require_relative '../cvss_property'
require_relative '../cvss_metric'
require_relative '../helpers/cvss3_helper'

##
# This class represents a CVSS Base metric in version 3.

class Cvss3Base < CvssMetric

  ##
  # Property of this metric

  attr_reader :attack_vector, :attack_complexity, :privileges_required, :user_interaction,
              :scope, :confidentiality, :integrity, :availability

  ##
  # Returns score of this metric

  def score

    privilege_score = Cvss3Helper.privileges_required_score @privileges_required, @scope

    exploitability = 8.22 * @attack_vector.score * @attack_complexity.score * privilege_score * @user_interaction.score

    isc_base = 1 - ((1 - @confidentiality.score) * (1 - @integrity.score) * (1 - @availability.score))

    if @scope.selected_choice[:name] == 'Changed'
      impact_sub_score = 7.52 * (isc_base - 0.029) - 3.25 * (isc_base - 0.02)**15
    else
      impact_sub_score = 6.42 * isc_base
    end

    return 0 if impact_sub_score <= 0

    if @scope.selected_choice[:name] == 'Changed'
      [10, 1.08 * (impact_sub_score + exploitability)].min
    else
      [10, impact_sub_score + exploitability].min
    end
  end

  private

  def init_properties
    @properties.push(@attack_vector =
                      CvssProperty.new(name: 'Attack Vector', abbreviation: 'AV', position: [0],
                                       choices: [{ name: 'Network', abbreviation: 'N', weight: 0.85 },
                                                 { name: 'Adjacent', abbreviation: 'A', weight: 0.62 },
                                                 { name: 'Local', abbreviation: 'L', weight: 0.55 },
                                                 { name: 'Physical', abbreviation: 'P', weight: 0.2 }]))
    @properties.push(@attack_complexity =
                      CvssProperty.new(name: 'Attack Complexity', abbreviation: 'AC', position: [1],
                                       choices: [{ name: 'Low', abbreviation: 'L', weight: 0.77 },
                                                 { name: 'High', abbreviation: 'H', weight: 0.44 }]))
    @properties.push(@privileges_required =
                      CvssProperty.new(name: 'Privileges Required', abbreviation: 'PR', position: [2],
                                       choices: [{ name: 'None', abbreviation: 'N', weight: 0.85 },
                                                 { name: 'Low', abbreviation: 'L', weight: 0.62 },
                                                 { name: 'High', abbreviation: 'H', weight: 0.27 }]))
    @properties.push(@user_interaction =
                      CvssProperty.new(name: 'User Interaction', abbreviation: 'UI', position: [3],
                                       choices: [{ name: 'None', abbreviation: 'N', weight: 0.85 },
                                                 { name: 'Required', abbreviation: 'R', weight: 0.62 }]))
    @properties.push(@scope =
                      CvssProperty.new(name: 'Scope', abbreviation: 'S', position: [4],
                                       choices: [{ name: 'Unchanged', abbreviation: 'U' },
                                                 { name: 'Changed', abbreviation: 'C' }]))
    @properties.push(@confidentiality =
                      CvssProperty.new(name: 'Confidentiality', abbreviation: 'C', position: [5],
                                       choices: [{ name: 'None', abbreviation: 'N', weight: 0.0 },
                                                 { name: 'Low', abbreviation: 'L', weight: 0.22 },
                                                 { name: 'High', abbreviation: 'H', weight: 0.56 }]))
    @properties.push(@integrity =
                      CvssProperty.new(name: 'Integrity', abbreviation: 'I', position: [6],
                                       choices: [{ name: 'None', abbreviation: 'N', weight: 0.0 },
                                                 { name: 'Low', abbreviation: 'L', weight: 0.22 },
                                                 { name: 'High', abbreviation: 'H', weight: 0.56 }]))
    @properties.push(@availability =
                      CvssProperty.new(name: 'Availability', abbreviation: 'A', position: [7],
                                       choices: [{ name: 'None', abbreviation: 'N', weight: 0.0 },
                                                 { name: 'Low', abbreviation: 'L', weight: 0.22 },
                                                 { name: 'High', abbreviation: 'H', weight: 0.56 }]))
  end
end