More human time periods on event show title

app/helpers/application_helper.rb

@@ -36,4 +36,42 @@ def nav_link_to(page, path, route = {})
     active = route.all? { |key, value| params[key] == value }
     link_to(page, path, class: ('active' if active)).html_safe
   end
+
+  def fancy_time_format(time)
+    time.strftime(time.min == 0 ? '%l%P' : '%l.%M%P')
+  end
+
+  def fancy_date_format(time)
+    day_s = time.day.ordinalize
+
+    time.strftime "%A #{day_s} %B, %Y"
+  end
+
+  def fancy_time_period_format(start_at, end_at)
+    # minutes
+    delta = ((end_at - start_at) / 60).floor
+    return 'zero minutes' if delta < 1
+    return 'all day' if delta >= 1410 # 11 hours, 30 minutes
+
+    hour_v = delta / 60
+    minute_v = delta % 60
+
+    minute_s = pluralize(minute_v, 'minute')
+
+    if hour_v == 0
+      return minute_v == 30 ? 'half an hour' : minute_s
+    end
+
+    hour_s = "#{hour_v} hours"
+    if minute_v == 0
+      return hour_v == 1 ? 'an hour' : hour_s
+    end
+
+    if minute_v == 30
+      return "#{hour_v == 1 ? 'one' : hour_v} and a half hours"
+    end
+
+    "#{hour_s} and #{minute_s}"
+  end
+  # hmm: why am i not using `distance_of_time_in_words`?
 end

app/helpers/events_helper.rb

@@ -6,16 +6,6 @@ def link_to_day(date)
     link_to fancy_date_format(date), events_path(day: date.strftime('%Y-%m-%d'))
   end
 
-  def fancy_time_format(time)
-    time.strftime(time.min == 0 ? '%l%P' : '%l.%M%P')
-  end
-
-  def fancy_date_format(time)
-    day_s = time.day.ordinalize
-
-    time.strftime "%A #{day_s} %B, %Y"
-  end
-
   def link_to_event_instance_with_time_and_partner(event_instance)
     event = event_instance.event
     time_part = fancy_time_format(event_instance.starts_at)

app/views/events/show.html.haml

@@ -6,7 +6,7 @@
 %h2
   - if @event_instance.ends_at.present?
     From <em>#{@event_instance.starts_at.strftime(EventsHelper::DATE_TIME_FORMAT)}</em>
-    to <em>#{@event_instance.ends_at.strftime(EventsHelper::DATE_TIME_FORMAT)}</em>
+    for <em title="#{@event_instance.ends_at.strftime(EventsHelper::DATE_TIME_FORMAT)}">#{fancy_time_period_format(@event_instance.starts_at, @event_instance.ends_at)}</em>
   - else
     At <em>#{@event_instance.starts_at.strftime(EventsHelper::DATE_TIME_FORMAT)}</em>
   on #{fancy_date_format(@event_instance.starts_at)}

spec/helpers/application_helper_spec.rb

@@ -0,0 +1,26 @@
+require 'rails_helper'
+
+RSpec.describe ApplicationHelper, type: :helper do
+  context 'fancy_time_period_format' do
+    it 'gives correct text for a given input' do
+      times = [
+        { hour:  0, minute:  0, text: "zero minutes" },
+        { hour: 23, minute: 59, text: 'all day' },
+        { hour:  0, minute: 15, text: '15 minutes' },
+        { hour:  0, minute: 30, text: 'half an hour' },
+        { hour:  1, minute:  0, text: 'an hour' },
+        { hour:  2, minute:  0, text: '2 hours' },
+        { hour:  3, minute: 30, text: '3 and a half hours' },
+        { hour:  4, minute: 45, text: '4 hours and 45 minutes' }
+      ]
+
+      times.each do |check|
+        starts_at = Time.new(2000, 1, 1, 0, 0, 0)
+        ends_at = Time.new(2000, 1, 1, check[:hour], check[:minute], 0)
+
+        out = fancy_time_period_format(starts_at, ends_at)
+        expect(out).to eq check[:text]
+      end
+    end
+  end
+end