"""
Check that the rev value in the example from ``the_basics.md`` matches
the latest version of Black. This saves us from forgetting to update that
during the release process.
"""

import os
import sys

import commonmark
from bs4 import BeautifulSoup  # type: ignore[import]


def main(changes: str, the_basics: str) -> None:
    changes_html = commonmark.commonmark(changes)
    changes_soup = BeautifulSoup(changes_html, "html.parser")
    headers = changes_soup.find_all("h2")
    tags = [header.string for header in headers if header.string != "Unreleased"]
    latest_tag = tags[0]

    the_basics_html = commonmark.commonmark(the_basics)
    the_basics_soup = BeautifulSoup(the_basics_html, "html.parser")
    version_examples = [
        code_block.string
        for code_block in the_basics_soup.find_all(class_="language-console")
        if "$ black --version" in code_block.string
    ]

    for tag in tags:
        for version_example in version_examples:
            if tag in version_example and tag != latest_tag:
                print(
                    "Please set the version in the ``black --version`` "
                    "examples from ``the_basics.md`` to be the latest one.\n"
                    f"Expected {latest_tag}, got {tag}.\n"
                )
                sys.exit(1)


if __name__ == "__main__":
    with open("CHANGES.md", encoding="utf-8") as fd:
        changes = fd.read()
    with open(
        os.path.join("docs", "usage_and_configuration", "the_basics.md"),
        encoding="utf-8",
    ) as fd:
        the_basics = fd.read()
    main(changes, the_basics)