class ActionDispatch::MiddlewareStack

def [](i)
  middlewares[i]
end

def assert_index(index, where)
  index = get_class index
  i = index.is_a?(Integer) ? index : middlewares.index { |m| m.klass == index }
  raise "No such middleware to insert #{where}: #{index.inspect}" unless i
  i
end

def build(app = Proc.new)
  middlewares.freeze.reverse.inject(app) { |a, e| e.build(a) }
end

def build_middleware(klass, args, block)
  Middleware.new(get_class(klass), args, block)
end

def delete(target)
  target = get_class target
  middlewares.delete_if { |m| m.klass == target }
end

def each
  @middlewares.each { |x| yield x }
end

def get_class(klass)
  if klass.is_a?(String) || klass.is_a?(Symbol)
    classcache = ActiveSupport::Dependencies::Reference
    converted_klass = classcache[klass.to_s]
    ActiveSupport::Deprecation.warn <<-eowarn
ing strings or symbols to the middleware builder is deprecated, please change
 to actual class references.  For example:
{klass}" => #{converted_klass}
    eowarn
    converted_klass
  else
    klass
  end
end

def initialize(*args)
  @middlewares = []
  yield(self) if block_given?
end

def initialize_copy(other)
  self.middlewares = other.middlewares.dup
end

def insert(index, klass, *args, &block)
  index = assert_index(index, :before)
  middlewares.insert(index, build_middleware(klass, args, block))
end

def insert_after(index, *args, &block)
  index = assert_index(index, :after)
  insert(index + 1, *args, &block)
end

def last
  middlewares.last
end

def size
  middlewares.size
end

def swap(target, *args, &block)
  index = assert_index(target, :before)
  insert(index, *args, &block)
  middlewares.delete_at(index + 1)
end

def unshift(klass, *args, &block)
  middlewares.unshift(build_middleware(klass, args, block))
end

def use(klass, *args, &block)
  middlewares.push(build_middleware(klass, args, block))
end