#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright: Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function
__metaclass__ = type


DOCUMENTATION = '''
---
module: vertica_user
short_description: Adds or removes Vertica database users and assigns roles.
description:
  - Adds or removes Vertica database user and, optionally, assigns roles.
  - A user will not be removed until all the dependencies have been dropped.
  - In such a situation, if the module tries to remove the user it
    will fail and only remove roles granted to the user.
options:
  name:
    description:
      - Name of the user to add or remove.
    required: true
  profile:
    description:
      - Sets the user's profile.
  resource_pool:
    description:
      - Sets the user's resource pool.
  password:
    description:
      - The user's password encrypted by the MD5 algorithm.
      - The password must be generated with the format C("md5" + md5[password + username]),
        resulting in a total of 35 characters. An easy way to do this is by querying
        the Vertica database with select 'md5'||md5('<user_password><user_name>').
  expired:
    description:
      - Sets the user's password expiration.
    type: bool
  ldap:
    description:
      - Set to true if users are authenticated via LDAP.
      - The user will be created with password expired and set to I($ldap$).
    type: bool
  roles:
    description:
      - Comma separated list of roles to assign to the user.
    aliases: ['role']
  state:
    description:
      - Whether to create C(present), drop C(absent) or lock C(locked) a user.
    choices: ['present', 'absent', 'locked']
    default: present
  db:
    description:
      - Name of the Vertica database.
  cluster:
    description:
      - Name of the Vertica cluster.
    default: localhost
  port:
    description:
      - Vertica cluster port to connect to.
    default: 5433
  login_user:
    description:
      - The username used to authenticate with.
    default: dbadmin
  login_password:
    description:
      - The password used to authenticate with.
notes:
  - The default authentication assumes that you are either logging in as or sudo'ing
    to the C(dbadmin) account on the host.
  - This module uses C(pyodbc), a Python ODBC database adapter. You must ensure
    that C(unixODBC) and C(pyodbc) is installed on the host and properly configured.
  - Configuring C(unixODBC) for Vertica requires C(Driver = /opt/vertica/lib64/libverticaodbc.so)
    to be added to the C(Vertica) section of either C(/etc/odbcinst.ini) or C($HOME/.odbcinst.ini)
    and both C(ErrorMessagesPath = /opt/vertica/lib64) and C(DriverManagerEncoding = UTF-16)
    to be added to the C(Driver) section of either C(/etc/vertica.ini) or C($HOME/.vertica.ini).
requirements: [ 'unixODBC', 'pyodbc' ]
author: "Dariusz Owczarek (@dareko)"
'''

EXAMPLES = """
- name: creating a new vertica user with password
  vertica_user: name=user_name password=md5<encrypted_password> db=db_name state=present

- name: creating a new vertica user authenticated via ldap with roles assigned
  vertica_user:
    name=user_name
    ldap=true
    db=db_name
    roles=schema_name_ro
    state=present
"""
import traceback

PYODBC_IMP_ERR = None
try:
    import pyodbc
except ImportError:
    PYODBC_IMP_ERR = traceback.format_exc()
    pyodbc_found = False
else:
    pyodbc_found = True

from ansible.module_utils.basic import AnsibleModule, missing_required_lib
from ansible.module_utils._text import to_native


class NotSupportedError(Exception):
    pass


class CannotDropError(Exception):
    pass

# module specific functions


def get_user_facts(cursor, user=''):
    facts = {}
    cursor.execute("""
        select u.user_name, u.is_locked, u.lock_time,
        p.password, p.acctexpired as is_expired,
        u.profile_name, u.resource_pool,
        u.all_roles, u.default_roles
        from users u join password_auditor p on p.user_id = u.user_id
        where not u.is_super_user
        and (? = '' or u.user_name ilike ?)
    """, user, user)
    while True:
        rows = cursor.fetchmany(100)
        if not rows:
            break
        for row in rows:
            user_key = row.user_name.lower()
            facts[user_key] = {
                'name': row.user_name,
                'locked': str(row.is_locked),
                'password': row.password,
                'expired': str(row.is_expired),
                'profile': row.profile_name,
                'resource_pool': row.resource_pool,
                'roles': [],
                'default_roles': []}
            if row.is_locked:
                facts[user_key]['locked_time'] = str(row.lock_time)
            if row.all_roles:
                facts[user_key]['roles'] = row.all_roles.replace(' ', '').split(',')
            if row.default_roles:
                facts[user_key]['default_roles'] = row.default_roles.replace(' ', '').split(',')
    return facts


