#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
app/core/chunk_payload.py  — Mindnet V2 (compat)

Ziele (ohne Bruch zur lauffähigen v1-Basis):
- Akzeptiert `file_path=` (Alias zu path_arg)
- Verarbeitet Chunks sowohl als `dict` **als auch** als Objekt (z. B. Dataclass `Chunk`)
- Schreibt v1-kompatible Felder:
    * `id`  (Alias von `chunk_id` – **wichtig** für app/core/edges.py v1)
    * `neighbors: {prev, next}` wird **berechnet** (Sequenz), falls nicht vorhanden
- Denormalisiert optional `tags` der Note auf Chunks
- Fügt Nummern-Aliase hinzu: `ord`, `chunk_num`, `Chunk_Nummer`

Wichtig:
- `edge_defaults` gehören zur *Note* (Typ-Regeln), nicht pro Chunk. Werden hier **nicht** gespiegelt.
"""
from __future__ import annotations

import json
import os
import pathlib
import hashlib
from typing import Any, Dict, List, Optional

from app.core.chunker import assemble_chunks

# ---------- Helpers ----------

def _as_dict(obj):
    if isinstance(obj, dict):
        return obj
    # Objekt → (teilweise) Dict-Ansicht via Attribute
    d = {}
    for k in ("index","ord","chunk_index","text","window","id","chunk_id","neighbors","note_id","type","title"):
        if hasattr(obj, k):
            d[k] = getattr(obj, k)
    # Fallback: bestehe nicht auf Vollständigkeit
    return d

def _coalesce(*vals):
    for v in vals:
        if v is not None:
            return v
    return None

def _env_float(name: str, default: float) -> float:
    try:
        return float(os.environ.get(name, default))
    except Exception:
        return default

def _ensure_list(x) -> list:
    if x is None: return []
    if isinstance(x, list): return [str(i) for i in x]
    if isinstance(x, (set, tuple)): return [str(i) for i in x]
    return [str(x)]

def _text_from_note(note: Dict[str, Any]) -> str:
    return note.get("body") or note.get("text") or ""

def _iter_chunks(note: Dict[str, Any], chunk_profile: str, fulltext: str) -> List[Dict[str, Any]]:
    """Nutze bestehenden assemble_chunks(note_id, body, type). Rückgabe kann Objektliste sein."""
    note_id = note.get("id") or (note.get("frontmatter") or {}).get("id")
    ntype = (note.get("frontmatter") or {}).get("type") or note.get("type") or "note"
    raw_list = assemble_chunks(note_id, fulltext, ntype)
    # Normalisiere auf Dicts (unter Bewahrung vorhandener Keys)
    out: List[Dict[str, Any]] = []
    for c in raw_list:
        out.append(_as_dict(c) if not isinstance(c, dict) else c)
    return out

# ---------- Main ----------

def make_chunk_payloads(
    note: Any,
    path_arg: Optional[str] = None,
    chunks_from_chunker: Optional[List[Dict[str, Any]]] = None,
    *,
    file_path: Optional[str] = None,
    note_text: Optional[str] = None,
    types_cfg: Optional[dict] = None,
) -> List[Dict[str, Any]]:
    """
    Erzeugt Chunk-Payloads im v1-kompatiblen Format (plus V2-Aliase).
    """
    # ---- Note-Kontext ----
    n = note if isinstance(note, dict) else {"frontmatter": {}}
    fm = n.get("frontmatter") or {}
    note_type = str(fm.get("type") or n.get("type") or "note")
    types_cfg = types_cfg or {}
    cfg_for_type = types_cfg.get(note_type, {}) if isinstance(types_cfg, dict) else {}

    default_rw = _env_float("MINDNET_DEFAULT_RETRIEVER_WEIGHT", 1.0)
    retriever_weight = _coalesce(fm.get("retriever_weight"), cfg_for_type.get("retriever_weight"), default_rw)
    try:
        retriever_weight = float(retriever_weight)
    except Exception:
        retriever_weight = default_rw

    chunk_profile = _coalesce(fm.get("chunk_profile"), cfg_for_type.get("chunk_profile"), os.environ.get("MINDNET_DEFAULT_CHUNK_PROFILE","medium"))
    chunk_profile = chunk_profile if isinstance(chunk_profile, str) else "medium"

    note_id = n.get("note_id") or n.get("id") or fm.get("id")
    title = n.get("title") or fm.get("title") or ""

    # Pfadauflösung: file_path > note['path'] > path_arg
    path = file_path or n.get("path") or path_arg
    if isinstance(path, pathlib.Path):
        path = str(path)
    path = path or ""

    # Tags denormalisieren (optional)
    tags = fm.get("tags") or fm.get("keywords") or n.get("tags")
    tags_list = _ensure_list(tags) if tags else []

    # ---- Chunks besorgen ----
    fulltext = note_text if isinstance(note_text, str) else _text_from_note(n)
    raw_chunks = chunks_from_chunker if isinstance(chunks_from_chunker, list) else _iter_chunks(n, chunk_profile, fulltext)

    payloads: List[Dict[str, Any]] = []
    for c in raw_chunks:
        cdict = c if isinstance(c, dict) else _as_dict(c)
        # Index/Basisdaten robust ermitteln
        idx = _coalesce(cdict.get("index"), cdict.get("ord"), cdict.get("chunk_index"), len(payloads))
        try:
            idx = int(idx)
        except Exception:
            idx = len(payloads)

        text = _coalesce(cdict.get("window"), cdict.get("text"), "")
        if not isinstance(text, str):
            text = str(text or "")

        # deterministische ID (kompatibel & stabil)
        key = f"{note_id}|{idx}"
        h = hashlib.sha1(key.encode("utf-8")).hexdigest()[:12] if note_id else hashlib.sha1(f"{path}|{idx}".encode("utf-8")).hexdigest()[:12]
        chunk_id = cdict.get("chunk_id") or cdict.get("id") or (f"{note_id}-{idx:03d}-{h}" if note_id else h)

        payload = {
            # v1 Kernfelder (+Erweiterungen)
            "id": chunk_id,             # <— WICHTIG: v1 edges.py erwartet 'id'
            "chunk_id": chunk_id,       # v2-Alias
            "index": idx,
            "ord": idx,                 # v2-Alias
            "chunk_num": idx,
            "Chunk_Nummer": idx,
            "note_id": note_id,
            "type": note_type,
            "title": title,
            "path": path,
            "text": text,
            "window": text,             # falls der Chunker bereits ein Fenster liefert, bleibt es identisch
            "retriever_weight": retriever_weight,
            "chunk_profile": chunk_profile,
        }

        # Bestehende neighbors vom Chunk übernehmen (falls vorhanden)
        nb = cdict.get("neighbors")
        if isinstance(nb, dict):
            prev_id = nb.get("prev"); next_id = nb.get("next")
            payload["neighbors"] = {"prev": prev_id, "next": next_id}
        # Tags spiegeln
        if tags_list:
            payload["tags"] = tags_list

        # JSON-Roundtrip als Validierung
        json.loads(json.dumps(payload, ensure_ascii=False))
        payloads.append(payload)

    # Nachgelagert: neighbors berechnen, falls fehlend
    for i, p in enumerate(payloads):
        nb = p.get("neighbors") or {}
        prev_id = nb.get("prev")
        next_id = nb.get("next")
        if prev_id is None and i > 0:
            prev_id = payloads[i-1]["id"]
        if next_id is None and i+1 < len(payloads):
            next_id = payloads[i+1]["id"]
        p["neighbors"] = {"prev": prev_id, "next": next_id}

    return payloads