# -*- coding: utf-8 -*-
#
# Authors:
# Benoît Allard <benoit.allard@greenbone.net>
#
# Copyright:
# Copyright (C) 2014 Greenbone Networks GmbH
#
# This program 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.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

"""\
Vulnerability Objects related to CVRF Documents
"""

from .common import ValidationError
from .document import CVRFPublisher


class CVRFVulnerabilityID(object):
    def __init__(self, systemname, value):
        self._systemname = systemname
        self._value = value

    def validate(self):
        if not self._systemname:
            raise ValidationError('A Vulnerability ID must have a System Name')
        if not self._value:
            raise ValidationError('A Vulnerability ID must have a value')


class CVRFVulnerability(object):
    def __init__(self, ordinal):
        self._ordinal = ordinal
        self._title = None
        self._id = None
        self._notes = []
        self._discoverydate = None
        self._releasedate = None
        self._involvements = []
        self._cve = None
        self._cwes = []
        self._productstatuses = []
        self._threats = []
        self._cvsss = []
        self._remediations = []
        self._references = []
        self._acknowledgments = []

    def setTitle(self, title):
        self._title = title

    def setID(self, _id):
        self._id = _id

    def addNote(self, note):
        self._notes.append(note)

    def setDiscoveryDate(self, date):
        self._discoverydate = date

    def setReleaseDate(self, date):
        self._releasedate = date

    def addInvolvement(self, involvement):
        self._involvements.append(involvement)

    def setCVE(self, cve):
        self._cve = cve

    def addCWE(self, cwe):
        self._cwes.append(cwe)

    def addProductStatus(self, productstatus):
        self._productstatuses.append(productstatus)

    def addThreat(self, threat):
        self._threats.append(threat)

    def addCVSSSet(self, cvss_set):
        self._cvsss.append(cvss_set)

    def addRemediation(self, remediation):
        self._remediations.append(remediation)

    def addReference(self, ref):
        self._references.append(ref)

    def addAcknowledgment(self, ack):
        self._acknowledgments.append(ack)

    def getTitle(self):
        """ return something that can be used as a title """
        if self._title:
            if self._id:
                return "%s (%s)" % (self._title, self._id._value)
            return self._title
        if self._id:
            return self._id._value
        return "#%d" % self._ordinal

    def getNote(self, ordinal):
        for note in self._notes:
            if note._ordinal == ordinal:
                return note
        return None

    def mentionsProdId(self, productid):
        """ Returns in which sub element, self is mentioning the productid """
        for category in (self._productstatuses, self._threats, self._cvsss, self._remediations):
            for subelem in category:
                if productid in subelem._productids:
                    yield subelem

    def isMentioningProdId(self, productid):
        """ Returns if self is mentioning the productid """
        for e in self.mentionsProdId(productid):
            # We only need to know if the generator yield at least one elem.
            return True
        return False

    def mentionsGroupId(self, groupid):
        for category in (self._threats, self._remediations):
            for subelem in category:
                if groupid in subelem._groupids:
                    yield subelem

    def isMentioningGroupId(self, groupids):
        """ Make sure you call this with a list (not a generator or a tuple)
        when wished """
        if not isinstance(groupids, list):
            groupids = [groupids]
        for groupid in groupids:
            for _ in self.mentionsGroupId(groupid):
                # We only need to know if the generator yield at least one elem.
                return True
        return False

    def validate(self, productids, groupids):
        if not self._ordinal:
            raise ValidationError('A Vulnerability must have an ordinal')
        if self._id is not None:
            self._id.validate()
        ordinals = set()
        for note in self._notes:
            note.validate()
            if note._ordinal in ordinals:
                raise ValidationError('Vulnerability Note Ordinal %d duplicated' % note._ordinal)
            ordinals.add(note._ordinal)
        for involvement in self._involvements:
            involvement.validate()
        for cwe in self._cwes:
            cwe.validate()
        for status in self._productstatuses:
            status.validate(productids)
        pids = set()
        for status in self._productstatuses:
            for pid in status._productids:
                if pid in pids:
                    raise ValidationError('ProductID %s mentionned in two different ProductStatuses for Vulnerability %d' % (pid, self._ordinal))
                pids.add(pid)
        for threat in self._threats:
            threat.validate(productids, groupids)
        for cvss in self._cvsss:
            cvss.validate(productids)
        pids = set()
        for cvss in self._cvsss:
            for pid in (cvss._productids or productids):
                if pid in pids:
                    raise ValidationError('ProductID %s mentionned in two different CVSS Score Sets for Vulnerability %d' % (pid, self._ordinal))
                pids.add(pid)
        for remediation in self._remediations:
            remediation.validate(productids, groupids)
        for reference in self._references:
            reference.validate()
        for acknowledgment in self._acknowledgments:
            acknowledgment.validate()


class CVRFInvolvement(object):
    PARTIES = CVRFPublisher.TYPES
    STATUSES = ('Open', 'Disputed', 'In Progress', 'Completed',
                'Contact Attempted', 'Not Contacted')
    def __init__(self, party, status):
        self._party = party
        self._status = status
        self._description = None

    def setDescription(self, description):
        self._description = description

    def getTitle(self):
        return "From %s: %s" % (self._party, self._status)

    def validate(self):
        if not self._party:
            raise ValidationError('An Involvement must have a Party')
        if self._party not in self.PARTIES:
            raise ValidationError("An Involvement's Party must be one of %s" % ', '.join(self.PARTIES))
        if not self._status:
            raise ValidationError('An Involvement must have a Status')
        if self._status not in self.STATUSES:
            raise ValidationError("An Involvement's Status must be one of %s" % ', '.join(self.STATUSES))


