# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: t -*-
# vi: set ft=python sts=4 ts=4 sw=4 noet :

# This file is part of Fail2Ban.
#
# Fail2Ban 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 2 of the License, or
# (at your option) any later version.
#
# Fail2Ban 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 Fail2Ban; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

import sys
if sys.version_info < (2, 7):
    raise ImportError("badips.py action requires Python >= 2.7")
import json
import threading
import logging
if sys.version_info >= (3, ):
    from urllib.request import Request, urlopen
    from urllib.parse import urlencode
    from urllib.error import HTTPError
else:
    from urllib2 import Request, urlopen, HTTPError
    from urllib import urlencode

from fail2ban.server.actions import ActionBase


class BadIPsAction(ActionBase):
    """Fail2Ban action which reports bans to badips.com, and also
    blacklist bad IPs listed on badips.com by using another action's
    ban method.

    Parameters
    ----------
    jail : Jail
        The jail which the action belongs to.
    name : str
        Name assigned to the action.
    category : str
        Valid badips.com category for reporting failures.
    score : int, optional
        Minimum score for bad IPs. Default 3.
    age : str, optional
        Age of last report for bad IPs, per badips.com syntax.
        Default "24h" (24 hours)
    key : str, optional
        Key issued by badips.com to report bans, for later retrieval
        of personalised content.
    banaction : str, optional
        Name of banaction to use for blacklisting bad IPs. If `None`,
        no blacklist of IPs will take place.
        Default `None`.
    bancategory : str, optional
        Name of category to use for blacklisting, which can differ
        from category used for reporting. e.g. may want to report
        "postfix", but want to use whole "mail" category for blacklist.
        Default `category`.
    bankey : str, optional
        Key issued by badips.com to blacklist IPs reported with the
        associated key.
    updateperiod : int, optional
        Time in seconds between updating bad IPs blacklist.
        Default 900 (15 minutes)
    agent : str, optional
        User agent transmitted to server.
        Default `Fail2Ban/ver.`

    Raises
    ------
    ValueError
        If invalid `category`, `score`, `banaction` or `updateperiod`.
    """

    TIMEOUT = 10
    _badips = "http://www.badips.com"
    def _Request(self, url, **argv):
        return Request(url, headers={'User-Agent': self.agent}, **argv)

    def __init__(self, jail, name, category, score=3, age="24h", key=None,
        banaction=None, bancategory=None, bankey=None, updateperiod=900, agent="Fail2Ban",
        timeout=TIMEOUT):
        super(BadIPsAction, self).__init__(jail, name)

        self.timeout = timeout
        self.agent = agent
        self.category = category
        self.score = score
        self.age = age
        self.key = key
        self.banaction = banaction
        self.bancategory = bancategory or category
        self.bankey = bankey
        self.updateperiod = updateperiod

        self._bannedips = set()
        # Used later for threading.Timer for updating badips
        self._timer = None

    def getCategories(self, incParents=False):
        """Get badips.com categories.

        Returns
        -------
        set
            Set of categories.

        Raises
        ------
        HTTPError
            Any issues with badips.com request.
        ValueError
            If badips.com response didn't contain necessary information
        """
        try:
            response = urlopen(
                self._Request("/".join([self._badips, "get", "categories"])), timeout=self.timeout)
        except HTTPError as response:
            messages = json.loads(response.read().decode('utf-8'))
            self._logSys.error(
                "Failed to fetch categories. badips.com response: '%s'",
                messages['err'])
            raise
        else:
            response_json = json.loads(response.read().decode('utf-8'))
            if not 'categories' in response_json:
                err = "badips.com response lacked categories specification. Response was: %s" \
                  % (response_json,)
                self._logSys.error(err)
                raise ValueError(err)
            categories = response_json['categories']
            categories_names = set(
                value['Name'] for value in categories)
            if incParents:
                categories_names.update(set(
                    value['Parent'] for value in categories
                    if "Parent" in value))
            return categories_names

    def getList(self, category, score, age, key=None):
        """Get badips.com list of bad IPs.

        Parameters
        ----------
        category : str
            Valid badips.com category.
        score : int
            Minimum score for bad IPs.
        age : str
            Age of last report for bad IPs, per badips.com syntax.
        key : str, optional
            Key issued by badips.com to fetch IPs reported with the
            associated key.

        Returns
        -------
        set
            Set of bad IPs.

