module Quickery
  module ActiveRecordExtensions
    module DSL
      class << self
        def included(base)
          base.extend ClassMethods
          base.include InstanceMethods
        end
      end

      module ClassMethods
        attr_accessor :quickery_association_chain_dependers
        attr_accessor :quickery_association_chain_dependees
        attr_accessor :quickery_association_chain_intermediaries
        attr_accessor :quickery_builders

        def quickery(mappings)
          mappings_builder = MappingsBuilder.new(model: self, mappings: mappings.with_indifferent_access)
          mappings_builder.map_attributes
        end

        # subclass overrideable
        def quickery_before_create_or_update(dependent_record, new_values)
          dependent_record.assign_attributes(new_values)
        end

        # subclass overrideable
        def quickery_before_association_update(dependent_records, record_to_be_updated, new_values)
          dependent_records.update_all(new_values)
        end

        # subclass overrideable
        def quickery_before_association_destroy(dependent_records, record_to_be_destroyed, new_values)
          dependent_records.update_all(new_values)
        end
      end

      module InstanceMethods
        def recreate_quickery_cache!
          self.class.quickery_builders.each do |depender_column_name, quickery_builder|
            new_value = determine_quickery_value(depender_column_name)
            update_columns(depender_column_name => new_value)
          end
        end

        def determine_quickery_value(depender_column_name)
          quickery_builder = self.class.quickery_builders[depender_column_name.to_sym]

          raise ArgumentError, "No defined quickery builder for #{depender_column_name}. Defined values are #{self.class.quickery_builders.keys}" unless quickery_builder

          dependee_record = quickery_builder.association_chains.first.dependee_record(self)
          dependee_record.public_send(quickery_builder.dependee_column_name) if dependee_record
        end

        def determine_quickery_values
          quickery_values = {}
          self.class.quickery_builders.each do |depender_column_name, quickery_builder|
            quickery_values[depender_column_name] = determine_quickery_value(depender_column_name)
          end
          quickery_values
        end

        # only considers quickery-defined attributes that has corresponding *_is_synced attribute
        def autoload_unsynced_quickery_attributes!
          model = self.class
          new_values = {}.with_indifferent_access

          defined_quickery_attribute_names = model.quickery_builders.keys

          defined_quickery_attribute_names.each do |defined_quickery_attribute_name|
            if has_attribute?(:"#{defined_quickery_attribute_name}_is_synced") && !send(:"#{defined_quickery_attribute_name}_is_synced")
              new_values[defined_quickery_attribute_name] = determine_quickery_value(defined_quickery_attribute_name)
              new_values[:"#{defined_quickery_attribute_name}_is_synced"] = true
            end
          end

          update_columns(new_values) if new_values.present?
        end
      end
    end
  end
end