import subprocess

from pyinfra import host
from pyinfra.facts.files import FindInFile
from pyinfra.operations import files, systemd

import wireguard_pubkey

# other options:
#   https://www.reddit.com/r/WireGuard/comments/fkr240/shortest_path_between_peers/
#   https://github.com/k4yt3x/wireguard-mesh-configurator
#   https://github.com/mawalu/wireguard-private-networking
#


def peer_block(hostname, allowed_ips, endpoint=None, keepalive=None):
    # allowed_ips should be determined mostly from host.data.wireguard_address

    public_key = wireguard_pubkey.pubkey[hostname]
    out = f'''\

[Peer]
# {hostname}
PublicKey = {public_key}
AllowedIPs = {allowed_ips}
'''
    if endpoint is not None:
        out += f'Endpoint = {endpoint}\n'
    if keepalive is not None:
        out += f'PersistentKeepalive = {keepalive}\n'
    return out


def get_priv_key(wireguard_interface) -> str:
    priv_key_lines = host.get_fact(FindInFile, path=f'/etc/wireguard/{wireguard_interface}.conf', pattern=r'PrivateKey.*')
    if not priv_key_lines:
        priv_key = subprocess.check_output(['wg', 'genkey']).strip().decode('ascii')
    else:
        priv_key = priv_key_lines[0].split(' = ')[1]
    return priv_key


def compute_pub_key(priv_key: str) -> str:
    pub_key = subprocess.check_output(['wg', 'pubkey'], input=priv_key.encode('ascii')).strip().decode('ascii')
    # todo: if this was new, it should be added to a file of pubkeys that
    # peer_block can refer to. meanwhile, edit the template.
    return pub_key


for wireguard_interface in ['wg0', 'bogasterisk']:
    if wireguard_interface == 'bogasterisk' and host.name != 'prime':
        continue

    # note- this is specific to the wg0 setup. Other conf files don't use it.
    wireguard_ip = host.host_data.get('wireguard_address')
    if wireguard_interface == 'wg0' and wireguard_ip is None:
        continue

    # new pi may fail with 'Unable to access interface: Protocol not supported'. reboot fixes.

    priv_key = get_priv_key(wireguard_interface)

    # unused since I still hand-maintain wireguard_pubkey.py :(
    # pub_key = compute_pub_key(priv_key)

    files.template(
        src=f'templates/wireguard/{wireguard_interface}.conf.j2',
        dest=f'/etc/wireguard/{wireguard_interface}.conf',
        mode='600',
        wireguard_ip=wireguard_ip,
        priv_key=priv_key,
        peer_block=peer_block,
    )
    svc = f'wg-quick@{wireguard_interface}.service'

    files.template(src='templates/wireguard/wg.service.j2',
                   dest=f'/etc/systemd/system/{svc}',
                   wireguard_interface=wireguard_interface)
    systemd.service(service=svc, daemon_reload=True, restarted=True, enabled=True)