# encoding: utf-8
module ProxyPacRb
  # Environment in which a proxy.pac will be evaluated
  class Environment
    private

    attr_reader :days, :months, :client_ip, :time, :io, :javascript_function_templates, :dns_timeout

    public

    attr_reader :available_methods

    def initialize(options = {})
      @dns_timeout   = 1
      @days          = { 'MON' => 1, 'TUE' => 2, 'WED' => 3, 'THU' => 4, 'FRI' => 5, 'SAT' => 6, 'SUN' => 0 }
      @months        = { 'JAN' => 1, 'FEB' => 2, 'MAR' => 3, 'APR' => 4, 'MAY' => 5, 'JUN' => 6, 'JUL' => 7, 'AUG' => 8, 'SEP' => 9, 'OCT' => 10, 'NOV' => 11, 'DEC' => 12 }

      @client_ip     = IPAddr.new(options.fetch(:client_ip, '127.0.0.1').to_s).to_s
      @time          = Time.parse(options.fetch(:time, Time.now).to_s).to_s
      @io            = options.fetch(:io, $stderr)

      @javascript_function_templates = ProxyPacJs

      @available_methods = [
        :alert,
        :isPlainHostName,
        :dnsDomainIs,
        :localHostOrDomainIs,
        :isResolvable,
        :isInNet,
        :dnsResolve,
        :dnsDomainLevels,
        :shExpMatch
      ]
    end

    def alert(msg)
      io.puts msg
    end

    def isPlainHostName(host)
      !host.include? '.'
    end

    def dnsDomainIs(host, domain)
      host.end_with? domain
    end

    def localHostOrDomainIs(host, hostdom)
      host == hostdom || hostdom.include?(host)
    end

    def isResolvable(host)
      !resolve_host(host).blank?
    end

    def isInNet(host, base_ip, mask)
      raise ArgumentError, "<base ip> needs to be defined" if base_ip.nil? || base_ip.empty?
      raise ArgumentError, "<mask> needs to be defined" if mask.nil? || mask.empty?

      IPAddr.new(base_ip).mask(mask).include? resolve_host(host)
    end

    def dnsResolve(host)
      resolve_host(host)
    end

    def dnsDomainLevels(host)
      host.scan('.').size
    end

    def shExpMatch(str, shexp)
      ::File.fnmatch(shexp, str)
    end

    private

    def resolve_host(host)
      return nil if host.blank?

      Timeout.timeout(dns_timeout) do
        Resolv.each_address(host.force_encoding('ASCII-8BIT')) do |address|
          begin
            return address if IPAddr.new(address).ipv4?
            # rubocop:disable Lint/HandleExceptions
          rescue ArgumentError
          end
          # rubocop:enable Lint/HandleExceptions
        end
      end

      # We couldn't find an IPv4 address for the host
      nil
    rescue Resolv::ResolvError, NoMethodError, Timeout::Error
      # Have to rescue NoMethodError because jruby has a bug with non existant hostnames
      # See http://jira.codehaus.org/browse/JRUBY-6054
      nil
    end

    public

    def prepare(string)
      if client_ip
        string << "\n\n"
        string << javascript_function_templates.my_ip_address_template(client_ip)
      end

      if time
        string << javascript_function_templates.time_variables
        string << "\n\n"
        string << javascript_function_templates.week_day_range_template(time)
        string << "\n\n"
        string << javascript_function_templates.week_day_range_template(time)
        string << "\n\n"
        string << javascript_function_templates.date_range_template(time)
        string << "\n\n"
        string << javascript_function_templates.time_range_template(time)
      end

      string
    end
  end
end