module CacheAssociations

# File lib/cache_associations.rb, line 9
def cache_association(name, **options, &cache_name_block)
  unless reflection = reflect_on_association(name)
    raise UndefinedAssociationError, "Undefined asscociation #{name}"
  end

  unless block_given?
    cache_name_block = lambda { [self.class.name, id, name, updated_at.to_i] }
  end

  register_cache_name_block(name, cache_name_block)
  options = Rails.cache.options.merge(options)

  define_method("cached_#{name}") do |*args, &block|
    break send(name) unless association_instance_get(name).nil?

    cache_name = cache_name_block.nil? ? default_cache_name(name) : instance_exec(&cache_name_block)
    cache = Rails.cache.fetch(cache_name, **options) do
      break instance_exec(*args, &block) if !block.nil?

      if reflection.collection?
        send("#{name}", *args).to_a
      else
        send("#{name}", *args)
      end
    end

    if association_instance_get(name).nil?
      association = reflection.association_class.new(self, reflection)
      association.target = cache
      association_instance_set(name.to_sym, association)
    end

    cache
  end
end

# File lib/cache_associations.rb, line 95
def cache_association_name(name)
  if !!cache_name_block = self.class.cache_name_block(name)
    instance_exec(&cache_name_block)
  elsif self.class.has_cache_association?(name)
    default_cache_name(name)
  else
    nil
  end
end

# File lib/cache_associations.rb, line 45
def cache_global_association(name, global_key = nil, **options)
  reflection = reflect_on_association(name)
  foreign_key = reflection.foreign_key

  if global_key.blank?
    global_key = reflection.klass.name
  end

  cache_name_block = lambda { [global_key, send(foreign_key)] }
  cache_association(name, **options, &cache_name_block)
end

# File lib/cache_associations.rb, line 57
def cache_method(name, **options, &cache_name_block)
  register_cache_name_block(name, cache_name_block)
  options = Rails.cache.options.merge(options)

  define_method("cached_#{name}") do |*args, &block|
    cache_name = cache_name_block.nil? ? default_cache_name(name) : instance_exec(&cache_name_block)
    Rails.cache.fetch(cache_name, **options) do
      break instance_exec(*args, &block) if !block.nil?
      
      send("#{name}", *args)
    end
  end
end

# File lib/cache_associations.rb, line 79
def cache_name_block(name)
  cache_name_blocks[name.to_sym]
end

# File lib/cache_associations.rb, line 90
def cache_name_blocks
  @cache_name_blocks ||= {}
end

# File lib/cache_associations.rb, line 105
def clear_caching_on_association(name)
  return nil if !cache_name = cache_association_name(name)

  Rails.cache.delete(cache_name)
end

# File lib/cache_associations.rb, line 75
def custom_cache_name?(name)
  !!cache_name_blocks[name.to_sym]
end

# File lib/cache_associations.rb, line 71
def has_cache_association?(name)
  cache_name_blocks.has_key?(name.to_sym)
end

# File lib/cache_associations.rb, line 85
def register_cache_name_block(name, cache_name_block)
  warn "#{name} has been cached before." if has_cache_association?(name)
  cache_name_blocks[name] = cache_name_block
end

# File lib/cache_associations.rb, line 113
def default_cache_name(name)
  [self.class.name, id, name.to_s, updated_at.to_i]
end