class Gem::Commands::ContentsCommand

def arguments # :nodoc:
  "GEMNAME       name of gem to list contents for"
end

def defaults_str # :nodoc:
  "--no-lib-only --prefix"
end

def description # :nodoc:
  <<-EOF
e contents command lists the files in an installed gem.  The listing can
 given as full file names, file names without the installed directory
efix or only the files that are requireable.
  EOF
end

def execute
  @version   = options[:version] || Gem::Requirement.default
  @spec_dirs = specification_directories
  @path_kind = path_description @spec_dirs
  names = gem_names
  names.each do |name|
    found =
      if options[:show_install_dir]
        gem_install_dir name
      else
        gem_contents name
      end
    terminate_interaction 1 unless found || names.length > 1
  end
end

def files_in(spec)
  if spec.default_gem?
    files_in_default_gem spec
  else
    files_in_gem spec
  end
end

def files_in_default_gem(spec)
  spec.files.filter_map do |file|
    if file.start_with?("#{spec.bindir}/")
      [RbConfig::CONFIG["bindir"], file.delete_prefix("#{spec.bindir}/")]
    else
      gem spec.name, spec.version
      require_path = spec.require_paths.find do |path|
        file.start_with?("#{path}/")
      end
      requirable_part = file.delete_prefix("#{require_path}/")
      resolve = $LOAD_PATH.resolve_feature_path(requirable_part)&.last
      next unless resolve
      [resolve.delete_suffix(requirable_part), requirable_part]
    end
  end
end

def files_in_gem(spec)
  gem_path  = spec.full_gem_path
  extra     = "/{#{spec.require_paths.join ","}}" if options[:lib_only]
  glob      = "#{gem_path}#{extra}/**/*"
  prefix_re = %r{#{Regexp.escape(gem_path)}/}
  Dir[glob].map do |file|
    [gem_path, file.sub(prefix_re, "")]
  end
end

def gem_contents(name)
  spec = spec_for name
  return false unless spec
  files = files_in spec
  show_files files
  true
end

def gem_install_dir(name)
  spec = spec_for name
  return false unless spec
  say spec.gem_dir
  true
end

def gem_names # :nodoc:
  if options[:all]
    Gem::Specification.map(&:name)
  else
    get_all_gem_names
  end
end

def initialize
  super "contents", "Display the contents of the installed gems",
        specdirs: [], lib_only: false, prefix: true,
        show_install_dir: false
  add_version_option
  add_option("--all",
             "Contents for all gems") do |all, options|
    options[:all] = all
  end
  add_option("-s", "--spec-dir a,b,c", Array,
             "Search for gems under specific paths") do |spec_dirs, options|
    options[:specdirs] = spec_dirs
  end
  add_option("-l", "--[no-]lib-only",
             "Only return files in the Gem's lib_dirs") do |lib_only, options|
    options[:lib_only] = lib_only
  end
  add_option("--[no-]prefix",
             "Don't include installed path prefix") do |prefix, options|
    options[:prefix] = prefix
  end
  add_option("--[no-]show-install-dir",
             "Show only the gem install dir") do |show, options|
    options[:show_install_dir] = show
  end
  @path_kind = nil
  @spec_dirs = nil
  @version   = nil
end

def path_description(spec_dirs) # :nodoc:
  if spec_dirs.empty?
    "default gem paths"
  else
    "specified path"
  end
end

def show_files(files)
  files.sort.each do |prefix, basename|
    absolute_path = File.join(prefix, basename)
    next if File.directory? absolute_path
    if options[:prefix]
      say absolute_path
    else
      say basename
    end
  end
end

def spec_for(name)
  spec = Gem::Specification.find_all_by_name(name, @version).first
  return spec if spec
  say "Unable to find gem '#{name}' in #{@path_kind}"
  if Gem.configuration.verbose
    say "\nDirectories searched:"
    @spec_dirs.sort.each {|dir| say dir }
  end
  nil
end

def specification_directories # :nodoc:
  options[:specdirs].flat_map do |i|
    [i, File.join(i, "specifications")]
  end
end

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