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

from __future__ import print_function, unicode_literals
import logging
import re
import time

import ffstatus
from .exceptions import VpnKeyFormatError


def sanitize_node(data, include_raw_data=False):
    """
    Filters potentially harmful entries from the node's data.
    """
    export = ffstatus.dict_merge({}, data)

    # remove fields from output: __RAW__
    if '__RAW__' in export and not include_raw_data:
        del export['__RAW__']

    return export


class BaseStorage(object):
    """
    Provides operations on the storage data.
    This class gets subclassed to actually write the data
    to a file, database, whatever.
    """

    DATAKEY_VPN = '__VPN__'
    FIELDKEY_UPDATED = '__UPDATED__'

    __data = None

    @property
    def data(self):
        """Contains the data handled by this storage."""
        return self.__data

    def init_data(self, data):
        """setter for data property"""
        if self.__data is not None:
            msg = 'Tried to initialize storage data a second time.'
            logging.error(msg)
            raise Exception(msg)

        logging.debug('Setting initial storage data (%d items).',
                      len(data) if data is not None else 0)
        self.__data = data

    def open(self):
        """
        When overridden in a subclass,
        closes the persistent storage.
        """
        pass

    def save(self):
        """
        When overriden in a subclass,
        stores the data to a persistent storage.
        """
        pass

    def close(self):
        """
        When overridden in a subclass,
        closes the persistent storage.
        """
        pass

    def merge_new_data(self, newdata):
        """Updates data in the storage by merging the new data."""

        if newdata is None or not isinstance(newdata, dict):
            raise ValueError("Expected a dict as new data.")

        # start merge on a copy of the current data
        current = ffstatus.dict_merge(self.data, {})
        for item_id in current:
            if not item_id in newdata:
                continue

            current[item_id]['aliases'] = []
            current[item_id]['clients'] = []
            current[item_id]['neighbours'] = []

            if not '__RAW__' in current[item_id]:
                current[item_id]['__RAW__'] = {}

            if '__RAW__' in newdata[item_id]:
                for key in newdata[item_id]['__RAW__']:
                    if key in current[item_id]['__RAW__']:
                        del current[item_id]['__RAW__'][key]

        # merge the dictionaries
        updated = ffstatus.dict_merge(current, newdata)

        # sanitize each item's data
        for itemid in updated:
            if itemid.startswith('__'):
                continue
            item = updated[itemid]

            # remove node's MACs from clients list
            clients = [x for x in item.get('clients', [])]
            if 'mac' in item and item['mac'] in clients:
                clients.remove(item['mac'])
            for mac in item.get('macs', []):
                if mac in clients:
                    clients.remove(mac)

            # set clientcount
            updated[itemid]['clientcount'] = len(clients)

        # set the new data
        self.__data = updated

    def get_nodes(self, sortby=None, include_raw_data=False):
        """Gets a list of all known nodes."""

        sorted_ids = self.data.keys()
        if sortby is not None:
            if sortby == 'name':
                sortkey = lambda x: self.data[x]['hostname'].lower()
                sorted_ids = sorted(self.data, key=sortkey)
            elif sortby == 'id':
                sorted_ids = sorted(self.data)

        result = []
        for nodeid in sorted_ids:
            if nodeid.startswith('__'):
                continue
            node = sanitize_node(self.data[nodeid], include_raw_data)
            result.append(node)

        return result

    def find_node(self, rawid):
        """
        Fetch node data by given id.
        If necessary, look through node aliases.
        """

        # if we have a direct hit, return it immediately
        if rawid in self.data:
            return sanitize_node(self.data[rawid])

        # no direct hit -> search via aliases
        nodeid = rawid
        for nid in self.data:
            node = self.data[nid]
            if 'aliases' in node and rawid in node['aliases']:
                nodeid = nid

        # return found node
        if nodeid in self.data:
            return sanitize_node(self.data[nodeid])
        else:
            return None

    def find_node_by_mac(self, mac):
        """Fetch node data by given MAC address."""

        needle = mac.lower()

        # iterate over all nodes
        for nodeid in self.data:
            if nodeid.startswith('__'):
                continue
            node = self.data[nodeid]

            # check node's primary MAC
            if 'mac' in node and needle == node['mac'].lower():
                return sanitize_node(node)

            # check alias MACs
            if 'macs' in node:
                haystack = [x.lower() for x in node['macs']]
                if mac in haystack:
                    return sanitize_node(node)

        # MAC address not found
        return None

    def get_nodestatus(self, rawid):
        """Determine node's status."""

