"""
chunk_payload.py — Mindnet core payload builder (v0.5, 2025-11-08)

Purpose
-------
Builds a list of **JSON-serializable** payload dicts for chunks of a note to be
stored in `<prefix>_chunks`. Ensures `retriever_weight` is set on every chunk.

Public API
----------
make_chunk_payloads(parsed_note, chunks, *args, retriever_weight=None, vault_root=None, type_defaults=None, **kwargs) -> list[dict]
"""

from __future__ import annotations
from pathlib import Path
from typing import Any, Dict, List, Optional, Union, Mapping
import datetime, math

Json = Union[None, bool, int, float, str, list, dict]

# ------------------------- helpers -------------------------

def _is_mapping(x: Any) -> bool:
    return isinstance(x, Mapping)

def _get(obj: Any, *names: str, default: Any=None) -> Any:
    for n in names:
        if hasattr(obj, n):
            try:
                return getattr(obj, n)
            except Exception:
                pass
        if _is_mapping(obj) and n in obj:
            try:
                return obj[n]
            except Exception:
                pass
    return default

def _to_float(x: Any, default: float=1.0) -> float:
    if x is None:
        return float(default)
    if isinstance(x, (int, float)) and math.isfinite(x):
        return float(x)
    try:
        s = str(x).strip().replace(',', '.')
        return float(s)
    except Exception:
        return float(default)

def _ensure_list(x: Any) -> list:
    if x is None:
        return []
    if isinstance(x, list):
        return x
    if isinstance(x, (set, tuple)):
        return list(x)
    return [x]

def _sanitize(obj: Any) -> Json:
    if obj is None or isinstance(obj, (bool, int, float, str)):
        return obj
    if callable(obj):
        return None
    if isinstance(obj, (list, tuple, set)):
        return [_sanitize(v) for v in obj]
    if isinstance(obj, dict):
        out = {}
        for k, v in obj.items():
            if callable(v):
                continue
            out[str(k)] = _sanitize(v)
        return out
    if isinstance(obj, Path):
        return str(obj)
    if isinstance(obj, datetime.datetime):
        return obj.isoformat()
    if hasattr(obj, "__str__"):
        try:
            return str(obj)
        except Exception:
            return None
    return None

def _compute_retriever_weight(explicit: Any, frontmatter: dict, type_defaults: Optional[dict], note_type: Optional[str]) -> float:
    if explicit is not None:
        return _to_float(explicit, 1.0)
    for key in ("retriever_weight", "retriever.weight", "retrieverWeight"):
        if key in frontmatter:
            return _to_float(frontmatter.get(key), 1.0)
    if type_defaults and note_type:
        tdef = type_defaults.get(note_type) or {}
        for key in ("retriever_weight", "retriever.weight", "retrieverWeight"):
            if key in tdef:
                return _to_float(tdef.get(key), 1.0)
    return 1.0

# ------------------------- public API -------------------------

def make_chunk_payloads(parsed_note: Any,
                        chunks: List[Any],
                        *args,
                        retriever_weight: Optional[float]=None,
                        vault_root: Optional[str]=None,
                        type_defaults: Optional[dict]=None,
                        **kwargs) -> List[Dict[str, Json]]:
    """
    Build JSON-safe payloads for all chunks in a note.

    Parameters
    ----------
    parsed_note : object or dict
    chunks : list of objects or dicts
        Expected per-chunk fields/keys (best-effort): text, index, start/end offsets,
        tokens/n_tokens, section/heading.
    retriever_weight : float|None
    vault_root : str|None
    type_defaults : dict|None

    Returns
    -------
    list[dict] suitable for Qdrant payloads
    """
    fm = _get(parsed_note, "frontmatter", "fm", default={})
    if not isinstance(fm, dict):
        fm = {}

    note_id = _get(parsed_note, "note_id", "id", default=fm.get("id"))
    title = _get(parsed_note, "title", default=fm.get("title"))
    ntype = _get(parsed_note, "type", default=fm.get("type"))
    raw_path = _get(parsed_note, "path", "rel_path", "relpath", default=fm.get("path"))
    chunk_profile = _get(parsed_note, "chunk_profile", "profile", default=fm.get("chunk_profile"))
    tags = _ensure_list(_get(parsed_note, "tags", default=fm.get("tags")))

    rel_path = raw_path
    if raw_path and vault_root:
        try:
            rel_path = str(Path(raw_path)).replace(str(Path(vault_root)), "").lstrip("/\\")
        except Exception:
            rel_path = str(raw_path)

    rw = _compute_retriever_weight(retriever_weight, fm, type_defaults, ntype)

    out: List[Dict[str, Json]] = []
    for i, ch in enumerate(chunks):
        # tolerate missing/variant fields
        text = _get(ch, "text", "content", "body", "value", default="")
        idx = _get(ch, "index", "idx", default=i)
        start = _get(ch, "start", "start_char", "offset_start", "char_start", default=None)
        end = _get(ch, "end", "end_char", "offset_end", "char_end", default=None)
        tokens = _get(ch, "n_tokens", "tokens", "token_count", default=None)
        section = _get(ch, "section", "section_title", "heading", default=None)
        section_level = _get(ch, "section_level", "heading_level", default=None)

        payload = {
            "note_id": note_id,
            "title": title,
            "type": ntype,
            "path": rel_path or raw_path,
            "chunk_index": int(idx) if isinstance(idx, (int, float)) else i,
            "text": text,
            "start": start,
            "end": end,
            "tokens": tokens,
            "section": section,
            "section_level": section_level,
            "chunk_profile": chunk_profile,
            "tags": tags,
            "retriever_weight": float(rw),
        }
        out.append(_sanitize(payload))

    return out