#!/usr/bin/python
# -*- coding: utf-8 -*-

# 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/>.

DOCUMENTATION = '''
---
module: postgresql_db
short_description: Add or remove PostgreSQL databases from a remote host.
description:
   - Add or remove PostgreSQL databases from a remote host.
version_added: "0.6"
options:
  name:
    description:
      - name of the database to add or remove
    required: true
    default: null
  login_user:
    description:
      - The username used to authenticate with
    required: false
    default: null
  login_password:
    description:
      - The password used to authenticate with
    required: false
    default: null
  login_host:
    description:
      - Host running the database
    required: false
    default: localhost
  owner:
    description:
      - Name of the role to set as owner of the database
    required: false
    default: null
  template:
    description:
      - Template used to create the database
    required: false
    default: null
  encoding:
    description:
      - Encoding of the database
    required: false
    default: null
  encoding:
    description:
      - Encoding of the database
    required: false
    default: null
  lc_collate:
    description:
      - Collation order (LC_COLLATE) to use in the database. Must match collation order of template database unless C(template0) is used as template.
    required: false
    default: null
  lc_ctype:
    description:
      - Character classification (LC_CTYPE) to use in the database (e.g. lower, upper, ...) Must match LC_CTYPE of template database unless C(template0) is used as template.
    required: false
    default: null
  state:
    description:
      - The database state
    required: false
    default: present
    choices: [ "present", "absent" ]
notes:
   - The default authentication assumes that you are either logging in as or sudo'ing to the C(postgres) account on the host.
   - This module uses I(psycopg2), a Python PostgreSQL database adapter. You must ensure that psycopg2 is installed on
     the host before using this module. If the remote host is the PostgreSQL server (which is the default case), then PostgreSQL must also be installed on the remote host. For Ubuntu-based systems, install the C(postgresql), C(libpq-dev), and C(python-psycopg2) packages on the remote host before using this module.
requirements: [ psycopg2 ]
author: Lorin Hochstein
'''

EXAMPLES = '''
# Create a new database with name "acme"
- postgresql_db: name=acme

# Create a new database with name "acme" and specific encoding and locale
# settings. If a template different from "template0" is specified, encoding
# and locale settings must match those of the template.
- postgresql_db: name=acme
                 encoding='UTF-8'
                 lc_collate='de_DE.UTF-8'
                 lc_ctype='de_DE.UTF-8'
                 template='template0'
'''

try:
    import psycopg2
    import psycopg2.extras
except ImportError:
    postgresqldb_found = False
else:
    postgresqldb_found = True

class NotSupportedError(Exception):
    pass


# ===========================================
# PostgreSQL module specific support methods.
#

def set_owner(cursor, db, owner):
    query = "ALTER DATABASE \"%s\" OWNER TO \"%s\"" % (db, owner)
    cursor.execute(query)
    return True

def get_encoding_id(cursor, encoding):
    query = "SELECT pg_char_to_encoding(%(encoding)s) AS encoding_id;"
    cursor.execute(query, {'encoding': encoding})
    return cursor.fetchone()['encoding_id']

def get_db_info(cursor, db):
    query = """
    SELECT rolname AS owner,
    pg_encoding_to_char(encoding) AS encoding, encoding AS encoding_id,
    datcollate AS lc_collate, datctype AS lc_ctype
    FROM pg_database JOIN pg_roles ON pg_roles.oid = pg_database.datdba
    WHERE datname = %(db)s
    """
    cursor.execute(query, {'db':db})
    return cursor.fetchone()

def db_exists(cursor, db):
    query = "SELECT * FROM pg_database WHERE datname=%(db)s"
    cursor.execute(query, {'db': db})
    return cursor.rowcount == 1

def db_delete(cursor, db):
    if db_exists(cursor, db):
        query = "DROP DATABASE \"%s\"" % db
        cursor.execute(query)
        return True
    else:
        return False

