class ArpScanner

# File lib/arpscanner.rb, line 16
def initialize(nic: `ip addr`[/(?<=global )\w+/], vendors: {}, 
               nameserver: nil)
  
  package = 'arp-scan'
  @vendors, @nameserver = vendors, nameserver
  
  found = `dpkg --get-selections | grep #{package}`
  
  if found.empty? then
    raise 'ArpScanner: arp-scan package not found'.error
  end
  
  @arpscan_cmd = "sudo #{package} --interface=#{nic} --localnet"
  
end

# File lib/arpscanner.rb, line 32
def scan()
  
  a = `#{@arpscan_cmd}`.lines
  
  a2 = a[2..-4].map do |x|

    r = %i(ip mfr mac).zip(x.chomp.split("\t").values_at(0,2,1))      
    
    if @nameserver then
              
      begin
        hostname = Resolv::DNS.new(:nameserver => [@nameserver]).getname(r[0][1]).to_s
      rescue
        hostname = ''
        puts ($!).to_s.warning
      end
      
      r.insert(1, [:hostname, hostname])
      
    else
      %i(ip mfr mac).zip(x.chomp.split("\t")).to_h
    end
    
    h = r.to_h
    
    if h[:mfr] == '(Unknown)' then
      vendor = MacToVendor.find h[:mac] 
      h[:mfr] = vendor if vendor
    end
    
    h 
    
  end
  
  # Add additional vendors
  h = {/^b8:27:eb:/ => 'Raspberry Pi Foundation'}.merge(@vendors)
  
  a2.map! do |x|
    
    _, vendor = h.detect {|mac, mfr| x[:mac] =~ mac }
    x[:mfr] = vendor if vendor
    x

  end    
      
  # sort by IP address
  Dynarex.new.import a2.sort_by {|x| x[:ip][/\d+$/].to_i}

end