#!/usr/bin/python

# (c) 2012, Stephen Fromm <sfromm@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

try:
    import json
except ImportError:
    import simplejson as json
import os
import pwd
import grp
import shlex
import subprocess
import sys
import syslog
try:
    import spwd
    HAVE_SPWD=True
except:
    HAVE_SPWD=False

USERADD = "/usr/sbin/useradd"
USERMOD = "/usr/sbin/usermod"
USERDEL = "/usr/sbin/userdel"

def exit_json(rc=0, **kwargs):
    if 'name' in kwargs:
        add_user_info(kwargs)
    print json.dumps(kwargs)
    sys.exit(rc)

def fail_json(**kwargs):
    kwargs['failed'] = True
    exit_json(rc=1, **kwargs)

def add_user_info(kwargs):
    name = kwargs['name']
    if user_exists(name):
        kwargs['state'] = 'present'
        info = user_info(name)
        kwargs['uid'] = info[2]
        kwargs['group'] = info[3]
        kwargs['comment'] = info[4]
        kwargs['home'] = info[5]
        kwargs['shell'] = info[6]
        kwargs['createhome'] = os.path.exists(info[5])
        groups = user_group_membership(name)
        if len(groups) > 0:
            kwargs['groups'] = groups
    else:
        kwargs['state'] = 'absent'
    return kwargs

def user_del(user, **kwargs):
    cmd = [USERDEL]
    for key in kwargs:
        if key == 'force' and kwargs[key]:
            cmd.append('-f')
        elif key == 'remove' and kwargs[key]:
            cmd.append('-r')
    cmd.append(user)
    p = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    (out, err) = p.communicate()
    rc = p.returncode
    return (rc, out, err)

def user_add(user, **kwargs):
    cmd = [USERADD]
    for key in kwargs:
        if key == 'uid' and kwargs[key] is not None:
            cmd.append('-u')
            cmd.append(kwargs[key])
        elif key == 'group' and kwargs[key] is not None:
            if not group_exists(kwargs[key]):
                fail_json(msg="Group %s does not exist" % (kwargs[key]))
            cmd.append('-g')
            cmd.append(kwargs[key])
        elif key == 'groups' and kwargs[key] is not None:
            for g in kwargs[key].split(','):
                if not group_exists(g):
                    fail_json(msg="Group %s does not exist" % (g))
            cmd.append('-G')
            cmd.append(kwargs[key])
        elif key == 'comment' and kwargs[key] is not None:
            cmd.append('-c')
            cmd.append(kwargs[key])
        elif key == 'home' and kwargs[key] is not None:
            cmd.append('-d')
            cmd.append(kwargs[key])
        elif key == 'shell' and kwargs[key] is not None:
            cmd.append('-s')
            cmd.append(kwargs[key])
        elif key == 'password' and kwargs[key] is not None:
            cmd.append('-p')
            cmd.append(kwargs[key])
        elif key == 'createhome':
            if kwargs[key] is not None:
                if kwargs[key] == 'yes':
                    cmd.append('-m')
                else:
                    cmd.append('-M')
        elif key == 'system' and kwargs[key] == 'yes':
            cmd.append('-r')
    cmd.append(user)
    p = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    (out, err) = p.communicate()
    rc = p.returncode
    return (rc, out, err)

"""
Without spwd, we would have to resort to reading /etc/shadow
to get the encrypted string.  For now, punt on idempotent password changes.
"""
def user_mod(user, **kwargs):
    cmd = [USERMOD]
    info = user_info(user)
    for key in kwargs:
        if key == 'uid':
            if kwargs[key] is not None and info[2] != int(kwargs[key]):
                cmd.append('-u')
                cmd.append(kwargs[key])
        elif key == 'group' and kwargs[key] is not None:
            if not group_exists(kwargs[key]):
                fail_json(msg="Group %s does not exist" % (kwargs[key]))
            ginfo = group_info(group)
            if info[3] != ginfo[2]:
                cmd.append('-g')
                cmd.append(kwargs[key])
        elif key == 'groups' and kwargs[key] is not None:
            current_groups = user_group_membership(user)
            groups = kwargs[key].split(',')
            for g in groups:
                if not group_exists(g):
                    fail_json(msg="Group %s does not exist" % (g))
            group_diff = set(sorted(current_groups)).symmetric_difference(set(sorted(groups)))
            groups_need_mod = False

            if group_diff:
                if kwargs['append'] is not None and kwargs['append'] == 'yes':
                    for g in groups:
                        if g in group_diff:
                            cmd.append('-a')
                            groups_need_mod = True
                else:
                   groups_need_mod = True

            if groups_need_mod:
                cmd.append('-G')
                cmd.append(','.join(groups))

