module AttributeCache

# File lib/attribute_cache.rb, line 10
def self.attribute_cache(name, options = {}, &block)
  options.default! :attribute_prefix, 'cached'
  options.default! :callback_prefix,  'calculate'

  options.default! :attribute, :"#{options[:attribute_prefix]}_#{name}"
  options.default! :callback,  :"#{options[:callback_prefix]}_#{name}"

  options[:callback] = block if block_given?

  options.default! :cache_on_create, false
  options.default! :dependent_on, []

  options[:dependent_on] = [options[:dependent_on]] unless options[:dependent_on].is_a? Array

  attr_cache = AttributeCache.new(
    name: name,
    attribute: options[:attribute],
    callback: options[:callback]
  )

  if options[:cache_on_create]
    before_create(if: -> { read_attribute(options[:attribute]).nil? }) do
      attr_cache.set_attribute(self)
    end
  end

  if options[:dependent_on].count.positive?
    before_update(if: -> { dependent_attribute_will_change(self, options[:dependent_on]) }) do
      attr_cache.invalidate_attribute(self)
    end
  end

  define_method("set_#{name}") do |save: false, args: []|
    attr_cache.set_attribute(self, save: save, args: args)
  end

  define_method("invalidate_#{name}") do |save: false, args: []|
    attr_cache.invalidate_attribute(self, save: save, args: args)
  end

  define_method("set_#{name}!") do |args: []|
    attr_cache.set_attribute!(self, args: args)
  end

  define_method("invalidate_#{name}!") do |args: []|
    attr_cache.invalidate_attribute!(self, args: args)
  end

  define_method(name) do |save: true, keep_blanks: true, args: []|
    attr_cache.value(self, save: save, keep_blanks: keep_blanks, args: args)
  end
end

# File lib/attribute_cache.rb, line 63
def self.attribute_store(name, options = {}, &block)
  options.default! :cache_on_create, true
  options.default! :attribute_prefix, 'stored'

  attribute_cache(name, options, &block)
end

# File lib/attribute_cache.rb, line 73
def dependent_attribute_will_change(record, dependent_on)
  dependent_on.any? { |d| record.will_save_change_to_attribute?(d) }
end