        # search node by the given id
        node = self.find_node(rawid)

        # handle unknown nodes
        if node is None:
            return None

        # check that the last batadv update is noted in the data
        updated = node.get(self.FIELDKEY_UPDATED, None)
        if updated is None or not 'batadv' in updated:
            return 'unknown'

        # make decision based on time of last batadv update
        diff = time.time() - updated['batadv']
        if diff < 150:
            return 'active'
        elif diff < 300:
            return 'stale'
        else:
            return 'offline'

    def resolve_vpn_remotes(self):
        if not self.DATAKEY_VPN in self.data:
            return

        vpn = self.data[self.DATAKEY_VPN]
        init_vpn_cache = {}
        for key in vpn:
            if not isinstance(vpn[key], dict):
                continue

            for mode in vpn[key]:
                if not isinstance(vpn[key][mode], dict):
                    continue

                for gateway in vpn[key][mode]:
                    if not isinstance(vpn[key][mode][gateway], dict):
                        continue

                    item = vpn[key][mode][gateway]
                    if 'remote' in item and not 'remote_raw' in item:
                        item['remote_raw'] = item['remote']
                        resolved = None
                        if item['remote'] in init_vpn_cache:
                            resolved = init_vpn_cache[item['remote']]
                        else:
                            resolved = ffstatus.resolve_ipblock(item['remote'])
                            init_vpn_cache[item['remote']] = resolved
                            if resolved is not None:
                                logging.info(
                                    'Resolved VPN entry \'%s\' to net \'%s\'.',
                                    item['remote'],
                                    resolved['name'],
                                )

                        if resolved is not None:
                            item['remote'] = resolved

        self.save()

    def __get_vpn_item(self, key, create=False):
        if key is None or re.match(r'^[a-fA-F0-9]+$', key) is None:
            raise VpnKeyFormatError(key)
            return

        if not self.DATAKEY_VPN in self.data:
            if not create:
                return None
            self.data[self.DATAKEY_VPN] = {}

        if not key in self.data[self.DATAKEY_VPN]:
            if not create:
                return None
            self.data[self.DATAKEY_VPN][key] = {'active': {}, 'last': {}}

        return self.data[self.DATAKEY_VPN][key]

    def get_vpn_gateways(self):
        if not self.DATAKEY_VPN in self.data:
            return []

        gateways = set()
        vpn = self.data[self.DATAKEY_VPN]
        for key in vpn:
            for conntype in vpn[key]:
                for gateway in vpn[key][conntype]:
                    gateways.add(gateway)

        return sorted(gateways)

    def get_vpn_connections(self):
        if not self.DATAKEY_VPN in self.data:
            return []

        conntypes = ['active', 'last']
        result = []
        vpn = self.data[self.DATAKEY_VPN]
        for key in vpn:
            vpn_entry = vpn[key]
            if not isinstance(vpn_entry, dict):
                continue

            item = {
                'key': key,
                'count': {},
                'remote': {},
            }
            names = set()
            for conntype in conntypes:
                item['count'][conntype] = 0
                item['remote'][conntype] = {}
                if conntype in vpn_entry:
                    for gateway in vpn_entry[conntype]:
                        if 'remote' in vpn_entry[conntype][gateway]:
                            remote = vpn_entry[conntype][gateway]['remote']
                            if remote is None or remote == '':
                                continue

                            item['count'][conntype] += 1
                            item['remote'][conntype][gateway] = remote
                        if 'peer' in vpn_entry[conntype][gateway]:
                            names.add(vpn_entry[conntype][gateway]['peer'])

            item['names'] = sorted(names)
            item['online'] = item['count']['active'] > 0
            result.append(item)

        return result

    def log_vpn_connect(self, key, peername, remote, gateway, timestamp):
        item = self.__get_vpn_item(key, create=True)

        # resolve remote addr to its netblock
        remote_raw = remote
        remote_resolved = None
        if remote is not None:
            remote_resolved = ffstatus.resolve_ipblock(remote)
            if remote_resolved is not None:
                logging.debug('Resolved IP \'{0}\' to block \'{1}\'.'.format(
                    remote, remote_resolved['name'],
                ))
                remote = remote_resolved

        # store connection info
        item['active'][gateway] = {
            'establish': timestamp,
            'peer': peername,
            'remote': remote,
            'remote_raw': remote_raw,
        }

    def log_vpn_disconnect(self, key, gateway, timestamp):
        item = self.__get_vpn_item(key, create=True)

        active = {}
        if gateway in item['active']:
            active = item['active'][gateway]
            del item['active'][gateway]

        active['disestablish'] = timestamp
        item['last'][gateway] = active