cacheable.rb

# frozen_string_literal: true

require "view_component/cache_registry"
require "view_component/cache_digestor"

module ViewComponent::Cacheable
  extend ActiveSupport::Concern

  included do
    class_attribute :__vc_cache_options, default: Set[:identifier]
    class_attribute :__vc_cache_dependencies, default: Set.new

    # For caching, such as #cache_if
    #
    # @private
    def view_cache_dependencies
      self.class.__vc_cache_dependencies.map { |dep| public_send(dep) }
    end

    def view_cache_options
      return if __vc_cache_options.blank?

      computed_view_cache_options = __vc_cache_options.map { |opt| if respond_to?(opt) then public_send(opt) end }
      combined_fragment_cache_key(ActiveSupport::Cache.expand_cache_key(computed_view_cache_options + component_digest))
    end

    # Render component from cache if possible
    #
    # @private
    def __vc_render_cacheable(safe_call)
      if (__vc_cache_options - [:identifier]).any?
        ViewComponent::CachingRegistry.track_caching do
          template_fragment(safe_call)
        end
      else
        instance_exec(&safe_call)
      end
    end

    def template_fragment
      if (content = read_fragment)
        @view_renderer.cache_hits[@current_template&.virtual_path] = :hit if defined?(@view_renderer)
        content
      else
        @view_renderer.cache_hits[@current_template&.virtual_path] = :miss if defined?(@view_renderer)
        write_fragment
      end
    end

    def read_fragment
      Rails.cache.fetch(view_cache_options)
    end

    def write_fragment
      content = instance_exec(&safe_call)
      Rails.cache.fetch(view_cache_options) do
        content
      end
      content
    end

    def combined_fragment_cache_key(key)
      cache_key = [:view_component, ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"], key]
      cache_key.flatten!(1)
      cache_key.compact!
      cache_key
    end

    def component_digest
      ViewComponent::CacheDigestor.new(component: self).digest
    end
  end

  class_methods do
    # For caching the component
    def cache_on(*args)
      __vc_cache_options.merge(args)
    end

    def inherited(child)
      child.__vc_cache_options = __vc_cache_options.dup

      super
    end
  end
end