class Rosh

# File lib/rosh.rb, line 8
def initialize(*args)
  @interval = 3
  @ssh_opts = []
  alive_interval = 5
  @escape = '^t'
  OptionParser.new("test").tap do |opt|
    opt.banner = 'Usage: rosh [options] hostname [session-name]'
    opt.on('-a alive-interval'){|v| alive_interval = v.to_i}
    opt.on('-e escape'){|v| @escape = v}
    opt.on('-I interval'){|v| @interval = v.to_f}
  end.parse! args
  @host, @name = *args, :default
  abort 'hostname is required' if @host == :default
  @ssh_opts << "-o ServerAliveInterval=#{alive_interval}"
  @ssh_opts << "-o ServerAliveCountMax=1"

  # check ~/.ssh/config to resolve alias name
  config = Net::SSH::Config.for(@host)
  @host = config[:host_name] if config[:host_name]
  @ssh_opts << "-l #{config[:user]}" if config[:user]
  @ssh_opts << "-p #{config[:port]}" if config[:port]
  if keys = config[:keys]
    keys.each{|k| @ssh_opts << "-i #{k}"}
  end
  @first_try = true
end

# File lib/rosh.rb, line 35
def connect
  reconnect until system ["ssh", *@ssh_opts, resolv,
    '-t', "'screen -rx #{@name}'", '2>/dev/null']*' '
end

# File lib/rosh.rb, line 40
def reconnect
  if @first_try
    if !sh('-p 0 -X echo ok', '2>&1 >/dev/null')
      print "creating new screen session #{@name}... "
      if sh %{-c /dev/null -e "#{@escape*2}" -dm} and
        sh '-p 0 -X eval "stuff STY=\\040screen\\015"'
        puts "done."
      else
        puts "failed."
      end
    end
    @first_try = false
  else
    sleep [@last_try - Time.now + @interval, 0].max if @last_try
    puts "reconnecting..."
    @last_try = Time.now
  end
end

# File lib/rosh.rb, line 64
def resolv
  uri = URI("//#{@host}")
  uri.host = Resolv::DNS.new.getaddress(uri.host).to_s
  uri.to_s[2..-1]
rescue Exception
  @host
end

# File lib/rosh.rb, line 60
def sh(a, r=nil)
  system "ssh #{resolv} #{@ssh_opts*' '} 'screen -S #{@name} #{a}' #{r}"
end