require 'highline/import'
require 'uri'
require 'socket'

module Lux

  # Determine the IPv4 address of the current Docker host
  # Used to avoid long reverse DNS lookups on .local names
  # Returns either nil if the lookup failed, or a triplet:
  # - the IPv4 address as a string
  # - a URI object
  # - a string saying which variable was used, 'URL' or 'HOST'
  # Note that DOCKER_URL is used by the docker-api client, but
  # as Docker uses the misleading DOCKER_HOST we fallback to that.
  #
  def self.dockerip
    vars = ['DOCKER_URL', 'DOCKER_HOST']
    var, url = vars.map{|v| [v, ENV[v]]}.find{|d| d[1]}
    return nil unless var
    uri = URI.parse(url)
    name = uri.host
    addrs = Socket.getaddrinfo(name, nil, :INET, :STREAM, 0, 0, false) rescue []
    name = addrs.first[3] if addrs.size > 0
    return name, var, uri
  end

  # Get the current list of images and make a guess at which one it is...
  #
  def self.findimage image
    local_images = `docker images`.strip.split("\n")[1..-1].map{|l| l.gsub!(/^(\S+)\s+(\S+).*/,'\1:\2')}.sort
    matching_images = local_images.select{|l| l.include? image }
    if matching_images.size > 0
      if image.count(':') == 0 and image.count('/') > 0
        matching_image = matching_images.select{|l| l.end_with? ':latest' }.first
      end
      unless matching_image
        matching_image = HighLine.choose do |menu|
          menu.header = 'List of matching (local) images'
          menu.choices(*matching_images)
          menu.choice('None of the above') { nil }
        end
        exit 2 unless matching_image
      end
    else
      matching_image = image
    end
    return matching_image
  end

  # Return two elements:
  # - user name (defaults to current user), and
  # - a bash script setup command
  #
  def self.user_setup_cmd user = `id -nu`.strip
    [user, <<-COMMAND.gsub(/^\s*/,'').gsub(/\n/,' ; ')]
      uid=$(echo $(stat -c %u:%g #{ENV['HOME']}) | cut -d: -f2)
      useradd -M -d #{ENV['HOME']} -u $uid -s #{ENV['SHELL']} #{user}
      echo "#{user} ALL=(ALL:ALL) NOPASSWD: ALL" > /etc/sudoers.d/#{user}
    COMMAND
  end

  def self.die msg, rc = 1
    HighLine.new(STDIN, STDERR).say HighLine.color(msg, HighLine::RED)
    exit(rc)
  end

end

# vim: ft=ruby sts=2 sw=2 ts=8