# -----------------------------------------------------------------------------
# Home-Ka — US real-estate aggregator (Groupe KA)
# Author: Simon-Pierre Boucher — contact@spboucher.ai
# connectors/_maputil.py : shared helpers for config-driven field mapping.
#
# Family connectors (json, xml, csv, sftp, reso) turn a raw record into a
# Listing through a declarative mapping stored in the source config:
#   "mapping": {"external_id": "ListingId", "list_price": "price.amount",
#               "images": "photos[].url", "city": "address.city", ...}
# Paths are dot-separated; "[]" fans out over a list. Unmapped raw fields are
# preserved in Listing.details for the RESO passthrough in schema.finalize().
# -----------------------------------------------------------------------------
from __future__ import annotations

from ..schema import Listing

__all__ = ["dig", "apply_mapping"]

_LIST_FIELDS = {"images", "features"}


def dig(record, path: str):
    """Resolve a dot path in a nested dict/list structure.

    "photos[].url" → [p["url"] for p in record["photos"]];
    "address.city" → record["address"]["city"]. Returns None when absent.
    """
    cur = record
    for part in str(path).split("."):
        if cur is None:
            return None
        fan = part.endswith("[]")
        key = part[:-2] if fan else part
        if key:
            if isinstance(cur, dict):
                cur = cur.get(key)
            elif isinstance(cur, list):
                cur = [c.get(key) if isinstance(c, dict) else None for c in cur]
            else:
                return None
        if fan and not isinstance(cur, list):
            cur = [cur] if cur is not None else []
    return cur


def apply_mapping(source_id: str, record: dict, mapping: dict,
                  static: dict | None = None) -> Listing | None:
    """Build a Listing from a raw record and a declarative mapping."""
    kw: dict = {"source": source_id, "external_id": "", "url": ""}
    for field, path in (mapping or {}).items():
        v = dig(record, path)
        if v is None:
            continue
        if field in _LIST_FIELDS:
            v = [x for x in (v if isinstance(v, list) else [v]) if x]
        kw[field] = v
    for field, v in (static or {}).items():
        kw.setdefault(field, v)
    if not kw.get("external_id"):
        return None
    kw["external_id"] = str(kw["external_id"])
    kw.setdefault("details", {})
    # keep flat raw scalars for the RESO passthrough / debugging
    if isinstance(record, dict):
        for k, v in record.items():
            if isinstance(v, (str, int, float, bool)) and k not in kw["details"]:
                kw["details"][k] = v
    allowed = set(Listing.__dataclass_fields__)
    return Listing(**{k: v for k, v in kw.items() if k in allowed})