        Raises
        ------
        HTTPError
            Any issues with badips.com request.
        """
        try:
            url = "?".join([
                "/".join([self._badips, "get", "list", category, str(score)]),
                urlencode({'age': age})])
            if key:
                url = "&".join([url, urlencode({'key': key})])
            response = urlopen(self._Request(url), timeout=self.timeout)
        except HTTPError as response:
            messages = json.loads(response.read().decode('utf-8'))
            self._logSys.error(
                "Failed to fetch bad IP list. badips.com response: '%s'",
                messages['err'])
            raise
        else:
            return set(response.read().decode('utf-8').split())

    @property
    def category(self):
        """badips.com category for reporting IPs.
        """
        return self._category

    @category.setter
    def category(self, category):
        if category not in self.getCategories():
            self._logSys.error("Category name '%s' not valid. "
                "see badips.com for list of valid categories",
                category)
            raise ValueError("Invalid category: %s" % category)
        self._category = category

    @property
    def bancategory(self):
        """badips.com bancategory for fetching IPs.
        """
        return self._bancategory

    @bancategory.setter
    def bancategory(self, bancategory):
        if bancategory not in self.getCategories(incParents=True):
            self._logSys.error("Category name '%s' not valid. "
                "see badips.com for list of valid categories",
                bancategory)
            raise ValueError("Invalid bancategory: %s" % bancategory)
        self._bancategory = bancategory

    @property
    def score(self):
        """badips.com minimum score for fetching IPs.
        """
        return self._score

    @score.setter
    def score(self, score):
        score = int(score)
        if 0 <= score <= 5:
            self._score = score
        else:
            raise ValueError("Score must be 0-5")

    @property
    def banaction(self):
        """Jail action to use for banning/unbanning.
        """
        return self._banaction

    @banaction.setter
    def banaction(self, banaction):
        if banaction is not None and banaction not in self._jail.actions:
            self._logSys.error("Action name '%s' not in jail '%s'",
                banaction, self._jail.name)
            raise ValueError("Invalid banaction")
        self._banaction = banaction

    @property
    def updateperiod(self):
        """Period in seconds between banned bad IPs will be updated.
        """
        return self._updateperiod

    @updateperiod.setter
    def updateperiod(self, updateperiod):
        updateperiod = int(updateperiod)
        if updateperiod > 0:
            self._updateperiod = updateperiod
        else:
            raise ValueError("Update period must be integer greater than 0")

    def _banIPs(self, ips):
        for ip in ips:
            try:
                self._jail.actions[self.banaction].ban({
                    'ip': ip,
                    'failures': 0,
                    'matches': "",
                    'ipmatches': "",
                    'ipjailmatches': "",
                })
            except Exception as e:
                self._logSys.error(
                    "Error banning IP %s for jail '%s' with action '%s': %s",
                    ip, self._jail.name, self.banaction, e,
                    exc_info=self._logSys.getEffectiveLevel()<=logging.DEBUG)
            else:
                self._bannedips.add(ip)
                self._logSys.info(
                    "Banned IP %s for jail '%s' with action '%s'",
                    ip, self._jail.name, self.banaction)

    def _unbanIPs(self, ips):
        for ip in ips:
            try:
                self._jail.actions[self.banaction].unban({
                    'ip': ip,
                    'failures': 0,
                    'matches': "",
                    'ipmatches': "",
                    'ipjailmatches': "",
                })
            except Exception as e:
                self._logSys.info(
                    "Error unbanning IP %s for jail '%s' with action '%s': %s",
                    ip, self._jail.name, self.banaction, e,
                    exc_info=self._logSys.getEffectiveLevel()<=logging.DEBUG)
            else:
                self._logSys.info(
                    "Unbanned IP %s for jail '%s' with action '%s'",
                    ip, self._jail.name, self.banaction)
            finally:
                self._bannedips.remove(ip)

    def start(self):
        """If `banaction` set, blacklists bad IPs.
        """
        if self.banaction is not None:
            self.update()

    def update(self):
        """If `banaction` set, updates blacklisted IPs.

        Queries badips.com for list of bad IPs, removing IPs from the
        blacklist if no longer present, and adds new bad IPs to the
        blacklist.
        """
        if self.banaction is not None:
            if self._timer:
                self._timer.cancel()
                self._timer = None

            try:
                ips = self.getList(
                    self.bancategory, self.score, self.age, self.bankey)
                # Remove old IPs no longer listed
                self._unbanIPs(self._bannedips - ips)
                # Add new IPs which are now listed
                self._banIPs(ips - self._bannedips)

                self._logSys.info(
                    "Updated IPs for jail '%s'. Update again in %i seconds",
                    self._jail.name, self.updateperiod)
            finally:
                self._timer = threading.Timer(self.updateperiod, self.update)
                self._timer.start()

    def stop(self):
        """If `banaction` set, clears blacklisted IPs.
        """
        if self.banaction is not None:
            if self._timer:
                self._timer.cancel()
                self._timer = None
            self._unbanIPs(self._bannedips.copy())

    def ban(self, aInfo):
        """Reports banned IP to badips.com.

        Parameters
        ----------
        aInfo : dict
            Dictionary which includes information in relation to
            the ban.

        Raises
        ------
        HTTPError
            Any issues with badips.com request.
        """
        try:
            url = "/".join([self._badips, "add", self.category, aInfo['ip']])
            if self.key:
                url = "?".join([url, urlencode({'key': self.key})])
            response = urlopen(self._Request(url), timeout=self.timeout)
        except HTTPError as response:
            messages = json.loads(response.read().decode('utf-8'))
            self._logSys.error(
                "Response from badips.com report: '%s'",
                messages['err'])
            raise
        else:
            messages = json.loads(response.read().decode('utf-8'))
            self._logSys.info(
                "Response from badips.com report: '%s'",
                messages['suc'])

Action = BadIPsAction
