"""Item library for control_test: meshes are DISCOVERED in items/, classes are READ from
items/labels.json.

No geometric auto-measurement. Dimensions and k are taken from the labelling, which is the
ground truth this cell is verified against - measuring them from the mesh was tried and
the roundness estimate under-read handled/hollow bodies (bucket 0.737 vs 0.995, mug 0.731
vs 0.985), i.e. class D silently became B. Reading the label removes that whole class of
error from the mechanics test.

The folder is still the source of items: drop a .usd in, add one line to labels.json, and
it joins the next run. Anything in the folder without a label is reported and skipped
rather than guessed at.

The documented rules are kept in `classify()` so a labelling can be checked for internal
consistency (`verify_labels()`), not to derive it:

  D  "не подходит без доупаковки"  габариты как у B, но k > 0.8 хотя бы в одном сечении
  C  "не подходит по габаритам"    любой размер < 10 мм ИЛИ не влезает в 450x320x320 мм.
                                   Форма не важна.
  B  "подходит для сортировки"     всё от 10x10x10 до 450x320x320 мм и k <= 0.8

Fit is tested with the item's extents and the envelope both sorted descending - a parcel
may be presented on any face.
"""
from __future__ import annotations

import json
import pathlib

ENVELOPE_MM = sorted((450.0, 320.0, 320.0), reverse=True)
MIN_DIM_MM = 10.0
K_THRESHOLD = 0.8

LABELS_FILE = "labels.json"


def classify(dims_mm, k):
    """the documented decision, D checked first"""
    d = sorted(dims_mm, reverse=True)
    undersize = min(d) < MIN_DIM_MM
    fits = all(a <= b + 1e-9 for a, b in zip(d, ENVELOPE_MM))
    if undersize or not fits:
        return "C"                      # shape irrelevant
    return "D" if k > K_THRESHOLD else "B"


def load_library(items_dir):
    """every .usd in items_dir, sorted, paired with its label.

    Returns dicts with name/path/cls/dims_mm/k, or name/path/error for meshes that have
    no entry in labels.json - those are skipped by the runner, never guessed.
    """
    items_dir = pathlib.Path(items_dir)
    labels_path = items_dir / LABELS_FILE
    if not labels_path.exists():
        raise FileNotFoundError(f"{labels_path} missing - the item classes live there")
    labels = json.loads(labels_path.read_text())

    out = []
    for f in sorted(items_dir.glob("*.usd")):
        rec = labels.get(f.stem)
        if rec is None:
            out.append(dict(name=f.stem, path=str(f),
                            error="no entry in labels.json"))
            continue
        out.append(dict(name=f.stem, path=str(f), cls=rec["zone"],
                        dims_mm=rec.get("dims_mm"), k=rec.get("k")))
    return out


def verify_labels(items_dir):
    """check each label against the documented rules; returns the rows that disagree.

    A label whose own dims/k imply a different class is a labelling bug, and it would
    otherwise show up as a mysterious mechanical failure.
    """
    bad = []
    for r in load_library(items_dir):
        if "error" in r or r.get("dims_mm") is None or r.get("k") is None:
            continue
        implied = classify(r["dims_mm"], r["k"])
        if implied != r["cls"]:
            bad.append(dict(name=r["name"], labelled=r["cls"], implied=implied,
                            dims_mm=r["dims_mm"], k=r["k"]))
    return bad