class Gem::Commands::UninstallCommand

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

def check_version # :nodoc:
  if options[:version] != Gem::Requirement.default and
       get_all_gem_names.size > 1
    alert_error "Can't use --version with multiple gems. You can specify multiple gems with" \
                " version requirements using `gem uninstall 'my_gem:1.0.0' 'my_other_gem:~>2.0.0'`"
    terminate_interaction 1
  end
end

def defaults_str # :nodoc:
  "--version '#{Gem::Requirement.default}' --no-force " +
  "--user-install"
end

def description # :nodoc:
  <<-EOF
e uninstall command removes a previously installed gem.
byGems will ask for confirmation if you are attempting to uninstall a gem
at is a dependency of an existing gem.  You can use the
ignore-dependencies option to skip this check.
  EOF
end

def execute
  check_version
  if options[:all] and not options[:args].empty?
    uninstall_specific
  elsif options[:all]
    uninstall_all
  else
    uninstall_specific
  end
end

def initialize
  super 'uninstall', 'Uninstall gems from the local repository',
        :version => Gem::Requirement.default, :user_install => true,
        :check_dev => false, :vendor => false
  add_option('-a', '--[no-]all',
    'Uninstall all matching versions'
  ) do |value, options|
    options[:all] = value
  end
  add_option('-I', '--[no-]ignore-dependencies',
             'Ignore dependency requirements while',
             'uninstalling') do |value, options|
    options[:ignore] = value
  end
  add_option('-D', '--[no-]check-development',
             'Check development dependencies while uninstalling',
             '(default: false)') do |value, options|
    options[:check_dev] = value
  end
  add_option('-x', '--[no-]executables',
               'Uninstall applicable executables without',
               'confirmation') do |value, options|
    options[:executables] = value
  end
  add_option('-i', '--install-dir DIR',
             'Directory to uninstall gem from') do |value, options|
    options[:install_dir] = File.expand_path(value)
  end
  add_option('-n', '--bindir DIR',
             'Directory to remove executables from') do |value, options|
    options[:bin_dir] = File.expand_path(value)
  end
  add_option('--[no-]user-install',
             'Uninstall from user\'s home directory',
             'in addition to GEM_HOME.') do |value, options|
    options[:user_install] = value
  end
  add_option('--[no-]format-executable',
             'Assume executable names match Ruby\'s prefix and suffix.') do |value, options|
    options[:format_executable] = value
  end
  add_option('--[no-]force',
             'Uninstall all versions of the named gems',
             'ignoring dependencies') do |value, options|
    options[:force] = value
  end
  add_option('--[no-]abort-on-dependent',
             'Prevent uninstalling gems that are',
             'depended on by other gems.') do |value, options|
    options[:abort_on_dependent] = value
  end
  add_version_option
  add_platform_option
  add_option('--vendor',
             'Uninstall gem from the vendor directory.',
             'Only for use by gem repackagers.') do |value, options|
    unless Gem.vendor_dir
      raise OptionParser::InvalidOption.new 'your platform is not supported'
    end
    alert_warning 'Use your OS package manager to uninstall vendor gems'
    options[:vendor] = true
    options[:install_dir] = Gem.vendor_dir
  end
end

def uninstall(gem_name)
  Gem::Uninstaller.new(gem_name, options).uninstall
end

def uninstall_all
  specs = Gem::Specification.reject {|spec| spec.default_gem? }
  specs.each do |spec|
    options[:version] = spec.version
    uninstall_gem spec.name
  end
  alert "Uninstalled all gems in #{options[:install_dir] || Gem.dir}"
end

def uninstall_gem(gem_name)
  uninstall(gem_name)
rescue Gem::GemNotInHomeException => e
  spec = e.spec
  alert("In order to remove #{spec.name}, please execute:\n" +
        "\tgem uninstall #{spec.name} --install-dir=#{spec.installation_path}")
rescue Gem::UninstallError => e
  spec = e.spec
  alert_error("Error: unable to successfully uninstall '#{spec.name}' which is " +
        "located at '#{spec.full_gem_path}'. This is most likely because" +
        "the current user does not have the appropriate permissions")
  terminate_interaction 1
end

def uninstall_specific
  deplist = Gem::DependencyList.new
  original_gem_version = {}
  get_all_gem_names_and_versions.each do |name, version|
    original_gem_version[name] = version || options[:version]
    gem_specs = Gem::Specification.find_all_by_name(name, original_gem_version[name])
    say("Gem '#{name}' is not installed") if gem_specs.empty?
    gem_specs.each do |spec|
      deplist.add spec
    end
  end
  deps = deplist.strongly_connected_components.flatten.reverse
  gems_to_uninstall = {}
  deps.each do |dep|
    unless gems_to_uninstall[dep.name]
      gems_to_uninstall[dep.name] = true
      unless original_gem_version[dep.name] == Gem::Requirement.default
        options[:version] = dep.version
      end
      uninstall_gem(dep.name)
    end
  end
end

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