module Memoist

# File lib/memoist.rb, line 40
def self.escape_punctuation(string)
  string = string.is_a?(String) ? string.dup : string.to_s.dup

  return string unless string.end_with?('?'.freeze, '!'.freeze)

  # A String can't end in both ? and !
  if string.sub!(/\?\Z/, '_query'.freeze)
  else
    string.sub!(/!\Z/, '_bang'.freeze)
  end
  string
end

# File lib/memoist.rb, line 6
def self.extended(extender)
  Memoist.memoist_eval(extender) do
    unless singleton_class.method_defined?(:memoized_methods)
      def self.memoized_methods
        @_memoized_methods ||= []
      end
    end
  end
end

# File lib/memoist.rb, line 61
def self.extract_reload!(method, args)
  if args.length == method.arity.abs + 1 && (args.last == true || args.last == :reload)
    reload = args.pop
  end
  reload
end

# File lib/memoist.rb, line 53
def self.memoist_eval(klass, *args, &block)
  if klass.respond_to?(:class_eval)
    klass.class_eval(*args, &block)
  else
    klass.singleton_class.class_eval(*args, &block)
  end
end

# File lib/memoist.rb, line 16
def self.memoized_ivar_for(method_name, identifier = nil)
  "@#{memoized_prefix(identifier)}_#{escape_punctuation(method_name)}"
end

# File lib/memoist.rb, line 9
def self.memoized_methods
  @_memoized_methods ||= []
end

# File lib/memoist.rb, line 24
def self.memoized_prefix(identifier = nil)
  if identifier
    "_memoized_#{identifier}"
  else
    '_memoized'.freeze
  end
end

# File lib/memoist.rb, line 20
def self.unmemoized_method_for(method_name, identifier = nil)
  "#{unmemoized_prefix(identifier)}_#{method_name}".to_sym
end

# File lib/memoist.rb, line 32
def self.unmemoized_prefix(identifier = nil)
  if identifier
    "_unmemoized_#{identifier}"
  else
    '_unmemoized'.freeze
  end
end

# File lib/memoist.rb, line 104
def all_memoized_structs
  @all_memoized_structs ||= begin
    structs = memoized_methods.dup

    # Collect the memoized_methods of ancestors in ancestor order
    # unless we already have it since self or parents could be overriding
    # an ancestor method.
    ancestors.grep(Memoist).each do |ancestor|
      ancestor.memoized_methods.each do |m|
        structs << m unless structs.any? { |am| am.memoized_method == m.memoized_method }
      end
    end
    structs
  end
end

# File lib/memoist.rb, line 120
def clear_structs
  @all_memoized_structs = nil
end

# File lib/memoist.rb, line 124
  def memoize(*method_names)
    identifier = method_names.pop[:identifier] if method_names.last.is_a?(Hash)

    method_names.each do |method_name|
      unmemoized_method = Memoist.unmemoized_method_for(method_name, identifier)
      memoized_ivar = Memoist.memoized_ivar_for(method_name, identifier)

      Memoist.memoist_eval(self) do
        include InstanceMethods

        if method_defined?(unmemoized_method)
          warn "Already memoized #{method_name}"
          return
        end
        alias_method unmemoized_method, method_name

        mm = MemoizedMethod.new(method_name, memoized_ivar, instance_method(method_name).arity)
        memoized_methods << mm
        if mm.arity == 0

          # define a method like this;

          # def mime_type(reload=true)
          #   skip_cache = reload || !instance_variable_defined?("@_memoized_mime_type")
          #   set_cache = skip_cache && !frozen?
          #
          #   if skip_cache
          #     value = _unmemoized_mime_type
          #   else
          #     value = @_memoized_mime_type
          #   end
          #
          #   if set_cache
          #     @_memoized_mime_type = value
          #   end
          #
          #   value
          # end

          module_eval <<-EOS, __FILE__, __LINE__ + 1
            def #{method_name}(reload = false)
              skip_cache = reload || !instance_variable_defined?("#{memoized_ivar}")
              set_cache = skip_cache && !frozen?

              if skip_cache
                value = #{unmemoized_method}
              else
                value = #{memoized_ivar}
              end

              if set_cache
                #{memoized_ivar} = value
              end

              value
            end
          EOS
        else

          # define a method like this;

          # def mime_type(*args)
          #   reload = Memoist.extract_reload!(method(:_unmemoized_mime_type), args)
          #
          #   skip_cache = reload || !memoized_with_args?(:mime_type, args)
          #   set_cache = skip_cache && !frozen
          #
          #   if skip_cache
          #     value = _unmemoized_mime_type(*args)
          #   else
          #     value = @_memoized_mime_type[args]
          #   end
          #
          #   if set_cache
          #     @_memoized_mime_type ||= {}
          #     @_memoized_mime_type[args] = value
          #   end
          #
          #   value
          # end

          module_eval <<-EOS, __FILE__, __LINE__ + 1
            def #{method_name}(*args)
              reload = Memoist.extract_reload!(method(#{unmemoized_method.inspect}), args)

              skip_cache = reload || !(instance_variable_defined?(#{memoized_ivar.inspect}) && #{memoized_ivar} && #{memoized_ivar}.has_key?(args))
              set_cache = skip_cache && !frozen?

              if skip_cache
                value = #{unmemoized_method}(*args)
              else
                value = #{memoized_ivar}[args]
              end

              if set_cache
                #{memoized_ivar} ||= {}
                #{memoized_ivar}[args] = value
              end

              value
            end
          EOS
        end

        if private_method_defined?(unmemoized_method)
          private method_name
        elsif protected_method_defined?(unmemoized_method)
          protected method_name
        end
      end
    end
    # return a chainable method_name symbol if we can
    method_names.length == 1 ? method_names.first : method_names
  end