"""
Manage groups on Mac OS 10.7+
"""

import salt.utils.functools
import salt.utils.itertools
import salt.utils.stringutils
from salt.exceptions import CommandExecutionError, SaltInvocationError
from salt.modules.mac_user import _dscl, _flush_dscl_cache

try:
    import grp
except ImportError:
    pass


# Define the module's virtual name
__virtualname__ = "group"


def __virtual__():
    global _dscl, _flush_dscl_cache
    if __grains__.get("kernel") != "Darwin" or __grains__["osrelease_info"] < (10, 7):
        return (
            False,
            "The mac_group execution module cannot be loaded: only available on Darwin-based systems >= 10.7",
        )
    _dscl = salt.utils.functools.namespaced_function(_dscl, globals())
    _flush_dscl_cache = salt.utils.functools.namespaced_function(
        _flush_dscl_cache, globals()
    )
    return __virtualname__


def add(name, gid=None, **kwargs):
    """
    Add the specified group

    CLI Example:

    .. code-block:: bash

        salt '*' group.add foo 3456
    """
    ### NOTE: **kwargs isn't used here but needs to be included in this
    ### function for compatibility with the group.present state
    if info(name):
        raise CommandExecutionError("Group '{}' already exists".format(name))
    if salt.utils.stringutils.contains_whitespace(name):
        raise SaltInvocationError("Group name cannot contain whitespace")
    if name.startswith("_"):
        raise SaltInvocationError(
            "Salt will not create groups beginning with underscores"
        )
    if gid is not None and not isinstance(gid, int):
        raise SaltInvocationError("gid must be an integer")
    # check if gid is already in use
    gid_list = _list_gids()
    if str(gid) in gid_list:
        raise CommandExecutionError("gid '{}' already exists".format(gid))

    cmd = ["dseditgroup", "-o", "create"]
    if gid:
        cmd.extend(["-i", gid])
    cmd.append(name)
    return __salt__["cmd.retcode"](cmd, python_shell=False) == 0


def _list_gids():
    """
    Return a list of gids in use
    """
    output = __salt__["cmd.run"](
        ["dscacheutil", "-q", "group"], output_loglevel="quiet", python_shell=False
    )
    ret = set()
    for line in salt.utils.itertools.split(output, "\n"):
        if line.startswith("gid:"):
            ret.update(line.split()[1:])
    return sorted(ret)


def delete(name):
    """
    Remove the named group

    CLI Example:

    .. code-block:: bash

        salt '*' group.delete foo
    """
    if salt.utils.stringutils.contains_whitespace(name):
        raise SaltInvocationError("Group name cannot contain whitespace")
    if name.startswith("_"):
        raise SaltInvocationError(
            "Salt will not remove groups beginning with underscores"
        )
    if not info(name):
        return True
    cmd = ["dseditgroup", "-o", "delete", name]
    return __salt__["cmd.retcode"](cmd, python_shell=False) == 0


def adduser(group, name):
    """
    Add a user in the group.

    CLI Example:

    .. code-block:: bash

         salt '*' group.adduser foo bar

    Verifies if a valid username 'bar' as a member of an existing group 'foo',
    if not then adds it.
    """
    cmd = "dscl . -merge /Groups/{} GroupMembership {}".format(group, name)
    return __salt__["cmd.retcode"](cmd) == 0


def deluser(group, name):
    """
    Remove a user from the group

    .. versionadded:: 2016.3.0

    CLI Example:

    .. code-block:: bash

         salt '*' group.deluser foo bar

    Removes a member user 'bar' from a group 'foo'. If group is not present
    then returns True.
    """
    cmd = "dscl . -delete /Groups/{} GroupMembership {}".format(group, name)
    return __salt__["cmd.retcode"](cmd) == 0


def members(name, members_list):
    """
    Replaces members of the group with a provided list.

    .. versionadded:: 2016.3.0

    CLI Example:

    .. code-block:: bash

        salt '*' group.members foo 'user1,user2,user3,...'

    Replaces a membership list for a local group 'foo'.
    """
    retcode = 1
    grp_info = __salt__["group.info"](name)
    if grp_info and name in grp_info["name"]:
        cmd = "/usr/bin/dscl . -delete /Groups/{} GroupMembership".format(name)
        retcode = __salt__["cmd.retcode"](cmd) == 0
        for user in members_list.split(","):
            cmd = "/usr/bin/dscl . -merge /Groups/{} GroupMembership {}".format(
                name, user
            )
            retcode = __salt__["cmd.retcode"](cmd)
            if not retcode == 0:
                break
            # provided list is '': users previously deleted from group
            else:
                retcode = 0

    return retcode == 0


def info(name):
    """
    Return information about a group

    CLI Example:

    .. code-block:: bash

        salt '*' group.info foo
    """
    if salt.utils.stringutils.contains_whitespace(name):
        raise SaltInvocationError("Group name cannot contain whitespace")
    try:
        # getgrnam seems to cache weirdly, so don't use it
        grinfo = next(iter(x for x in grp.getgrall() if x.gr_name == name))
    except StopIteration:
        return {}
    else:
        return _format_info(grinfo)


def _format_info(data):
    """
    Return formatted information in a pretty way.
    """
    return {
        "name": data.gr_name,
        "gid": data.gr_gid,
        "passwd": data.gr_passwd,
        "members": data.gr_mem,
    }


def getent(refresh=False):
    """
    Return info on all groups

    CLI Example:

    .. code-block:: bash

        salt '*' group.getent
    """
    if "group.getent" in __context__ and not refresh:
        return __context__["group.getent"]

    ret = []
    for grinfo in grp.getgrall():
        if not grinfo.gr_name.startswith("_"):
            ret.append(_format_info(grinfo))
    __context__["group.getent"] = ret
    return ret


def chgid(name, gid):
    """
    Change the gid for a named group

    CLI Example:

    .. code-block:: bash

        salt '*' group.chgid foo 4376
    """
    if not isinstance(gid, int):
        raise SaltInvocationError("gid must be an integer")
    pre_gid = __salt__["file.group_to_gid"](name)
    pre_info = info(name)
    if not pre_info:
        raise CommandExecutionError("Group '{}' does not exist".format(name))
    if gid == pre_info["gid"]:
        return True
    cmd = ["dseditgroup", "-o", "edit", "-i", gid, name]
    return __salt__["cmd.retcode"](cmd, python_shell=False) == 0
