import os
import unicodedata


def _slug(s: str) -> str:
    if not s:
        return ''
    s = unicodedata.normalize('NFKD', s)
    s = ''.join(c for c in s if not unicodedata.combining(c))
    s = ''.join(c for c in s if c.isalnum() or c in (' ', '_', '-'))
    return s.replace(' ', '_')


def generate_vcard(adresse, base_dir: str):
    """Generate a vCard 4.0 file for the given adresse object.

    adresse: object with attributes vorname, nachname, strasse, hausnummer,
             plz, ort, land, email, telefon_vorwahl, telefon_nummer, id
    base_dir: directory where 'vcards/' will be created

    Returns the path to the written vcard file.
    """
    vcards_dir = os.path.join(base_dir, 'vcards')
    os.makedirs(vcards_dir, exist_ok=True)

    filename = f"{_slug(adresse.nachname)}_{_slug(adresse.vorname)}_{adresse.id}.vcf"
    filepath = os.path.join(vcards_dir, filename)

    # build vCard 4.0 content
    lines = [
        'BEGIN:VCARD',
        'VERSION:4.0',
        f'N:{adresse.nachname};{adresse.vorname};;;',
        f'FN:{adresse.vorname} {adresse.nachname}',
    ]

    street = getattr(adresse, 'strasse', '') or ''
    hausnummer = getattr(adresse, 'hausnummer', '') or ''
    if hausnummer:
        street = f"{street} {hausnummer}".strip()

    adr = f'ADR:;;{street};{getattr(adresse, "ort", "")};;{getattr(adresse, "plz", "")};{getattr(adresse, "land", "")}'
    lines.append(adr)

    if getattr(adresse, 'email', None):
        lines.append(f'EMAIL;TYPE=internet:{adresse.email}')

    if getattr(adresse, 'telefon_vorwahl', None) or getattr(adresse, 'telefon_nummer', None):
        tel = f"+{getattr(adresse, 'telefon_vorwahl', '')}{getattr(adresse, 'telefon_nummer', '')}".replace('++', '+')
        lines.append(f'TEL;TYPE=voice:{tel}')

    lines.append('END:VCARD')

    with open(filepath, 'w', encoding='utf-8') as f:
        f.write('\n'.join(lines))

    return filepath