#!/usr/bin/python

# -*- coding: utf-8 -*-

# Copyright (C) 2009-2012:
#    Gabes Jean, naparuba@gmail.com
#    Gerhard Lausser, Gerhard.Lausser@consol.de
#    Gregory Starck, g.starck@gmail.com
#    Hartmut Goebel, h.goebel@goebel-consult.de
#
# This file is part of Shinken.
#
# Shinken is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Shinken 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with Shinken.  If not, see <http://www.gnu.org/licenses/>.

# import von modules/livestatus_logstore

"""
This class is for attaching a mongodb database to a livestatus broker module.
It is one possibility for an exchangeable storage for log broks
"""

import os
import time
import datetime
import re
import sys
import pymongo

from shinken.objects.service import Service
from shinken.modulesctx import modulesctx

# Import a class from the livestatus module, should be already loaded!
livestatus = modulesctx.get_module('livestatus')

LiveStatusStack = livestatus.LiveStatusStack
LOGCLASS_INVALID = livestatus.LOGCLASS_INVALID
Logline = livestatus.Logline


from pymongo import Connection
try:
    from pymongo import ReplicaSetConnection, ReadPreference
except ImportError:
    ReplicaSetConnection = None
    ReadPreference = None
from pymongo.errors import AutoReconnect

from shinken.basemodule import BaseModule
from shinken.objects.module import Module
from shinken.log import logger
from shinken.util import to_bool

properties = {
    'daemons': ['livestatus'],
    'type': 'logstore_mongodb',
    'external': False,
    'phases': ['running'],
    }


# called by the plugin manager
def get_instance(plugin):
    logger.info("[LogstoreMongoDB] Get an LogStore MongoDB module for plugin %s" % plugin.get_name())
    instance = LiveStatusLogStoreMongoDB(plugin)
    return instance


def row_factory(cursor, row):
    """Handler for the sqlite fetch method."""
    return Logline(cursor.description, row)

CONNECTED = 1
DISCONNECTED = 2
SWITCHING = 3


class LiveStatusLogStoreError(Exception):
    pass


class LiveStatusLogStoreMongoDB(BaseModule):

    def __init__(self, modconf):
        BaseModule.__init__(self, modconf)
        self.plugins = []
        # mongodb://host1,host2,host3/?safe=true;w=2;wtimeoutMS=2000
        self.mongodb_uri = getattr(modconf, 'mongodb_uri', None)
        self.replica_set = getattr(modconf, 'replica_set', None)
        if self.replica_set and not ReplicaSetConnection:
            logger.error('[LogStoreMongoDB] Can not initialize LogStoreMongoDB module with '
                         'replica_set because your pymongo lib is too old. '
                         'Please install it with a 2.x+ version from '
                         'https://github.com/mongodb/mongo-python-driver/downloads')
            return None
        self.database = getattr(modconf, 'database', 'logs')
        self.collection = getattr(modconf, 'collection', 'logs')
        self.use_aggressive_sql = True
        self.mongodb_fsync = to_bool(getattr(modconf, 'mongodb_fsync', "True"))
        max_logs_age = getattr(modconf, 'max_logs_age', '365')
        maxmatch = re.match(r'^(\d+)([dwmy]*)$', max_logs_age)
        if maxmatch is None:
            logger.warning('[LogStoreMongoDB] Wrong format for max_logs_age. Must be <number>[d|w|m|y] or <number> and not %s' % max_logs_age)
            return None
        else:
            if not maxmatch.group(2):
                self.max_logs_age = int(maxmatch.group(1))
            elif maxmatch.group(2) == 'd':
                self.max_logs_age = int(maxmatch.group(1))
            elif maxmatch.group(2) == 'w':
                self.max_logs_age = int(maxmatch.group(1)) * 7
            elif maxmatch.group(2) == 'm':
                self.max_logs_age = int(maxmatch.group(1)) * 31
            elif maxmatch.group(2) == 'y':
                self.max_logs_age = int(maxmatch.group(1)) * 365
        self.use_aggressive_sql = (getattr(modconf, 'use_aggressive_sql', '1') == '1')
        # This stack is used to create a full-blown select-statement
        self.mongo_filter_stack = LiveStatusMongoStack()
        # This stack is used to create a minimal select-statement which
        # selects only by time >= and time <=
        self.mongo_time_filter_stack = LiveStatusMongoStack()
        self.is_connected = DISCONNECTED
        self.backlog = []
        # Now sleep one second, so that won't get lineno collisions with the last second
        time.sleep(1)
        self.lineno = 0