def update_roles(user_facts, cursor, user,
                 existing_all, existing_default, required):
    del_roles = list(set(existing_all) - set(required))
    if del_roles:
        cursor.execute("revoke {0} from {1}".format(','.join(del_roles), user))
    new_roles = list(set(required) - set(existing_all))
    if new_roles:
        cursor.execute("grant {0} to {1}".format(','.join(new_roles), user))
    if required:
        cursor.execute("alter user {0} default role {1}".format(user, ','.join(required)))


def check(user_facts, user, profile, resource_pool,
          locked, password, expired, ldap, roles):
    user_key = user.lower()
    if user_key not in user_facts:
        return False
    if profile and profile != user_facts[user_key]['profile']:
        return False
    if resource_pool and resource_pool != user_facts[user_key]['resource_pool']:
        return False
    if locked != (user_facts[user_key]['locked'] == 'True'):
        return False
    if password and password != user_facts[user_key]['password']:
        return False
    if (expired is not None and expired != (user_facts[user_key]['expired'] == 'True') or
            ldap is not None and ldap != (user_facts[user_key]['expired'] == 'True')):
        return False
    if roles and (sorted(roles) != sorted(user_facts[user_key]['roles']) or
                  sorted(roles) != sorted(user_facts[user_key]['default_roles'])):
        return False
    return True


def present(user_facts, cursor, user, profile, resource_pool,
            locked, password, expired, ldap, roles):
    user_key = user.lower()
    if user_key not in user_facts:
        query_fragments = ["create user {0}".format(user)]
        if locked:
            query_fragments.append("account lock")
        if password or ldap:
            if password:
                query_fragments.append("identified by '{0}'".format(password))
            else:
                query_fragments.append("identified by '$ldap$'")
        if expired or ldap:
            query_fragments.append("password expire")
        if profile:
            query_fragments.append("profile {0}".format(profile))
        if resource_pool:
            query_fragments.append("resource pool {0}".format(resource_pool))
        cursor.execute(' '.join(query_fragments))
        if resource_pool and resource_pool != 'general':
            cursor.execute("grant usage on resource pool {0} to {1}".format(
                resource_pool, user))
        update_roles(user_facts, cursor, user, [], [], roles)
        user_facts.update(get_user_facts(cursor, user))
        return True
    else:
        changed = False
        query_fragments = ["alter user {0}".format(user)]
        if locked is not None and locked != (user_facts[user_key]['locked'] == 'True'):
            if locked:
                state = 'lock'
            else:
                state = 'unlock'
            query_fragments.append("account {0}".format(state))
            changed = True
        if password and password != user_facts[user_key]['password']:
            query_fragments.append("identified by '{0}'".format(password))
            changed = True
        if ldap:
            if ldap != (user_facts[user_key]['expired'] == 'True'):
                query_fragments.append("password expire")
                changed = True
        elif expired is not None and expired != (user_facts[user_key]['expired'] == 'True'):
            if expired:
                query_fragments.append("password expire")
                changed = True
            else:
                raise NotSupportedError("Unexpiring user password is not supported.")
        if profile and profile != user_facts[user_key]['profile']:
            query_fragments.append("profile {0}".format(profile))
            changed = True
        if resource_pool and resource_pool != user_facts[user_key]['resource_pool']:
            query_fragments.append("resource pool {0}".format(resource_pool))
            if user_facts[user_key]['resource_pool'] != 'general':
                cursor.execute("revoke usage on resource pool {0} from {1}".format(
                    user_facts[user_key]['resource_pool'], user))
            if resource_pool != 'general':
                cursor.execute("grant usage on resource pool {0} to {1}".format(
                    resource_pool, user))
            changed = True
        if changed:
            cursor.execute(' '.join(query_fragments))
        if roles and (sorted(roles) != sorted(user_facts[user_key]['roles']) or
                      sorted(roles) != sorted(user_facts[user_key]['default_roles'])):
            update_roles(user_facts, cursor, user,
                         user_facts[user_key]['roles'], user_facts[user_key]['default_roles'], roles)
            changed = True
        if changed:
            user_facts.update(get_user_facts(cursor, user))
        return changed


