require "forwardable"

module Searchkick
  class Results
    include Enumerable
    extend Forwardable

    attr_reader :klass, :response, :options

    def_delegators :results, :each, :any?, :empty?, :size, :length, :slice, :[], :to_ary

    def initialize(klass, response, options = {})
      @klass = klass
      @response = response
      @options = options
    end

    def results
      @results ||= begin
        if options[:load]
          # results can have different types
          results = {}

          hits.group_by { |hit, i| hit["_type"] }.each do |type, grouped_hits|
            records = type.camelize.constantize
            if options[:includes]
              if defined?(NoBrainer::Document) && records < NoBrainer::Document
                records = records.preload(options[:includes])
              else
                records = records.includes(options[:includes])
              end
            end
            results[type] = results_query(records, grouped_hits)
          end

          # sort
          hits.map do |hit|
            results[hit["_type"]].find { |r| r.id.to_s == hit["_id"].to_s }
          end.compact
        else
          hits.map do |hit|
            result =
              if hit["_source"]
                hit.except("_source").merge(hit["_source"])
              else
                hit.except("fields").merge(hit["fields"])
              end
            result["id"] ||= result["_id"] # needed for legacy reasons
            Hashie::Mash.new(result)
          end
        end
      end
    end

    def suggestions
      if response["suggest"]
        response["suggest"].values.flat_map { |v| v.first["options"] }.sort_by { |o| -o["score"] }.map { |o| o["text"] }.uniq
      else
        raise "Pass `suggest: true` to the search method for suggestions"
      end
    end

    def each_with_hit(&block)
      results.zip(hits).each(&block)
    end

    def with_details
      each_with_hit.map do |model, hit|
        details = {}
        if hit["highlight"]
          details[:highlight] = Hash[hit["highlight"].map { |k, v| [(options[:json] ? k : k.sub(/\.analyzed\z/, "")).to_sym, v.first] }]
        end
        [model, details]
      end
    end

    def facets
      response["facets"]
    end

    def model_name
      klass.model_name
    end

    def entry_name
      model_name.human.downcase
    end

    def total_count
      response["hits"]["total"]
    end
    alias_method :total_entries, :total_count

    def current_page
      options[:page]
    end

    def per_page
      options[:per_page]
    end
    alias_method :limit_value, :per_page

    def padding
      options[:padding]
    end

    def total_pages
      (total_count / per_page.to_f).ceil
    end
    alias_method :num_pages, :total_pages

    def offset_value
      (current_page - 1) * per_page + padding
    end
    alias_method :offset, :offset_value

    def previous_page
      current_page > 1 ? (current_page - 1) : nil
    end
    alias_method :prev_page, :previous_page

    def next_page
      current_page < total_pages ? (current_page + 1) : nil
    end

    def first_page?
      previous_page.nil?
    end

    def last_page?
      next_page.nil?
    end

    def hits
      @response["hits"]["hits"]
    end

    private

    def results_query(records, grouped_hits)
      if records.respond_to?(:primary_key) && records.primary_key
        # ActiveRecord
        records.where(records.primary_key => grouped_hits.map { |hit| hit["_id"] }).to_a
      elsif records.respond_to?(:all) && records.all.respond_to?(:for_ids)
        # Mongoid 2
        records.all.for_ids(grouped_hits.map { |hit| hit["_id"] }).to_a
      elsif records.respond_to?(:queryable)
        # Mongoid 3+
        records.queryable.for_ids(grouped_hits.map { |hit| hit["_id"] }).to_a
      elsif records.respond_to?(:unscoped) && records.all.respond_to?(:preload)
        # Nobrainer
        records.unscoped.where(:id.in => grouped_hits.map { |hit| hit["_id"] }).to_a
      else
        raise "Not sure how to load records"
      end
    end
  end
end