    def load(self, app):
        self.app = app

    def init(self):
        pass

    def open(self):
        try:
            if self.replica_set:
                self.conn = pymongo.ReplicaSetConnection(self.mongodb_uri, replicaSet=self.replica_set, fsync=self.mongodb_fsync)
            else:
                # Old versions of pymongo do not known about fsync
                if ReplicaSetConnection:
                    self.conn = pymongo.Connection(self.mongodb_uri, fsync=self.mongodb_fsync)
                else:
                    self.conn = pymongo.Connection(self.mongodb_uri)
            self.db = self.conn[self.database]
            self.db[self.collection].ensure_index([('host_name', pymongo.ASCENDING), ('time', pymongo.ASCENDING), ('lineno', pymongo.ASCENDING)], name='logs_idx')
            self.db[self.collection].ensure_index([('time', pymongo.ASCENDING), ('lineno', pymongo.ASCENDING)], name='time_1_lineno_1')
            if self.replica_set:
                pass
                # This might be a future option prefer_secondary
                #self.db.read_preference = ReadPreference.SECONDARY
            self.is_connected = CONNECTED
            self.next_log_db_rotate = time.time()
        except AutoReconnect, exp:
            # now what, ha?
            logger.error("[LogStoreMongoDB] LiveStatusLogStoreMongoDB.AutoReconnect %s" % (exp))
            # The mongodb is hopefully available until this module is restarted
            raise LiveStatusLogStoreError
        except Exception, exp:
            # If there is a replica_set, but the host is a simple standalone one
            # we get a "No suitable hosts found" here.
            # But other reasons are possible too.
            logger.error("[LogStoreMongoDB] Could not open the database" % exp)
            raise LiveStatusLogStoreError

    def close(self):
        self.conn.disconnect()

    def commit(self):
        pass

    def commit_and_rotate_log_db(self):
        """For a MongoDB there is no rotate, but we will delete old contents."""
        now = time.time()
        if self.next_log_db_rotate <= now:
            today = datetime.date.today()
            today0000 = datetime.datetime(today.year, today.month, today.day, 0, 0, 0)
            today0005 = datetime.datetime(today.year, today.month, today.day, 0, 5, 0)
            oldest = today0000 - datetime.timedelta(days=self.max_logs_age)
            self.db[self.collection].remove({u'time': {'$lt': time.mktime(oldest.timetuple())}})

            if now < time.mktime(today0005.timetuple()):
                nextrotation = today0005
            else:
                nextrotation = today0005 + datetime.timedelta(days=1)

            # See you tomorrow
            self.next_log_db_rotate = time.mktime(nextrotation.timetuple())
            logger.info("[LogStoreMongoDB] Next log rotation at %s " % time.asctime(time.localtime(self.next_log_db_rotate)))


    def manage_log_brok(self, b):
        data = b.data
        line = data['log']
        if re.match("^\[[0-9]*\] [A-Z][a-z]*.:", line):
            # Match log which NOT have to be stored
            # print "Unexpected in manage_log_brok", line
            return
        logline = Logline(line=line)
        values = logline.as_dict()
        if logline.logclass != LOGCLASS_INVALID:
            try:
                self.db[self.collection].insert(values)
                self.is_connected = CONNECTED
                # If we have a backlog from an outage, we flush these lines
                # First we make a copy, so we can delete elements from
                # the original self.backlog
                backloglines = [bl for bl in self.backlog]
                for backlogline in backloglines:
                    try:
                        self.db[self.collection].insert(backlogline)
                        self.backlog.remove(backlogline)
                    except AutoReconnect, exp:
                        self.is_connected = SWITCHING
                    except Exception, exp:
                        logger.error("[LogStoreMongoDB] Got an exception inserting the backlog" % str(exp))
            except AutoReconnect, exp:
                if self.is_connected != SWITCHING:
                    self.is_connected = SWITCHING
                    time.sleep(5)
                    # Under normal circumstances after these 5 seconds
                    # we should have a new primary node
                else:
                    # Not yet? Wait, but try harder.
                    time.sleep(0.1)
                # At this point we must save the logline for a later attempt
                # After 5 seconds we either have a successful write
                # or another exception which means, we are disconnected
                self.backlog.append(values)
            except Exception, exp:
                self.is_connected = DISCONNECTED
                logger.error("[LogStoreMongoDB] Databased error occurred:" % exp)
            # FIXME need access to this #self.livestatus.count_event('log_message')
        else:
            logger.info("[LogStoreMongoDB] This line is invalid: %s" % line)


