#!/usr/bin/env ruby
# frozen_string_literal: false

#
#   check-whois-domain-expiration-multi
#
# DESCRIPTION:
#   This plugin checks domain expiration dates using the 'whois' gem.
#
# OUTPUT:
#   plain text
#
# PLATFORMS:
#   *nix systems
#
# DEPENDENCIES:
#   gem: sensu-plugin
#   gem: whois
#
# USAGE:
#   ./check-whois-domain-expiration-multi.rb -d therealtimsmith.com,mightyoakspreschool.com
#   WhoisDomainExpirationCheck WARNING: mightyoakspreschool.com: 30 days
#
# LICENSE:
#   Copyright 2015 Tim Smith (tim@cozy.co) - Cozy Services Ltd.
#   Based on check-whois-domain-expiration, Copyright 2015 michael j talarczyk <mjt@mijit.com>
#    and contributors.
#   Released under the same terms as Sensu (the MIT license); see LICENSE
#   for details.

require 'sensu-plugin/check/cli'
require 'whois'
require 'whois-parser'

#
# Check Whois domain expiration
#
class WhoisDomainExpirationCheck < Sensu::Plugin::Check::CLI
  option :domain,
         short: '-d DOMAINS',
         long: '--domains DOMAIN',
         required: true,
         description: 'Domain(s) to check. Separate by commas for 2+'

  option :warning,
         short: '-w DAYS',
         long: '--warn DAYS',
         default: 30,
         proc: proc(&:to_i),
         description: 'Warn if fewer than DAYS away'

  option :critical,
         short: '-c DAYS',
         long: '--critical DAYS',
         proc: proc(&:to_i),
         default: 7,
         description: 'Critical if fewer than DAYS away'

  option :'ignore-errors',
         short: '-i',
         long: '--ignore-errors',
         boolean: true,
         default: false,
         description: 'Ignore connection or parsing errors'

  option :'report-errors',
         short: '-r LEVEL',
         long: '--report-errors LEVEL',
         proc: proc(&:to_sym),
         in: %i[unknown warning critical],
         default: :unknown,
         description: 'Level for reporting connection or parsing errors'

  option :timeout,
         short: '-t SECONDS',
         long: '--timeout SECONDS',
         proc: proc(&:to_i),
         default: 10,
         description: 'Timeout for whois lookup'

  option :help,
         short: '-h',
         long: '--help',
         description: 'Show this message',
         on: :tail,
         boolean: true,
         show_options: true,
         exit: 0

  # split the provided domain list and perform whois lookups on each
  # return a hash with domains grouped by their status level
  def expiration_results
    domains = config[:domain].split(',')
    warning_days = config[:warning].to_i
    critical_days = config[:critical].to_i
    max_retries = 4

    results = {
      critical: {},
      warning: {},
      ok: {},
      unknown: {}
    }
    whois = Whois::Client.new(timeout: config[:timeout])

    domains.each do |domain|
      begin
        tries ||= 0
        whois_result = whois.lookup(domain).parser
      rescue Timeout::Error, Errno::ECONNRESET, Whois::ConnectionError
        tries += 1
        if tries < max_retries
          retry
        else
          results[:unknown][domain] = 'Connection error' unless config[:'ignore-errors']
          next
        end
      end

      begin
        expires_on = DateTime.parse(whois_result.expires_on.to_s)
        domain_result = (expires_on - DateTime.now).to_i
        if domain_result <= critical_days
          results[:critical][domain] = domain_result
        elsif domain_result <= warning_days
          results[:warning][domain] = domain_result
        else
          results[:ok][domain] = domain_result
        end
      rescue StandardError
        results[:unknown][domain] = 'Parsing error' unless config[:'ignore-errors']
      end
    end
    results
  end

  def run
    results = expiration_results

    warn_results = results[:critical].merge(results[:warning]).map { |u, v| "#{u} (#{v} days left)" }
    unknown_results = results[:unknown].map { |u, v| "#{u} (#{v})" }
    message warn_results.concat(unknown_results).join(', ')

    if !results[:critical].empty? || (!results[:unknown].empty? && config[:'report-errors'] == :critical)
      critical
    elsif !results[:warning].empty? || (!results[:unknown].empty? && config[:'report-errors'] == :warning)
      warning
    elsif !results[:unknown].empty?
      unknown
    else
      ok 'No domains expire in the near term'
    end
  end
end