import subprocess
from io import StringIO

import pyinfra
from pyinfra import host
from pyinfra.operations import files, server, systemd


def dnsmasq_instance(net_name,
                     house_iface,
                     dhcp_range='10.2.0.10,10.2.0.11',
                     listen_address='reqd',
                     dhcp_hosts_filename='/dev/null'):
    files.directory(path=f'/opt/dnsmasq/{net_name}')
    files.template(
        src='templates/dnsmasq/dnsmasq.conf.j2',
        dest=f'/opt/dnsmasq/{net_name}/dnsmasq.conf',
        net=net_name,
        house_iface=house_iface,
        dhcp_range=dhcp_range,
        listen_address=listen_address,
        dhcp_enabled=net_name == '10.2' and host.name == 'pipe',
        dns_server=listen_address,
        router=listen_address,
    )
    files.template(src='templates/dnsmasq/hosts.j2', dest=f'/opt/dnsmasq/{net_name}/hosts', net=net_name)

    dhcp_hosts = subprocess.check_output(['python3', '/my/serv/lanscape/src/public/make_dhcp_hosts.py'], encoding='utf8')
    files.put(src=StringIO(dhcp_hosts), dest=f'/opt/dnsmasq/{net_name}/dhcp_hosts')

    files.template(src='templates/dnsmasq/dnsmasq.service.j2',
                   dest=f'/etc/systemd/system/dnsmasq_{net_name}.service',
                   net=net_name)
    if net_name in ['10.2', '10.2-filtered']:
        systemd.service(service=f'dnsmasq_{net_name}', enabled=True, restarted=True, daemon_reload=True)


def standard_host_dns():
    files.template(src='templates/hosts.j2', dest='/etc/hosts')
    if 'pi' in host.groups:
        files.put(dest='/etc/resolv.conf',
                  src=StringIO('''
# written by pyinfra
nameserver 10.2.0.3
search bigasterisk.com
                  '''))
    else:
        files.link(path='/etc/resolv.conf', target='/run/systemd/resolve/resolv.conf', force=True)
        files.template(src='templates/resolved.conf.j2', dest='/etc/systemd/resolved.conf')
        systemd.service(service='systemd-resolved.service', running=True, restarted=True)


def rpi_net_boot():
    files.directory(path='/opt/dnsmasq/tftp')


standard_host_dns()

# no default instance; i'll add some specific ones below
systemd.service(service='dnsmasq', enabled=False, running=False)


def watchLeasesFile():
    """summary:
    1. dnsmasq_10.2 leases an address and writes to /opt/dnsmasq/10.2/leases
    2. dhcp_graph_watch.path notices that change
    3. dhcp_graph_update.service posts /opt/dnsmasq/10.2/leases to dhcp_graph (k8s deploy)
    4. dhcp_graph serves the data as rdf
    """
    dhcp_graph_url = "http://10.5.0.7:8005"
    leases = "/opt/dnsmasq/10.2/leases"
    files.put(dest='/etc/systemd/system/dhcp_graph_watch.path',
              src=StringIO(f'''
[Unit]
Description=dhcp leases file changed- run dhcp_graph_update
After=localfs.target

[Path]
PathModified={leases}
Unit=dhcp_graph_update.service

[Install]
WantedBy=multi-user.target
'''))

    files.put(dest='/etc/systemd/system/dhcp_graph_update.service',
              src=StringIO(f'''
[Unit]
Description=Send new dhcp leases content to dhcp_graph
After=network.target

[Service]
Type=oneshot
ExecStart=/usr/bin/curl -s {dhcp_graph_url}/leases -H "content-type: text/plain" --data-binary "@{leases}"

[Install]
WantedBy=multi-user.target
'''))
    systemd.service(service='dhcp_graph_watch.path', enabled=True, restarted=True, daemon_reload=True)
    systemd.service(service='dhcp_graph_update.service', enabled=True, restarted=True, daemon_reload=True)


if host.name == 'pipe':
    rpi_net_boot()
    files.directory(path='/opt/dnsmasq')
    dnsmasq_instance('10.2',
                     house_iface='eth1',
                     dhcp_range='10.2.0.110,10.2.0.240',
                     listen_address='10.2.0.3',
                     dhcp_hosts_filename='templates/dnsmasq/dhcp_hosts.j2')
    out = '/opt/dnsmasq/10.2'
    # This mtail is for dhcp command counts and errors.
    files.put(src='files/dnsmasq/metrics.mtail', dest=f'{out}/metrics.mtail')
    files.put(src='files/dnsmasq/run_mtail.sh', dest=f'{out}/run_mtail.sh')

    watchLeasesFile()

    files.put(src='files/dnsmasq/dnsmasq-mtail.service', dest='/etc/systemd/system/dnsmasq-mtail.service')
    systemd.service(service='dnsmasq-mtail', enabled=True, restarted=True, daemon_reload=True)

    # Serve another dns, no dhcp, and include the dynamic-blocking file written by net_routes.
    dnsmasq_instance(
        net_name='10.2-filtered',
        house_iface='eth1',
        listen_address='10.2.0.4',
    )