class Gem::Commands::CleanupCommand

def arguments # :nodoc:
  "GEMNAME       name of gem to cleanup"
end

def clean_gems
  @original_home = Gem.dir
  @original_path = Gem.path
  get_primary_gems
  get_candidate_gems
  get_gems_to_cleanup
  @full = Gem::DependencyList.from_specs
  deplist = Gem::DependencyList.new
  @gems_to_cleanup.each do |spec| deplist.add spec end
  deps = deplist.strongly_connected_components.flatten
  deps.reverse_each do |spec|
    uninstall_dep spec
  end
  Gem::Specification.reset
end

def defaults_str # :nodoc:
  "--no-dryrun"
end

def description # :nodoc:
  <<-EOF
e cleanup command removes old versions of gems from GEM_HOME that are not
quired to meet a dependency.  If a gem is installed elsewhere in GEM_PATH
e cleanup command won't delete it.
 no gems are named all gems in GEM_HOME are cleaned.
  EOF
end

def execute
  say "Cleaning up installed gems..."
  if options[:args].empty? then
    done     = false
    last_set = nil
    until done do
      clean_gems
      this_set = @gems_to_cleanup.map { |spec| spec.full_name }.sort
      done = this_set.empty? || last_set == this_set
      last_set = this_set
    end
  else
    clean_gems
  end
  say "Clean Up Complete"
  verbose do
    skipped = @default_gems.map { |spec| spec.full_name }
    "Skipped default gems: #{skipped.join ', '}"
  end
end

def get_candidate_gems
  @candidate_gems = unless options[:args].empty? then
                      options[:args].map do |gem_name|
                        Gem::Specification.find_all_by_name gem_name
                      end.flatten
                    else
                      Gem::Specification.to_a
                    end
end

def get_gems_to_cleanup
  gems_to_cleanup = @candidate_gems.select { |spec|
    @primary_gems[spec.name].version != spec.version
  }
  default_gems, gems_to_cleanup = gems_to_cleanup.partition { |spec|
    spec.default_gem?
  }
  gems_to_cleanup = gems_to_cleanup.select { |spec|
    spec.base_dir == @original_home
  }
  @default_gems += default_gems
  @default_gems.uniq!
  @gems_to_cleanup = gems_to_cleanup.uniq
end

def get_primary_gems
  @primary_gems = {}
  Gem::Specification.each do |spec|
    if @primary_gems[spec.name].nil? or
       @primary_gems[spec.name].version < spec.version then
      @primary_gems[spec.name] = spec
    end
  end
end

def initialize
  super 'cleanup',
        'Clean up old versions of installed gems',
        :force => false, :install_dir => Gem.dir
  add_option('-n', '-d', '--dryrun',
             'Do not uninstall gems') do |value, options|
    options[:dryrun] = true
  end
  @candidate_gems  = nil
  @default_gems    = []
  @full            = nil
  @gems_to_cleanup = nil
  @original_home   = nil
  @original_path   = nil
  @primary_gems    = nil
end

def uninstall_dep spec
  return unless @full.ok_to_remove?(spec.full_name)
  if options[:dryrun] then
    say "Dry Run Mode: Would uninstall #{spec.full_name}"
    return
  end
  say "Attempting to uninstall #{spec.full_name}"
  uninstall_options = {
    :executables => false,
    :version => "= #{spec.version}",
  }
  uninstall_options[:user_install] = Gem.user_dir == spec.base_dir
  uninstaller = Gem::Uninstaller.new spec.name, uninstall_options
  begin
    uninstaller.uninstall
  rescue Gem::DependencyRemovalException, Gem::InstallError,
         Gem::GemNotInHomeException, Gem::FilePermissionError => e
    say "Unable to uninstall #{spec.full_name}:"
    say "\t#{e.class}: #{e.message}"
  end
ensure
  # Restore path Gem::Uninstaller may have changed
  Gem.use_paths @original_home, *@original_path
end

def usage # :nodoc:
  "#{program_name} [GEMNAME ...]"
end