from datetime import datetime
from subprocess import check_output

from jwebsite.content import Content
from jwebsite.context import Context


def load_extension(context: Context) -> None:
    context.add_filters(git_creation_date=_git_creation_date)


def _git_creation_date(content: Content) -> datetime:
    git_dir = check_output(["git", "rev-parse", "--show-toplevel"], encoding="utf-8")
    git_dir = git_dir.strip()
    log = check_output(
        [
            "git",
            "log",
            "--pretty=format:%ad",
            "--date=iso-strict",
            "--diff-filter=A",
            "--",
            str(content.path.relative_to(git_dir)),
        ],
        encoding="utf-8",
    )
    log_lines = log.splitlines()
    if len(log_lines) == 0:
        return datetime.now()

    return datetime.fromisoformat(log_lines[0])