except Exception:
        return {}

def _get_types_map(reg: dict) -> dict:
    if isinstance(reg, dict) and isinstance(reg.get("types"), dict):
        return reg["types"]
    return reg if isinstance(reg, dict) else {}

def _edge_defaults_for(note_type: Optional[str], reg: dict) -> List[str]:
    """
    Liefert die edge_defaults-Liste für den gegebenen Notiztyp.
    Fallback-Reihenfolge:
      1) reg['types'][note_type]['edge_defaults']
      2) reg['defaults']['edge_defaults']  (oder 'default'/'global')
      3) []
    """
    types_map = _get_types_map(reg)
    # 1) exakter Typ
    if note_type and isinstance(types_map, dict):
        t = types_map.get(note_type)
        if isinstance(t, dict) and isinstance(t.get("edge_defaults"), list):
            return [str(x) for x in t["edge_defaults"] if isinstance(x, str)]
    # 2) Fallback
    for key in ("defaults", "default", "global"):
        v = reg.get(key)
        if isinstance(v, dict) and isinstance(v.get("edge_defaults"), list):
            return [str(x) for x in v["edge_defaults"] if isinstance(x, str)]
    # 3) leer
    return []


# --------------------------- Hauptfunktion ---------------------------------

def build_edges_for_note(
    note_id: str,
    chunks: List[dict],
    note_level_references: Optional[List[str]] = None,
    include_note_scope_refs: bool = False,
) -> List[dict]:
    """
    Erzeugt Kanten für eine Note.

    - belongs_to:   für jeden Chunk   (chunk -> note)
    - next / prev:  zwischen aufeinanderfolgenden Chunks
    - references:   pro Chunk aus window/text (via extract_wikilinks)
    - optional note-scope references/backlinks: dedupliziert über alle Chunk-Funde + note_level_references
    - NEU: typenbasierte, abgeleitete Kanten (edge_defaults) je gefundener Referenz
    """
    edges: List[dict] = []

    # --- 0) Note-Typ ermitteln (aus erstem Chunk erwartet) ---
    note_type = None
    if chunks:
        note_type = _get(chunks[0], "type")

    # --- 1) belongs_to ---
    for ch in chunks:
        cid = _get(ch, "chunk_id", "id")
        if not cid:
            continue
        edges.append(_edge("belongs_to", "chunk", cid, note_id, note_id, {"chunk_id": cid}))

    # --- 2) next/prev ---
    for i in range(len(chunks) - 1):
        a, b = chunks[i], chunks[i + 1]
        a_id = _get(a, "chunk_id", "id")
        b_id = _get(b, "chunk_id", "id")
        if not a_id or not b_id:
            continue
        edges.append(_edge("next", "chunk", a_id, b_id, note_id, {"chunk_id": a_id}))
        edges.append(_edge("prev", "chunk", b_id, a_id, note_id, {"chunk_id": b_id}))

    # --- 3) references (chunk-scope) + abgeleitete Relationen je Ref ---
    reg = _load_types_registry()
    defaults = _edge_defaults_for(note_type, reg)
    refs_all: List[str] = []

    for ch in chunks:
        cid = _get(ch, "chunk_id", "id")
        if not cid:
            continue
        txt = _chunk_text_for_refs(ch)
        refs = extract_wikilinks(txt)  # Parser-Logik nicht verändert
        for r in refs:
            # reale Referenz (wie bisher)
            edges.append(_edge("references", "chunk", cid, r, note_id, {"chunk_id": cid, "ref_text": r}))
            # abgeleitete Kanten je default-Relation
            for rel in defaults:
                if rel == "references":
                    continue  # doppelt vermeiden
                edges.append(_edge(rel, "chunk", cid, r, note_id, {"chunk_id": cid, "rule_id": f"edge_defaults:{note_type}:{rel}", "confidence": 0.7}))
                # symmetrisch?
                if rel in {"related_to", "similar_to"}:
                    edges.append(_edge(rel, "chunk", r, cid, note_id, {"chunk_id": cid, "rule_id": f"edge_defaults:{note_type}:{rel}", "confidence": 0.7}))
        refs_all.extend(refs)

    # --- 4) optional: note-scope references/backlinks (+ defaults) ---
    if include_note_scope_refs:
        refs_note = refs_all[:]
        if note_level_references:
            refs_note.extend([r for r in note_level_references if isinstance(r, str) and r])
        refs_note = _dedupe(refs_note)
        for r in refs_note:
            # echte note-scope Referenz & Backlink (wie bisher)
            edges.append(_edge("references", "note", note_id, r, note_id))
            edges.append(_edge("backlink", "note", r, note_id, note_id))
            # und zusätzlich default-Relationen (note-scope)
            for rel in defaults:
                if rel == "references":
                    continue
                edges.append(_edge(rel, "note", note_id, r, note_id, {"rule_id": f"edge_defaults:{note_type}:{rel}", "confidence": 0.7}))
                if rel in {"related_to", "similar_to"}:
                    edges.append(_edge(rel, "note", r, note_id, note_id, {"rule_id": f"edge_defaults:{note_type}:{rel}", "confidence": 0.7}))

    # --- 5) Dedupe (unverändert kompatibel) ---
    dedup = {}
    for e in edges:
        k = (e["kind"], e["source_id"], e["target_id"], e.get("scope", ""))
        dedup[k] = e
    return list(dedup.values())