"""Model-facing text units.

``text`` is a list of strings with one entry per sentence or metrical line, in
the same order as ``conllu``. It used to be a JSON-encoded string; it is now a
plain list, so nothing needs decoding before use.
"""

from __future__ import annotations

from typing import Any


def load_text_units(units: Any) -> list[str]:
    """Validate a published text column and return it unchanged."""
    if not isinstance(units, list) or not units:
        raise ValueError("text must be a non-empty list")
    if not all(isinstance(unit, str) and unit.strip() for unit in units):
        raise ValueError("every text unit must be a non-empty string")
    return units


def source_text_units(value: Any) -> list[str]:
    """Accept either one internal string or an already-published list."""
    if isinstance(value, str):
        if not value.strip():
            raise ValueError("source text must be a non-empty string")
        return [value]
    return load_text_units(value)


def encode_text_units(units: list[str]) -> list[str]:
    """Validate text units for publication without changing them."""
    return load_text_units(units)