# -*- coding: utf-8 -*-
'''
Module for managing NFS version 3.
'''
from __future__ import absolute_import, print_function, unicode_literals

# Import python libs
import logging

# Import salt libs
from salt.ext import six
import salt.utils.files
import salt.utils.path
import salt.utils.stringutils

log = logging.getLogger(__name__)


def __virtual__():
    '''
    Only work on POSIX-like systems
    '''
    if not salt.utils.path.which('showmount'):
        return (False, 'The nfs3 execution module failed to load: the showmount binary is not in the path.')
    return True


def list_exports(exports='/etc/exports'):
    '''
    List configured exports

    CLI Example:

    .. code-block:: bash

        salt '*' nfs.list_exports
    '''
    ret = {}
    with salt.utils.files.fopen(exports, 'r') as efl:
        for line in salt.utils.stringutils.to_unicode(efl.read()).splitlines():
            if not line:
                continue
            if line.startswith('#'):
                continue
            comps = line.split()

            # Handle the case where the same path is given twice
            if not comps[0] in ret:
                ret[comps[0]] = []

            newshares = []
            for perm in comps[1:]:
                if perm.startswith('/'):
                    newshares.append(perm)
                    continue
                permcomps = perm.split('(')
                permcomps[1] = permcomps[1].replace(')', '')
                hosts = permcomps[0]
                if not isinstance(hosts, six.string_types):
                    # Lists, etc would silently mangle /etc/exports
                    raise TypeError('hosts argument must be a string')
                options = permcomps[1].split(',')
                ret[comps[0]].append({'hosts': hosts, 'options': options})
            for share in newshares:
                ret[share] = ret[comps[0]]
    return ret


def del_export(exports='/etc/exports', path=None):
    '''
    Remove an export

    CLI Example:

    .. code-block:: bash

        salt '*' nfs.del_export /media/storage
    '''
    edict = list_exports(exports)
    del edict[path]
    _write_exports(exports, edict)
    return edict


def add_export(exports='/etc/exports', path=None, hosts=None, options=None):
    '''
    Add an export

    CLI Example:

    .. code-block:: bash

        salt '*' nfs3.add_export path='/srv/test' hosts='127.0.0.1' options=['rw']
    '''
    if options is None:
        options = []
    if not isinstance(hosts, six.string_types):
        # Lists, etc would silently mangle /etc/exports
        raise TypeError('hosts argument must be a string')
    edict = list_exports(exports)
    if path not in edict:
        edict[path] = []
    new = {'hosts': hosts, 'options': options}
    edict[path].append(new)
    _write_exports(exports, edict)

    return new


def _write_exports(exports, edict):
    '''
    Write an exports file to disk

    If multiple shares were initially configured per line, like:

        /media/storage /media/data *(ro,sync,no_subtree_check)

    ...then they will be saved to disk with only one share per line:

        /media/storage *(ro,sync,no_subtree_check)
        /media/data *(ro,sync,no_subtree_check)
    '''
    with salt.utils.files.fopen(exports, 'w') as efh:
        for export in edict:
            line = salt.utils.stringutils.to_str(export)
            for perms in edict[export]:
                hosts = perms['hosts']
                options = ','.join(perms['options'])
                line += ' {0}({1})'.format(hosts, options)
            efh.write('{0}\n'.format(line))


def reload_exports():
    '''
    Trigger a reload of the exports file to apply changes

    CLI Example:

    .. code-block:: bash

        salt '*' nfs3.reload_exports
    '''
    ret = {}

    command = 'exportfs -r'

    output = __salt__['cmd.run_all'](command)
    ret['stdout'] = output['stdout']
    ret['stderr'] = output['stderr']
    # exportfs always returns 0, so retcode is useless
    # We will consider it an error if stderr is nonempty
    ret['result'] = output['stderr'] == ''

    return ret