    def add_filter(self, operator, attribute, reference):
        if attribute == 'time':
            self.mongo_time_filter_stack.put_stack(self.make_mongo_filter(operator, attribute, reference))
        self.mongo_filter_stack.put_stack(self.make_mongo_filter(operator, attribute, reference))


    def add_filter_and(self, andnum):
        self.mongo_filter_stack.and_elements(andnum)


    def add_filter_or(self, ornum):
        self.mongo_filter_stack.or_elements(ornum)


    def add_filter_not(self):
        self.mongo_filter_stack.not_elements()


    def get_live_data_log(self):
        """Like get_live_data, but for log objects"""
        # finalize the filter stacks
        self.mongo_time_filter_stack.and_elements(self.mongo_time_filter_stack.qsize())
        self.mongo_filter_stack.and_elements(self.mongo_filter_stack.qsize())
        if self.use_aggressive_sql:
            # Be aggressive, get preselected data from sqlite and do less
            # filtering in python. But: only a subset of Filter:-attributes
            # can be mapped to columns in the logs-table, for the others
            # we must use "always-true"-clauses. This can result in
            # funny and potentially ineffective sql-statements
            mongo_filter_func = self.mongo_filter_stack.get_stack()
        else:
            # Be conservative, get everything from the database between
            # two dates and apply the Filter:-clauses in python
            mongo_filter_func = self.mongo_time_filter_stack.get_stack()
        dbresult = []
        mongo_filter = mongo_filter_func()
        logger.debug("[Logstore MongoDB] Mongo filter is %s" % str(mongo_filter))
        # We can apply the filterstack here as well. we have columns and filtercolumns.
        # the only additional step is to enrich log lines with host/service-attributes
        # A timerange can be useful for a faster preselection of lines

        filter_element = eval('{ ' + mongo_filter + ' }')
        logger.debug("[LogstoreMongoDB] Mongo filter is %s" % str(filter_element))
        columns = ['logobject', 'attempt', 'logclass', 'command_name', 'comment', 'contact_name', 'host_name', 'lineno', 'message', 'plugin_output', 'service_description', 'state', 'state_type', 'time', 'type']
        if not self.is_connected == CONNECTED:
            logger.warning("[LogStoreMongoDB] sorry, not connected")
        else:
            dbresult = [Logline([(c,) for c in columns], [x[col] for col in columns]) for x in self.db[self.collection].find(filter_element).sort([(u'time', pymongo.ASCENDING), (u'lineno', pymongo.ASCENDING)])]
        return dbresult


    def make_mongo_filter(self, operator, attribute, reference):
        # The filters are text fragments which are put together to form a sql where-condition finally.
        # Add parameter Class (Host, Service), lookup datatype (default string), convert reference
        # which attributes are suitable for a sql statement
        good_attributes = ['time', 'attempt', 'logclass', 'command_name', 'comment', 'contact_name', 'host_name', 'plugin_output', 'service_description', 'state', 'state_type', 'type']
        good_operators = ['=', '!=']
        #  put strings in '' for the query
        string_attributes = ['command_name', 'comment', 'contact_name', 'host_name', 'plugin_output', 'service_description', 'state_type', 'type']
        if attribute in string_attributes:
            reference = "'%s'" % reference

        # We should change the "class" query into the internal "logclass" attribute
        if attribute == 'class':
            attribute = 'logclass'

        def eq_filter():
            if reference == '':
                return '\'%s\' : \'\'' % (attribute,)
            else:
                return '\'%s\' : %s' % (attribute, reference)

        def match_filter():
            return '\'%s\' : { \'$regex\' : %s }' % (attribute, reference)

        def eq_nocase_filter():
            if reference == '':
                return '\'%s\' : \'\'' % (attribute,)
            else:
                return '\'%s\' : { \'$regex\' : %s, \'$options\' : \'i\' }' % (attribute, '^' + reference + '$')

        def match_nocase_filter():
            return '\'%s\' : { \'$regex\' : %s, \'$options\' : \'i\' }' % (attribute, reference)

        def lt_filter():
            return '\'%s\' : { \'$lt\' : %s }' % (attribute, reference)

