VCARD_KEY_KEY = "KEY:data:application/pgp-keys;base64,"


def parse_vcard(vcard: str) -> (str, str, str):
    """Parse a vCard and return the email, public key, and display name.

    :param vcard: the vCard string
    :return: a tuple with the email, the public key, and the display name
    """
    email, public_key, display_name = ("", "", "")
    for line in vcard.splitlines():
        if line.startswith("EMAIL:"):
            email = line.strip("EMAIL:")
        elif line.startswith(VCARD_KEY_KEY):
            public_key = line.strip(VCARD_KEY_KEY)
        elif line.startswith("FN:"):
            display_name = line.strip("FN:")
    return email, public_key, display_name


def construct_vcard(email: str, public_key: str, display_name: str) -> str:
    """Construct a VCard 4.0 string with the email address and the public key

    :param email: the email address of the requested contact
    :param public_key: the public key of the requested contact
    :param display_name: the display name of the requested contact
    :return: the VCard string
    """
    lines = [
        "BEGIN:VCARD",
        "VERSION:4.0",
        f"EMAIL:{email}",
        f"KEY:data:application/pgp-keys;base64,{public_key}",
    ]
    if display_name:
        lines.append(f"FN:{display_name}")
    lines.append("END:VCARD")
    return "\n".join(lines)


def save_vcard(path: str, content: str) -> None:
    """Save the VCard string to the blob directory

    :param path: the /tmp path of the .vcf file
    :param content: the VCard content
    """
    with open(path, "w+") as f:
        f.write(content)