import nh3

SAFE_CSS_PROPERTIES = {
    'font-size',
    'font-family',
    'font-weight',
    'font-style',
    'color',
    'background-color',
    'vertical-align',
    'text-decoration',
    'text-decoration-line',
    'text-decoration-skip-ink',
    'line-height',
    'margin-top',
    'margin-bottom',
    'padding-inline-start',
    'white-space',
    'white-space-collapse',
    'text-wrap-mode',
    'list-style-type',
    'font-variant-numeric',
    'font-variant-east-asian',
    'font-variant-alternates',
    'font-variant-position',
    'font-variant-emoji',
}


SAFE_TAGS = {
    'b',
    'i',
    'strong',
    'em',
    'u',
    'strike',
    'a',
    'br',
    'ol',
    'ul',
    'li',
    'span',
    'div',
    'p',
    'font',
}


SAFE_ATTRS = {
    'a': {'href', 'target', 'rel'},
    'span': {'style', 'id', 'dir'},
    'div': {'style', 'id'},
    'p': {'style', 'id', 'dir', 'role'},
    'ol': {'style', 'dir'},
    'ul': {'style', 'dir'},
    'li': {'style', 'dir', 'aria-level'},
    'font': {'color', 'face'},
}


SAFE_PROTOCOLS = {'http', 'https'}


def sanitize_relationship_notes(html: str) -> str:
    """
    Sanitize the relationship notes HTML by allowing only a restricted set of
    safe tags, attributes, and protocols.

    Args:
        html (str): Raw HTML string to sanitize.

    Returns:
        str: Cleaned HTML where disallowed tags and attributes are removed.
    """
    return nh3.clean(
        html,
        tags=SAFE_TAGS,
        attributes=SAFE_ATTRS,
        url_schemes=SAFE_PROTOCOLS,
        link_rel=None,
        filter_style_properties=SAFE_CSS_PROPERTIES,
    )