require 'digest/md5'

module Travis::Api
  class App
    module Responders
      class Service < Base
        include Helpers::Accept

        def apply?
          resource.respond_to?(:run)
        end

        def apply
          cache_control
          result = normalize(resource.run)
          result[:flash] = resource.messages if result && resource.respond_to?(:messages) # TODO should rather happen in the JSON responder, no?
          result
        end

        private

          def cache_control
            if final?
              mode = endpoint.public? ? :public : :private
              endpoint.expires(31536000, mode) # 1 year
            else
              # FIXME: Chrome WTF?
              endpoint.cache_control :no_cache
            end

            endpoint.etag cache_key if cache_key
          end

          def final?
            resource.respond_to?(:final?) && resource.final?
          end

          def cache_key
            cache_key ||= begin
              key = resource_cache_key || resource_updated_at
              Digest::MD5.hexdigest([App.deploy_sha, key].join('-')) if key
            end
          end

          def resource_cache_key
            resource.respond_to?(:updated_at) && resource.updated_at
          end

          def resource_updated_at
            resource.respond_to?(:updated_at) && resource.updated_at.try(:strftime, '%FT%T%:z')
          end

          # Services potentially return all sorts of things
          # If it's a string, true or false we'll wrap it into a hash.
          # If it's an active record or scope we just pass so it can be processed by the json responder.
          # If it's nil we also pass it but yield not_found.
          def normalize(result)
            case result
            when Symbol, String, true, false
              { result: result }
            else
              result
            end
          end
      end
    end
  end
end