class Gem::Commands::UpdateCommand

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

def check_latest_rubygems(version) # :nodoc:
  if Gem.rubygems_version == version
    say "Latest version already installed. Done."
    terminate_interaction
  end
end

def check_oldest_rubygems(version) # :nodoc:
  if oldest_supported_version > version
    alert_error "rubygems #{version} is not supported. The oldest supported version is #{oldest_supported_version}"
    terminate_interaction 1
  end
end

def check_update_arguments # :nodoc:
  unless options[:args].empty?
    alert_error "Gem names are not allowed with the --system option"
    terminate_interaction 1
  end
end

def defaults_str # :nodoc:
  "--document --no-force --install-dir #{Gem.dir}"
end

def description # :nodoc:
  <<-EOF
e update command will update your gems to the latest version.
e update command does not remove the previous version. Use the cleanup
mmand to remove old versions.
  EOF
end

def execute
  if options[:system]
    update_rubygems
    return
  end
  gems_to_update = which_to_update(
    highest_installed_gems,
    options[:args].uniq
  )
  if options[:explain]
    say "Gems to update:"
    gems_to_update.each do |name_tuple|
      say "  #{name_tuple.full_name}"
    end
    return
  end
  say "Updating installed gems"
  updated = update_gems gems_to_update
  updated_names = updated.map {|spec| spec.name }
  not_updated_names = options[:args].uniq - updated_names
  if updated.empty?
    say "Nothing to update"
  else
    say "Gems updated: #{updated_names.join(' ')}"
    say "Gems already up-to-date: #{not_updated_names.join(' ')}" unless not_updated_names.empty?
  end
end

def fetch_remote_gems(spec) # :nodoc:
  dependency = Gem::Dependency.new spec.name, "> #{spec.version}"
  dependency.prerelease = options[:prerelease]
  fetcher = Gem::SpecFetcher.fetcher
  spec_tuples, errors = fetcher.search_for_dependency dependency
  error = errors.find {|e| e.respond_to? :exception }
  raise error if error
  spec_tuples
end

def highest_installed_gems # :nodoc:
  hig = {} # highest installed gems
  # Get only gem specifications installed as --user-install
  Gem::Specification.dirs = Gem.user_dir if options[:user_install]
  Gem::Specification.each do |spec|
    if hig[spec.name].nil? or hig[spec.name].version < spec.version
      hig[spec.name] = spec
    end
  end
  hig
end

def highest_remote_name_tuple(spec) # :nodoc:
  spec_tuples = fetch_remote_gems spec
  matching_gems = spec_tuples.select do |g,_|
    g.name == spec.name and g.match_platform?
  end
  highest_remote_gem = matching_gems.max
  highest_remote_gem ||= [Gem::NameTuple.null]
  highest_remote_gem.first
end

def initialize
  super 'update', 'Update installed gems to the latest version',
    :document => %w[rdoc ri],
    :force    => false
  add_install_update_options
  OptionParser.accept Gem::Version do |value|
    Gem::Version.new value
    value
  end
  add_option('--system [VERSION]', Gem::Version,
             'Update the RubyGems system software') do |value, options|
    value = true unless value
    options[:system] = value
  end
  add_local_remote_options
  add_platform_option
  add_prerelease_option "as update targets"
  @updated   = []
  @installer = nil
end

def install_rubygems(version) # :nodoc:
  args = update_rubygems_arguments
  update_dir = File.join Gem.dir, 'gems', "rubygems-update-#{version}"
  Dir.chdir update_dir do
    say "Installing RubyGems #{version}" unless options[:silent]
    installed = preparing_gem_layout_for(version) do
      system Gem.ruby, '--disable-gems', 'setup.rb', *args
    end
    say "RubyGems system software updated" if installed unless options[:silent]
  end
end

def oldest_supported_version
  # for Ruby 2.3
  @oldest_supported_version ||= Gem::Version.new("2.5.2")
end

def preparing_gem_layout_for(version)
  if Gem::Version.new(version) >= Gem::Version.new("3.2.a")
    yield
  else
    require "tmpdir"
    tmpdir = Dir.mktmpdir
    FileUtils.mv Gem.plugindir, tmpdir
    status = yield
    if status
      FileUtils.rm_rf tmpdir
    else
      FileUtils.mv File.join(tmpdir, "plugins"), Gem.plugindir
    end
    status
  end
end

def rubygems_target_version
  version = options[:system]
  update_latest = version == true
  if update_latest
    version     = Gem::Version.new     Gem::VERSION
    requirement = Gem::Requirement.new ">= #{Gem::VERSION}"
  else
    version     = Gem::Version.new     version
    requirement = Gem::Requirement.new version
  end
  rubygems_update         = Gem::Specification.new
  rubygems_update.name    = 'rubygems-update'
  rubygems_update.version = version
  hig = {
    'rubygems-update' => rubygems_update,
  }
  gems_to_update = which_to_update hig, options[:args], :system
  up_ver = gems_to_update.first.version
  target = if update_latest
             up_ver
           else
             version
           end
  return target, requirement
end

def update_gem(name, version = Gem::Requirement.default)
  return if @updated.any? {|spec| spec.name == name }
  update_options = options.dup
  update_options[:prerelease] = version.prerelease?
  @installer = Gem::DependencyInstaller.new update_options
  say "Updating #{name}" unless options[:system] && options[:silent]
  begin
    @installer.install name, Gem::Requirement.new(version)
  rescue Gem::InstallError, Gem::DependencyError => e
    alert_error "Error installing #{name}:\n\t#{e.message}"
  end
  @installer.installed_gems.each do |spec|
    @updated << spec
  end
end

def update_gems(gems_to_update)
  gems_to_update.uniq.sort.each do |name_tuple|
    update_gem name_tuple.name, name_tuple.version
  end
  @updated
end

def update_rubygems
  if Gem.disable_system_update_message
    alert_error Gem.disable_system_update_message
    terminate_interaction 1
  end
  check_update_arguments
  version, requirement = rubygems_target_version
  check_latest_rubygems version
  check_oldest_rubygems version
  update_gem 'rubygems-update', version
  installed_gems = Gem::Specification.find_all_by_name 'rubygems-update', requirement
  version        = installed_gems.first.version
  install_rubygems version
end

def update_rubygems_arguments # :nodoc:
  args = []
  args << '--silent' if options[:silent]
  args << '--prefix' << Gem.prefix if Gem.prefix
  args << '--no-document' unless options[:document].include?('rdoc') || options[:document].include?('ri')
  args << '--no-format-executable' if options[:no_format_executable]
  args << '--previous-version' << Gem::VERSION if
    options[:system] == true or
      Gem::Version.new(options[:system]) >= Gem::Version.new(2)
  args
end

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

def which_to_update(highest_installed_gems, gem_names, system = false)
  result = []
  highest_installed_gems.each do |l_name, l_spec|
    next if not gem_names.empty? and
            gem_names.none? {|name| name == l_spec.name }
    highest_remote_tup = highest_remote_name_tuple l_spec
    highest_remote_ver = highest_remote_tup.version
    highest_installed_ver = l_spec.version
    if system or (highest_installed_ver < highest_remote_ver)
      result << Gem::NameTuple.new(l_spec.name, [highest_installed_ver, highest_remote_ver].max, highest_remote_tup.platform)
    end
  end
  result
end