PiCopy/picopy/wifi.py

"""PiCopy – WiFi: wifi_state, wifi_lock, nm(), Helpers, wifi_monitor."""

import subprocess
import threading
import time

from picopy.config import (
    NM_AP_CON, NM_CLIENT_CON,
    load_cfg, log
)

wifi_state = {
    'mode': 'unknown',   # 'client' | 'ap' | 'disconnected'
    'ssid': '',
    'ip': '',
}
wifi_lock = threading.Lock()


def nm(*args):
    return subprocess.run(['nmcli'] + list(args),
                          capture_output=True, text=True, timeout=20)


def get_wlan0_info():
    r = nm('-t', '-f', 'DEVICE,STATE,CONNECTION', 'dev')
    for line in r.stdout.splitlines():
        parts = line.split(':')
        if parts and parts[0] == 'wlan0':
            return {
                'state': parts[1] if len(parts) > 1 else '',
                'connection': ':'.join(parts[2:]) if len(parts) > 2 else '',
            }
    return {'state': '', 'connection': ''}


def get_wifi_ip():
    r = nm('-t', '-f', 'IP4.ADDRESS', 'dev', 'show', 'wlan0')
    for line in r.stdout.splitlines():
        if 'IP4.ADDRESS' in line:
            ip = line.split(':')[-1].split('/')[0].strip()
            if ip:
                return ip
    return ''


def is_client_connected():
    info = get_wlan0_info()
    return (info['state'] == 'connected'
            and info['connection']
            and NM_AP_CON not in info['connection'])


def is_ap_active():
    r = nm('-t', '-f', 'NAME,STATE', 'con', 'show', '--active')
    return any(NM_AP_CON in l and 'activated' in l for l in r.stdout.splitlines())


def start_ap(ssid, password):
    if len(password) < 8:
        log.error(f'AP-Passwort zu kurz ({len(password)} Zeichen, min. 8 für WPA2)')
        return False
    log.info(f'Starte AP: {ssid}')
    nm('con', 'delete', NM_AP_CON)
    time.sleep(1)
    r = nm('dev', 'wifi', 'hotspot',
           'ifname', 'wlan0',
           'ssid', ssid,
           'password', password,
           'con-name', NM_AP_CON)
    ok = r.returncode == 0
    if ok:
        log.info('AP gestartet')
    else:
        log.error(f'AP Fehler: {r.stderr}')
    return ok


def stop_ap():
    log.info('Stoppe AP')
    nm('con', 'down', NM_AP_CON)


def _purge_foreign_wifi_profiles():
    """Löscht alle WLAN-Profile die nicht von PiCopy verwaltet werden (z.B. Imager-Profile)."""
    r = nm('-t', '-f', 'NAME,TYPE', 'con', 'show')
    for line in r.stdout.splitlines():
        parts = line.split(':', 1)
        if len(parts) == 2 and parts[1] == '802-11-wireless' and parts[0] not in (NM_CLIENT_CON, NM_AP_CON):
            nm('con', 'delete', parts[0])
            log.info(f'Fremdprofil gelöscht: {parts[0]}')


def connect_client_wifi(ssid, password):
    log.info(f'Verbinde mit WiFi: {ssid}')
    nm('con', 'delete', NM_CLIENT_CON)
    time.sleep(1)

    # Scan erzwingen – sonst findet nmcli das Netz nach dem Boot nicht im Cache
    log.info('WiFi-Scan läuft...')
    nm('dev', 'wifi', 'rescan')
    time.sleep(4)

    try:
        # --wait 45: genug Zeit für Scan + WPA-Handshake + DHCP
        r = subprocess.run(
            ['nmcli', '--wait', '45', 'dev', 'wifi', 'connect', ssid,
             'password', password, 'name', NM_CLIENT_CON, 'ifname', 'wlan0'],
            capture_output=True, text=True, timeout=55,
        )
    except subprocess.TimeoutExpired:
        log.warning(f'WiFi-Verbindung Timeout (SSID: {ssid})')
        return False
    ok = r.returncode == 0
    if ok:
        log.info(f'Verbunden mit {ssid}')
    else:
        log.error(f'WiFi-Verbindung fehlgeschlagen: {r.stderr.strip()}')
    return ok


def scan_wifi_networks():
    nm('dev', 'wifi', 'rescan')
    time.sleep(2)
    r = nm('-t', '-f', 'SSID,SIGNAL,SECURITY', 'dev', 'wifi', 'list')
    seen, nets = set(), []
    for line in r.stdout.splitlines():
        parts = line.split(':')
        if len(parts) >= 2:
            ssid = parts[0].strip()
            signal = parts[1].strip() if len(parts) > 1 else '0'
            security = ':'.join(parts[2:]).strip() if len(parts) > 2 else ''
            if ssid and ssid not in seen:
                seen.add(ssid)
                nets.append({'ssid': ssid, 'signal': int(signal) if signal.isdigit() else 0, 'security': security})
    return sorted(nets, key=lambda x: -x['signal'])


def update_wifi_state():
    info = get_wlan0_info()
    if info['state'] == 'connected':
        if NM_AP_CON in info['connection']:
            with wifi_lock:
                wifi_state.update(mode='ap',
                                  ssid=load_cfg().get('ap_ssid', 'PiCopy'),
                                  ip='10.42.0.1')
        else:
            ip = get_wifi_ip()
            with wifi_lock:
                wifi_state.update(mode='client',
                                  ssid=info['connection'],
                                  ip=ip)
    else:
        with wifi_lock:
            wifi_state.update(mode='disconnected', ssid='', ip='')


def _wait_for_nm(max_wait: int = 30) -> None:
    """Wartet bis NetworkManager bereit ist, statt eine feste Zeit zu schlafen."""
    for i in range(max_wait):
        r = nm('general', 'status')
        if r.returncode == 0:
            if i > 0:
                log.info(f'NetworkManager bereit nach {i}s')
            return
        time.sleep(1)
    log.warning('NetworkManager nach 30s noch nicht bereit')


def wifi_monitor():
    log.info('WiFi-Monitor: warte auf NetworkManager...')
    _wait_for_nm()
    _purge_foreign_wifi_profiles()

    connect_failures = 0

    while True:
        try:
            update_wifi_state()
            with wifi_lock:
                mode = wifi_state['mode']

            cfg  = load_cfg()
            ssid = cfg.get('wifi_ssid', '')
            pw   = cfg.get('wifi_password', '')

            if mode == 'client':
                connect_failures = 0  # Verbindung OK – Zähler zurücksetzen

            elif mode == 'disconnected':
                connected = False
                if ssid:
                    log.info(f'Verbindungsversuch {connect_failures + 1}: {ssid}')
                    connected = connect_client_wifi(ssid, pw)
                    if connected:
                        connect_failures = 0
                        time.sleep(5)
                        update_wifi_state()
                    else:
                        connect_failures += 1

                # AP erst starten wenn kein SSID konfiguriert ODER nach 2 Fehlversuchen
                if not connected and (not ssid or connect_failures >= 2):
                    ap_ssid = cfg.get('ap_ssid', 'PiCopy')
                    ap_pw   = cfg.get('ap_password', 'PiCopy123')
                    log.info(f'Starte Fallback-AP nach {connect_failures} Fehlversuchen')
                    if start_ap(ap_ssid, ap_pw):
                        connect_failures = 0
                        time.sleep(3)
                        with wifi_lock:
                            wifi_state.update(mode='ap', ssid=ap_ssid, ip='10.42.0.1')

        except Exception as e:
            log.error(f'WiFi-Monitor Fehler: {e}')

        time.sleep(30)