# Copyright 2026 AutomatosX
# SPDX-License-Identifier: AGPL-3.0-only
# Modified 2026-10-19 for v1.3; prior component notices are in NOTICE.
"""Canonical 11-class layout taxonomy."""
from __future__ import annotations

from ax_doclayout.errors import TaxonomyError

TAXONOMY_ID = "ax-doclayout-11/1"
RESERVED_ID = 0

CLASS_NAMES: dict[int, str] = {
    1: "caption",
    2: "footnote",
    3: "formula",
    4: "list_item",
    5: "page_footer",
    6: "page_header",
    7: "picture",
    8: "section_header",
    9: "table",
    10: "text",
    11: "title",
}

NAME_TO_ID: dict[str, int] = {name: class_id for class_id, name in CLASS_NAMES.items()}


def public_name(class_id: int) -> str:
    if class_id == RESERVED_ID:
        raise TaxonomyError("class_id_reserved")
    try:
        return CLASS_NAMES[class_id]
    except KeyError as exc:
        raise TaxonomyError("class_id_unknown") from exc


def public_id(class_name: str) -> int:
    try:
        return NAME_TO_ID[class_name]
    except KeyError as exc:
        raise TaxonomyError("class_name_unknown") from exc


def to_internal(class_id: int) -> int:
    """Map public 1–11 to zero-based indices 0–10."""
    if class_id not in CLASS_NAMES:
        raise TaxonomyError("class_id_unknown")
    return class_id - 1


def from_internal(index: int) -> int:
    class_id = index + 1
    if class_id not in CLASS_NAMES:
        raise TaxonomyError("class_id_unknown")
    return class_id