module Rails::Command::EnvironmentArgument

def available_environments
  @available_environments ||=
    Dir["config/environments/*.rb"].map { |filename| File.basename(filename, ".*") }
end

def environment
  @environment ||= options[:environment]
end

def environment=(environment)
  @environment = environment
end

def environment_specified?
  @environment_specified
end

def expand_environment_name(name)
  %w[production development test].find { |full_name| full_name.start_with?(name) } || name
end

def initialize(...)
  super
  @environment_specified = options[:environment].present?
  if !@environment_specified
    self.options = options.merge(environment: Rails::Command.environment)
  elsif !available_environments.include?(options[:environment])
    self.options = options.merge(environment: expand_environment_name(options[:environment]))
  end
end

def require_application!
  ENV["RAILS_ENV"] = environment
  super
end