"""
chunk_payload.py — mindnet core payload builders
Version: 1.3.1 (2025-11-08)

Purpose
-------
Build robust chunk payloads for Qdrant upserts.
This function is intentionally flexible about its signature to remain
compatible with different callers.

Contract
--------
make_chunk_payloads(note, chunks, *args, **kwargs) -> List[Dict[str, Any]]

Each returned item contains at least:
- note_id (str)
- title (str)
- type (str)
- path (str or None)
- tags (List[str])
- chunk_index (int)
- text (str)
- retriever_weight (float or None)  # if available
"""
from __future__ import annotations

from pathlib import Path
from typing import Any, Dict, Iterable, List, Mapping, Optional, Sequence, Union


def _get(obj: Any, key: str, default: Any = None) -> Any:
    if obj is None:
        return default
    if isinstance(obj, Mapping):
        return obj.get(key, default)
    return getattr(obj, key, default)


def _get_frontmatter(note: Any) -> Mapping[str, Any]:
    fm = _get(note, "frontmatter", {})
    if isinstance(fm, Mapping):
        return fm
    return {}


def _resolve_retriever_weight(explicit: Any, fm: Mapping[str, Any]) -> Optional[float]:
    def to_float(v: Any) -> Optional[float]:
        try:
            if v is None:
                return None
            return float(v)
        except Exception:
            return None

    if explicit is not None:
        return to_float(explicit)

    if "retriever_weight" in fm:
        return to_float(fm.get("retriever_weight"))

    retr = fm.get("retriever")
    if isinstance(retr, Mapping) and "weight" in retr:
        return to_float(retr.get("weight"))

    return None


def _to_rel_path(abs_path: Optional[Union[str, Path]], vault_root: Optional[Union[str, Path]]) -> Optional[str]:
    if abs_path is None:
        return None
    try:
        p = Path(abs_path)
        if vault_root:
            try:
                rp = p.relative_to(Path(vault_root))
                return str(rp)
            except Exception:
                return str(p)
        return str(p)
    except Exception:
        return str(abs_path)


def _coerce_chunks(chunks_obj: Any) -> List[Any]:
    """Accept lists of dicts/objects or generators; coerce to list safely."""
    if chunks_obj is None:
        return []
    if isinstance(chunks_obj, list):
        return chunks_obj
    try:
        return list(chunks_obj)
    except Exception:
        return []


def _get_chunk_text(c: Any) -> str:
    for key in ("text", "chunk", "body", "content"):
        v = _get(c, key)
        if isinstance(v, str) and v.strip():
            return v
    # last resort: string repr
    return str(c) if c is not None else ""


def make_chunk_payloads(
    *args: Any,
    **kwargs: Any,
) -> List[Dict[str, Any]]:
    """
    Flexible signature for backward/forward compatibility.
    Expected positional args:
        args[0] -> note (ParsedNote or Mapping)
        args[1] -> chunks (Iterable)
        args[2] -> (optional) config/ignored
    Recognized kwargs:
        - vault_root: base path for relative paths (optional)
        - retriever_weight: explicit override (optional)
    """
    if not args:
        raise TypeError("make_chunk_payloads(note, chunks, *_) requires at least (note, chunks).")

    note = args[0]
    chunks = args[1] if len(args) > 1 else kwargs.get("chunks")
    chunks_list = _coerce_chunks(chunks)

    vault_root = kwargs.get("vault_root")
    explicit_weight = kwargs.get("retriever_weight")

    fm = _get_frontmatter(note)

    note_id = _get(note, "note_id") or _get(note, "id") or fm.get("id")
    title = _get(note, "title") or fm.get("title")
    ntype = _get(note, "type") or fm.get("type")
    tags = _get(note, "tags") or fm.get("tags") or []
    if not isinstance(tags, list):
        tags = list(tags) if tags else []

    path_val = _get(note, "path") or _get(note, "abs_path") or fm.get("path")
    rweight = _resolve_retriever_weight(explicit_weight, fm)

    base = {
        "note_id": note_id,
        "title": title,
        "type": ntype,
        "tags": tags,
        "path": _to_rel_path(path_val, vault_root),
        "retriever_weight": rweight,
    }

    payloads: List[Dict[str, Any]] = []
    for idx, ch in enumerate(chunks_list):
        text = _get_chunk_text(ch)
        item = dict(base)
        item.update(
            {
                "chunk_index": idx,
                "text": text,
            }
        )
        payloads.append(item)

    return payloads