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

Ziele:
- Bewahrt bestehendes Verhalten (index, chunk_profile, retriever_weight, etc.)
- Denormalisiert optional `tags` aus der Note‑FM auf Chunks
- Fügt Aliase für die Chunk‑Nummer hinzu: `ord` (v2‑Schema), `chunk_num`, `Chunk_Nummer`
- **Kompatibilität:** akzeptiert sowohl `path_arg` (positional) als auch `file_path` (keyword)

Hinweis:
- `edge_defaults` sind Note‑Regeln (Typ) und werden nicht pro Chunk 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

def _as_dict(obj):
    if isinstance(obj, dict): return obj
    try:
        return dict(obj)  # type: ignore
    except Exception:
        return {"value": obj}

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 _load_types_config(types_cfg_explicit: Optional[dict] = None) -> dict:
    """Types-Registry *optional* einspeisen (bereits geparst), sonst lazy-laden vermeiden."""
    return types_cfg_explicit or {}

def _text_from_note(note: Dict[str, Any]) -> str:
    # Erwartete Inputs (siehe parser.py / import_markdown.py):
    # note["body"] oder note["text"]; Fallback leerer String
    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)."""
    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"
    # assemble_chunks liefert Liste von Dicts mit mindestens {"index","text"} (v1)
    return assemble_chunks(note_id, fulltext, ntype)

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. Erwartet:
      - `note`: Normalisierte Note-Struktur (inkl. frontmatter)
      - `path_arg` oder `file_path`: Pfad der Note
      - `chunks_from_chunker`: optional: Ergebnis von assemble_chunks (sonst wird intern erzeugt)

    Rückgabe: Liste aus Payload-Dicts, jedes mit mind.:
      - note_id, chunk_id, index, ord (Alias), title, type, path, text, retriever_weight, chunk_profile
      - optional: tags (aus Note-FM), chunk_num, Chunk_Nummer (Aliases von index/ord)
    """
    n = _as_dict(note)
    fm = n.get("frontmatter") or {}
    note_type = str(fm.get("type") or n.get("type") or "note")
    types_cfg = _load_types_config(types_cfg)

    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 ""
    # Pfad-Auflösung: Priorität 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 ""  # garantiert vorhanden

    # Denormalisierte Tags (optional): auf Chunks spiegeln, wenn vorhanden
    tags = fm.get("tags") or fm.get("keywords") or n.get("tags")
    tags_list = _ensure_list(tags) if tags else []

    # Quelltext
    fulltext = note_text if isinstance(note_text, str) else _text_from_note(n)

    # Chunks besorgen
    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 chunks:
        idx = c.get("index", len(payloads))
        text = c.get("text") if isinstance(c, dict) else (str(c) if c is not None else "")
        text = text if isinstance(text, str) else str(text or "")

        # deterministische ID (unter Beibehaltung deines bisherigen Schemas)
        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 = f"{note_id}-{idx:03d}-{h}" if note_id else f"{h}"

        payload = {
            "note_id": note_id,
            "chunk_id": chunk_id,
            "index": idx,
            "ord": idx,               # Alias für v2‑Schema
            "chunk_num": idx,         # neutraler Alias
            "Chunk_Nummer": idx,      # deutschsprachiger Alias
            "title": title,
            "type": note_type,
            "path": path,             # garantiert vorhanden
            "text": text,             # nie leer
            "retriever_weight": retriever_weight,
            "chunk_profile": chunk_profile,
        }
        if tags_list:
            payload["tags"] = tags_list

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

    return payloads