"""Coverage checks."""

from __future__ import annotations

from zsgdp.schema import PageProfile, ParsedDocument


def page_text_chars(parsed: ParsedDocument, page_num: int) -> int:
    return sum(len(element.content()) for element in parsed.elements if element.page_num == page_num)


def coverage_ratio(page: PageProfile, parsed: ParsedDocument) -> float:
    expected = max(page.digital_text_chars, 1)
    observed = page_text_chars(parsed, page.page_num)
    return min(observed / expected, 1.0)