#!/usr/bin/expect

set timeout 10
set user [lindex $argv 0]
set password [lindex $argv 1]
set principal [lindex $argv 2]

set distribution [exec "lsb_release" "-is"]

if { $distribution == "Ubuntu" } {
    set welcome "Welcome to"
} elseif { $distribution == "Debian" } {
    set welcome "Debian GNU/Linux comes"
} else {
    puts "Unsupported linux distribution $distribution"
    exit 1
}

spawn login
expect "login:"
send "$user\r"
expect "Password:"
send "$password\r"
expect {
  timeout
  {
    puts "Expect error: timeout after password\r\r"
    exit 1
  }
  "Login incorrect"
  {
    puts "Expect error: incorrect credentials\r\r"
    exit 1
  }
  "$welcome"
}
expect {
  timeout
  {
    puts "Expect error: timeout waiting for prompt\r\r"
    exit 1
  }
  "$ "
}
send "id -un\r"
expect {
  timeout
  {
    puts "Expect error: timeout waiting for 'id' result\r\r"
    exit 1
  }
  "$user"
}
expect {
  timeout
  {
    puts "Expect error: timeout waiting for prompt\r\r"
    exit 1
  }
  "$ "
}
if { $principal != "" } {
  send "klist\r"
  expect {
    timeout
    {
      puts "Expect error: timeout waiting for klist output\r\r"
      exit 1
    }
    "Default principal: $principal"
  }
}
send "logout\r"
exit 0