Google Calendaer Link

app/helpers/events_helper.rb

@@ -191,6 +191,29 @@ module EventsHelper
     end
   end
 
+  def calendar_timestamp(timestamp, timezone)
+    timestamp = timestamp.in_time_zone('GMT')
+    timestamp -= timestamp.utc_offset
+    timestamp.strftime('%Y%m%dT%H%M%S')
+  end
+
+  def google_calendar_link(event_schedule)
+    event = event_schedule.event
+    conference = event.conference
+    calendar_base = 'https://www.google.com/calendar/render'
+    start_timestamp = calendar_timestamp(event_schedule.start_time, conference.timezone)
+    end_timestamp = calendar_timestamp(event_schedule.end_time, conference.timezone)
+    event_details = {
+      action: 'TEMPLATE',
+      text: "#{event.title} at #{conference.title}",
+      details: "#{conference.title}:\n\n#{event.room&.url}\n\n#{truncate(event.abstract, length: 200)}",
+      location: "#{event.room.name} #{event.room&.url}",
+      dates: "#{start_timestamp}/#{end_timestamp}",
+      ctz: event_schedule.timezone
+    }
+    "#{calendar_base}?#{event_details.to_param}"
+  end
+
   private
 
   def active_dropdown(selection, options)

app/views/proposals/show.html.haml

@@ -13,7 +13,7 @@
 
 .container
   .row.page-header
-    .col-md-10
+    .col-md-8
       %h2
         = @event.title
         - if @event.subtitle
@@ -22,8 +22,12 @@
             = @event.subtitle
       %h3
         = join_event_link(@event, current_user)
-    .col-md-2
+    .col-md-4
       %p{style: "margin-top: 20px"}
+        - if @event_schedule.start_time
+          = link_to google_calendar_link(@event_schedule), target: '_blank', class: 'btn btn-success' do
+            %i.fa.fa-calendar
+            Google Calendar
         - if can?(:update, @event) && @event.require_registration?
           = link_to 'Registrations', registrations_conference_program_proposal_path(@conference.short_title, @event), class: 'btn btn-mini btn-success'
         - if can?(:edit, @event)

app/views/schedules/_event.html.haml

@@ -27,7 +27,7 @@
       -# TODO: More informative text or aria-label.
       = link_to 'more', conference_program_proposal_path(@conference.short_title, event.id) if event.abstract.length > 400
     - if event_schedule.present?
-      = inyourtz(event_schedule.start_time, @conference.timezone) do
+      = inyourtz(event_schedule.start_time) do
         %span.track
           %span.fa.fa-clock-o
           %span.label{ style: "background-color: grey" }