Merge pull request #30 from bus-detective/scheduled-departures

Scheduled departures

app/controllers/api/departures_controller.rb

@@ -1,6 +1,12 @@
 class Api::DeparturesController < ApiController
   def index
-    fetcher = departure_fetcher.new(agency, stop, time)
+    fetcher = departure_fetcher.new(
+      agency: agency,
+      stop: stop,
+      start_time: start_time,
+      end_time: end_time
+    )
+
     if fetcher.valid?
       render json: fetcher, serializer: DepartureFetcherSerializer
     else
@@ -32,4 +38,18 @@ def time
     # offset to work correctly I think.
     params[:time] ? Time.zone.parse(params[:time]) : Time.current
   end
+
+  def start_time
+    time - 10.minutes
+  end
+
+  def end_time
+    time + duration_in_hours
+  end
+
+  DEFAULT_DURATION_IN_HOURS = 1
+
+  def duration_in_hours
+    params.fetch(:duration, DEFAULT_DURATION_IN_HOURS).to_i.hours
+  end
 end

app/models/departure_fetcher.rb

@@ -1,40 +1,44 @@
 class DepartureFetcher
   include ActiveModel::SerializerSupport
 
-  attr_reader :agency, :stop, :time
-  def initialize(agency, stop, time, params = {})
+  attr_reader :agency, :stop, :start_time, :end_time
+  def initialize(agency:, stop:, start_time:, end_time:)
     @agency = agency
-    @time = time.in_time_zone
     @stop = stop
+    @start_time = start_time
+    @end_time = end_time
   end
 
   def departures
     @departures ||= stop_times.map { |stop_time|
       Departure.new(stop_time: stop_time, stop_time_update: nil)
-    }.sort_by(&:time)
+    }.sort_by(&:time).select { |d| active?(d) }
   end
 
   def stop_times
     @stop_times ||= begin
       agency.calculated_stop_times
         .where(stop: stop)
-        .between(start_time, end_time)
+        .between(query_start_time, query_end_time)
         .preload(:stop, :trip, :route)
     end
   end
 
-  def valid?
-    @agency.present? && @stop.present?
+  def query_start_time
+    start_time
   end
 
-  protected
+  def query_end_time
+    end_time
+  end
 
-  def start_time
-    @time - 10.minutes
+  def valid?
+    @agency.present? && @stop.present?
   end
 
-  def end_time
-    @time + 1.hour
+  private
+
+  def active?(departure)
+    true
   end
 end
-

app/models/realtime_departure_fetcher.rb

@@ -1,30 +1,26 @@
 class RealtimeDepartureFetcher < DepartureFetcher
   include ActiveModel::SerializerSupport
 
-  def initialize(agency, stop, time, params = {})
-    super(agency, stop, time, params)
-
-    time_limit = params.fetch(:time_limit, 10).to_i
-    @active_duration = Interval.new((-1 * time_limit.minutes))
-  end
-
   def departures
     @departures ||= stop_times.map { |stop_time|
       stop_time_update = realtime_updates.for_stop_time(stop_time) if realtime_updates
       Departure.new(stop_time: stop_time, stop_time_update: stop_time_update)
     }.sort_by(&:time).select { |d| active?(d) }
   end
 
-  private
-
-  def start_time
-    @time - 1.hour
+  # Realtime updates may shift the departures into the time window we are
+  # asking for. Therefor we need to query further back in time in order capture
+  # all the applicable departures.
+  def query_start_time
+    start_time - 1.hour
   end
 
   def active?(departure)
-    departure.duration_from(@time) >= @active_duration
+    departure.time >= start_time && departure.time <= end_time
   end
 
+  private
+
   def realtime_updates
     # Non-standard memoization because we want to allow nulls so we don't
     # continually try and call the service

spec/models/departure_fetcher_spec.rb

@@ -6,7 +6,7 @@
   let(:agency) { stop.agency }
   let(:service) { create(:service, agency: agency, thursday: true) }
   let(:trip) { create(:trip, agency: agency, service: service) }
-  subject { DepartureFetcher.new(agency, stop, now) }
+  subject { DepartureFetcher.new(agency: agency, stop: stop, start_time: now - 10.minutes, end_time: now + 1.hour) }
 
   describe "#stop_times" do
     let!(:applicable_stop_time) {

spec/models/realtime_departure_fetcher_spec.rb

@@ -5,7 +5,7 @@
   let(:agency) { create(:agency, :with_rt_endpoint) }
   let(:stop) { create(:stop, agency: agency) }
   let(:trip) { create(:trip, agency: agency, service: create(:service, agency: agency, thursday: true)) }
-  subject { RealtimeDepartureFetcher.new(agency, stop, now) }
+  subject { RealtimeDepartureFetcher.new(agency: agency, stop: stop, start_time: now - 10.minutes, end_time: now + 1.hour) }
 
   describe "#stop_times" do
     let!(:applicable_stop_time) {
@@ -110,10 +110,10 @@
     end
 
     context "when a departure is more than an hour in the past" do
-      let(:departure_time) { now - 65.minutes }
+      let(:departure_time) { now - 75.minutes }
 
       context "and realtime updates are available showing upcoming departure for the stop time" do
-        let(:fake_stop_time_update) { OpenStruct.new(departure_time: Interval.for_time(now + 5.minutes)) }
+        let(:fake_stop_time_update) { OpenStruct.new(departure_time: now + 5.minutes) }
 
         it "it won't show that stop time" do
           expect(subject.departures.size).to be_zero

spec/requests/departures_request_spec.rb

@@ -5,7 +5,13 @@
   let(:now) { Time.zone.parse("2015-02-16 17:55:00 -0500") }
   let!(:trip) { create(:trip, agency: agency, remote_id: 940135, service: create(:service, agency: agency, monday: true)) }
   let!(:stop) { create(:stop, agency: agency, remote_id: "HAMBELi") }
-  let!(:stop_time) { create(:stop_time, agency: agency, stop: stop, trip: trip, departure_time: Interval.for_time(now + 10.minutes)) }
+  let!(:stop_times) {
+    [
+      create(:stop_time, agency: agency, stop: stop, trip: trip, departure_time: Interval.for_time(now + 10.minutes)),
+      create(:stop_time, agency: agency, stop: stop, trip: trip, departure_time: Interval.for_time(now + 2.hours)),
+      create(:stop_time, agency: agency, stop: stop, trip: trip, departure_time: Interval.for_time(now + 2.hours + 1.second)),
+    ]
+  }
 
   before do
     fixture = File.read('spec/fixtures/realtime_updates.buf')
@@ -29,6 +35,13 @@
       end
     end
 
+    context "with a duration" do
+      it "returns stops with an end time N hours in the future" do
+        get "/api/departures", stop_id: stop.id, time: now, duration: 2
+        expect(json["data"]["departures"].length).to eq(2)
+      end
+    end
+
     context "missing a stop id" do
       it "responds with a bad request" do
         get "/api/departures/?stop_id=&time=#{now}"