        def gt_filter():
            return '\'%s\' : { \'$gt\' : %s }' % (attribute, reference)

        def le_filter():
            return '\'%s\' : { \'$lte\' : %s }' % (attribute, reference)

        def ge_filter():
            return '\'%s\' : { \'$gte\' : %s }' % (attribute, reference)

        def ne_filter():
            if reference == '':
                return '\'%s\' : { \'$ne\' : '' }' % (attribute,)
            else:
                return '\'%s\' : { \'$ne\' : %s }' % (attribute, reference)

        def not_match_filter():
            # http://myadventuresincoding.wordpress.com/2011/05/19/mongodb-negative-regex-query-in-mongo-shell/
            return '\'%s\' : { \'$regex\' : %s }' % (attribute, '^((?!' + reference + ').)')

        def ne_nocase_filter():
            if reference == '':
                return '\'%s\' : \'\'' % (attribute,)
            else:
                return '\'%s\' : { \'$regex\' : %s, \'$options\' : \'i\' }' % (attribute, '^((?!' + reference + ').)')

        def not_match_nocase_filter():
            return '\'%s\' : { \'$regex\' : %s, \'$options\' : \'i\' }' % (attribute, '^((?!' + reference + ').)')

        def no_filter():
            return '\'time\' : { \'$exists\' : True }'

        if attribute not in good_attributes:
            return no_filter
        if operator == '=':
            return eq_filter
        elif operator == '~':
            return match_filter
        elif operator == '=~':
            return eq_nocase_filter
        elif operator == '~~':
            return match_nocase_filter
        elif operator == '<':
            return lt_filter
        elif operator == '>':
            return gt_filter
        elif operator == '<=':
            return le_filter
        elif operator == '>=':
            return ge_filter
        elif operator == '!=':
            return ne_filter
        elif operator == '!~':
            return not_match_filter
        elif operator == '!=~':
            return ne_nocase_filter
        elif operator == '!~~':
            return not_match_nocase_filter


class LiveStatusMongoStack(LiveStatusStack):
    """A Lifo queue for filter functions.

    This class inherits either from MyLifoQueue or Queue.LifoQueue
    whatever is available with the current python version.

    Public functions:
    and_elements -- takes a certain number (given as argument)
    of filters from the stack, creates a new filter and puts
    this filter on the stack. If these filters are lambda functions,
    the new filter is a boolean and of the underlying filters.
    If the filters are sql where-conditions, they are also concatenated
    with and to form a new string containing a more complex where-condition.

    or_elements --- the same, only that the single filters are
    combined with a logical or.

    """

    def __init__(self, *args, **kw):
        self.type = 'mongo'
        self.__class__.__bases__[0].__init__(self, *args, **kw)

    def not_elements(self):
        top_filter = self.get_stack()
        #negate_filter = lambda: '\'$not\': { %s }' % top_filter()
        # mongodb doesn't have the not-operator like sql, which can negate
        # a complete expression. Mongodb $not can only reverse one operator
        # at a time. This would require rewriting of the whole expression.
        # So instead of deciding whether a record can pass the filter or not,
        # we let it pass in any case. That's no problem, because the result
        # of the database query will have to go through the in-memory-objects
        # filter too.
        negate_filter = lambda: '\'time\' : { \'$exists\' : True }'
        self.put_stack(negate_filter)

    def and_elements(self, num):
        """Take num filters from the stack, and them and put the result back"""
        if num > 1:
            filters = []
            for _ in range(num):
                filters.append(self.get_stack())
            # Take from the stack:
            # Make a combined anded function
            # Put it on the stack
            logger.debug("[Logstore MongoDB] Filter is %s" % str(filters))
            and_clause = lambda: '\'$and\' : [%s]' % ', '.join('{ ' + x() + ' }' for x in filters)
            logger.debug("[Logstore MongoDB] and_elements %s" % str(and_clause))
            self.put_stack(and_clause)

    def or_elements(self, num):
        """Take num filters from the stack, or them and put the result back"""
        if num > 1:
            filters = []
            for _ in range(num):
                filters.append(self.get_stack())
            or_clause = lambda: '\'$or\' : [%s]' % ', '.join('{ ' + x() + ' }' for x in filters)
            self.put_stack(or_clause)

    def get_stack(self):
        """Return the top element from the stack or a filter which is always true"""
        if self.qsize() == 0:
            return lambda: ''
        else:
            return self.get()