def db_create(cursor, db, owner, template, encoding, lc_collate, lc_ctype):
    if not db_exists(cursor, db):
        if owner:
            owner = " OWNER \"%s\"" % owner
        if template:
            template = " TEMPLATE \"%s\"" % template
        if encoding:
            encoding = " ENCODING '%s'" % encoding
        if lc_collate:
            lc_collate = " LC_COLLATE '%s'" % lc_collate
        if lc_ctype:
            lc_ctype = " LC_CTYPE '%s'" % lc_ctype
        query = 'CREATE DATABASE "%s"%s%s%s%s%s' % (db, owner,
                                                    template, encoding,
                                                    lc_collate, lc_ctype)
        cursor.execute(query)
        return True
    else:
        db_info = get_db_info(cursor, db)
        if (encoding and 
            get_encoding_id(cursor, encoding) != db_info['encoding_id']):
            raise NotSupportedError(
                'Changing database encoding is not supported. '
                'Current encoding: %s' % db_info['encoding']
            )
        elif lc_collate and lc_collate != db_info['lc_collate']:
            raise NotSupportedError(
                'Changing LC_COLLATE is not supported. '
                'Current LC_COLLATE: %s' % db_info['lc_collate']
            )
        elif lc_ctype and lc_ctype != db_info['lc_ctype']:
            raise NotSupportedError(
                'Changing LC_CTYPE is not supported.'
                'Current LC_CTYPE: %s' % db_info['lc_ctype']
            )
        elif owner and owner != db_info['owner']:
            return set_owner(cursor, db, owner)
        else:
            return False

def db_matches(cursor, db, owner, template, encoding, lc_collate, lc_ctype):
    if not db_exists(cursor, db):
       return False
    else:
        db_info = get_db_info(cursor, db)
        if (encoding and 
            get_encoding_id(cursor, encoding) != db_info['encoding_id']):
            return False
        elif lc_collate and lc_collate != db_info['lc_collate']:
            return False
        elif lc_ctype and lc_ctype != db_info['lc_ctype']:
            return False
        elif owner and owner != db_info['owner']:
            return False
        else:
            return True

# ===========================================
# Module execution.
#

def main():
    module = AnsibleModule(
        argument_spec=dict(
            login_user=dict(default="postgres"),
            login_password=dict(default=""),
            login_host=dict(default=""),
            port=dict(default="5432"),
            db=dict(required=True, aliases=['name']),
            owner=dict(default=""),
            template=dict(default=""),
            encoding=dict(default=""),
            lc_collate=dict(default=""),
            lc_ctype=dict(default=""),
            state=dict(default="present", choices=["absent", "present"]),
        ),
        supports_check_mode = True
    )

    if not postgresqldb_found:
        module.fail_json(msg="the python psycopg2 module is required")

    db = module.params["db"]
    port = module.params["port"]
    owner = module.params["owner"]
    template = module.params["template"]
    encoding = module.params["encoding"]
    lc_collate = module.params["lc_collate"]
    lc_ctype = module.params["lc_ctype"]
    state = module.params["state"]
    changed = False

    # To use defaults values, keyword arguments must be absent, so 
    # check which values are empty and don't include in the **kw
    # dictionary
    params_map = {
        "login_host":"host",
        "login_user":"user",
        "login_password":"password",
        "port":"port"
    }
    kw = dict( (params_map[k], v) for (k, v) in module.params.iteritems() 
              if k in params_map and v != '' )
    try:
        db_connection = psycopg2.connect(database="template1", **kw)
        # Enable autocommit so we can create databases
        if psycopg2.__version__ >= '2.4.2':
            db_connection.autocommit = True
        else:
            db_connection.set_isolation_level(psycopg2
                                              .extensions
                                              .ISOLATION_LEVEL_AUTOCOMMIT)
        cursor = db_connection.cursor(
                cursor_factory=psycopg2.extras.DictCursor)
    except Exception, e:
        module.fail_json(msg="unable to connect to database: %s" % e)

    try:
        if module.check_mode:
            if state == "absent":
                changed = not db_exists(cursor, db)
            elif state == "present":
                changed = not db_matches(cursor, db, owner, template, encoding,
                                         lc_collate, lc_ctype)
            module.exit_json(changed=changed,db=db)

        if state == "absent":
            changed = db_delete(cursor, db)

        elif state == "present":
            changed = db_create(cursor, db, owner, template, encoding,
                                lc_collate, lc_ctype)
    except NotSupportedError, e:
        module.fail_json(msg=str(e))
    except Exception, e:
        module.fail_json(msg="Database query failed: %s" % e)

    module.exit_json(changed=changed, db=db)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
main()