"""
NETCONF for APK Distributions server:
    ietf-interfaces module

Copyright © 2020 Adélie Software in the Public Benefit, Inc.

Released under the terms of the NCSA license.  See the LICENSE file included
with this source distribution for more information.

SPDX-License-Identifier: NCSA
"""

import logging
import pathlib
import subprocess

from lxml import etree
from netconf import util

from ncserver.base.util import _, yang_dt_for_timestamp


QName = etree.QName  # pylint: disable=I1101


LOGGER = logging.getLogger(__name__)
"""The object used for logging informational messages."""


M_ABI_VERSION = 1
"""The ABI version of this NETCONF module."""


M_PREFIX = "if"
"""The XML tag prefix for this module's tags."""


M_NS = "urn:ietf:params:xml:ns:yang:ietf-interfaces"
"""The XML namespace for this module."""


M_NAME = "ietf-interfaces"
"""The YANG model name for this module."""


M_REVISION = "2018-02-20"
"""The YANG revision date for this module."""


M_IMPORTS = {
    'ietf-yang-types@2013-07-15': {
        'ns': "urn:ietf:params:xml:ns:yang:ietf-yang-types", 'prefix': "yang"
    },
    'iana-if-type@2017-01-19': {
        'ns': "urn:ietf:params:xml:ns:yang:iana-if-type", 'prefix': "ianaift"
    }
}
"""The imported YANG modules for this module."""


M_FEATURES = ['pre-provisioning']
"""The supported features declared in YANG for this module."""


def _add_running_contents(ifaces):
    """Retrieve the interface configuration for this device.

    Allows returning the 'config true' data for both datastores."""
    types = {
            '1': 'ethernetCsmacd',
            '3': 'rfc877x25',
            '7': 'arcnet',
            '8': 'arap',
            '19': 'atm',
            '24': 'ieee1394',
            '32': 'infiniband',
            '256': 'slip',
            '512': 'ppp',
            '513': 'hdlc',
            '516': 'lapb',
            '768': 'tunnel',
            '770': 'frameRelay',
            '772': 'softwareLoopback',
            '774': 'fddi',
            '804': 'ieee802154'
    }

    for ifname in pathlib.Path('/sys/class/net').iterdir():
        iface = util.subelm(ifaces, 'if:interface')
        iface.append(util.leaf_elm('if:name', ifname.name))
        type_file = open(ifname / "type", 'r')
        type_num = type_file.read()
        type_file.close()
        type_num = type_num.strip()
        if type_num in types.keys():
            iana_xmlns = "urn:ietf:params:xml:ns:yang:iana-if-type"
            iface.append(util.leaf_elm('if:type', 'ianaift:'+types[type_num],
                         nsmap={'ianaift': iana_xmlns}))
        else:
            LOGGER.warning(_('unknown Linux hwtype for %s: %s'),
                           ifname.name, type_num)


def running(node):
    """Retrieve the service configuration for this device."""
    ifaces = util.subelm(node, 'if:interfaces')
    _add_running_contents(ifaces)


def _add_stats_to(iface, name: str):
    """Add the statistics node to +iface+."""
    counter_tags = {
            'rx.octets': 'if:in-octets',
            'rx.discard': 'if:in-discards',
            'rx.errors': 'if:in-errors',
            'tx.octets': 'if:out-octets',
            'tx.discard': 'if:out-discards',
            'tx.errors': 'if:out-errors'
    }

    stats = util.subelm(iface, 'if:statistics')
    # XXX BAD vvv
    stats.append(util.leaf_elm('if:discontinuity-time',
                               '2020-01-01T01:01:01.011Z'))
    # XXX BAD ^^^

    result = subprocess.run(['/sbin/ifupdown', 'ifctrstat', name],
                            stdout=subprocess.PIPE, check=False)
    if result.returncode != 0:
        LOGGER.error(_('ifctrstat failed for %s: %s'),
                     name, result.returncode)
        return

    counters = result.stdout.decode('utf-8').split('\n')
    counters.pop()
    for counter, value in [data.split(': ') for data in counters]:
        if counter not in counter_tags.keys():
            LOGGER.warning(_('unhandled ifctrstat counter for %s: %s'),
                           name, counter)
            continue
        stats.append(util.leaf_elm(counter_tags[counter], value))


def operational(node):
    """Retrieve the service state for this device."""
    ifaces = util.subelm(node, 'if:interfaces')
    _add_running_contents(ifaces)

    for iface in ifaces.iterchildren():
        name = iface.find('{'+M_NS+'}name').text
        ifpath = pathlib.Path("/sys/class/net/" + name)

        # if-index
        if (ifpath / "ifindex").exists():
            index_file = open(ifpath / "ifindex", 'r')
            iface.append(util.leaf_elm('if:if-index',
                                       index_file.read().strip()))
            index_file.close()

        # oper-status
        status = "unknown"
        if (ifpath / "operstate").exists():
            status_file = open(ifpath / "operstate", 'r')
            status = status_file.read().strip()
            status_file.close()
        iface.append(util.leaf_elm('if:oper-status', status))

        # speed
        if status == "up" and (ifpath / "speed").exists():
            try:
                with open(ifpath / "speed", 'r') as speed_file:
                    speed = int(speed_file.read().strip())
                    speed *= 1000
                    iface.append(util.leaf_elm('if:speed', speed))
            except IOError:
                pass  # if the interface does not have measurable speed, omit
            except ValueError:
                LOGGER.warning("%s has non-integral speed; kernel bug?", name)

        # phys-address
        if (ifpath / "address").exists():
            addr_file = open(ifpath / "address", 'r')
            iface.append(util.leaf_elm('if:phys-address',
                                       addr_file.read().strip()))
            addr_file.close()

        # statistics
        _add_stats_to(iface, name)


def edit(session, rpc, node, def_op):
    """Edit the interface configuration for this device."""