module Mime

def [](type)
  return type if type.is_a?(Type)
  Type.lookup_by_extension(type)
end

def const_defined?(sym, inherit = true)
  ext = sym.downcase
  if Mime[ext]
    ActiveSupport::Deprecation.warn(<<-MSG.squish)
      Accessing mime types via constants is deprecated.
      Please change `Mime.const_defined?(#{sym})` to `Mime[:#{ext}]`.
    MSG
    true
  else
    super
  end
end

def const_missing(sym)
  ext = sym.downcase
  if Mime[ext]
    ActiveSupport::Deprecation.warn(<<-MSG.squish)
      Accessing mime types via constants is deprecated.
      Please change `Mime::#{sym}` to `Mime[:#{ext}]`.
    MSG
    Mime[ext]
  else
    super
  end
end

def fetch(type)
  return type if type.is_a?(Type)
  EXTENSION_LOOKUP.fetch(type.to_s) { |k| yield k }
end