namespace :ssh do
  desc "Install your public key on a remote server."
  task :install_public_key do
    begin
      require 'rubygems'
      require 'net/ssh'
      require 'net/scp'
      require 'highline'
    rescue LoadError
      abort "There was a problem loading net-ssh, net-scp, or highline. Please make sure you have them installed via RubyGems."
    end

    public_key = if ENV["public_key_path"]
      if File.exists?(ENV["public_key_path"]) then ENV["public_key_path"]
      else abort "The key you provided via the command line does not exist!"
      end
    else
      discovered_key = %w[id_rsa id_dsa identity].map { |f| "#{ENV['HOME']}/.ssh/#{f}.pub" }.detect { |f| File.exists?(f) }
      if discovered_key then discovered_key
      else abort <<-EOS
I wasn't able to discover your public key. I tried to find id_rsa.pub, id_dsa.pub,
or identity.pub in "#{ENV['HOME']}/.ssh". You can hard code the path to the file by
passing public_key_path via the command line.
        EOS
      end
    end

    h = HighLine.new
    not_blank = Proc.new { |s| !s.empty? }
    def not_blank.to_s; "not blank"; end

    h.say "I need some information to SSH into the server."
    hostname = h.ask("Remote Hostname: ") { |q| q.validate = not_blank }
    port = h.ask("Remote port: ") { |q| q.default = 22 }
    username = h.ask("Username, enter for default: ") { |q| q.default = ENV["USER"] }
    password = h.ask("Password: ") { |q| q.echo = "*" }

    begin
      Net::SSH.start(hostname, username, :password => password, :port => port) do |ssh|
        puts "Uploading your public key... "
        ssh.scp.upload! public_key, "my_public_key"

        puts "Creating '.ssh' directory in your home directory"
        ssh.exec!("mkdir .ssh")

        puts "Concatenating your public key into the authorized_keys file"
        ssh.exec!("cat my_public_key >> .ssh/authorized_keys")

        puts "Removing your public key"
        ssh.exec!("rm my_public_key")

        puts "Setting permissions on .ssh"
        ssh.exec!("chmod 700 .ssh")

        puts "Setting permissions on your authorized_keys file"
        ssh.exec!("chmod 600 .ssh/authorized_keys")

        puts "\nAll done! Enjoy your new, potentially password-free login."
      end
    rescue Net::SSH::AuthenticationFailed
      puts "\nWhat we've got here... is a failure to communicate. There was a problem authenticating you."
    end
  end
end