# -*- encoding: utf-8 -*-
#
# Copyright © 2014 Alexey Dubkov
#
# This file is part of py-zabbix.
#
# Py-zabbix 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.
#
# Py-zabbix 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 py-zabbix. If not, see <http://www.gnu.org/licenses/>.

import json
import logging
import os
import ssl
import sys
import base64

# For Python 2 and 3 compatibility
try:
    import urllib2
except ImportError:
    # Since Python 3, urllib2.Request and urlopen were moved to
    # the urllib.request.
    import urllib.request as urllib2

from .version import __version__
from .logger import NullHandler, HideSensitiveFilter, HideSensitiveService

null_handler = NullHandler()
logger = logging.getLogger(__name__)
logger.addHandler(null_handler)
logger.addFilter(HideSensitiveFilter())


class ZabbixAPIException(Exception):
    """ZabbixAPI exception class.

    :code list:
    :32602: Invalid params (eg already exists)
    :32500: No permissions
    """
    def __init__(self, *args):
        super(Exception, self).__init__(*args)
        if len(args) == 1 and isinstance(args[0], dict):
            self.error = args[0]
            self.error['json'] = HideSensitiveService.hide_sensitive(self.error['json'])
            self.message = self.error['message']
            self.code = self.error['code']
            self.data = self.error['data']
            self.json = self.error['json']


class ZabbixAPIObjectClass(object):
    """ZabbixAPI Object class.

    :type group: str
    :param group: Zabbix API method group name.
        Example: `apiinfo.version` method it will be `apiinfo`.

    :type parent: :class:`zabbix.api.ZabbixAPI` object
    :param parent: ZabbixAPI object to use as parent.
    """

    def __init__(self, group, parent):
        self.group = group
        self.parent = parent

    def __getattr__(self, name):
        """Dynamically create a method.

        :type name: str
        :param name: Zabbix API method name.
            Example: `apiinfo.version` method it will be `version`.
        """

        def fn(*args, **kwargs):
            if args and kwargs:
                raise TypeError("Found both args and kwargs")

            method = '{0}.{1}'.format(self.group, name)
            logger.debug("Call %s method", method)

            return self.parent.do_request(
                method,
                args or kwargs
            )['result']

        return fn


def ssl_context_compat(func):
    def inner(req):
        # We should explicitly disable cert verification to support
        # self-signed certs with urllib2 since Python 2.7.9 and 3.4.3

        default_version = (2, 7, 9)
        version = {
            2: default_version,
            3: (3, 4, 3),
        }

        python_version = sys.version_info[0]
        minimum_version = version.get(python_version, default_version)

        if sys.version_info[0:3] >= minimum_version:
            # Create default context to skip SSL cert verification.
            ctx = ssl.create_default_context()
            ctx.check_hostname = False
            ctx.verify_mode = ssl.CERT_NONE
            res = func(req, context=ctx)
        else:
            res = func(req)

        return res

    return inner


@ssl_context_compat
def urlopen(*args, **kwargs):
    return urllib2.urlopen(*args, **kwargs)


class ZabbixAPI(object):
    """ZabbixAPI class, implement interface to zabbix api.

    :type url: str
    :param url: URL to zabbix api. Default: `ZABBIX_URL` or
        `https://localhost/zabbix`

    :type use_authenticate: bool
    :param use_authenticate: Use `user.authenticate` method if `True` else
        `user.login`.

    :type use_basic_auth: bool
    :param use_basic_auth: Using basic auth if `True`

    :type user: str
    :param user: Zabbix user name. Default: `ZABBIX_USER` or `'Admin'`.

    :type password: str
    :param password: Zabbix user password. Default `ZABBIX_PASSWORD` or
        `zabbix`.

    >>> from pyzabbix import ZabbixAPI
    >>> z = ZabbixAPI('https://zabbix.server', user='Admin', password='zabbix')
    >>> # Get API Version
    >>> z.api_info.version()
    >>> u'2.2.1'
    >>> # or
    >>> z.do_request('apiinfo.version')
    >>> {u'jsonrpc': u'2.0', u'result': u'2.2.1', u'id': u'1'}
    >>> # Get all disabled hosts
    >>> z.host.get(status=1)
    >>> # or
    >>> z.do_request('host.getobjects', {'status': 1})
    """

    def __init__(self, url=None, use_authenticate=False, use_basic_auth=False, user=None,
                 password=None):

        url = url or os.environ.get('ZABBIX_URL') or 'https://localhost/zabbix'
        user = user or os.environ.get('ZABBIX_USER') or 'Admin'
        password = password or os.environ.get('ZABBIX_PASSWORD') or 'zabbix'

        self.use_authenticate = use_authenticate
        self.use_basic_auth = use_basic_auth
        self.auth = None
        self.url = url + '/api_jsonrpc.php'
        self.base64_cred = self.cred_to_base64(user, password) if self.use_basic_auth else None
        self._login(user, password)
        logger.debug("JSON-PRC Server: %s", self.url)

    def __getattr__(self, name):
        """Dynamically create an object class (ie: host).

        :type name: str
        :param name: Zabbix API method group name.
            Example: `apiinfo.version` method it will be `apiinfo`.
        """

        return ZabbixAPIObjectClass(name, self)

    def _login(self, user='', password=''):
        """Do login to zabbix server.

