# See the Pagy documentation: https://ddnexus.github.io/pagy/extras/elasticsearch_rails
# frozen_string_literal: true

class Pagy

  VARS[:elasticsearch_rails_search_method] ||= :pagy_search

  module ElasticsearchRails
    # returns an array used to delay the call of #search
    # after the pagination variables are merged to the options
    # it also pushes to the same array an eventually called method
    def pagy_elasticsearch_rails(query_or_payload, **options)
      [self, query_or_payload, options].tap do |args|
        args.define_singleton_method(:method_missing){|*a| args += a}
      end
    end
    alias_method VARS[:elasticsearch_rails_search_method], :pagy_elasticsearch_rails
  end

  # create a Pagy object from an Elasticsearch::Model::Response::Response object
  def self.new_from_elasticsearch_rails(response, vars={})
    vars[:items] = response.search.options[:size] || 10
    vars[:page]  = (response.search.options[:from] || 0) / vars[:items] + 1
    total        = response.respond_to?(:raw_response) ? response.raw_response['hits']['total'] : response.response['hits']['total']
    vars[:count] = total.is_a?(Hash) ? total['value'] : total
    new(vars)
  end

  # Add specialized backend methods to paginate ElasticsearchRails searches
  module Backend
    private

    # Return Pagy object and items
    def pagy_elasticsearch_rails(pagy_search_args, vars={})
      model, query_or_payload, options, *called = pagy_search_args
      vars           = pagy_elasticsearch_rails_get_vars(nil, vars)
      options[:size] = vars[:items]
      options[:from] = vars[:items] * (vars[:page] - 1)
      response       = model.search(query_or_payload, **options)
      total          = response.respond_to?(:raw_response) ? response.raw_response['hits']['total'] : response.response['hits']['total']
      vars[:count]   = total.is_a?(Hash) ? total['value'] : total

      pagy = Pagy.new(vars)
      # with :last_page overflow we need to re-run the method in order to get the hits
      return pagy_elasticsearch_rails(pagy_search_args, vars.merge(page: pagy.page)) \
             if defined?(Pagy::UseOverflowExtra) && pagy.overflow? && pagy.vars[:overflow] == :last_page

      [ pagy, called.empty? ? response : response.send(*called) ]
    end

    # Sub-method called only by #pagy_elasticsearch_rails: here for easy customization of variables by overriding
    # the _collection argument is not available when the method is called
    def pagy_elasticsearch_rails_get_vars(_collection, vars)
      pagy_set_items_from_params(vars) if defined?(UseItemsExtra)
      vars[:items] ||= VARS[:items]
      vars[:page]  ||= (params[ vars[:page_param] || VARS[:page_param] ] || 1).to_i
      vars
    end

  end
end