class CVRFCWE(object):
    def __init__(self, _id, value):
        self._id = _id
        self._value = value

    def validate(self):
        if not self._id:
            raise ValidationError('A CWE must have an ID')
        if not self._value:
            raise ValidationError('A CWE must have a description')


class CVRFProductStatus(object):
    TYPES = ('First Affected', 'Known Affected', 'Known Not Affected',
             'First Fixed', 'Fixed', 'Recommended', 'Last Affected')
    NAME = "Product Status"
    def __init__(self, _type):
        self._type = _type
        self._productids = []

    def addProductID(self, productid):
        self._productids.append(productid)

    def getTitle(self):
        return "%s: %d products" % (self._type, len(self._productids))

    def validate(self, productids):
        if not self._type:
            raise ValidationError('A Product Status must have a Type')
        if self._type not in self.TYPES:
            raise ValidationError("A Product Status' Type must be one of %s" % ', '.join(self.TYPES))
        if len(self._productids) < 1:
            raise ValidationError('A Product Status must mention at least one Product')
        for productid in self._productids:
            if productid not in productids:
                raise ValidationError('Unknown ProductID: %s' % productid)


class CVRFThreat(object):
    TYPES = ('Impact', 'Exploit Status', 'Target Set')
    NAME = "Threat"
    def __init__(self, _type, description):
        self._type = _type
        self._description = description
        self._date = None
        self._productids = []
        self._groupids = []

    def setDate(self, date):
        self._date = date

    def addProductID(self, productid):
        self._productids.append(productid)

    def addGroupID(self, groupid):
        self._groupids.append(groupid)

    def getTitle(self):
        return self._type

    def validate(self, productids, groupids):
        if not self._type:
            raise ValidationError('A Threat must have a Type')
        if self._type not in self.TYPES:
            raise ValidationError("A Threat's Type must be one of %s" % ', '.join(self.TYPES))
        if not self._description:
            raise ValidationError('A Threat must have a Description')
        for productid in self._productids:
            if productid not in productids:
                raise ValidationError('Unknown ProductID: %s' % productid)
        for groupid in self._groupids:
            if groupid not in groupids:
                raise ValidationError('Unknown GroupID: %s' % groupid)


class CVRFCVSSSet(object):
    # To determine the base Score
    VALUES = {'AV': {'L':0.395, 'A':0.646, 'N':1.0},
              'AC': {'H':0.35, 'M':0.61 ,'L':0.71},
              'Au': {'M':0.45, 'S':0.56, 'N':0.704},
              'C': {'N':0.0, 'P':0.275, 'C':0.66},
              'I': {'N':0.0, 'P':0.275, 'C':0.66},
              'A': {'N':0.0, 'P':0.275, 'C':0.66}}
    NAME = "CVSS Score Set"
    def __init__(self, basescore):
        self._basescore = basescore
        self._temporalscore = None
        self._environmentalscore = None
        self._vector = None
        self.vector = None
        self._productids = []

    def setTemporalScore(self, tempscore):
        self._temporalscore = tempscore

    def setEnvironmentalScore(self, envscore):
        self._environmentalscore = envscore

    def setVector(self, vector):
        self._vector = vector
        if vector is None:
            self.vector = vector
            return
        try:
            self.vector = {}
            for component in vector[:26].split('/'):
                name, value = component.split(':')
                self.vector[name] = self.VALUES[name][value]
        except (KeyError, ValueError):
            self.vector = None

    def addProductID(self, productid):
        self._productids.append(productid)

    def baseScore(self):
        v = self.vector # make an alias for shorter lines
        exploitability = 20 * v['AV'] * v['AC'] * v['Au']
        impact = 10.41 * (1 - (1 - v['C']) * (1 - v['I']) * (1 - v['A']))
        def f(i): return 0 if i == 0 else 1.176
        return ((0.6 * impact) + (0.4 * exploitability) - 1.5) * f(impact)

    def validate(self, productids):
        if not self._basescore:
            raise ValidationError('A CVSS Score Set must have a Base Score')
        if self._vector and not self.vector:
            raise ValidationError('Syntax Error in CVSS Vector')
        if self.vector and (abs(self._basescore - self.baseScore()) >= 0.05):
            raise ValidationError('Inconsistency in CVSS Score Set between Vector (%f) and Base Score (%f)' % (self.baseScore(), self._basescore))
        for productid in self._productids:
            if productid not in productids:
                raise ValidationError('Unknown ProductID: %s' % productid)


class CVRFRemediation(object):
    TYPES = ('Workaround', 'Mitigation', 'Vendor Fix', 'None Available',
             'Will Not Fix')
    NAME = "Remediation"
    def __init__(self, _type, description):
        self._type = _type
        self._description = description
        self._date = None
        self._entitlement = None
        self._url = None
        self._productids = []
        self._groupids = []

    def setDate(self, date):
        self._date = date

    def setEntitlement(self, entitlement):
        self._entitlement = entitlement

    def setURL(self, url):
        self._url = url

    def addProductID(self, productid):
        self._productids.append(productid)

    def addGroupID(self, groupid):
        self._groupids.append(groupid)

    def getTitle(self):
        return self._type

    def validate(self, productids, groupids):
        if not self._type:
            raise ValidationError('A Remediation must have a Type')
        if self._type not in self.TYPES:
            raise ValidationError("A Remediation's Type must be one of %s" % ', '.join(self.TYPES))
        if not self._description:
            raise ValidationError('A Remediation must have a Description')
        for productid in self._productids:
            if productid not in productids:
                raise ValidationError('Unknown ProductID: %s' % productid)
        for groupid in self._groupids:
            if groupid not in groupids:
                raise ValidationError('Unknown GroupID: %s' % groupid)