        :type user: str
        :param user: Zabbix user

        :type password: str
        :param password: Zabbix user password
        """

        logger.debug("ZabbixAPI.login({0},{1})".format(user, HideSensitiveService.HIDEMASK))

        self.auth = None

        if self.use_authenticate:
            self.auth = self.user.authenticate(user=user, password=password)
        else:
            self.auth = self.user.login(user=user, password=password)

    def _logout(self):
        """Do logout from zabbix server."""

        if self.auth:
            logger.debug("ZabbixAPI.logout()")

            if self.user.logout():
                self.auth = None

    def __enter__(self):
        return self

    def __exit__(self, *args):
        self._logout()

    @staticmethod
    def cred_to_base64(user, password):
        """Create header for basic authorization
        :type user: str
        :param user: Zabbix user

        :type password: str
        :param password: Zabbix user password
        :return: str
        """
        base64string = base64.b64encode('{}:{}'.format(user, password).encode())
        return base64string.decode()

    def api_version(self):
        """Return version of server Zabbix API.

        :rtype: str
        :return: Version of server Zabbix API.
        """

        return self.apiinfo.version()

    def do_request(self, method, params=None):
        """Make request to Zabbix API.

        :type method: str
        :param method: ZabbixAPI method, like: `apiinfo.version`.

        :type params: str
        :param params: ZabbixAPI method arguments.

        >>> from pyzabbix import ZabbixAPI
        >>> z = ZabbixAPI()
        >>> apiinfo = z.do_request('apiinfo.version')
        """

        request_json = {
            'jsonrpc': '2.0',
            'method': method,
            'params': params or {},
            'id': '1',
        }

        # apiinfo.version and user.login doesn't require auth token
        if self.auth and (method not in ('apiinfo.version', 'user.login')):
            request_json['auth'] = self.auth

        logger.debug(
            'urllib2.Request({0}, {1})'.format(
                self.url,
                json.dumps(request_json)))

        data = json.dumps(request_json)
        if not isinstance(data, bytes):
            data = data.encode("utf-8")

        req = urllib2.Request(self.url, data)
        req.get_method = lambda: 'POST'
        req.add_header('Content-Type', 'application/json-rpc')
        req.add_header('User-Agent', 'py-zabbix/{}'.format(__version__))

        if self.use_basic_auth:
            req.add_header("Authorization", "Basic {}".format(self.base64_cred))

        try:
            res = urlopen(req)
            res_str = res.read().decode('utf-8')
            res_json = json.loads(res_str)
        except ValueError as e:
            raise ZabbixAPIException("Unable to parse json: %s" % e.message)

        res_str = json.dumps(res_json, indent=4, separators=(',', ': '))
        logger.debug("Response Body: %s", res_str)

        if 'error' in res_json:
            err = res_json['error'].copy()
            err.update({'json': str(request_json)})
            raise ZabbixAPIException(err)

        return res_json

    def get_id(self, item_type, item=None, with_id=False, hostid=None, **args):
        """Return id or ids of zabbix objects.

        :type item_type: str
        :param item_type: Type of zabbix object. (eg host, item etc.)

        :type item: str
        :param item: Name of zabbix object. If it is `None`, return list of
            all objects in the scope.

        :type with_id: bool
        :param with_id: Returned values will be in zabbix json `id` format.
            Examlpe: `{'itemid: 128}`

        :type name: bool
        :param name: Return name instead of id.

        :type hostid: int
        :param hostid: Filter objects by specific hostid.

        :type templateids: int
        :param tempateids: Filter objects which only belong to specific
            templates by template id.

        :type app_name: str
        :param app_name: Filter object which only belong to specific
            application.

        :rtype: int or list
        :return: Return single `id`, `name` or list of values.
        """

        result = None
        name = args.get('name', False)

        type_ = '{item_type}.get'.format(item_type=item_type)

        item_filter_name = {
            'mediatype': 'description',
            'trigger': 'description',
            'triggerprototype': 'description',
            'user': 'alias',
            'usermacro': 'macro',
        }

        item_id_name = {
            'discoveryrule': 'item',
            'graphprototype': 'graph',
            'hostgroup': 'group',
            'itemprototype': 'item',
            'map': 'selement',
            'triggerprototype': 'trigger',
            'usergroup': 'usrgrp',
            'usermacro': 'hostmacro',
        }

        filter_ = {
            'filter': {
                item_filter_name.get(item_type, 'name'): item,
            },
            'output': 'extend'}

        if hostid:
            filter_['filter'].update({'hostid': hostid})

        if args.get('templateids'):
            if item_type == 'usermacro':
                filter_['hostids'] = args['templateids']
            else:
                filter_['templateids'] = args['templateids']

        if args.get('app_name'):
            filter_['application'] = args['app_name']

        logger.debug(
            'do_request( "{type}", {filter} )'.format(
                type=type_,
                filter=filter_))
        response = self.do_request(type_, filter_)['result']

        if response:
            item_id_str = item_id_name.get(item_type, item_type)
            item_id = '{item}id'.format(item=item_id_str)
            result = []
            for obj in response:
                # Check if object not belong current template
                if args.get('templateids'):
                    if (not obj.get('templateid') in ("0", None) or
                            not len(obj.get('templateids', [])) == 0):
                        continue

                if name:
                    o = obj.get(item_filter_name.get(item_type, 'name'))
                    result.append(o)
                elif with_id:
                    result.append({item_id: int(obj.get(item_id))})
                else:
                    result.append(int(obj.get(item_id)))

            list_types = (list, type(None))
            if not isinstance(item, list_types):
                result = result[0]

        return result