def absent(user_facts, cursor, user, roles):
    user_key = user.lower()
    if user_key in user_facts:
        update_roles(user_facts, cursor, user,
                     user_facts[user_key]['roles'], user_facts[user_key]['default_roles'], [])
        try:
            cursor.execute("drop user {0}".format(user_facts[user_key]['name']))
        except pyodbc.Error:
            raise CannotDropError("Dropping user failed due to dependencies.")
        del user_facts[user_key]
        return True
    else:
        return False

# module logic


def main():

    module = AnsibleModule(
        argument_spec=dict(
            user=dict(required=True, aliases=['name']),
            profile=dict(default=None),
            resource_pool=dict(default=None),
            password=dict(default=None, no_log=True),
            expired=dict(type='bool', default=None),
            ldap=dict(type='bool', default=None),
            roles=dict(default=None, aliases=['role']),
            state=dict(default='present', choices=['absent', 'present', 'locked']),
            db=dict(default=None),
            cluster=dict(default='localhost'),
            port=dict(default='5433'),
            login_user=dict(default='dbadmin'),
            login_password=dict(default=None, no_log=True),
        ), supports_check_mode=True)

    if not pyodbc_found:
        module.fail_json(msg=missing_required_lib('pyodbc'), exception=PYODBC_IMP_ERR)

    user = module.params['user']
    profile = module.params['profile']
    if profile:
        profile = profile.lower()
    resource_pool = module.params['resource_pool']
    if resource_pool:
        resource_pool = resource_pool.lower()
    password = module.params['password']
    expired = module.params['expired']
    ldap = module.params['ldap']
    roles = []
    if module.params['roles']:
        roles = module.params['roles'].split(',')
        roles = filter(None, roles)
    state = module.params['state']
    if state == 'locked':
        locked = True
    else:
        locked = False
    db = ''
    if module.params['db']:
        db = module.params['db']

    changed = False

    try:
        dsn = (
            "Driver=Vertica;"
            "Server={0};"
            "Port={1};"
            "Database={2};"
            "User={3};"
            "Password={4};"
            "ConnectionLoadBalance={5}"
        ).format(module.params['cluster'], module.params['port'], db,
                 module.params['login_user'], module.params['login_password'], 'true')
        db_conn = pyodbc.connect(dsn, autocommit=True)
        cursor = db_conn.cursor()
    except Exception as e:
        module.fail_json(msg="Unable to connect to database: {0}.".format(e))

    try:
        user_facts = get_user_facts(cursor)
        if module.check_mode:
            changed = not check(user_facts, user, profile, resource_pool,
                                locked, password, expired, ldap, roles)
        elif state == 'absent':
            try:
                changed = absent(user_facts, cursor, user, roles)
            except pyodbc.Error as e:
                module.fail_json(msg=to_native(e), exception=traceback.format_exc())
        elif state in ['present', 'locked']:
            try:
                changed = present(user_facts, cursor, user, profile, resource_pool,
                                  locked, password, expired, ldap, roles)
            except pyodbc.Error as e:
                module.fail_json(msg=to_native(e), exception=traceback.format_exc())
    except NotSupportedError as e:
        module.fail_json(msg=to_native(e), ansible_facts={'vertica_users': user_facts})
    except CannotDropError as e:
        module.fail_json(msg=to_native(e), ansible_facts={'vertica_users': user_facts})
    except SystemExit:
        # avoid catching this on python 2.4
        raise
    except Exception as e:
        module.fail_json(msg=to_native(e), exception=traceback.format_exc())

    module.exit_json(changed=changed, user=user, ansible_facts={'vertica_users': user_facts})


if __name__ == '__main__':
    main()