require 'git'
require 'json'
require 'date'
require 'bulk_insert'

# This class can be used to import cvelist json data from mitre from their github repo
class CveListImporter
  attr_accessor :repo_url, :repo_path

  def initialize
    @repo_url = 'https://github.com/CVEProject/cvelist.git'
    @repo_path = '/data_importer/data/cve_list'
  end

  def git_clone_repo
    Git.clone(repo_url, repo_path)
  end

  def pull_latest_changes
    `cd #{repo_path}; git pull;`
    puts "Now pulling latest changes from #{repo_path}"
  end

  def read_json(filename)
    JSON.parse(File.read(filename))
  end

  def list_jsons_for_year(year)
    year_fp = "#{repo_path}/#{year}/*"
    Dir["#{year_fp}/*.json"]
  end

  def read_jsons_for_year(year)
    filenames = list_jsons_for_year(year)
    filenames.map { |filename| read_json(filename) }
  end

  def read_all_jsons
    (1999..Date.today.year).map do |year|
      read_jsons_for_year(year.to_s)
    end
  end

  def cve_attrs_from_item(json)
    cve_attrs = {}
    cve_attrs[:cve_data_meta] = json['CVE_data_meta']
    cve_attrs[:cve_id] = json['CVE_data_meta']['ID']
    cve_attrs[:affects] = json['affects']
    cve_attrs[:data_format] = json['data_format']
    cve_attrs[:data_type] = json['data_type']
    cve_attrs[:data_version] = json['data_version']
    cve_attrs[:description] = json['description']
    cve_attrs[:impact] = json['impact']
    cve_attrs[:problemtype] = json['problemtype']
    cve_attrs[:references] = json['references']
    cve_attrs[:source] = json['source']
    cve_attrs
  end

  # for bulk inserting
  def cves_for_year(year)
    json_data = read_jsons_for_year(year)
    json_data.map do |json_f|
      cve_attrs_from_item(json_f)
    end
  end

  def import
    if Dir.exist?(repo_path)
      pull_latest_changes
    else
      git_clone_repo
    end

    (1999..Date.today.year).map do |year|
      cves_from_json = cves_for_year(year)

      ids = cves_from_json.map { |cve| cve[:cve_id] }
      cve_ids_in_db = Cve.where(:cve_id => ids).pluck(:cve_id)

      new_cve_ids = ids - cve_ids_in_db
      new_cves = cves_from_json.select { |cve| cve if new_cve_ids.include?(cve[:cve_id]) }
      puts "Importing any new CVEs from #{year}"

      bulk_insert(new_cves)
    end
  end

  def bulk_insert(cves)
    Cve.bulk_insert do |worker|
      cves.each do |attrs|
        worker.add(attrs)
      end
    end
  end
end