        elif key == 'comment':
            if kwargs[key] is not None and info[4] != kwargs[key]:
                cmd.append('-c')
                cmd.append(kwargs[key])
        elif key == 'home':
            if kwargs[key] is not None and info[5] != kwargs[key]:
                cmd.append('-d')
                cmd.append(kwargs[key])
        elif key == 'shell':
            if kwargs[key] is not None and info[6] != kwargs[key]:
                cmd.append('-s')
                cmd.append(kwargs[key])
        elif key == 'password':
            if kwargs[key] is not None and info[1] != kwargs[key]:
                cmd.append('-p')
                cmd.append(kwargs[key])
    # skip if no changes to be made
    if len(cmd) == 1:
        return (None, '', '')
    cmd.append(user)
    p = subprocess.Popen(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    (out, err) = p.communicate()
    rc = p.returncode
    return (rc, out, err)

def group_exists(group):
    try:
        if group.isdigit():
            if grp.getgrgid(group):
                return True
        else:
            if grp.getgrnam(group):
                return True
    except KeyError:
        return False

def group_info(group):
    if not group_exists(group):
        return False
    if group.isdigit():
        return list(grp.getgrgid(group))
    else:
        return list(grp.getgrnam(group))

def user_group_membership(user):
    groups = []
    info = get_pwd_info(user)
    for group in grp.getgrall():
        if user in group[3] and info[3] != group[2]:
            groups.append(group[0])
    return groups

def user_exists(user):
    try:
        if pwd.getpwnam(user):
            return True
    except KeyError:
        return False

def get_pwd_info(user):
    if not user_exists(user):
        return False
    return list(pwd.getpwnam(user))

def user_info(user):
    if not user_exists(user):
        return False
    try:
        info = get_pwd_info(user)
        if HAVE_SPWD:
            sinfo = spwd.getspnam(user)
    except KeyError:
        return False
    if HAVE_SPWD:
        info[1] = sinfo[1]
    return info

# ===========================================

if not os.path.exists(USERADD):
    if os.path.exists("/sbin/useradd"):
        USERADD = "/sbin/useradd"
    else:
        fail_json(msg="Cannot find useradd")
if not os.path.exists(USERMOD):
    if os.path.exists("/sbin/usermod"):
        USERMOD = "/sbin/usermod"
    else:
        fail_json(msg="Cannot find usermod")
if not os.path.exists(USERDEL):
    if os.path.exists("/sbin/userdel"):
        USERDEL = "/sbin/userdel"
    else:
        fail_json(msg="Cannot find userdel")

argfile = sys.argv[1]
args    = open(argfile, 'r').read()
items   = shlex.split(args)
syslog.openlog('ansible-%s' % os.path.basename(__file__))
syslog.syslog(syslog.LOG_NOTICE, 'Invoked with %s' % args)

if not len(items):
    fail_json(msg='the module requires arguments -a')
    sys.exit(1)

params = {}
for x in items:
    (k, v) = x.split("=")
    params[k] = v

state      = params.get('state','present')
name       = params.get('name', None)
uid        = params.get('uid', None)
group      = params.get('group', None)
groups     = params.get('groups', None)
comment    = params.get('comment', None)
home       = params.get('home', None)
shell      = params.get('shell', None)
password   = params.get('password', None)

# ===========================================
# following options are specific to userdel
force      = params.get('force', False)
remove     = params.get('remove', False)

# ===========================================
# following options are specific to useradd
createhome = params.get('createhome', 'yes')
system     = params.get('system', 'no')

# ===========================================
# following options are specific to usermod
append     = params.get('append', 'no')

if state not in [ 'present', 'absent' ]:
    fail_json(msg='invalid state')
if createhome not in [ 'yes', 'no' ]:
    fail_json(msg='invalid createhome')
if system not in ['yes', 'no']:
    fail_json(msg='invalid system')
if append not in [ 'yes', 'no' ]:
    fail_json(msg='invalid append')
if name is None:
    fail_json(msg='name is required')

result = {}
rc = 0
out = ''
err = ''
result['name'] = name
if state == 'absent':
    if not user_exists(name):
        result['changed'] = False
    else:
        (rc, out, err) = user_del(name, force=force, remove=remove)
        if rc != 0:
            fail_json(name=name, msg=err)
        else:
            result['changed'] = True
        result['force'] = force
        result['remove'] = remove
elif state == 'present':
    if not user_exists(name):
        (rc, out, err) = user_add(name, uid=uid, group=group, groups=groups,
                                  comment=comment, home=home, shell=shell,
                                  password=password, createhome=createhome,
                                  system=system)
    else:
        (rc, out, err) = user_mod(name, uid=uid, group=group, groups=groups,
                                  comment=comment, home=home, shell=shell,
                                  password=password, append=append)
    if rc is not None and rc != 0:
        fail_json(name=name, msg=err)
    if rc is None:
        result['changed'] = False
    else:
        result['changed'] = True
    if password is not None:
        result['password'] = 'NOTLOGGINGPASSWORD'

if out:
    result['stdout'] = out
if err:
    result['stderr'] = err
exit_json(**result)
sys.exit(0)