"""
External Nodes Classifier
=========================

The External Nodes Classifier is a master tops subsystem that retrieves mapping
information from major configuration management systems. One of the most common
external nodes classifiers system is provided by Cobbler and is called
``cobbler-ext-nodes``.

The cobbler-ext-nodes command can be used with this configuration:

.. code-block:: yaml

    master_tops:
      ext_nodes: cobbler-ext-nodes

It is noteworthy that the Salt system does not directly ingest the data
sent from the ``cobbler-ext-nodes`` command, but converts the data into
information that is used by a Salt top file.

Any command can replace the call to 'cobbler-ext-nodes' above, but currently the
data must be formatted in the same way that the standard 'cobbler-ext-nodes'
does.

See (admittedly degenerate and probably not complete) example:

.. code-block:: yaml

    classes:
      - basepackages
      - database

The above essentially is the same as a top.sls containing the following:

.. code-block:: yaml

    base:
      '*':
        - basepackages
        - database

    base:
      '*':
        - basepackages
        - database
"""

import logging
import shlex
import subprocess

import salt.utils.platform
import salt.utils.yaml

if salt.utils.platform.is_windows():
    from salt.utils.win_functions import escape_argument as _cmd_quote
else:
    _cmd_quote = shlex.quote

log = logging.getLogger(__name__)


def __virtual__():
    """
    Only run if properly configured
    """
    if __opts__["master_tops"].get("ext_nodes"):
        return True
    return False


def top(**kwargs):
    """
    Run the command configured
    """
    if "id" not in kwargs["opts"]:
        return {}
    proc = subprocess.run(
        [
            _cmd_quote(part)
            for part in shlex.split(
                __opts__["master_tops"]["ext_nodes"],
                posix=salt.utils.platform.is_windows() is False,
            )
            + [_cmd_quote(kwargs["opts"]["id"])]
        ],
        stdout=subprocess.PIPE,
        check=True,
    )
    ndata = salt.utils.yaml.safe_load(proc.stdout)
    if not ndata:
        log.info("master_tops ext_nodes call did not return any data")
    ret = {}
    if "environment" in ndata:
        env = ndata["environment"]
    else:
        env = "base"

    if "classes" in ndata:
        if isinstance(ndata["classes"], dict):
            ret[env] = list(ndata["classes"])
        elif isinstance(ndata["classes"], list):
            ret[env] = ndata["classes"]
        else:
            return ret
    else:
        log.info(
            'master_tops ext_nodes call did not have a dictionary with a "classes" key.'
        )

    return ret
