from urllib.parse import urlparse, quote_plus


def from_string(text):
    url = urlparse(text)
    if url.scheme != "project": # schema must be repository://
        raise Exception("Wrong scheme, should be project://")
    if not url.path:
        raise Exception("Missing slug part")
    split = url.path.split("@", 1)
    if len(split) == 2:
        domain = urlparse(f"ignore://{split[1]}")
        return (split[0], domain.netloc)
    return (split[0], None)


def to_string(slug, domain=None):
    if domain:
        return quote_plus(f"project:{slug}@{domain}")
    else:
        return quote_plus(f"project:{slug}")


print(from_string("project://fuu/bar@example.org"))
print(from_string("project://fuu/bar/baz/qux@example.org"))
print(from_string("project://fuu/bar/baz/qux"))
print(from_string("project://~hello/world"))
print(from_string("project://~hello/world@example.org"))
print(to_string("fuu/bar/baz", None))
print(to_string("fuu/bar/baz", "example.org"))