"""Internal shared utilities for chardet."""

from __future__ import annotations

import warnings

#: Default maximum number of bytes to examine during detection.
DEFAULT_MAX_BYTES: int = 200_000

#: Default minimum confidence threshold for filtering results.
MINIMUM_THRESHOLD: float = 0.20

#: Default chunk_size value (deprecated, kept for backward-compat signatures).
_DEFAULT_CHUNK_SIZE: int = 65_536


def _warn_deprecated_chunk_size(chunk_size: int, stacklevel: int = 3) -> None:
    """Emit a deprecation warning if *chunk_size* differs from the default."""
    if chunk_size != _DEFAULT_CHUNK_SIZE:
        warnings.warn(
            "chunk_size is not used in this version of chardet and will be ignored",
            DeprecationWarning,
            stacklevel=stacklevel,
        )


def _validate_max_bytes(max_bytes: int) -> None:
    """Raise ValueError if *max_bytes* is not a positive integer."""
    if isinstance(max_bytes, bool) or not isinstance(max_bytes, int) or max_bytes < 1:
        msg = "max_bytes must be a positive integer"
        raise ValueError(msg)


def _resolve_prefer_superset(
    should_rename_legacy: bool, prefer_superset: bool, stacklevel: int = 3
) -> bool:
    """Resolve the deprecated *should_rename_legacy* into *prefer_superset*."""
    if should_rename_legacy:
        warnings.warn(
            "should_rename_legacy is deprecated, use prefer_superset instead",
            DeprecationWarning,
            stacklevel=stacklevel,
        )
        return True
    return prefer_superset


#: Mapping from ISO 639-1 language codes to English names.
#: Includes ``"und"`` (ISO 639-3 "Undetermined") for use when language is unknown.
ISO_TO_LANGUAGE: dict[str, str] = {
    "ar": "arabic",
    "be": "belarusian",
    "bg": "bulgarian",
    "br": "breton",
    "cs": "czech",
    "cy": "welsh",
    "da": "danish",
    "de": "german",
    "el": "greek",
    "en": "english",
    "eo": "esperanto",
    "es": "spanish",
    "et": "estonian",
    "fa": "farsi",
    "fi": "finnish",
    "fr": "french",
    "ga": "irish",
    "gd": "gaelic",
    "he": "hebrew",
    "hr": "croatian",
    "hu": "hungarian",
    "id": "indonesian",
    "is": "icelandic",
    "it": "italian",
    "ja": "japanese",
    "kk": "kazakh",
    "ko": "korean",
    "lt": "lithuanian",
    "lv": "latvian",
    "mk": "macedonian",
    "ms": "malay",
    "mt": "maltese",
    "nl": "dutch",
    "no": "norwegian",
    "pl": "polish",
    "pt": "portuguese",
    "ro": "romanian",
    "ru": "russian",
    "sk": "slovak",
    "sl": "slovene",
    "sr": "serbian",
    "sv": "swedish",
    "tg": "tajik",
    "th": "thai",
    "tr": "turkish",
    "uk": "ukrainian",
    "und": "undetermined",
    "ur": "urdu",
    "vi": "vietnamese",
    "zh": "chinese",
}