module CreateItinerary
  class BuildHiddenCityEventsMap < UseCaseBase
    DEPARTURE_EVENT_INDEX_OFFSETS = [0, 1, 2].freeze
    ARRIVAL_EVENT_INDEX_OFFSETS = [-2, -1, 0].freeze
    SELF_INDEX_OFFSET = [0].freeze

    def before
      @calendar_entries = context.calendar_entries
      @hidden_cities = context.hidden_cities
    end

    def perform_core
      result = {}
      hidden_city_ids = @hidden_cities.map(&:city_id)
      @calendar_entries.each_with_index do |entry, index|
        next unless hidden_city_ids.include?(entry.city_id)
        affected_entries = index_offsets(entry).map { |offset| @calendar_entries[index + offset] }
        affected_entries.each { |affected_entry| result[affected_entry.uuid] = affected_entry }
      end
      context.hidden_city_events_map = result
    end

    private

    def index_offsets(event)
      departure_event_indexes(event) || arrival_event_indexes(event) || SELF_INDEX_OFFSET
    end

    def departure_event_indexes(event)
      DEPARTURE_EVENT_INDEX_OFFSETS if event.uuid.end_with?(Calendar::DEPARTURE_EVENT_SUFFIX)
    end

    def arrival_event_indexes(event)
      ARRIVAL_EVENT_INDEX_OFFSETS if event.uuid.end_with?(Calendar::ARRIVAL_EVENT_SUFFIX)
    end
  end
end

require "test_helper"

describe CreateItinerary::BuildHiddenCityEventsMap do
  describe "perform" do
    let(:hidden_cities) { [] }
    let(:calendar_entries) { [] }

    subject do
      CreateItinerary::BuildHiddenCityEventsMap.perform(
        hidden_cities: hidden_cities,
        calendar_entries: calendar_entries
      )
    end

    describe "hidden_cities is empty" do
      it "sets hidden_city_events_map to an empty hash" do
        result = subject

        assert_equal({}, result.hidden_city_events_map)
      end
    end

    describe "hidden cities is not empty" do
      let(:hidden_city) { FactoryGirl.create(:hidden_city) }

      before { hidden_cities.push(hidden_city) }

      describe "calendar entries is empty" do
        it "sets hidden_city_events_map to an empty hash" do
          result = subject

          assert_equal({}, result.hidden_city_events_map)
        end
      end

      describe "calendar_entries is not empty" do
        let(:calendar_entry1) { FactoryGirl.build(:calendar_entry, city: hidden_city.city) }
        let(:calendar_entry2) { FactoryGirl.build(:calendar_entry) }
        let(:calendar_entry3) { FactoryGirl.build(:calendar_entry, city: hidden_city.city) }

        before { calendar_entries.push(calendar_entry1, calendar_entry2, calendar_entry3) }

        it "adds the events from hidden cities to the hidden_city_events_map" do
          result = subject

          expected_map = { calendar_entry1.uuid => calendar_entry1, calendar_entry3.uuid => calendar_entry3 }
          assert_equal expected_map, result.hidden_city_events_map
        end

        describe "calendar_entries has expanded flight events" do
          let(:in_flight_event) do
            calendar_entry = FactoryGirl.build(:calendar_entry)
            calendar_entry.origin = FactoryGirl.build(:event_origin, calendar: calendar_entry)
            calendar_entry
          end
          let(:departure_event) { FactoryGirl.build(:calendar_entry, uuid: "#{in_flight_event.uuid}_departure") }
          let(:arrival_event) { FactoryGirl.build(:calendar_entry, uuid: "#{in_flight_event.uuid}_arrival") }

          before { calendar_entries.push(departure_event, in_flight_event, arrival_event) }

          describe "the departure event is from the same city as the hidden cities" do
            before { departure_event.city = hidden_city.city }

            it "adds the related events to the hidden_city_events_map" do
              result = subject

              assert_equal in_flight_event, result.hidden_city_events_map[in_flight_event.uuid]
              assert_equal departure_event, result.hidden_city_events_map[departure_event.uuid]
              assert_equal arrival_event, result.hidden_city_events_map[arrival_event.uuid]
            end
          end

          describe "the arrival event is from the same city as the hidden cities" do
            before { arrival_event.city = hidden_city.city }

            it "adds the related events to the hidden_city_events_map" do
              result = subject

              assert_equal in_flight_event, result.hidden_city_events_map[in_flight_event.uuid]
              assert_equal departure_event, result.hidden_city_events_map[departure_event.uuid]
              assert_equal arrival_event, result.hidden_city_events_map[arrival_event.uuid]
            end
          end
        end
      end
    end
  end
end