class Gem::Commands::OpenCommand

def arguments # :nodoc:
  "GEMNAME     name of gem to open in editor"
end

def defaults_str # :nodoc:
  "-e #{get_env_editor}"
end

def description # :nodoc:
  <<-EOF
      The open command opens gem in editor and changes current path
      to gem's source directory.
      Editor command can be specified with -e option, otherwise rubygems
      will look for editor in $EDITOR, $VISUAL and $GEM_EDITOR variables.
  EOF
end

def execute
  @version = options[:version] || Gem::Requirement.default
  @editor  = options[:editor] || get_env_editor
  found = open_gem(get_one_gem_name)
  terminate_interaction 1 unless found
end

def get_env_editor
  ENV["GEM_EDITOR"] ||
    ENV["VISUAL"] ||
    ENV["EDITOR"] ||
    "vi"
end

def initialize
  super "open", "Open gem sources in editor"
  add_option("-e", "--editor COMMAND", String,
             "Prepends COMMAND to gem path. Could be used to specify editor.") do |command, options|
    options[:editor] = command || get_env_editor
  end
  add_option("-v", "--version VERSION", String,
             "Opens specific gem version") do |version|
    options[:version] = version
  end
end

def open_editor(path)
  system(*@editor.split(/\s+/) + [path], { chdir: path })
end

def open_gem(name)
  spec = spec_for name
  return false unless spec
  if spec.default_gem?
    say "'#{name}' is a default gem and can't be opened."
    return false
  end
  open_editor(spec.full_gem_path)
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}'"
end

def usage # :nodoc:
  "#{program_name} [-e COMMAND] GEMNAME"
end